ArticlePDF Available

Revised chitinozoan classification

July 1999
Journal of Paleontology 73(4):549-570

July 1999
73(4):549-570

DOI:10.1017/S0022336000032388

Authors:

Florentin Paris

Université de Rennes 1

Yngve Grahn

Viiu Nestor

Tallinn University of Technology

Lakova Iskra

Bulgarian Academy of Sciences

The successful definition of chitinozoan genera depends primarily on the precision of the criteria used. A standardized morphological terminology based upon details from scanning electron microscope observations of the most representative taxa bearing these characters is therefore proposed. The 143 genera, or subgenera, described so far in the literature are reviewed in order to exclude invalid taxa and obvious junior synonyms. Particular attention is paid to preventing the overlap of generic definitions of the 56 genera ultimately retained. A brief account of the diagnostic features and stratigraphic range of selected genera is given, and basic information concerning the type material of these genera is listed. Finally, a suprageneric classification of the whole Chitinozoa group based on diagnostic features whose hierarchy is established on statistical and evolutionary grounds, is given. One new subfamily, Pogonochitininae, three new genera, Baltochitina, Hyalochitina, and Saharochitina, and a new species Baltochitina nolvaki, are defined. The subspecies Fungochitina fungiformis spinifera is elevated to a specific rank.

The basic chamber shape of the chitinozoans.

…

Factorial Analysis of Correspondence (FAC) of the chitinozoan genera (open circles) and of the characteristics of the apertural plug, neck, and chamber shape (12 variables) (open stars). Dark grey = Desmochitinidae; light grey = Lagenochitinidae; open = Conochitinidae.

…

Hierarchic Ascendant Classification (HAC) using Euclidean distances for the 56 selected genera and the characteristics of the apertural plug, neck, surface pattern, and vesicle structures (12 states). Dark grey = Operculatifera; light grey = Prosomatifera.

…

Figures - uploaded by Yngve Grahn

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J. Paleont., 73(4), 1999, pp. 549-570

0022-3360/99/0073-0549$03.00

A REVISED

CHITINOZOAN

CLASSIFICATION

FLORENTIN PARIS, YNGVE GRAHN, VIIU NESTOR, AND ISKRA LAKOVA

Laboratoire

de Paleontologie,

UPR 4661 du CNRS,

Universit6

de Rennes

I, 35042 Rennes-cedex,

France

<florentin.paris@univ-rennesl.fr>,

Universidade

de Estato

do Rio de Janeiro-UERJ,

Faculdade

de Geologia,

20559-900 Rio de Janeiro,

Brazil

<grahn@uerj.br>,

Tallinn

Technical

University,

Institute of Geology,

7 Estonia

Avenue, 10143 Tallinn,

Estonia

<vnestor@gi.ee>, and

Geological

Institute,

Bulgarian

Academy

of Sciences, 1113 Sofia,

Bulgaria

<lakova@geology.acad.bg>

ABSTRACT-The successful

definition

of chitinozoan

genera depends

primarily

on the precision

of the criteria used. A standardized

morphological

terminology

based

upon

details

from

scanning

electron

microscope

observations of the most

representative

taxa

bearing

these characters

is therefore

proposed.

The 143 genera,

or subgenera,

described

so far

in the literature

are

reviewed

in order to exclude

invalid

taxa and

obvious

junior

synonyms.

Particular attention

is paid

to preventing

the overlap

of generic

definitions of the 56 genera

ultimately

retained.

A brief

account

of the diagnostic

features

and

stratigraphic

range

of selected

genera

is given, and basic information

concerning

the type material of these genera

is listed. Finally,

a suprageneric

classification

of the whole Chitinozoa

group

based on

diagnostic

features

whose hierarchy

is established

on statistical

and evolutionary grounds,

is given. One new subfamily, Pogonochitin-

inae, three new genera,

Baltochitina,

Hyalochitina,

and Saharochitina,

and a new species Baltochitina

nolvaki,

are defined.

The sub-

species Fungochitina fungiformis

spinifera

is elevated to a specific

rank.

INTRODUCTION

C HITINOZOANS

CONSTITUTE

a group

of organic-walled

micro-

fossils, well represented in Early Ordovician (late Trema-

doc) to latest Devonian (latest Famennian) marine sediments

from nearly all Paleozoic oceans. They are found isolated or in

chainlike structures in most sedimentary or low grade metamor-

phic rocks, where their abundance usually ranges from a small

number of specimens to several hundred (exceptionally up to

several thousand) specimens per gram of rock. The length of a

chitinozoan vesicle (basic isolated element) ranges from ca. 50

to 2,000 Jim (with an average size of around 150-250 Jim).

They constitute an enigmatic group of fossils whose biologic

affinities and significance are still interpreted in a variety of

ways (see review in Miller, 1996), more than 60 years after their

first description by Eisenack (1931). Personally, we favor the

hypothesis of eggs of soft-bodied metazoans (Paris, 1981, p. 84;

Paris and Nolvak, in press) referred as chitinozoophorans by

Grahn (1981). They have proven to be very efficient stratigraph-

ic tools, and they are extremely useful for paleogeographic re-

constructions. However, a unanimously accepted taxonomy is

now strongly needed in order to make application of chitinozoan

genera for paleogeographic and paleoenvironmental investiga-

tions more reliable.

There have been many attempts to classify chitinozoans. They

were carried out through individual initiatives (Eisenack, 1931,

1968, 1972; Van Oyen and Calandra, 1963; Jansonius, 1964,

1967, 1970; Tappan, 1966; Taugourdeau,

1966, 1981; Paris,

1981; Achab et al., 1993) or under the authority

of the chiti-

nozoan Subcommission of the "Commission Internationale de

Microflore

du Paleozoique"

(CIMP)

(Taugourdeau

et al., 1967).

In the last 25 years, major improvements

in the knowledge of

chitinozoan

morphology

have been achieved, primarily

due to

the routine

use of the Scanning

Electron

Microscope

(SEM).

addition,

numerous new occurrences have greatly

increased the

chitinozoan

record,

so that it now includes more than 1,000 taxa

described

from almost all continents. We are

convinced that suf-

ficient data exist to propose a standard

terminology and a general

classification of chitinozoans that integrates

the taxa described

since the last extensive revision

(Taugourdeau

et al., 1967;

Com-

baz et al., 1967). Our aim is to integrate

all original morpholo-

gies recorded during the last 30 years into a general classification

of the group.

Particular attention

is paid to the definition

of the

morphologic

characters,

and to the establishment

of a hierarchy

among these morphologic elements. A critical review is made

of all 143 genera described and, after excluding those genera

regarded as invalid by ICZN (third version), we propose a syn-

onymy list based on the criteria we consider to be essential.

Because many of the existing generic diagnoses are not suffi-

ciently definite, we supplement the original definition of selected

genera with their respective diagnostic features. By doing so, we

hope to prevent overlapping of the generic definitions, which

has proven to be one of the greatest and most constant problems

in chitinozoan taxonomy.

CHITINOZOAN MORPHOLOGY

General terminology.-A chitinozoan individual may be de-

fined as a small organic-walled vesicle with an opening. Well-

preserved chitinozoans (i.e., in full relief and not eroded or dis-

torted) share three major characteristics (Fig. 1): 1) they are

made up of an organic membrane delimiting a cavity; 2) they

have an aperture sealed with a plug; and 3) they normally dis-

play a radial symmetry. The actual chemical composition of the

chitinozoan vesicle remains unknown. Therefore, this definition

is so broad that various organisms, or part of organisms may be

included. Size limits (<2,000 Ijm and >50 jim) or stratigraphic

range restriction (exclusively of Paleozoic age, unless reworked)

restrict this definition and allow various present day cysts, co-

coons, or eggs of invertebrates (insects, annelids, molluscs, etc.)

to be excluded from the chitinozoans. When present, the external

ornamentation of a chitinozoan vesicle is fairly distinctive com-

pared to the ornament of almost all other organic-walled micro-

fossils of similar age (i.e., acritarchs, spores, and foraminiferal

linings).

A detailed morphological terminology was first introduced by

Combaz and Poumot (1962) and then subsequently completed

by Combaz et al. (1967) under the direction of the Chitinozoa

Subcommission of CIMP. Most recent papers dealing with chi-

tinozoan systematics have used either the English adaptation

proposed by Laufeld (1974) or the French terminology adopted

by Paris (1981). These terminologies are still valid and well

adapted for the description of the chitinozoans. Only a few mod-

ifications or additions are necessary in order to integrate the

most recent morphological details revealed by SEM observa-

tions. One of our aims is to promote a standard morphological

nomenclature that would be unanimously accepted and used.

The main parts of a chitinozoan vesicle are illustrated, show-

ing the three principal morphological types of chitinozoans (Fig.

1). The basic element is the vesicle, with a bulging part called

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JOURNAL OF PALEONTOLOGY,

V. 73, NO. 4, 1999

Apertural pole Apertural pole Apertural pole

process I

apex (=appendix) apex

Antiapertural pole Antiapertural pole

FIGURE 1-Main morphological features of the three principal types of chitinozoans (modified from Paris, 1981, fig. 56).

the chamber. The aperture is either situated directly on the cham-

ber or at the distal end of a tubelike neck. In order to clarify

discussion and descriptions, an arbitrary orientation of the ves-

icle has been adopted. The apertural pole is regarded as repre-

senting the top of the vesicle. This means that, in a chainlike

structure, the upper (or last) vesicle has a free aperture.

However,

no biological nor physiological significance has to be given to

this orientation, which is exclusively conventional. A collarette,

frequently corresponding to a thinning of the wall, may be pres-

ent around the aperture. The plug sealing this aperture is either

called an operculum or a prosome depending on its internal or

external position and on its role in inter-vesicle linking (see def-

initions below). The base, which corresponds to the antiapertural

end of the vesicle, may display various linkage structures around

the apex. This base is separated from the flanks by the margin.

This zone proves to be of prime importance for chitinozoan tax-

onomy, as it frequently bears peculiar ornamentation (e.g., pro-

cesses or carina). The flanks themselves may be separated from

the neck by the flexure (e.g., vesicles with well-differentiated

necks).

Lexicon of the morphologic features and structures.-This

lexicon is given in order to restrict some previous definitions

that were not accurate enough or were already used with a dif-

ferent meaning. It also introduces the morphologic terms we use

for the discrimination of the chitinozoan genera we have select-

ed. In addition, references are made to recently published SEM

images which illustrate almost all of these terms.

1) antiapertural pole: lower part of the vesicle, opposite the

aperture.

2) aperture: large opening at the top of the vesicle, delimited

either by the lips of the neck or collarette, or if these two other

elements are absent, by the border of the chamber (Fig. 1). This

term is preferred instead of "mouth", which has physiological

significance.

3) apertural plug: general term designating the simple or

complex plug sealing the aperture, represented either by the

operculum or by the prosome (see definitions below).

4) apertural pole: arbitrarily designated as the upper part of

the vesicle.

5) apex: point of emergence of the axis of symmetry on the

base of the chamber (Fig. 1).

6) apical pit: circular, depressed area surrounded by the rim

of the mucron. [N.B. the apertural pit does not open in the ves-

icle in well-preserved specimens (see Miller, 1996, pl. 1, fig. 1;

Verniers et al., 1995, fig. 6K)].

I-

E -

shoulder

flanks

margin

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PARIS ET AL.-REVISED CHITINOZOAN

CLASSIFICATION

1 2

5 6

3 4

10 11

FIGURE

2-Different kinds of vesicle wall surfaces of chitinozoans.

1, Smooth,

scabrate,

vermiculate; 2, foveolate;

3, feltlike; 4, spongy;

5, verrucate

(granules,

tubercules

and/or cones less than 2 microns

high);

6, simple spines;

7, simple

and

branched

hairs or spines;

8, bi and

multirooted

spines;

9, meshlike

structure; 10, crests with vertical rows of free or connected

spines; 11, crests of weblike to discontinuous

membranes; 12, complete

or perforated/reticulated

carina.

Stippled

= inner

layer;

black = outer

layer.

7) apical structure: includes the scar, callus, mucron, copula

and peduncle; the bulb is also regarded as an apical structure.

8) axis: imaginary line joining the center of the aperture to

the apex and representing the axis of symmetry of the vesicle.

9) base: part of the chamber opposite to the aperture (=an-

tiapertural end or chamber bottom).

10) bulb (=siphon): membranous ampoule extending from

the base of a vesicle (e.g., in Siphonochitina formosa) (see Jen-

kins, 1967, pl. 75, figs. 2-5).

11) callus: short stublike thickening on the apex (e.g., in Des-

mochitina densa illustrated by Laufeld, 1974, fig. 39D).

Lenticular

ovoid

Spherical /

hemispherical conical

claviform

. -

cyidia

FIGURE

3-The basic chamber

shape

of the chitinozoans.

12) carina: circular expansion of the wall (outer layer) round

the chamber; it may be located below, on, or above the margin

(Fig. 2.12).

13) catenary structure (=chainlike structure): vesicles con-

nected "aperture to base", along their axis (straight, curved or

coiled chain) (see Jenkins, 1970b, pl. 6, figs. 4-6; Paris and

Nolvak, in press, pl.1, figs. 1, 3-4), or vesicles connected "neck

to margin", with a coiled pattern (e.g., Lagenochitina navicula

in Paris, 1981, pl. 31, figs.1-3).

14) central cavity: inner cavity corresponding to the chamber

(Fig. 1) (contained the embryo if one adopts the egg hypothesis).

15) chamber: part of the vesicle (frequently bulging) situated

below the neck or below the collarette when present (see Fig. 3

for the different chamber shapes).

16) cluster: group of vesicles belonging to the same species

and connected by their flanks (aperture free); they are usually

arranged in a coiled pattern (see Koslowski, 1963, fig. 3; Miller,

1996, pl. 5, figs. 1-2; Paris and Nolvak, in press, pl. 1, figs. 5-

8). 17) coiled chain (=helicoidal chain): vesicles connected

"neck to margin" i.e., with a free aperture, or "aperture

to base"

i.e., aperture linked to the succeeding vesicle.

18) collarette (=collar): thinned cylindrical or flaring part of

the neck, or of the vesicle wall when the neck is absent. The

collarette surrounds the aperture.

19) copula: tubular, membranous expansion surrounding the

apex (see Paris, 1981, pl. 1, figs. 7, 13).

20) crests: vertical rows of free or connected spiny ornamen-

tation (Fig. 2.10), or of weblike to continuous membranes (Fig.

2.11) (see Achab et al., 1993, pl. 1, figs. 1-2; Miller, 1996, pl.

2, figs. 2-3).

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JOURNAL

OF PALEONTOLOGY,

V. 73, NO. 4, 1999

21) diameter: refers to the maximum

diameter of the chamber

(D), neck (dn), or aperture

(da);

a coefficient of correction

(e.g.,

0.7 or 0.8, depending

on the degree of flattening)

(see Paris in

Babin et al., 1979) must be used to restore the full-relief mea-

surement

where the vesicle is flattened or collapsed.

22) equatorial plane: corresponds

to the maximum

diameter

of lenticular

or spherical

chambers.

23) external structures:

include the carina and apical struc-

tures as well as the sleeve.

24) flanks:

part

of the chamber situated

between the margin

and the neck or collarette

(Fig. 1).

25) flexure: concave zone separating

the flank from

the neck

(Fig. 1).

26) glabrous:

state of the vesicle surface when lacking spiny

ornamentation

(Fig. 2.1-5).

27) inner

layer:

internal membrane

of the wall usually

acting

as a framework for the vesicle (Figs. 1, 2).

28) laciniated:

deeply indented borders of a carina

(e.g., Po-

gonochitina spinifera in Paris, 1996, pl. 1, fig. 9).

29) linear chain:

straight,

curved,

or coiled catenary

structure

where the apertural pole of one vesicle is fixed to the base of

the following one; the aperture

is not free (see above).

30) linkage

structures: elements

intervening

in the connection

of two successive vesicles in a catenary

structure

(e.g., opercu-

lum, apical structures,

lips, base).

31) lip: distal

part

of the collarette

(or of the neck), surround-

ing the aperture.

32) margin (=basal edge sensu Laufeld, 1974): transition

zone between the base and the flanks;

may be inconspicuous,

rounded,

blunt or sharp.

The margin

bears the major morpho-

logic elements

(e.g., carina,

processes).

33) mucron:

thickened,

raised

rim surrounding

the apical

pit

(e.g., see Laufeld, 1974, fig. 29D).

34) meshlike:

spiny ornamentation

making up a net-work or

a trellis-work

on the surface

of the wall (Fig. 2.9) (e.g., Acan-

thochitina barbata

in Nolvak and Grahn, 1993, pl. 4, fig. A, or

Muscochitina

muscosa

in Paris, 1981, pl. 30, figs.17-19).

35) neck (=apertural

tube):

tubular

structure

expanding aper-

turalward from the chamber;

frequently

terminated

by a collar-

ette.

36) operculum:

disklike

plug sealing the aperture

of the ves-

icles lacking a neck (see Paris and N6olvak,

in press, pl. 1, fig.

2); a membranous

expansion flaring antiaperturalward

("rica"

sensu Bockelie, 1981) is common (e.g., see Paris, 1996, pl. 1,

fig. 4).

37) ornamentation:

includes all the spiny, hairlike or linear

expansions

(e.g., crests) of the outer

layer (Fig. 2.6-11).

38) outer

layer:

external

membrane

forming

the vesicle wall

together

with the inner

layer;

the vesicle ornaments

(carina,

pro-

cesses, spiny ornamentation)

arise from

evaginations

of this out-

er layer (Figs. 1, 2), which may also be glabrous

(Fig. 2.1-5).

39) peduncle: solid short (e.g., Margachitina

catenaria in

Paris and Grahn, 1996, fig. 2) or elongated

cylindrical

structure

extending

from the apex (e.g., Urochitina

simplex

in Paris, 1996,

pl. 3, fig. 12).

40) perforated:

refers to closely distributed

holes occurring

on the carina

(e.g., Sagenachitina

oblonga in Paris, 1981, pl. 9,

fig. 8) or on the collarette

(e.g., Fungochitina

fenestrata

in Paris,

1996, pl. 1, fig. 1); the ultimate

stage is the reticulate

pattern

when holes are only separated by threadlike

remains

(e.g., Par-

isochitina perforata in Paris, 1996, pl. 3, fig. 2).

41) processes

(=appendices):

simple

or complex

spines

(e.g.,

Ancyrochitina

desmea

in Paris, 1996, pl. 2, fig. 6) arranged

in a

crown

on the margin,

or near

the margin

in the case of an ovoid

to claviform

chamber;

the processes

are usually

hollow but may

have a cell-like structure

(e.g., Plectochitina); they may be short

or very long (see Wood and

Miller,

1991, pl. 1, figs. 1-5). (N.B.

the processes

never communicate with the interior

of the cham-

ber).

42) prosome:

internal

plug situated

at the base of the neck;

may be simple (disklike)

or complex

(tubular

structure with sev-

eral or numerous horizontal

septa, i.e., "accordion

pleated

pro-

some" of previous

authors;

see Miller, 1996, pl. 4, fig. 8); it is

not involved in vesicle linkage.

43) reticulum: reticulated

outer

layer strongly

attached to the

flanks;

may extend

beyond

the base of the vesicle as a perforated

carina

(e.g., Parisochitina

perforata

in Paris, 1996, pl. 2, fig. 2);

reticulum

bearing

vesicles are regarded

as glabrous.

44) rib:

annular

(horizontal)

thickening

of the wall (e.g., Mar-

gachitina catenaria in Paris and Grahn,

1996, pl. 3, fig. 2).

45) rica: membranous,

flanging part

of the prosome

or oper-

culum, lining the upper part

of the chamber

(see Miller, 1996,

pl. 2, fig. 4).

46) ridge:

vertical linear

thickening

of the wall (e.g., Laufel-

dochitina stentor in Grahn

et al., 1996, pl. 2, fig. 6).

47) scar: circular mark

(depressed

or slightly protruding)

cor-

responding

either to a thinning

or to a thickening

at the apex

(see Grahn et al., 1996, pl. 1, figs.l, 10); may also exist on the

center of the operculum

(see Paris and Nolvak, in press, pl. 1,

fig. 2).

48) septa: horizontal

membranous

partition

(from a few to

more than 20) within a prosome (see Laufeld, 1974, fig. 72B;

Miller, 1996, pl. 2, fig. 4 and pl. 4, fig. 8).

49) sheathing

process: process whose proximal

end extends

horizontally from the margin (e.g., Salopochitina monterrosae;

see Tekbali and Wood, 1991, pl. 19, figs. 4-5).

50) shoulder: convex area at the top of the flanks,

just below

the flexure;

when both shoulder and flexure are present,

the up-

per part

of the chamber has a sigmoid

profile

(Fig.

1l).

51) sleeve:

partially

or totally

attached membrane

(usually

the

outer

layer) covering

the vesicle and extending beyond

the base

(see Achab et al., 1993, pl. 2, figs. 2-6).

52) spines: all kinds of simple to complex elongate expan-

sions of the outer layer (see below); spine length must be at

least twice their width and exceed two microns;

most frequently

hollow (Fig. 2.6-10). (N.B. the hollow spines never communi-

cate with the interior of the vesicle).

53) spiny ornamentation: vesicle bearing

spines, crests, and/

or processes

randomly

distributed

or arranged

in rows or crowns

(see below for additional

information).

54) vesicle: basic chitinozoan

individual,

including

the wall

of the chamber and the neck (and collarette when present)

well as the apertural

plug (Fig. 1).

55) wall (=test): organic

envelope of a chitinozoan;

includes

both the outer and inner

layer.

Shape of the chamber.-The following characteristics (Fig. 3)

concern only vesicles in full relief. In flattened

specimens

the

collapse of the vesicle is usually perpendicular

to the equatorial

plane

for lenticular and

spherical

chamber without

a neck.

It will

be parallel

to the axis for all the other cases. The collarette

not taken into account when defining

the shape

of the chamber.

1) lenticular:

width significantly

larger

than length (D > L);

margin rounded; base convex (e.g., Calpichitina, Fungochitina).

2) spherical:

width

of the chamber

equal

or close to its length

(D = -L); margin inconspicuous;

base rounded

(or exception-

ally evaginated

such as in Margachitina

elegans);

shoulder

pres-

ent (e.g., Hoegisphaera, Sphaerochitina).

3) hemispherical:

length

close to half the diameter

(L= D/2);

base flat;

margin

sharp

or blunt;

shoulder

conspicuous

(e.g., Bul-

bochitina, Cyathochitina).

4) ovoid: length

of the chamber

greater

than

its diameter

but

less than three times this diameter

(3D > L >D); margin

and

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PARIS

AL.

-REVISED CHITINOZOAN

CLASSIFICATION

flexure

inconspicuous;

base convex to rounded

(e.g., Desmochi-

tina, Angochitina), more rarely truncated (e.g., Lagenochitina

dalbyensis) or ogival (e.g., Lagenochitina conifundus).

5) claviform: the chamber length exceeds three times the

maximum

diameter

(L > 3D), base rounded;

margin inconspic-

uous; shoulder absent (e.g., Clavachitina, Laufeldochitina).

6) conical: straight, tapering

flanks;

base flat; margin

sharp

or blunt (e.g., Bursachitina, Euconochitina, Cyathochitina).

7) cylindrical: length usually several times the diameter;

flanks

straight

and

parallel;

base flat;

margin

sharp

or blunt

(e.g.,

Rhabdochitina).

Vesicle characteristics.-The vesicle surface may be glabrous

or spiny; it may also bear a carina

or an apical structure.

All

combinations

of these patterns

may exist, with the exception

both glabrous

and spiny surfaces

together.

1) Surface

pattern

of the wall (Fig. 2; see also Grahn et al.,

1996, pl. 1, figs. 1-11, and pl. 2, figs.1-3, 5-6, 9-10): this pat-

tern includes both totally smooth surfaces

(Fig. 2.1) as well as

scabrate, vermiculate

(Fig. 2.1), foveolate (Fig. 2.2), feltlike

(Fig.2.3), spongy (Fig. 2.4), or microgranulous

surfaces,

includ-

ing tubercles

and cones (Fig. 2.5). When these granules

are

less

than two microns

high, the wall surface is regarded

as glabrous.

A glabrous

surface

may or may not be associated with a carina

or with apical

structures.

Corrugations

(e.g., Armoricochitina re-

ticulifera in Nolvak and Grahn,

1993, pl. 3, fig. c) as well as

ridges (e.g., Laufeldochitina

stentor in Nolvak and

Grahn, 1993,

pl. 1, fig. G) or ribs (e.g., Margachitina

catenaria

in Paris et al.,

1996, pl. 3, figs. 1-2) may occur on glabrous

surfaces.

2) Spiny ornamentation

(Fig. 2.6-11): this ornamentation

in-

cludes all kinds of spiny extensions longer than two microns,

occurring

on the vesicle, i.e., simple (Fig. 2.6), bifurcated or

branching

spines (Fig. 2.7), bi- or multirooted

spines (Fig.2.8),

anastomosed

spines (Fig. 2.10) or those connected

by a meshlike

structure

(Fig. 2.9), spines in rows (Fig. 2.10), crowns

or crests

(Fig. 2.11), or randomly

distributed

on part

or all of the vesicle.

The spiny ornament,

which is usually

hollow, may coexist with

any of the other elements

(i.e., carina,

apical

structures)

with the

exception of a glabrous surface. It is of prime importance

distinguish

eroded

spines (rounded scars)

from a truly

glabrous

surface.

When

located

on the margin,

the spines

arranged

into a crown

are called processes.

They display

the same

range

of complexity

as the spines occurring

on the flanks;

in addition

they may have

a spongy or a cell-like texture

(e.g., Plectochitina).

External structures.-These include the carina, the apical

structures,

and the sleeve.

1) Carina: this corresponds

to an extension (annular

evagi-

nation)

of the outer

layer,

perpendicular

or not to the axis of the

vesicle; the carina

may be located either

below, on, or above the

margin;

it may be fairly thick (e.g., Laufeldochitina),

membra-

nous (e.g., Cyathochitina kuckersiana, Pterochitina perivelata),

extending horizontally (e.g., Cyathochitina vaurealensis), or

flaring

antiaperturalward

(e.g., Laufeldochitina).

The carina

may

also be complete (Fig. 2.12) (e.g., Cyathochitina),

perforated,

reticulated (Fig. 2.12) (e.g., Sagenachitina, Baltochitina) or la-

ciniated

(e.g., Pogonochitina

spinifera

in Paris, 1996, pl. 1, fig.

9). The carina

may be associated

either with a glabrous

or spiny

wall and/or

apical structures.

A carina does not coexist with processes (homologous ele-

ments);

however,

the threadlike

expansions

extending

from in-

sertion zones partially enveloping

the margin

of some taxa (e.g.,

"Conochitina

filifera" in Tekbali and

Wood, 1991, pl. 19, figs.1,

4-6) are regarded

here as the ultimate

case of processes (i.e.,

sheathing processes).

2) Apical structures:

they include the scar, callus, mucron,

copula and peduncle (see definitions above);

they usually serve

as a linkage medium

with the operculum

of the preceding

ves-

icle. The bulb is also considered

as an apical element,

but it is

not clearly involved in intervesicle

linkage.

3) Sleeve: this corresponds

to a partially

or totally unstuck

outer layer that may extend beyond the margin and even far

beyond the base of the vesicle (e.g., Pellichitina, Cutichitina,

Velatachitina

in Achab et al., 1993, pl. 2, figs; 2, 4, 6). This

term is not extended

to various types of vertical folding (e.g.,

Calpichitina

velata in Paris and Grahn, 1996, pl. 1, figs. 7, 9)

or to irregular

detachment

of the outer

layer (e.g., Desmochitina

juglandiformis

in Paris, 1981, pl. 17, figs. 16-17). Significant

flattening

of the vesicle may be responsible

for a secondary

de-

tachment of this outer

layer mirroring

a sleeve (especially

in the

Desmochitinidae).

PRINCIPLE AND METHODOLOGY

Since the first

description

of chitinozoans

by Eisenack

(1931),

two systems

have prevailed

in the classification

of these organic

microfossils. One involves the suprageneric

subdivisions first

in-

troduced

by Eisenack

(1931) and subsequently improved

by this

author (1968, 1972). This classification was adopted, and in

some cases further

developed by other authors

(Van Oyen and

Calandra,

1963; Jansonius, 1964, 1967, 1970; Tappan, 1966;

Taugourdeau,

1966, 1981; Paris, 1981; Schallreuter, 1981;

Achab

et al., 1993;

Nestor,

1994;

Paris and Grahn, 1996;

Miller,

1996). The chitinozoan

group was there by progressively

sub-

divided into Orders, Families, and even into Subfamilies

(see

Paris, 1981; Achab et al., 1993; Miller, 1996).

The second system involves an alphabetical

listing of genera.

It was principally

advocated

by Laufeld (1967, 1974) and Jen-

kins (1970b). Many supporters

of this simpler

method argued

that the affinities and the biologic significance

of the chitino-

zoans were too poorly known to justify any classification. In

reality, when grouping

several species within a genus on mor-

phological grounds,

a paleontologist

has already

started to clas-

sify these taxa. Despite the fact that

alphabetic

sorting

has been

widely used by numerous

authors,

it proves

to be of no help for

taxonomic

purposes.

The only positive aspect

of alphabetic

clas-

sification is to facilitate a rapid search and location of genera

within a long list of taxa.

Utility of a classification for chitinozoans.-Chitinozoan

workers have unanimously

adopted

the Linnean

binominal

tax-

onomy,

grouping

species into genera,

and

therefore

have already

initiated a classification at a higher

rank than

the basic

biological

entity,

i.e., the species. Consequently

we see no serious

reasons

to dismiss a suprageneric

classification

of the chitinozoans.

addition,

we believe that a formal classification,

including su-

prageneric

subdivisions,

may enhance

the knowledge

and study

of the chitinozoans

for the following reasons:

1) It encourages

chitinozoan workers to adopt

a logical tax-

onomic approach,

based on careful

morphological

analysis,

rath-

er than on a superficial

survey of the general outline of the

taxon.

2) It promotes

a clearly defined hierarchy

of morphological

characters used in the chitinozoan

identification,

consequently

preventing

overlap

of generic

diagnoses.

3) It provides a level of identification

compatible

with the

state of preservation

of the material,

while still remaining

infor-

mative for broad

stratigraphical

purposes.

4) It gives a framework

for cladistic

analysis.

5) It gives a better

ground

for phylogenetic

analysis,

even if

such approaches

are still very tentative in an enigmatic

group

such as the Chitinozoa.

6) It prevents

redundancy

in generic diagnosis

because it re-

quires

direct reference to family or subfamily

characteristics.

7) A suprageneric

classification

also provides an excellent

553

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JOURNAL OF PALEONTOLOGY, V. 73, NO. 4, 1999

framework for a computer-assisted system of identification, in-

volving large and very informative chitinozoan databases which

may include digitalized photos (Paris and Bernard, 1994).

The most common argument against suprageneric classifica-

tion is the poor knowledge of the biological significance of the

chitinozoans. We, however, are less pessimistic than the sup-

porters of the alphabetic classification. Indeed, converging ar-

guments have progressively emerged that convincingly support

the hypothesis (first advocated by Koslowski, 1963) that chiti-

nozoans represent eggs of soft-bodied marine metazoans (Paris,

1981; Paris and Nolvak, in press), i.e., of the "chitinozoophor-

ans" sensu Grahn (1981). This explanation, however, is not yet

unanimously accepted, and other diverse hypotheses (see dis-

cussion in Miller, 1996) have been proposed, e.g., a possible

relationship with cysts of tintinids (Reid and John, 1981), fungi

theory (Locquin, 1976), or rhizopod affinities (e.g., Cashman,

1990). Because the two latter hypotheses are based either on

unreliable arguments or on obvious misinterpretations of chiti-

nozoan morphology, they are not considered here. Nevertheless,

regardless of the affinities or the biological significance of chi-

tinozoans, these microfossils are in any case related to fossil

organisms. The morphology of the chitinozoans is certainly ge-

netically controlled, as demonstrated by the occurrence of pop-

ulations, that are statistically homogenous during time intervals

ranging from several hundred thousand to a few million years.

These populations display diagnostic morphologies, indicating

that they belong to the same species. Because the time intervals

involved exceed the usual duration of the life of any individual

by numerous orders of magnitude, they clearly represent nu-

merous successive generations of individuals. The stability of

their morphology through time is controlled by genetic mixing

(i.e., interfecundity of the organisms producing each "species"

of chitinozoans) that was efficient enough to prevent speciation

processes for periods of time corresponding to the total-range of

the involved species. In addition, the existence of evolutionary

processes is unquestionably demonstrated by the short range of

many chitinozoans species, making the group an outstanding

biostratigraphic tool. Therefore, we are convinced that the mor-

phology of chitinozoans reflects evolutionary processes just as

in any complete organism, even if the tempo might be slightly

different. Consequently, the usual rules, especially those of clas-

sification used for "around" true organisms, should also be ap-

plied to the chitinozoans.

Sorting of the available morphologic characters.-In order to

select the most suitable characters for generic and suprageneric

classification of the chitinozoans, we list the criteria used by

previous authors for the definition of the 143 previously pub-

lished chitinozoan genera. We eliminated from this general sur-

vey the redundant characters, i.e., those which correspond with

fragmentary or dissociated descriptors of a single morphologic

feature (e.g., "rounded base," "rounded flanks," and "rounded

margin" for a spherical chamber). We excluded dubious ele-

ments or features obviously related to misinterpretation or to

artifacts of preservation (e.g., crystal casts, folding of the vesicle

wall). After this preliminary sorting we ran a number of statis-

tical analyses on the remaining data set in order to control the

"weight" of each character and to identify the most definitive

criteria. The ultimate aims were to detect morphological features

that allow the separation of all genera by at least one character

and can be used to cluster large groups of genera (e.g., subfam-

ilies, families, and order).

We utilized different techniques and software for simple sta-

tistical analyses (histograms), multivariate analysis [e.g., Facto-

rial Analysis of Correspondence (FAC), Ascendant Hierarchic

Classification (AHC)], or cladistic approach. These sorting tech-

niques were employed in order to identify both the morphologic

0 E E

z 2

35-

30 - = 14

25 -2

20- i-

15-

5-5

plug neck [ chamber

0 carina

spn glabrous

| linkage ! processes

Characters

FIGURE

4-Histogram of frequency of the characters recorded in the 56

selected chitinozoan genera.

characters shared by the greatest number of genera and those

restricted to a single genus (Fig. 4). A general database was set

up as a table of the morphologic characters regarded as the "var-

iables" and reported in columns. In all calculations, genera were

referred to as "individuals" and reported on rows.

A better approach would have been to apply these sorting

procedures to all known chitinozoan species and subspecies;

however this was not undertaken because too many species are

poorly described.

Weight of the different morphologic characters.-The mor-

phologic characters we selected were generally of the same

"weight" for each calculation when they were taken separately;

all were of Boolean type (i.e., on the general table they are

quoted by "1" if present, and by "0" if absent). However, some

criteria were directly subordinate to the presence of another,

which was therefore considered to be of a higher magnitude,

e.g., the characteristics "spines in rows" or "spine in crown"

(second order characters) were subordinate to the existence of a

"spiny wall" (first order character). Similarly, the criterion

"anastomosed" (third order character) was subordinate to the

existence of "processes", themselves depending on the exis-

tence of a "spiny wall". For taxa sharing this feature, the or-

namentation of the surface of the vesicle had a "higher weight"

(three levels of answers) than the character "glabrous" shared

by other taxa (only one level of answer). Other characters were

totally dependent on each other, e.g., "operculum" and "neck

absent". Criteria related to the shape of the chamber, e.g., "cy-

lindrical," "claviform", and to a lesser extent "conical", were

closely tied (see Fig. 6) to the character "neck inconspicuous"

because in this type of chamber, neither the flexure nor the

shoulder were well distinct enough to indicate precisely the po-

sition of the boundary between the chamber and the neck.

Some discrepancies may have been introduced by a few fea-

tures satisfying several states. This concerned exclusively the

shape of the chamber and results both from some old definitions

(not conforming with the sorting procedure adopted here) and

from the existence of intrageneric, and even intraspecific varia-

tions of this parameter. Therefore, several genera may have in-

cluded up to three states for the "shape of the chamber" (e.g.,

"lenticular," "conical," and "ovoid" for Ancyrochitina). These

multiple answers influence the results of the multivariate anal-

ysis (Fig. 6).

Frequency histogram.-The histogram (Fig. 4) of all of the

36 characters finally selected reveals that only 5 variables are

restricted to only one genus ("widened base" in Pistillachitina;

"bulblike ampoule" in Siphonochitina; "cell-like processes" in

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PARIS ET AL -REVISED CHITINOZOAN

CLASSIFICATION

Alpenachitina

Ancyrochitina

Angochitina

Clathrochitina

Fungochitina

Muscochitina

Plectochitina

Ramochitina

Sommerochitina

Anthochitina

Cyathochitina

Lagenochitina

Parisochitina

Pellichitina

Sagenachitina

Axis 2

(29.1%)

.-o0

- neck

present spi

spiny

m 0

Prosome

Saharochitina 0

o 050

Sphaerochitina <

Urochitina

Acanthochitina

Belonechitina

Hercochitina

Pogonochitina

Spinachitina O

neck * l

inconspicuous

Baltochitina Laufeldochitina

Clavachitina Pistillachitina

Conochitina Rhabdochitina

Eremochitina Siphonochitina

Euconochitina Tanuchitina

Hyalochitina Velatachitina

- 0.98

operculum

neck absent i*

g u I

---

. --I

glabrous

- -1.1

1.0

FIGURE

5-Factorial Analysis

of Correspondence

(FAC)

of the chitinozoan

genera

(open circles) and of seven character

states (open stars)

of the

apertural

plug, neck, and wall surface.

Plectochitina; "anastomosed hollow processes" in Clathrochi-

tina; and "crown of spines on the shoulder" in Alpenachitina).

In contrast, 12 variables among the 36 selected are present in at

least 10 genera, and two of them ("prosome" and "glabrous

wall") are shared by 35 genera among the 56 accepted herein.

In the construction of this diagram (Fig. 4) we dissociated some

morphologic elements into their two mutually exclusive char-

acteristics. The apertural plug was therefore divided into "oper-

culum" and "prosome", while the wall surface was defined by

its two exclusive states "glabrous" and "spiny wall". In both

cases, the sum of the positive ("1") and negative ("0") answers

is 56, i.e., the total number of accepted chitinozoan genera. In

some other cases (e.g., the chamber shape) the sum of the dis-

sociated answers (i.e., "spherical," "lenticular," "hemispheri-

cal," "ovoid," "claviform," "cylindrical," and "conical") is

much greater than the total number of the selected genera, be-

cause some of them have several states (see above).

Multivariate analysis.-We used the multivariate analysis

programs ANALMUL program for Factorial Analysis of Cor-

respondence (FAC) on Macintosh (Febvay and Bonnot, 1991),

and STAT ITCF program for the construction of Ascendant Hi-

erarchic Classification (AHC using Euclidean distances). We ran

these successively with different combinations involving some,

or all, of the characters quoted in the 56 selected genera in order

to distinguish the most diagnostic and discriminating characters.

Our ultimate goal was to detect morphological features that

would allow us to separate all of the selected genera by at least

one character.

Based on the Factorial Analysis of Correspondence (FAC)

diagrams, we tested different combinations of characters (Figs.

5-7). Some are totally independent from each other (e.g., neck

differentiation/ornamentation, chamber shape/occurrence of a

carina). On the other hand, the FAC diagram of the variables

dealing with the apertural plug, the neck differentiation, and the

shape of the chamber indicates clear relationships between these

variables (Fig. 6).

The most discriminate combination involves only four char-

acters, i.e., "operculum," "neck present," "neck inconspicu-

ous," and "spiny wall". It yields a perfect clustering of the

genera into six groups with 43.7 percent of the variance ex-

plained by the first axis and 40.9 percent by the second axis. It

is worth noting that a similar clustering is obtained when using

characters complementary to those chosen for this combination

(the answer "operculum present" is identical to "prosome ab-

sent" and the lack of a "spiny wall" implicates a "glabrous

wall"). Consequently, the introduction of all the variables de-

scribing the first order characters (apertural plug, characteristics

of the neck, surface of the vesicle wall) does not improve the

distinctiveness of the clusters. In the corresponding FAC, using

seven variables, the main axis explains 50.2 percent of the var-

iance whereas the second axis explains only 29.1 percent of this

variance (Fig. 5).

Armigutta

Eisenackitina

Kalochitina

Orbichitina

Ordochitina

Salopochitina

Vinnalochitina

Axis 1

(50.2%)

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JOURNAL

OF PALEONTOLOGY,

V. 73, NO. 4, 1999

Axis 2

(19.4 %)

neck

present 1.4

Hamocm,itvina , Ancyrochitina

Urmch:itma

..-....-- - ' hemispherical

Anthochit:na~a --- 'r~ '* ., ovoid

Cvathocnit:na _

)

p:e^.yoch'bna Ciafthrechitina 1 Fungochitna

Saaenacht,lna .

-.. )

Lagenochitina

Alpenachitina 'S-haerochcflna

prosome SaharchlMna

-1.2 L..._T

..... conical

? cylindrical

) 4 Conochiina

* neck inconspicuous

5-. Sp.ihonochitina

claviform

Clavachtirna

Eremochnitna

Laufeldochittina

Ve!atachicina

-1.4

Atmorncocht'tna

Armaguta

Sa iopoch,tina C,utlc.I

tir..a

C.nga. .h;ina Desmtoct;tna

Eisenackh tina

Utr.och,ti,na

?!?na,oc.h:<t2a

Butbocrhtina

16 & Axis 1

soherical ;

(28.6 _-)

sherical

B'!.s ach,...: ?a

Kaioch.,tna

Linochiina Oachilna Orbch,tna

Ordochiti,na

Pseuaoccatnro.

FIGURE 6-Factorial Analysis

of Correspondence

(FAC)

of the

chitino-

zoan genera

(open circles) and of the characteristics

of the apertural

plug, neck, and chamber

shape

(12 variables)

(open stars).

Dark

grey

= Desmochitinidae;

light grey = Lagenochitinidae;

open = Conochi-

tinidae.

When we replaced

the characters

describing

the wall surface

(i.e., "spiny wall" and "glabrous") with different chamber

shapes, the clusters

were poorly defined,

but all genera

may be

referred

to one of the three

groups

distinguished

on the diagram

(Fig. 6). The "lenticular"

and the "spherical"

chambers

are

closely tied with the characters

"neck

absent/operculum,"

while

the "claviform"

and "cylindrical"

chamber

shape

(and

to a less-

er extent "conical") are well related

to the characteristic

"neck

inconspicuous".

In this FAC, the weight of each axis is fairly

reduced (28.6 percent for axis 1, 19.4 percent

for axis 2; the

first seven axes explain 92.8 percent

of the variance).

The FAC performed

using all 36 variables

(dissociated

char-

acters)

and all 56 individuals

(genera)

does not show any well-

defined

clusters

(Fig. 7). An important

point

is that all the genera

are clearly separated

from each other.

This means that

the mor-

phologic criteria

selected are distinctive

enough to prevent

the

occurrence

of synonyms (total overlapping).

The clustering

the taxa from the same subfamily

is not totally satisfactory,

a slight overlap

occurs in some circumstances

(Fig. 7). This is

due mainly to the "dilution

effect" introduced

by the greater

number

of low rank criteria

(second or third order

characters)

with respect

to the first

order ones. For that

reason,

we retained

all complementary

characters

of the first

order.

The Hierarchic

Ascendant Classification

(HAC), using Eu-

clidean distances

does not itself provide

totally distinct

clusters

at the suprageneric

level. A partial

mixing of the Lagenochitin-

idae and the Conochitinidae

was observed

in different

tests, and

as in the FAC, can be explained

by the excessive "weight" of

the second and third order characters

with regard

to the first

order

ones. A more satisfactory

HAC is obtained

at a suprage-

neric level when using only first

and second order

criteria

(Fig.

8), even if the Conochitinidae

and the Lagenochitinidae

are not

completely

separated

because of the higher "weight" of the or-

namentation

("spiny wall" and "processes")

with regard

to the

differentiation

of the neck. The subfamilies,

however,

are per-

fectly clustered,

with the exception

of Cingulochitina

(this

genus

both Pterochitininae

and

Margachitininae

characteristics).

Innovations

through

time.-In order

to evaluate

the tempo

the morphological

changes of the chitinozoan

vesicle through

time, we plotted the first occurrence

of successive major

inno-

vations recorded

from the appearance

of the group in the Tre-

madoc to its extinction

in the topmost

Famennian

(Fig. 9.1-2).

These innovations

should

provide

the best support

for establish-

ing tentative

phylogenetic

trees. However,

we have noted that

the appearance

of some peculiar characteristics

may occur at

different

times in different

families, e.g., the carina

is present

early as middle

Arenig

in the Conochitinidae

(e.g., Tanuchitina)

and the Lagenochitinidae

(e.g., Cyathochitina),

whereas

it is re-

ported

for the first time in the late Abereiddian

in the Desmo-

chitininae (e.g., Pterochitina retracta). Similar observations

have also been made of the first occurrence

of processes (of

whatever

type), which appeared

during

the Caradoc

in the Con-

ochitinidae

(e.g., Spinachitina)

and the Lagenochitinidae

(e.g.,

Ancyrochitina)

but not before the late Llandovery

for the Des-

mochitinidae

(e.g., Salopochitina),

if we exclude the single in-

dividual representing

Armigutta

in the Middle Ordovician

Sweden (see Schallreuter,

1981).

Depending

on the families,

sec-

ond order features such as crests or meshlike ornaments

also

display a clear diachronism

in their

first

appearance.

It must be

stressed

that the order

of appearance

of innovations

during

the

Ordovician

(earlier

in the Lagenochitinidae

and in the Conochi-

tinidae

than

in the Desmochitinidae)

was inverted

after the glob-

al crisis that affected the chitinozoan

group (see Grahn,

1988;

Paris, 1989) at the Ordovician-Silurian

boundary.

Another

important

observation

is the diachronism

between

the

first occurrence

of some innovations

through

space, i.e., in well-

separated

tectonic

plates

(for the timing

of the same innovations

in northern

Gondwana

and in Baltica (Fig. 9.1-2). This diach-

ronism

suggests an allopatric pattern

of speciation

for some chi-

tinozoan

taxa.

One of the most fruitful

approaches

for separating

a general

character

from a minor one involves tracing the evolution of

each of the characters

through

time.

When

a morphologic

feature

displays no obvious changes from the appearance

of the group

until

its extinction,

it indicates

that

the character

was not affected

by evolutionary processes. Such a character

is likely to be ple-

siomorphic.

However,

when a character

facilitates

a recognizable

differentiation

(demonstrates

a marked

sorting

with only a few

subdivisions)

among

the accepted

genera,

it may be regarded

a high rank criterion

(e.g., Family or Subfamily

level). In chi-

tinozoans,

the three

categories

of neck, or the differentiation

the apertural

plug either

as a prosome

or as an operculum,

may

play such a role, because

no other innovations

within

these char-

acters

have been recorded

from

their

first occurrence

in the Early

Ordovician

until the extinction

of the group

in the latest Devo-

nian (Fig. 9). In addition,

the surface of the vesicle wall, i.e.,

either

a glabrous

or a spiny wall, should

be discriminating

char-

acters

in suprageneric

subdivisions.

The "glabrous"

wall is pres-

ent in the first chitinozoans,

and the character

state "spiny" is

first

reported

in chitinozoan

taxa not older than the middle Ar-

enig in Gondwana

and Baltica

regions (Fig. 9.1-2). Since these

character

states were still present until the latest Famennian

when the group

disappeared,

they may be considered

plesiomor-

phic features.

Cladistic

approach.-The application

of a cladistic

approach

to test the relationship

between

the different

chitinozoan

genera

is justified

by the assumption

that changes in chitinozoan

mor-

phology reflect

genetic changes in the genetic patrimony

of the

"chitinozoophorans"

(i.e., the organisms

producing

the chiti-

nozoan vesicles). The hypothesis we have adopted-chitino-

zoans are reproductive

stages (eggs) of an extinct

marine

meta-

zoan group(s)-is not in conflict with this statement.

Indeed,

extant

birds

or insects clearly

demonstrate

a correspondence

be-

tween morphology and genetics because they can be readily

Angochltina

M,'scochtirna

Par!soch:iti;na

Pe'iichitrna

Sommerochr;na

Baeonrechitina

Euconochtitina

Pogonochitina

Hercoch:tira

Pistiliachiltina

Rhabdochiftna

Bal'och-i!itna

HvyaiocM,fina

Spinachitina

Tanuchalina

Acanthoc.;tina

556

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PARIS ET AL-REVISED CHITINOZOAN CLASSIFICATION

Axis 2

(9.3%)

Desmo.

1.00

Vinr nalo. Eisena.

1rmigutta

Kalo.

e~ Cuti.

Bursa. g

Uro. i

- Sphaero.

o-- .

Salopo.

Ordo. Orbi.

Ango. Ramo.

bdo.

-1.00

Pseudoclathro. -

Eremo. 0

I ll Rha,

Siphono. 9. Cono.

LVelata. /

Laufeldo.

Pistilla. Balto.

Saharo.

"f]Pelli. Ancyro.

Lageno.

Lageno. Alpena.

Belone.

i- Sommero.

Axis 1

(10.7%)

'-'"Plecto.

-- Clathro.

\ Musco.

Acantho.

Pogono.

FIGURE

7-Factorial Analysis

of Correspondence

(FAC)

of the chitinozoan

genera

(open

circles)

and

of the 36 morphological

variables of the vesicle.

The subfamilies are surrounded. Dark grey = Desmochitinidae;

light grey = Lagenochitinidae;

open = Conochitinidae.

Rectangles

indicate

monogeneric

subfamilies.

identified to genus and sometimes even to species level, based

exclusively on the external aspect of their eggs exclusively.

Since the characteristics of the eggs of living metazoans can be

used in generic identification, the morphology of the egg may

be fairly strictly tied to the processes of speciation. Hence, the

relationships existing between different metazoan genera should

also be reflected by their eggs. Based on this argument, we have

tried through a cladistic approach to depict the relationships be-

tween chitinozoan genera (Fig. 10). The application of the cla-

distic principle to the chitinozoans is relatively straightforward

as long as the procedure is applied to taxa within the same fam-

ily. However, difficulties arise when we attempt to include all

the chitinozoan genera in a single cladogram. This is due to a

diachronism of the appearance of apomorphic characters in sev-

eral chitinozoan families.

Some apomorphic characters occur earlier in the Conochitin-

idae and the Lagenochitinidae than in the Desmochitinidae, at

least up to the global faunal crisis at the Ordovician-Silurian

boundary (see above). This is illustrated in northern Gondwana

(Fig. 9.1) by the apomorphic character "carina below margin,"

which is already present in the middle Arenig in the Conochi-

tinidae (e.g., Tanuchitina), whereas it appears for the first time

in the late Abereiddian in the Desmochitinidae (e.g., Armori-

cochitina). Conversely, after the topmost Ordovician faunal

event, the Desmochitinidae show the best potential of innova-

tion, e.g., the apomorphic character "reticulum with perforated

Marga.

Urno.

Lino. -

Armorico.

Cingulo.

557

.:::

";:::::: .

.::

::: : :?::::::: . I.

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JOURNAL OF PALEONTOLOGY,

V. 73, NO. 4, 1999

Acanthochitina -

Belonechitina

Hercochitina

Pogonochitina

Spinachitina -

Alpenachitina

Ancyrochitina

Clathrochitina .

Sommerochitina -

Plectochitina i

Angochitina

Ramochitina

Muscochitina

Fungochitina

Siphonochitina

Eremochitina |

Baltochitina T0

Tanuchitina -

Laufeldochitina -

Hyalochitina - o

Clavachitina-

Conochitina - 2

Rhabdochitina -

Pistillachitina-

Euconochitina CD

Velatachitina -

Pellichitina -

Anthochitina ---

Cyathochitina -

Sagenachitina -

Parisochitina -

Sphaerochitina - - -

Saharochitina

Lagenochitina

Urochitina

Vinnalochitina

Eisenackitina

Ordochitina "

Kalochitina

Armigutta

Salopochitina

Orbichitina

Cutichitina

' '

Bulbochitina (

Bursachitina

Calpichitina c:

Desmochitina

Ollachitina l.

Hoegisphaera

Armoricochitina

Pterochitina

Pseudoclathrochitina

Cingulochitina

Urnochitina

Margachitina

Linochitina

FIGURE 8-Hierarchic Ascendant Classification

(HAC) using Euclidean

distances for the 56 selected

genera

and

the

characteristics of the

ap-

ertural

plug,

neck,

surface

pattern,

and vesicle structures

(12 states).

Dark

grey

= Operculatifera;

light grey

= Prosomatifera.

expansion"

occurs as early as the Wenlock

(Al-Hajri

and Paris,

1998) in the Desmochitinidae (e.g., Pseudoclathrochitina)

but

not reported

in the Lagenochitinidae

before the late Givetian

(e.g., Parisochitina).

Similar observations

are made for the apo-

morphic character

"sheathing processes" which occur for the

first time in Salopochitina,

a Late Llandovery-Early

Wenlock

Desmochitinidae,

but only in the late Frasnian-early

Famennian

for Sommerochitina,

a genus belonging

to the Lagenochitinidae.

This diachronism

of some apomorphic

characters leads to

poorly

resolved

cladograms

when all chitinozoan

genera

are an-

alyzed together.

This may be related to a possible polyphyletism

of the Chitinozoa.

Hierarchy of the used criteria.-Mathematical treatments of

all the morphological

data, using either a simple histogram (Fig.

4) or more sophisticated

multivariate

analysis (Figs. 5-8), re-

vealed which characters are shared

by the greatest

number of

taxa. The highest subdivision

is provided by the apertural

plug,

i.e., either a prosome

or an operculum.

Together

with the cham-

ber, aperture,

neck and glabrous

wall, the prosome was one of

the very basic characteristics

of a chitinozoan

vesicle when the

group

appeared

during

the Tremadoc.

The neck and the surface

of the walls themselves

showed modifications as early as those

of the apertural

plug (Fig. 8). However,

for the stability

of the

nomenclature,

as recommended

by the International Code of

Zoological

Nomenclature,

we prefer

the preservation

of the ple-

siomorphic characters "prosome" and "operculum" for the

highest suprageneric

subdivision of the group of the chitino-

zoans. The basic reason for this is because Eisenack

(1972) had

already

used them, as the diagnostic

elements

of his widely ac-

cepted Prosomatifera

and Operculatifera

orders respectively.

This scheme has been used for more than 20 years by almost

all the chitinozoan workers

who have accepted

and used a su-

prageneric

classification

(see discussion in Paris, 1981; Achab

et al., 1993), and there are no serious reasons to change it.

Other

highly diagnostic

features shared

by several

genera

(see

Figs. 5-6) are the various character states applied

to the differ-

entiation of the neck (i.e., "neck

present,"

"neck

absent,"

"neck

inconspicuous"),

the surface

of the vesicle wall (i.e., "glabrous"

and "spiny wall") and the shape of the chamber

(i.e., "lentic-

ular," "hemispherical," "spherical," "ovoid," "claviform,"

"conical," "cylindrical").

The most distinctive

combinations of

characters are those that relate neck differentiation

to apertural

plug. These combinations allow the division of the Chitinozoa

into three main categories regarded

here as families, i.e., the

Conochitinidae,

the Lagenochitinidae,

and the Desmochitinidae

(Fig. 11).

CLASSIFICATION OF THE ACCEVI'ED GENERA

Discussion.-In numerous

publications,

original generic di-

agnoses are too vague or introduce inconstancies

in application

of terminology. Consequently,

under the heading "diagnosis",

and in order to promote a more standardized

terminology,

have indicated

the discriminate

character(s)

(=diagnostic fea-

tures)

for each genus we accept.

The emended diagnoses

proposed

by Paris

(1981, p. 110) re-

spectively for the Desmochitinidae,

the Conochitinidae

and the

Lagenochitinidae

are strictly

adopted

here.

Age assignment

of Ordovician

taxa is given by reference to

the recently modified British chronostratigraphy

(Fortey

et al.,

1995).

SYSTEMATIC PALEONTOLOGY

Order PROSOMATIFERA

Eisenack, 1972

Family CONOCHITINIDAE

Eisenack, 1931 emend. Paris, 1981

Subfamily CONOCHMTININAE

Paris, 1981

Genus CLAVACHITINA

Taugourdeau, 1966

Type species.-Rhabdochitina claviformis Taugourdeau,

1961. Holotype in Taugourdeau,

1961, p. 150, pl. 4, fig. 69,

Avensac 101 borehole,

2051 m, Avensac Formation,

Llandeili-

an, south-western

France,

collections of the Museum National

d'Histoire

Naturelle de Paris,

France.

Diagnosis.-Conochitinidae with a glabrous

claviform cham-

ber and without mucron.

Occurrence.-Ordovician.

Genus CONOCHmNA

Eisenack, 1931

emend. Paris, Grahn, Nestor,

and Lakova

Type species.-Conochitina claviformis Eisenack, 1931. Lost

holotype in Eisenack, 1931, p. 84, pl. 1, fig. 17, from erratic

graptolitic

rocks ("Graptolithengestein");

neotype:

in Eisenack,

558

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Eisenau kilina

Vinnialoh

litifll

Ordoch itina

O/'bicliitiitt

Salopo'hitina

riuiigiitltt

rinorlcochiiinui

PArnetochitil, t

Ptfeochitilua

Cihl '/itilna

Mttf^/;f)t

'/ ifli//

Urnochlfiil

Li)wno

hitinat

Ctilichitilla

1hi'/i1sch/ lil

BifilochIififii7

Hoegisphaura

Calpichitilua

0'llitilitifind

c 00

-C -

- . 0 - .

o ~~~~ ~ Ct

0 0k4

-. L . 0

cT1

rio

ORDOVICIAN SILURIAN DEVONIAN

r - -n Chronostratigraphy

C. (0 ' . Innovations

. -. .---------.---. ----------------------------

--- -- -------------- claviform

chamber

....------------------------------------------------------------------------ neck present

* --- ------------------------------------------------------------------ prosome

.. ---. ---o - - - - - - - - - - - - - - glabrous

--- ---------------------------------------------------------------- -------- cylindrical

chamber

-- ---- ---------------------------- ---------------- -------------------- ovoid

chamber

----- --

.----0-- --

- ----- ---- -----.--------- --------------------------- mucron

.-----* - ----------o-------------------- ---------------- -------------------- conical

chamber

-. -

-------- ------o ------------------------------------------------------ copula

- ------------ 0 --------------- ------------------------------------- sleeve

-..-

.---- .-------- o -

------------------ -----------.---------------- -- carina

---------- ------------------------------- ------o ------------------------------- carina on margin

-----------------o -

------------------- ------------------------------------- carina below margin

..-------------o ----------------------------------------------------------------- neck absent

------------- ------------------------------------------------------------------ operculum

...- ------. ..--------.-----------------------------o-------------------------- perforated

carina

-.......-.

----- o ----------------------------- -------------------------- spines

--------......

--------.---------------------- ------------------------- chamber

hemispheric

Z.---

------. ..--- - ------- ----- ----------------------------------- -- bulb

..--- ---------0 -..-- ----------------------------------------------------- lenticular

chamber

--o--

? ------- ---

- * ---------------- --------------------------- -- spherical

chamber

....-

. ------------

--- ----------------.-------------------------------------- laciniated

carina

---- -

--- ---* o -------------------------------------- --------- ----- crests

-------------- - .-

-- -----

.-- - -

-----o --------- processes

.. ) _

.-------------------------- .

--------- --------------------------------mesh like ornament

--------------------- ------ -- --- -- --------- --- ----- - anastomosed

processes

- - ---------- --------------------- cell

processes

C --------- ---- --------- -------- collarette

absent

--- - -

-- - - - - -------

-o -- operculum/peduncle

fixed

..--- ....-- -------------- ---------------- o ---------------------- --------- peduncle

- - . -

.--------------------------- - ---- --------- -

------ - sheathing

processes

..... ----.----.------------------------ ---------- -------------------------- carina round

the aperture

... ...---------------------------- -- ---------- ------------- ------ reticulum

. ----------------------------------- -----------o ------ --------- evaginated

chamber

------------------------------------------------------- -- - * -------- ornaments in 3crowns

----- --------- ------------------------------------------ ---------------- --- claviform

chamber

-. ---

- - -

---- -

--------------------- --------------------

- -----------------

- -- neck

present

-...- . --------- ---------------------------------------- --------------------- prosome

-. 0 ---- -- ------------------------------------------ ----------------- -- glabrous

.--- -------- -- -

-----.-------------------. ------------- --------------------- cylindrical

chamber

-----.- - -----o - ---.----.------------------------ ------- --------------- ----- ovoid chamber

-------------0o -------------------------------------------------------------- mucron

-------- ------- ---------------------------------- ------ -------------------- conical chamber

-----.---------- ------------------------- .--- 0---------- ------------ ---- -- copula

------------------------------------------------------------------------------- sleeve

-------- ------- -- ---- ------------------------------- -- -------------------- carina

- -- - .--- --- -.----.-------.----------- ---- o-------- ---------------- -- carina on margin

---------- * ---- -o -.----.-------------------------------- ---------------- --- carina below margin

o ---- ----- -------------------------------------

----------------- -- neck

absent

-----o-- ---- - .-------------------------------------- ------------------ operculum

-----...------------ -- ..--------------- .--------------- --------------------- perforated

carina

..-----.. o .. . ............... spines

.. -------- ----- ---------------------------------- ----------------- chamber

hemispheric

---------------- --0 ------------------------------------- ----------------- -- bulb

...-

--- .--- *

-.--- --------- ----

- ---------------

--------------- lenticular

chamber

----------------- ------------...............-----

---------.....

---......---

o ------- ---------------- --- spherical chamber

- -------------- --------------------------------------- ----------- ----- --- laciniated

carina

--------------------------- --------.--------------------- -------------------- crests

-----.....----

- - --.-- -

. --------------.------------ -------------.------ processes

.----- ------- -- -

..--- -- -- ----- ---------------

- ------------- mesh like ornament

w..-- -------

---W----:----------------.-------- * ----- --------------------- anastomosed

processes

----- ------- -cell like processes

-- -------

.. ------.-------------

----------o ---------- --------------------- collarette

absent

----- . ------ --.--.--.-------------- ---------- --------- ----------------- -- operculum/peduncle

fixed

--- - -----------------------------o- ------- ---------------- -- peduncle

-----

------- ------------------------------------- ---------------- --- sheathing

processes

------------------.-------------o---- --- ------------ -- carina

round

the

aperture

---- ---------

-----------

------------------

---- -

--------- - -- reticulum

--- -----------

------ ---- - ----------------- -- evaginated

chamber

------------- -------- --------------- ------------

-- .--

- ----

---- -

- ornaments

3 crowns

ITI

0 a

N) O i

rT- n0

ON~ 0

m-Ce

P. tTi

0ri c

. o

i) 7

(D 1-3

W x

r0 4 W

..el.

p Oe

con

r.i

tIT

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JOURNAL OF PALEONTOLOGY,

V. 73, NO. 4, 1999

Order Family Sub-family Genera

Plug Neck differentiation Chamber

surface Chamber

shape

and

arrangement

of ornamentation

- I DESMOCHITINIDAE

^; $-4 (no neck)

Desmochitininae

(glabrous)

Cutichitininae

(sleeve)

Pterochitininae

(carina)

Margachitininae

(copula)

Eisenackitininae

(spiny)

Orbichitininae

(processes)

lenticular

...................................... Calpichitina

spherical ---------.......

...-- ---.... ---... Hoegisphaera

hemispherical

................................ Bulbochitina

conical --......................................... Bursachitina

ovoid

............................ ...............Desmochitina

cylindrical

--...----- -------...---------.....-

- - Ollachitina

ovoid-------------------------------------------

Cutichitina

lenticular

to spherical

....................... Pterochitina

ovoid (below margin)-....................... Armoricochitina

conical (reticulum,

perforated)

............ Pseudoclathrochitina

conical to ovoid (on margin)

---.....--------..--

Cingulochitina

lenticular

to spherical

(peduncle)

......... Margachitina

ovoid........................................... Urnochitina

claviform to cylindrical .................... Linochitina

hemispherical

................................ Vinnalochitina

conical ........................................ Kalochitina

conical (with crests)

-------------

..------------

Ordochitina

ovoid -..---------------------------...--------..---

Eisenackitina

conical ........................................ Orbichitina

ovoid

........................................... Armigutta

conical to ovoid (sheathing)

-.----------.- Salopochitina

CONOCHITINIDAE

( flexure

unconspicuous)

o; o

0 0

rt./_

LAGENOCHITINIDAE

(flexure

conspicuous)

Conochitininae

(glabrous)

Velatachitininae

(sleeve)

Eremochitininae

(copula)

Tanuchitininae

(carina)

Pogonochitininae

carina/spiny)

Belonechitininae

(spiny)

Spinachitininae

(processes)

Lagenochitininae

(glabrous)

Cyathochitininae

(carina)

Pellichitininae

(sleeve)

Urochitininae

(copula)

Angochitininae

(spiny)

, Ancyrochitininae

(processes)

conical

-----.---.----------------..--.--...-.- - Euconochitina

conical to claviform

(with mucron)

...... Conochitina

claviform

------------------------------------- Clavachitina

cylindrical (with widened

base) ---------- Pistillachitina

cylindrical --------------------------------........................

Rhabdochitina

claviform --...-----...------------------------------

Velatachitina

claviform

...................................... Eremochitina

claviform

to cylindrical (bulb) ----. ..-----

Siphonochitina

conical to cylindrical

(on margin)

......... Hyalochitina

claviform

(below margin)

------------------ Laufeldochitina

conical to cylindrical

(perforated)

-------- Baltochitina

cylindrical

(below margin)........-----------

Tanuchitina

conical (laciniated,

on margin)

------------ Pogonochitina

conical

......................................... Belonechitina

conical to cylindrical

(mesh-like)

--------- Acanthochitina

conical (with crests)

........................ Hercochitina

conical to cylindrical -----------------------

Spinachitina

lenticular to conical--------------------------

Saharochitina

spherical

....................................... Sphaerochitina

ovoid to cylindrical

-------.........--

-----------

Lagenochitina

conical to hemispherical

(laciniated)

-. - Anthochitina

conical to hemispherical

(perforated)

--....-

Sagenachitina

conical to hemispherical

(complete)

...... Cyathochitina

ovoid (reticulum,

perforated)

------. ....---

Parisochitina

ovoid------------------------------------------ Pellichitina

ovoid (peduncle).----------------------------

Urochitina

lenticular to conical

......................... Fungochitina

ovoid

----------------------------------------- Angochitina

ovoid (mesh-like) ---...---------------..

-.. - Muscochitina

ovoid (with crests)

-. ---. - .-.----------- Ramochitina

lenticular

to conical -.-------.-------.------ Ancyrochitina

conical (anastomosed).---------------------

Clathrochitina

conical to ovoid (cell-like) ---------------- Plectochitina

ovoid to cylindrical

(3 crowns) ----------- Alpenachitina

claviform

(sheathing)

..-.......--

-------- ----- Sommerochitina

FIGURE

11-Suprageneric and generic

classification

of the chitinozoans.

560

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PARIS

AL.-REVISED

CHITINOZOAN

CLASSIFICATION

formation

from the Rheinischen

Schiefergebirges,

Llanvimrn-ear-

ly Caradoc,

Germany,

collections of the Senckenberg

Museum,

Frankfurt

am Main, Germany.

Diagnosis.-Conochitinidae with a glabrous cylindrical

chamber

ended by a lenticular

to hemispherical

widening.

Occurrence.

-Middle-Upper Ordovician.

Discussion.-It must be stressed

the transition

between

cham-

ber and neck (position

of the prosome)

is within

the tubular

part

of the vesicle.

Genus RHABDOCHITINA

Eisenack, 1931

Type species. -Rhabdochitina magna Eisenack, 1931. Lost

holotype

in Eisenack,

1931, p. 90-91, pl. 3, fig. 18, erratic

Baltic

limestones

("Ostseekalk");

neotype in Eisenack, 1962, p. 292-

293, pl. 14, fig. 1, erratic

Baltic limestones,

Ordovician,

collec-

tions of the Geologisch-Palaontologischen

Institute

der Univer-

sitat,

Tiibingen,

Germany.

Diagnosis.-Conochitinidae with a glabrous

elongated cylin-

drical

vesicle.

Occurrence.

-Ordovician.

Discussion.-Mucron may occur.

Subfamily EREMOCHITININAE

Paris, 1981

Genus EREMOCHITINA

Taugourdeau

and de Jekhowsky,

1960

Type species.-Eremochitina baculata Taugourdeau and de

Jekhowsky, 1960. Lost holotype in Taugourdeau

and de Jek-

howsky, 1960, p. 1228, pl. 8, fig. 107, Or-I borehole,

core sam-

ple from 2930 m, Arenig, Sahara,

Algeria; neotype: in Tau-

gourdeau,

1967, pl. 1, fig. 19, (DD. 52), same references as for

the holotype,

collections

of the Museum

National

d'Histoire Na-

turelle

de Paris,

France.

Diagnosis.-Conochitinidae with claviform

glabrous

chamber

with a tubular

copula.

Occurrence.-Lower Ordovician.

Genus SIPHONOCHITINA

Jenkins, 1967

Type species.-Siphonochitina formosa Jenkins, 1967. Holo-

type in Jenkins, 1967, p. 469-471, pl. 75, fig. 2, Shelve area,

upper Hope Shale, early Abereiddian,

Shropshire,

England, S

17593, collections of the Centre

for Palynological

Studies,

Uni-

versity of Sheffield,

England.

Diagnosis.-Conochitinidae with a claviform to cylindrical

chamber with a membranous

bulb.

Occurrence.

-Lower-Middle Ordovician.

Subfamily TANUCHITININAE

Paris, 1981

Genus BALTOCHITINA

Paris and Grahn new genus

Type species.-By original designation: Baltochitina nolvaki

Paris and Grahn new species. Holotype: Sagenachitina sp. in

Nolvak and Grahn,

1993, pl. 5, figs. A and B, Rapla

borehole,

Voo Formation,

Lasnamagi Stage,

late Abereiddian,

south

of Tal-

linn, Estonia;

collections of the Institute of Geology, Estonian

Academy

of Sciences, Tallinn,

Estonia.

Diagnosis.-Conochitinidae with a conical to cylindrical

chamber with a perforated

carina on the margin.

Etymology.-from Baltic, its type area.

Occurrence.-Middle Ordovician.

Discussion.-This genus differs from Sagenachitina Jenkins,

1970a and from Parisochitina Boumendjel, 1985, which have a

well-defined neck.

BALTOCHITINA NOLVAKI Paris and Grahn new species

Sagenachitina sp. NOLVAK AND GRAHN, 1993, pl. 5, figs. A and B

Diagnosis.-Conochitinidae with an elongate subcylindrical

vesicle (ratio of vesicle length to chamber diameter

>five), a

smooth wall surface, straight

lip, sharp margin

bearing

a carina

turning

reticulated

distally and extending

more or less perpen-

dicular

to the axis.

Description.-Long and slender chitinozoan

(length

of the ho-

lotype:

440 microns,

chamber

diameter: 60 microns)

with a sub-

cylindrical

to slightly conical chamber;

cylindrical

neck ended

with straight

lips; chamber

bottom flat; wall surface entirely

smooth;

perforated

to reticulated carina

erected

on the margin;

this fairly short membranous

carina

extends more or less per-

pendicularly

to the flanks.

Etymology.-Dedicated to our colleague Jaak

N1olvak

(Esto-

nian Academy

of Sciences, Tallinn,

Estonia)

for his outstanding

investigations

on Ordovician

chitinozoans

from the Baltic area.

Holotype.-fig. A, pl. 5 in N1olvak and Grahn (1993), Ch.

1416/7631, collections of the Institute of Geology, Estonian

Academy of Sciences, Tallinn,

Estonia;

late Abereiddian,

Las-

namagi Stage, Voo Formation,

Rapla

borehole

(depth

179.2 m),

south of Tallinn,

Estonia.

Occurrence.-Late Abereiddian.

Discussion.-No other chitinozoan species has a subcylindri-

cal vesicle and a reticulated carina.

Genus HYALOCHITINA Paris and Grahn new genus

Type species.-By original designation: Cyathochitina hyalo-

phrys Eisenack, 1959. Holotype in Eisenack, 1959, p. 11-12, pl.

2, fig. 6, Cincinnati Group, Cincinnati, Ohio, late Maysvillian-

early Richmondian (early Ashgill), collections of the Geolo-

gisch-Palaontologischen Institute der Universitat, Tubingen,

Germany.

Diagnosis.-Conochitinidae with a conical to cylindrical

chamber provided with a complete membranous carina on the

margin.

Occurrence.-Upper Ordovician.

Discussion.-This new genus is separated from Tanuchitina

Jansonius, 1964, which has a carina below the margin, and from

Cyathochitina Eisenack, 1955b emend. Paris, Grahn, Nestor, and

Lakova herein, which has a conspicuous flexure.

Genus LAUFELDOCHITINA

Paris, 1981

Type species.-Cyathochitina stentor Eisenack, 1937 (lost ho-

lotype in Eisenack, 1937, p. 221-222, pl. 15, fig. 2, grayish

Ordovician

limestones;

neotype in Eisenack, 1962, p. 300, pl.

14, fig. 10, allochthonous

Kukruse

equivalents,

Halde bei Met-

zingen, Wurtemberg, Germany, collections of the Geologisch-

Palaontologischen Institute der Universitat, Tiibingen, Germa-

ny).

Diagnosis.-Conochitinidae with a claviform, glabrous cham-

ber and a complete, flaring membranous carina, below the mar-

gin.

Occurrence. -Ordovician.

Genus TANUCHITINA

Jansonius, 1964

emend. Paris,

Grahn, Nestor,

and Lakova

Type species.-Tanuchitina ontariensis Jansonius, 1964. Ho-

lotype in Jansonius, 1964, p. 910-911, pl. 1, fig. 6, cuttings from

Imperial-Calvan Anderson no. 9-6 borehole, depth 738 m (2,420

ft), Anderson Township, Essex County, Ontario, Canada, collec-

tions of Imperial Oil Limited, Calgary, Alberta, Canada.

Diagnosis.-Conochitinidae with a cylindrical

chamber and a

complete

membranous

carina

below the margin.

Occurrence.-Ordovician-Silurian.

Discussion.-The conical forms with a carina on the margin

are transferred into Hyalochitina Paris and Grahn, n. gen.

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JOURNAL OF PALEONTOLOGY,

V. 73, NO. 4, 1999

Subfamily

VELATACHITININAE

Achab, Asselin and

Soufiane,

1993

Genus VELATACHITINA

Poumot, 1968

Type species. -Velatachitina nebulosa Poumot, 1968. Holo-

type in Poumot, 1968, p. 50-51, pl. 1, fig. 9, borehole SN-1,

core sample from 3,082-3,083 m (referred

to "Llandeilo"

the author,

but likely Abereiddian),

Tunisia,

CZ 244, collections

of the Service Palynoplanctologique

de la SNPA-Elf,

France.

Diagnosis.-Conochitinidae with a claviform

chamber

envel-

oped within a membranous

sleeve.

Occurrence.

-Lower-Middle Ordovician.

Discussion.-The membranous

sleeve may extend

beyond

the

margin.

Subfamily

BELONECHITININAE

Paris, 1981

Genus ACANTHOCHITINA

Eisenack,

1931

Type species.-Acanthochitina barbata Eisenack, 1931 (Lost

holotype

in Eisenack,

1931, p. 82-83, pl. 1, fig. 10, erratic

lime-

stone

from the Baltic ["Ostseekalk"];

proposed

neotype:

in N61-

vak, 1980, pl. 29, fig. 1, Hullo borehole, 21.0 m, late Vormsi

Stage (early Ashgill), Estonia,

Ch. 701/5670, collections of the

Institute

of Geology of the Estonian

Academy of Science, Tal-

linn, Estonia.

Diagnosis.-Conochitinidae with a conical to cylindrical

chamber

and raised

meshlike

ornamentation;

may be surrounded

with a membranous

sleeve.

Occurrence.-Middle Ordovician

(?)-Upper

Ordovician.

Genus BELONECHITINA

Jansonius,

1964

Type species.-Conochitina micracantha subsp. robusta Ei-

senack, 1959. Holotype

in Eisenack

1959, p. 9-10, pl. 3, fig. 4,

Koppelmann,

Saku

Member

of the Wasalemma

Formation,

Oan-

du Stage, D3 (late Caradoc),

Estonia,

collections of the Senck-

enberg

Museum,

Frankfurt

am Main, Germany.

Diagnosis.-Conochitinidae with a conical chamber

and ran-

domly distributed

spines.

Occurrence.-Lower Ordovician-Silurian.

Genus HERCOCHITINA

Jansonius, 1964

Type species.-Hercochitina crickmayi Jansonius, 1964. Ho-

lotype in Jansonius,

1964, p. 908-909, pl. 1, fig. 9, Gamache

Princeton

Lake 1 borehole,

core sample from 210 m (690 ft.),

Vaureal

Formation,

Ashgill, Anticosti Island, Canada;

collec-

tions of Imperial

Oil Limited,

Calgary,

Alberta,

Canada.

Diagnosis.-Conochitinidae with a conical chamber

and dis-

tinct crests (vertical

rows of spiny or membranous

ornamenta-

tion).

Occurrence.-Middle Ordovician-Upper

Ordovician.

Subfamily

POGONOCHITININAE

new subfamily

Diagnosis.-Conochitinidae with a spiny ornamentation

and

a carina.

Genus POGONOCHITINA

Taugourdeau,

1961

Type species.-Pogonochitina simplex Taugourdeau, 1961.

Holotype

in Taugourdeau,

1961, p. 148, pl. 4, fig. 59, Avensac

101 borehole, 1,902 m, Avensac Formation,

Llandeilian,

south-

western

France,

collections of the Museum

National

d'Histoire

Naturelle de Paris, France. Representative

specimen in Paris,

1996, pl. 1, fig. 9.

Diagnosis.-Conochitinidae with a spiny conical chamber

and with a laciniated

carina

on the margin.

Occurrence.-Middle Ordovician-Silurian.

Subfamily

SPINACHITININAE

Paris, 1981

Genus SPINACHITINA

Schallreuter,

1963

emend.

Paris,

Grahn,

Nestor,

and Lakova

Type species.-Conochitina cervicornis Eisenack, 1931. Lost

holotype in Eisenack, 1931, p. 89, pl. 2, fig. 12, erratic calcar-

eous sandy siltstones; proposed neotype: Spinachitina cervicor-

nis in Nolvak and Grahn, 1993, pl. 3, fig. A, Rapla borehole,

core sample from 142.70 m, Kahula Formation,

Keila Stage

(early Caradoc),

south of Tallinn,

Estonia,

collections

of the In-

stitute

of Geology, Estonian

Academy

of Sciences, Tallinn,

Es-

tonia.

Diagnosis.-Conochitinidae with a conical to cylindrical

chamber bearing a crown of processes.

Occurrence.-Upper Ordovician-Lower

Silurian.

Discussion.-In addition

to the emendation

of Laufeld

(1967),

the genus

is here

restricted

to forms without

conspicuous

flexure.

Coronochitina

Eisenack, 1965 is here regarded

as a junior syn-

onym of Spinachitina.

Family LAGENOCHITINIDAE

Eisenack, 1931

emend. Paris, 1981

Subfamily

LAGENOCHITININAE

Paris, 1981

Genus LAGENOCHITINA

Eisenack, 1931

emend. Paris,

Grahn,

Nestor,

and Lakova

Type species.-Lagenochitina baltica Eisenack, 1931. Lost

holotype in Eisenack, 1931, p. 80-81, pl. 1, fig. 1, erratic Or-

dovician Baltic limestones

("Ostseekalk"); neotype

in Eisenack,

1959, p. 2, pl. 3, fig. 6, from Ordovician

erratic

limestones

the Baltic shore ("Ostseekalk"),

collections of the Geologisch-

Palaontologischen

Institute

der

Universitat,

Tuibingen,

Germany.

Diagnosis.-Lagenochitinidae with an ovoid to cylindrical

glabrous chamber.

Occurrence.-Lower Ordovician-Upper

Devonian.

Discussion.-Forms with glabrous spherical chambers are

transferred

into Sphaerochitina Eisenack, 1955a, emend. Paris,

Grahn, Nestor, and Lakova, herein.

Genus SAHAROCHITINA

Paris and Grahn new genus

Type species.-By original designation: Fungochitina? jaglini

Oulebsir and Paris, 1993. Holotype in Oulebsir and Paris, 1993,

p. 274-279, pl. 4, fig. 1, Gd-1 bis borehole,

north of Hassi Mes-

saoud, north-eastern Sahara, Hassi Touareg Formation, Azzel

Member, core sample at 4,033.50 m, late Abereiddian, IGR

60509 (R 41), collections of the Institut de Geologie de

l'Universit6 de Rennes, France.

Diagnosis.-Lagenochitinidae with a glabrous

conical to len-

ticular

chamber.

Occurrence.-Middle Ordovician-Silurian.

Discussion.-This genus differs from Fungochitina Taugour-

deau, 1966 in being smooth and from Pistillachitina

Taugour-

deau, 1966, which displays

a tubular

chamber

with an antiaper-

tural

widening.

Genus SPHAEROCHITINA

Eisenack, 1955a

emend.

Paris,

Grahn,

Nestor,

and Lakova

Type species.-Lagenochitina sphaerocephala Eisenack,

1932. Lost holotype in Eisenack, 1932, p. 271, pl. 12, fig. 14,

erratic

Beyrichia

Limestone

("Beyrichia-kalk");

neotype in Ei-

senack, 1955a, p. 162, pl. 1, fig. 6, erratic

Beyrichia

Limestone

from the Baltic sea floor?,

Pridoli,

collections of the Sencken-

berg Museum,

Frankfurt

am Main, Germany.

Diagnosis.-Lagenochitinidae with a glabrous spherical

chamber.

Occurrence.

-Upper Ordovician-Devonian.

562

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PARIS ET AL-REVISED CHITINOZOAN

CLASSIFICATION

Discussion.-The spiny forms (spines exceeding two mi-

crons) as well as those with a conical or a lenticular

chamber

are here excluded from the genus.

Subfamily

CYATHOCHITININAE

Paris, 1981

Genus ANTHOCHITINA

Eisenack, 1971

Type species.-Anthochitina superba Eisenack, 1971. Holo-

type in Eisenack, 1971, p. 452-454, fig. 1-1, erratic

Beyrichia

limestones

from the Baltic bottom?,

Pridoli(?),

collections

of the

Geologisch-Palaontologischen

Institute der Universitat,

Tubing-

en, Germany.

Representative

specimens

in Wrona, 1980, pl. 26,

figs. 1-9.

Diagnosis.-Lagenochitinidae

with a conical to hemispherical

chamber with a laciniated,

spongy to cell-like carina.

Occurrence.

-Upper Silurian-Lower Devonian.

Discussion.-Occasionally proximal perforations may exist.

Genus CYATHOCHITINA

Eisenack, 1955b

emend. Paris,

Grahn,

Nestor,

and Lakova

Type species.-Conochitina campanulaeformis Eisenack,

1931. Lost holotype in Eisenack, 1931, p. 86-87, pl. 2, fig. 2,

erratic calcareous to sandy

siltstone

of Ordovician

age; neotype:

Cyathochitina campanulaeformis in Eisenack, 1962, p. 297-298,

pl. 14, fig. 5, from

Harku near

Tallinn,

likely lower Uhaku

Stage

(Llandeilian),

Estonia,

collections of the Senckenberg

Museum,

Frankfurt

am Main, Germany.

Diagnosis.-Lagenochitinidae with a conical to hemispherical

glabrous

chamber and with a complete

membranous

carina on a

sharp

margin.

Discussion.-Conical species without a conspicuous

flexure

are transferred into Hyalochitina

Paris

and Grahn n. gen.

Occurrence.

-Ordovician-lower Silurian

(Llandovery).

Genus PARISOCHITINA

Boumendjel, 1985

Type species.-Parisochitina perforata Boumendjel, 1985.

Holotype in Boumendjel,

1985, p. 164-166, pl. 2, fig. 5, bore-

hole Taouratine-3, 1,352 m, Gazelle Formation,

late Devonian,

Illizi Basin, south-eastern

Sahara,

Algeria, IGR 60319 (M 39),

collections

of the Institut

de Geologie de l'Universite de Rennes,

France.

Diagnosis.-Lagenochitinidae with an ovoid chamber and

with a reticulum

extending

beyond the base as a perforated

ca-

rina.

Occurrence.-Upper Devonian.

Genus SAGENACHITINA

Jenkins, 1970a

Type species.-Clathrochitina oblonga Benoit and Taugour-

deau, 1961. Holotype

in Benoit and

Taugourdeau,

1961, p. 1406,

pl. 1, fig. 1, Amg-1 borehole, 1,482 m, "Complexe

argilo-gre-

seux superieur"

Formation,

late Arenig,

Sahara,

Algeria,

collec-

tions of the Museum National d'Histoire Naturelle de Paris,

France.

Diagnosis.-Lagenochitinidae with a glabrous conical to

hemispherical

chamber and with a perforated

or reticulated

ca-

rina extending

from the margin.

Occurrence.-Lower-Middle Ordovician.

Subfamily PELLICHITININAE

Achab, Asselin and Soufiane, 1993

Genus PELLICHITINA

Achab, Asselin and Soufiane, 1993

Type species.-Desmochitina pellucida Benoit and Taugour-

deau, 1961. Holotype in Benoit and Taugourdeau,

1961, p.

1408-1409, pl. 4, fig. 37, Amg-1 borehole, core sample from

1,577 m, lower part

of the Hamra

Quartzite

Formation,

middle

Arenig,

Central

Sahara,

Algeria,

collections of the Museum

Na-

tional d'Histoire

Naturelle de Paris,

France.

Diagnosis.-Lagenochitinidae with an ovoid chamber

envel-

oped by a membranous

sleeve.

Occurrence.-Lower-Middle Ordovician.

Subfamily UROCHITININAE

Paris, 1981

Genus UROCHITINA

Taugourdeau and de Jekhowsky, 1960

Type species.-Urochitina simplex Taugourdeau and de Jek-

howsky, 1960. Holotype in Taugourdeau

and de Jekhowsky,

1960, p. 1233, pl. 11, fig. 160, borehole

Ge-1, core sample

from

1,586 m, Oued Saret

Formation,

latest Lochkovian,

Sahara,

Al-

geria, collections of the Museum

National

d'Histoire

Naturelle

de Paris,

France.

Diagnosis.-Lagenochitinidae with an ovoid chamber

bearing

a long solid peduncle.

Occurrence.-Lower-Middle Devonian.

Subfamily ANCYROCHITININAE

Paris, 1981

Genus ALPENACHITINA

Dunn and Miller, 1964

Type species.-Alpenachitina eisenacki Dunn and Miller,

1964. Holotype in Dunn and Miller, 1964, p. 725, pl. 119, fig.

1, Dock Street

Clay Member,

Alpena

Limestone,

Alpena,

Mich-

igan, USA, Middle

Devonian,

USNM collections 144880.

Diagnosis.-Lagenochitinidae with ovoid to cylindrical

chamber

and three

distinct

horizontal

crowns

of spiny ornamen-

tation.

Occurrence.-Middle Devonian.

Genus ANCYROCHITINA

Eisenack, 1955a

Type species.-Conochitina ancyrea Eisenack, 1931. Lost ho-

lotype in Eisenack, 1931, p. 88-89, pl. 4, fig. 4, erratic

lime-

stones of the Baltic ("Ostseekalk");

neotype: Ancyrochitina

an-

cyrea in Eisenack, 1955a, p. 163-164, pl. 2, fig. 7, erratic

Bey-

richia limestones from the Baltic bottom?,

Pridoli;

collections

of the Senckenberg

Museum,

Frankfurt

am Main, Germany.

Diagnosis.-Lagenochitinidae with a lenticular to conical

chamber

bearing

a crown of nonanastomosed

hollow processes

on the margin.

Occurrence.-Upper Ordovician-Upper

Devonian.

Genus CLATHROCHITINA

Eisenack, 1959

Type species.-Clathrochitina clathrata Eisenack, 1959. Ho-

lotype in Eisenack,

1959, p. 15 pl. 1, fig. 3, Dalhem

canal,

Pen-

tamerus

gotlandicus

beds from

south

east Slite Marls,

late Shein-

woodian,

Wenlock,

Gotland,

Sweden, collections of the Geolo-

gisch-Palaontologischen

Institute der Universitat, Tiibingen,

Germany.

Diagnosis.-Lagenochitinidae with a conical chamber

and a

crown of anastomosed

processes

on the margin.

Occurrence.-Silurian.

Discussion.-In order to separate Clathrochitina from An-

thochitina,

the emendation

proposed

by Laufeld

(1974) focusing

on a membranous

carina

(cingulum)

is not followed.

Genus PLECTOCHITINA

Cramer, 1964

Type species.-Plectochitina carminae Cramer, 1964. Lost

holotype in Cramer,

1964, p. 346-347, pl. 20, fig. 21, La Vid

de Gordon

section, upper

San Pedro

Formation,

Pridoli,

north-

western Spain; neotype: Plectochitina

carminae

in Priewalder,

1997, p. 77, pl. 2, fig. 1, pl. 4, figs. 1, 7-8, slide 1997/1/1 (M.

35.3); collections of the Geological Survey of Austria,

Vienna.

Diagnosis.-Lagenochitinidae with a conical to ovoid cham-

ber provided

with a crown of cell-like processes.

Occurrence.-Upper Ordovician-Silurian.

Discussion.-The processes may be anastomosed.

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JOURNAL OF PALEONTOLOGY,

V. 73, NO. 4, 1999

Genus SOMMEROCHITINA

Costa Cruz and Quadros, 1985

Type species.-Sommerochitina langei Costa Cruz and Qua-

dros, 1985. Holotype

in Costa

Cruz

and

Quadros,

1985, p. 289-

293, pl. 1, fig. 1-2, 2-PM-1-MA borehole, core sample from

1,258-1,262 m, Cabefnas

Formation

(in Longa Formation ac-

cording

Grahn,

1992), early

Famennian,

Parnaiba

Basin, Brazil,

collections

of departamento

de Geologia

e Paleontologia,

Museu

Nacional,

Rio de Janeiro,

Brazil.

Diagnosis.-Lagenochitinidae

with a claviform

chamber with

sheathing processes.

Occurrence.-Upper Devonian.

Discussion.-When partly

broken,

threadlike

expansions

sim-

ulate a deeply laciniated

carina located

below the margin.

Subfamily ANGOCHITININAE

Paris, 1981

Genus ANGOCHITINA

Eisenack, 1931

Type species.-Angochitina echinata Eisenack, 1931. Lost

holotype

in Eisenack,

1931, p. 82, pl. 1, fig. 7, erratic

Beyrichia

limestones ("Beyrichia-kalk")

from the Baltic bottom?;

neo-

type:

Angochitina

echinata in Eisenack, 1964, p. 139, pl. 29, fig.

10, from the topmost part of the Hemse beds, Ludlow, early

Ludfordian,

Gotland,

Sweden,

collections

of the Geologisch-Pa-

laontologischen

Institute

der Universitat,

Ttibingen,

Germany.

Occurrence.

-Upper Ordovician-Devonian.

Diagnosis.-Lagenochitinidae with ovoid chamber

and ran-

domly distributed

simple or complex spines.

Genus FUNGOCHITINA

Taugourdeau, 1966

Type species.-Conochitina fungiformis Eisenack, 1931. Lost

holotype

in Eisenack, 1931, p. 89, pl. 2, fig. 17, erratic

grayish

limestones ("grauer

Kalk") referred

to the lower Silurian

but

likely from the Rakvere

Stage (late Caradoc);

proposed

neotype:

Conochitina fungiformis subsp. spinifera. Eisenack, 1962, p.

310, pl. 14, fig. 15, Rakvere

Stage (late Caradoc),

Wesenberg,

Estonia, collections of the Geologisch-Palaontologischen

Insti-

tute der Universitat,

Tubingen,

Germany.

Diagnosis.-Lagenochitinidae with conical to lenticular

chamber

and randomly

distributed

spines.

Occurrence.-Upper Ordovician-Upper

Devonian.

Discussion.-Eisenack's original holotype for the speciesfun-

giformis was spiny. The subspecies spinifera is therefore chosen

as the neotype for the genus and elevated

to a specific rank.

Genus MUSCOCHITINA

Paris, 1981

Type species.-Muscochitina muscosa Paris, 1981. Holotype

in Paris, 1981, p. 269-270, pl. 30, fig. 17, Saint-Germain-sur-

Ay section, upper part of LaHaye-du-Puits

Formation,

early

Lochkovian,

western

France,

IGR 51761 (M40/1), collections

the Institut

de Geologie de l'Universite

de Rennes,

France.

Diagnosis.-Lagenochitinidae with an ovoid chamber

and a

meshlike

ornamentation.

Occurrence.-Lower Devonian.

Genus RAMOCHITINA

Sommer and van Boekel, 1964

emend. Paris,

Grahn,

Nestor,

and Lakova

herein

Type species.-Ramochitina ramosi Sommer and van Boekel,

1964. Holotype

in Sommer

and van Boekel, 1964, p. 426, pl. 1,

fig. 3, Tocantina,

middle

Devonian,

Parana

Basin, Goias,

Brazil.

Representative

species of the genus in Laufeld, 1974, figs. 49-

50.

Diagnosis.-Lagenochitinidae with an ovoid chamber and

distinct

crests (vertical

rows of spines or membranes).

Occurrence.-Silurian-Devonian.

Discussion.-The vertical

rows of spines

(crests)

occurring

the holotype and confirmed

by SEM observation

on material

from the type locality (Grahn, unpublished),

necessitate the

emendation

of this genus. Gotlandochitina

Laufeld,

1974 which

has the same characters

is therefore

a junior synonym.

Order OPERCULATIFERA

Eisenack, 1931

Family DESMOCHITINIDAE

Eisenack, 1931, emend. Paris, 1981

Subfamily DESMOCHITININAE

Paris, 1981

Genus BULBOCHITINA

Paris, 1981

Type species.-Bulbochitina bulbosa Paris, 1981. Holotype in

Paris, 1981, p. 134-135, pl. 35, fig. 10, la Lezais section,

Bois-

Roux Formation, Aubriais Member, late Pragian, western

France,

IGR 51138 (P 36/3), collections of the Institut de Geo-

logie de l'Universite

de Rennes,

France.

Diagnosis.-Desmochitinidae with a hemispherical glabrous

chamber.

Occurrence.-Upper Silurian-Lower Devonian.

Genus BURSACHITINA

Taugourdeau, 1966

restrict.

Paris, 1981

Type species.-Desmochitina bursa Taugourdeau and de Jek-

howsky, 1960. Lost holotype,

in Taugourdeau

and de Jekhows-

ky, 1960, p. 1225, pl. 7, fig. 89, Tb-I borehole, core sample

from 1,268 m, Early

Devonian, Sahara,

Algeria;

neotype:

in Tau-

gourdeau,

1967, p. 256, pl. 1, fig. 3, Nm-1, core sample from

1,200 m, Early

Devonian

(likely lower

Emsian),

Sahara,

Algeria,

collections

of the Museum National

d'Histoire

Naturelle

de Par-

is, France).

Diagnosis.-Glabrous Desmochitinidae

with a conical cham-

ber.

Occurrence.-Ordovician

(?)-Middle Devonian.

Discussion.-We have adopted

the position

of Paris

(1981, p.

137) who restricted

the genus to glabrous

species.

Genus CALPICHITINA

Wilson and Hedlund, 1964

Type species.-Calpichitina scabiosa Wilson and Hedlund,

1964. Holotype

in Wilson and Hedlund,

1964, p. 164, pl. 1, fig.

1, lower Sylvan Shale, south of Davis, Murray County,

Oklahoma,

early Ashgill, OPC 235-113-1, collections of the

University

of Oklahoma,

Norman.

Diagnosis.-Desmochitinidae with a glabrous lenticular

chamber.

Occurrence.-Ordovician-Lower

Devonian.

Discussion.-Calpichitina has been selected despite the fact

that

Wilson and Dolly (1964) considered it as a junior

synonym

of Hoegisphaera.

The latter,

however,

is here restricted

to spe-

cies with a subspherical

chamber

(see discussion below). The

present

definition

includes

the two subgenera

Calpichitina

(Cal-

pichitina) and Calpichitina (Densichitina), erected by Paris

(1981, p.127 and 131), but no longer maintained.

Genus DESMOCHITINA

Eisenack, 1931

Type species.-Desmochitina nodosa Eisenack, 1931. Lost

holotype

in Eisenack,

1931,

p. 92, pl. 3, fig. 1, erratic Ordovician

calcareous

sandy

siltstone;

proposed

neotype:

Desmochitina

no-

dosa in Laufeld,

1967, p. 330-332, fig. 26 from

the Keila Stage

(Caradoc), Fjaka section, Dalarna,

Sweden, collections of the

Institute

of Palaeontology

of the University

of Lund, Sweden.

Diagnosis.-Desmochitinidae with an ovoid, glabrous

cham-

ber.

Occurrence.-Lower Ordovician-Lower

Devonian.

Discussion.-The present

definition

includes

the two subgen-

era Desmochitina (Desmochitina) and Desmochitina (Pseudo-

desmochitina),

erected

by Paris (1981, p. 116-117), but no lon-

ger maintained

as the presence

of a mucron

in the Desmochitin-

idae is not regarded here as a generic character.

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PARIS ET AL -REVISED CHITINOZOAN CLASSIFICATION

Genus HOEGISPHAERA

Staplin, 1961

emend. Paris,

Grahn, Nestor,

and Lakova

herein.

Type species.-Hoegisphaera glabra Staplin,

1961. Holotype

in Staplin, 1961, p. 419-420, pl. 50, fig. 5, Socony Vegreville

no. 1, Duvemay Member,

Woodbend

Formation,

cuttings

from

1,067-1,097 m (3,500-3,600 ft), Late Devonian (Frasnian),

Al-

berta, Canada;

collections of Imperial

Oil Limited,

Calgary,

Al-

berta,

Canada.

Diagnosis.-Desmochitinidae with a spherical, glabrous

chamber.

Occurrence.-Upper Devonian.

Discussion.-The genus is restricted here to forms

with a sub-

spherical

chamber.

Species with a lenticular chamber

are trans-

ferred into Calpichitina.

The emendations

proposed by Urban

(1972) and by Legault (1973b), based on the occurrence

of a

membranous

matlike structure,

are not adopted

as the primary

or secondary

origin of such a structure

is not yet demonstrated.

Genus OLLACHITINA

Poumot, 1968

Type

species.-Ollachitina ingens

Poumot,

1968. Holotype

Poumot, 1968, p. 47-48, pl. 1, fig. 1, Gs-2 borehole,

core sample

from 3,451.50 m, El Gassi, northern

Sahara,

Algeria, unknown

formation,

Tremadoc,

collections of the Service Palynoplancto-

logique de la SNPA-Elf,

France.

Diagnosis.-Desmochitinidae with a glabrous, cylindrical

chamber.

Occurrence.-Lower Ordovician.

Subfamily MARGACHITININAE

Paris, 1981

Genus LINOCHITINA

Eisenack, 1968

restrict.

Paris, 1981

Type species.-Desmochitina erratica Eisenack, 1931. Lost

holotype

in Eisenack, 1931, p. 92, pl. 3, fig. 6, erratic

graptolitic

rock of early Ludlow age ("Graptolithengestein");

neotype in

Eisenack, 1962, p. 307, pl. 17, fig. 11, erratic

graptolitic

rock,

Wenlock to early Ludlow,

collections of the Geologisch-Palaon-

tologischen

Institute

der Universitat,

Ttibingen, Germany.

Diagnosis.-Desmochitinidae with a claviform to cylindrical

chamber and a hollow tubular

copula.

Occurrence.-Middle Ordovician-Middle

Devonian.

Discussion.-As expressed by Paris (1981, p. 148), forms

bearing

a carina

are excluded from this genus.

Genus MARGACHITINA

Eisenack, 1968

Type species.-Desmochitina margaritana

Eisenack, 1937.

Lost holotype in Eisenack, 1937, p. 221, pl. 15, fig. 9, erratic

bluish-gray marly limestones of early Silurian

age; neotype in

Eisenack, 1962, p. 306, pl. 17, fig. 13, erratic Silurian

graptolitic

rocks, collections of the Geologisch-Palaontologischen

Institute

der Universitat,

Tiibingen, Germany. Representative

specimens

in Laufeld, 1974, fig. 62.

Diagnosis.-Desmochitinidae with a lenticular to spherical,

glabrous

chamber

and a solid peduncle linking the apex to the

operculum

of the preceding

vesicle.

Occurrence.-Silurian-Lower Devonian.

Discussion.-Collarette is absent.

Genus URNOCHITINA

Paris, 1981

Type species.

-Desmochitina urna Eisenack, 1934. Lost ho-

lotype, in Eisenack, 1934, p. 69-70, pl. 5, fig. 7, late Silurian

(Pridoli)

limestones from Karlstejn,

Bohemia, Czech Republic;

proposed neotype: Desmochitina urna in Paris, Laufeld and

Chlupac,

1981, p. 15-16, pl. 1, fig. 1, bed 29, late Pridoli

lime-

stones from Karlstejn,

Bohemia,

Czech Republic,

IGR 51365(0

35), collections of the Institut de Geologie de l'Universite de

Rennes, France.

Diagnosis.-Desmochitinidae with an ovoid, glabrous

cham-

ber, and short tubular

copula.

Occurrence.-Silurian-Lower Devonian.

Discussion.-Granules may be present on the wall.

Subfamily PTEROCHITININAE

Paris, 1981

Genus ARMORICOCHITINA

Paris, 1981

Type species.-Linochitina? ceneratiensis Paris, 1976. Holo-

type in Paris, 1976, p. 107, pl. 23, fig. 1, Saint-Cenere

section,

upper part of the Saint-Cenere

Formation,

Pragian, Western

France,

IGR 50160 (N 48/4), collections of the Institut de Geo-

logie de l'Universite

de Rennes,

France.

Diagnosis.-Desmochitinidae with an ovoid chamber and a

membranous

carina

extending

below the margin.

Occurrence.-Middle Ordovician-Lower Devonian.

Discussion.-Granules may be present on the wall.

Genus CINGULOCHITINA

Paris, 1981

Type species.-Desmochitina cingulata Eisenack, 1937. Lost

holotype in Eisenack, 1937, p. 220, pl. 15, fig. 6 from erratic

graptolitic

shale ("Graptolithengestein");

neotype: Linochitina

cingulata, in Eisenack, 1968, p. 170-171, pl. 29, fig. 29, from

erratic

graptolitic

shale, Ludlow;

collections of the Geologisch-

Palaontologischen

Institute der

Universitat,

Tiibingen, Germany.

Representative specimens from outcrops

in Laufeld, 1974, fig.

37 B and D, Valbyte 1, Slite Marls, Sheinwoodian, Wenlock,

Gotland,

Sweden.

Diagnosis.-Desmochitinidae with a thin-walled,

conical to

ovoid glabrous

chamber

bearing

a complete

membranous carina

on the margin;

a short tubular

copula is present.

Occurrence.-Silurian-Lower Devonian.

Genus PSEUDOCLATHROCHITINA

Cramer,

1966

emend. Priewalder,

1997

Type species.-Clathrochitina carmenchui Cramer, 1964. Ho-

lotype in Cramer, 1964, p. 346, pl. 24, fig. 18, La Vid de Gordon

section, upper San Pedro Formation, Pridoli, north-western

Spain; neotype: Pseudoclathrochitina carmenchui in Priewalder,

1997, p. 78-81, pl. 1, figs. 2, 6, pl. 5, fig. 8, slide 1997/1/2 (L.

39.3); collections of the Geological Survey of Austria,

Vienna.

Diagnosis.-Conical Desmochitinidae with a reticulum ex-

tending

in a perforated

carina.

Occurrence.-Silurian.

Discussion.-The emendation

proposed by Priewalder

(1997,

p. 78) is accepted. However, we consider the folding of the

meshwork around the margin

as a structure

equivalent

to a ca-

rina.

Genus PTEROCHITINA

Eisenack, 1955a

Type species.-Bion perivelatum Eisenack, 1937. Lost holo-

type in Eisenack, 1937, p. 229-230, pl. 16, fig. 4, erratic

Bey-

richia limestones ("Beyrichia-kalk");

neotype in Eisenack,

1955a, p. 177, pl. 3, fig. 10, erratic

Beyrichia limestones

from

the Baltic bottom?, Pridoli;

collections of the Senckenberg

Mu-

seum, Frankfurt am Main, Germany.

Diagnosis.-Desmochitinidae with a lenticular to spherical,

glabrous

chamber with a membranous

carina.

Occurrence.-Middle Ordovician-Lower Devonian.

Subfamily CUTICHITININAE

Achab, Asselin and Soufiane, 1993

Genus CUTICHITINA

Achab, Asselin and Soufiane, 1993

Type species.-Cutichitina legrandi Achab, Asselin and Sou-

fiane, 1993. Holotype in Achab et al., 1993, p. 7, pl. 1, fig. 9,

QD-1 borehole, core sample from 3,361 m, upper part of the

Ouargla

Sandstone

Formation, Arenig, Central

Sahara, Algeria,

565

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All use subject to JSTOR Terms and Conditions

JOURNAL OF PALEONTOLOGY,

V. 73, NO. 4, 1999

GSC 103 969 (J.55.3), collections of the Geological Survey of

Canada, Ottawa, Ontario,

Canada.

Diagnosis.-Desmochitinidae with an ovoid chamber envel-

oped by a membranous sleeve.

Occurrence. -Ordovician.

Subfamily EISENACKITININAE

Paris, 1981

Genus

EISENACKITINA

Jansonius,

1964

restrict.

Paris, 1981

Type species.-Eisenackitina castor Jansonius, 1964. Holo-

type in Jansonius, 1964, p. 912-913, pl. 2, fig. 16, Imperial

Cartridge

borehole, core sample from 253 m (758 ft.), Hume

Formation,

early Givetian,

northern

Canada,

collections of Im-

perial

Oil Limited,

Calgary,

Alberta,

Canada.

Emended

diagnosis.-Desmochitinidae with an ovoid cham-

ber and a randomly

distributed,

spiny ornamentation.

Occurrence.-Middle Ordovician-Middle

Devonian.

Discussion.-In agreement

with Paris

(1981, p. 155), smooth,

ovoid forms are transferred

into Desmochitina and smooth,

con-

ical ones into Bursachitina.

Genus KALOCHITINA

Jansonius, 1964

Type species.-Kalochitina multispinata Jansonius, 1964. Ho-

lotype in Jansonius, 1964, p. 909-910, pl. 2, fig. 21, Imperial-

Calvan Anderson 9-6 borehole, cuttings from 736-737 m

(2,420-2,425 ft), Anderson

Township,

Essex County,

Ontario,

Canada

Maeford-Dundas

Formation,

Cincinnatian

(late

Caradoc-

Ashgill), collections of Imperial

Oil Limited,

Calgary,

Alberta,

Canada.

Diagnosis.-Desmochitinidae with a conical chamber and

random

spines.

Occurrence.-Upper Ordovician.

Genus ORDOCHITINA

Achab, Asselin and Soufiane,

1993

Type species.-Ordochitina tadlaiensis Achab, Asselin and

Soufiane,

1993. Holotype

in Achab et al., 1993, p. 6, pl. 1, fig.

1, Bj-103 borehole,

cuttings sample

from 849 m, unnamed

for-

mation,

early Caradoc,

Tadla

Basin, Morocco,

GSC 103 965 (P

27.2), collections of the Geological Survey of Canada, Ottawa,

Ontario,

Canada.

Diagnosis.-Desmochitinidae with a conical chamber

covered

by crests

(vertical

rows of spiny or membranous

ornamentation).

Occurrence.-Middle Ordovician-Upper

Ordovician.

Genus VINNALOCHITINA

Sutherland,

1994

Type species.-Vinnalochitina granosa Sutherland, 1994. Ho-

lotype in Sutherland, 1994, p. 36-37, pl. 1, fig. 7, Ludlow

area,

Lower Leintwardine

Formation,

Ludfordian,

Shropshire,

Eng-

land,

MPK

9847, collections

of British

Geological

Survey,

Key-

worth,

England.

Diagnosis.-Desmochitinidae with a hemispherical

chamber

and randomly

distributed

spines.

Occurrence.-Silurian.

Subfamily

ORBICHITININAE

Achab, Asselin and Soufiane,

1993

Genus ARMIGUTTA

Schallreuter,

1981

Type species.-Armigutta hillmeri Schallreuter, 1981. Holo-

type in Schallreuter,

1981, p. 109, pl. 7, fig. 1, erratic

Sularp

shale, Keila Stage (Caradoc),

Sweden, collections of Geolo-

gisch-Palaontologisches

Institute

der Universitat

Hamburg,

Ger-

many.

Diagnosis.-Desmochitinidae with an ovoid chamber

and a

crown of processes

on the margin.

Occurrence.-Upper Ordovician.

Discussion.-This genus is based

on a single specimen,

which

may be a teratologic

specimen,

from anerratic

rock sample.

Genus ORBICHITINA

Achab, Asselin and Soufiane,

1993

Type species.-Orbichitina vulpina Achab, Asselin and Sou-

fiane, 1993. Holotype in Achab et al., 1993, p. 7, pl. 1, fig. 5,

Riviere-au-Renard,

Gaspe Peninsula, Quebec, Canada, lower

part of the Rosebush Cove Member of the Indian Point For-

mation, Pridoli,

GSC 103967 (E 44.3), collections of the Geo-

logical Survey of Canada,

Ottawa, Ontario,

Canada.

Diagnosis.-Desmochitinidae with a conical chamber

and a

crown of processes.

Occurrence.-Silurian (Pridoli).

Genus SALOPOCHITINA

Swire, 1990

emend Paris, Grahn, Nestor,

and Lakova

Type species.-Conochitina? monterrosae Cramer, 1969. Ho-

lotype: Salopochitina bella Swire, 1990 (=S. monterrosae), p.

109-110, pl. 2, fig.3, Lover Hill Farm

borehole,

Buildwas

For-

mation,

Sheinwoodian,

Shropshire,

England,

MPK

5913, collec-

tions of the British

Geological Survey,

Keyworth,

England.

Diagnosis.-Desmochitinidae with a conical to ovoid cham-

ber,

and sheathing processes.

Occurrence.-Silurian (Wenlock-Ludlow).

Discussion.-The chamber surface may be granulous

and,

when damaged,

the remaining processes may simulate a laci-

niated carina. The original

diagnosis

of the genus includes

mis-

interpretations

(e.g., central

process);

in addition we consider S.

bella Swire, 1990 to be a junior synonym of S. monterrosae

(Cramer,

1969).

ACKNOWLEDGMENTS

We are

particularly

grateful

to T. Winchester-Seeto,

and

to the

reviewers, M. A. Miller and S. J. E. Sutherland,

for valuable

suggestions

and for a careful

reading

of the manuscript. Many

colleagues from the Chitinozoan Subcommission

of the CIMP

(Commission

Internationale

de Microflore du Paleozoique)

made

helpful comments that improved the final version the manu-

script.

We also thank

the different museums that answered

our

requests

concerning

the repository places of type material.

This is a contribution

to the Chitinozoa Clade

Group

of IGCP

Project

number

410.

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ACCEPTED

18 FEBRUARY

1999

APPENDIX:

LIST OF THE REJECTED GENERA

Acmochitina Tsegelnyuk, 1982. Type species: Acmochitina corollata

Tsegelnyuk, 1982. Junior synonym of Ancyrochitina Eisenack,

1955a.

Agathochitina Tsegelnyuk, 1982. Type species: Ancyrochitina primitiva

Eisenack, 1955a. Junior synonym of Ancyrochitina Eisenack, 1955a.

Aleurochitina Locquin, 1976. Type-species: Desmochitina erinacea Ei-

senack, 1931. Nomen nudum.

Amphorachitina Poumot, 1968. Type species: Amphorachitina conifun-

dus Poumot, 1968. Junior synonym of Lagenochitina Eisenack, 1931.

568

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PARIS ET AL.-REVISED CHITINOZOAN CLASSIFICATION

Aqualichitina

Locquin,

1976.

Type species:

Lagenochitina

ovoidea

Tau-

gourdeau

and de Jekhowsky,

1960. Nomen nudum.

Ampullachitina

Collinson and Schwalb, 1955. Type species: Ampul-

lachitina laguncula

Collinson and Schwalb, 1955. Remarks:

Ampul-

lachitina

laguncula

Collinson

and

Schwalb

was published

on 16 May

1955. It is therefore

a senior synonym of Ancyrochitina

Eisenack,

1955a published

on 5 June 1955. However,

despite the fact that

it is

not a nomen oblitum,

Ampulachitina

has not been used since 1955,

thus for stability

of nomenclature,

it is suggested

to maintain

Ancy-

rochitina because Collinson

himself adopted

this genus (see Collin-

son and Scott, 1958).

Ascochitina Tsegelnyuk, 1982. Type species: Ascochitina seccata Tse-

gelnyuk, 1982. Junior synonym of Angochitina Eisenack, 1931,

emend. Eisenack,

1968.

Baculochitina Locquin, 1976. Type species: Cyathochitina cylindrica

Taugourdeau

and de Jekhowsky,

1960. Nomen nudum.

Biconigutta Schallreuter, 1981. Type species: Biconigutta catinus

Schallreuter,

1981. Considered

here as a junior

synonym

of Armigutta

Schallreuter,

1981. Remarks:

this genus is based on a single specimen

from an erratic

rock sample.

Calpichitina (Densichitina) Paris, 1981. Type species: Desmochitina

densa Eisenack, 1962. This subgenus,

sometimes

used at a generic

rank

(e.g., Grahn and Paris, 1992), is here included

within Calpichi-

tina emend.

Paris 1981.

Calychitina Tsegelnyuk, 1982. Type species: Desmochitina? urna Ei-

senack, 1934. Junior

synonym

of Urnochitina

Paris, 1981.

Catenachitina Jansonius, 1967. Type species: Desmochitina erratica Ei-

senack, 1931. Nomen nudum,

see Jansonius, 1967, p. 351.

Catenochitina Locquin, 1976. Type species: Desmochitina elegans Tau-

gourdeau

and de Jekhowsky,

1960. Nomen nudum.

Ceratochitina Tsegelnyuk, 1982. Type species: Ceratochitina cornuta

Tsegelnyuk,

1982. Junior

synonym

of Ancyrochitina

Eisenack,

1955a

Cingulochitina Locquin, 1976. Type species: Cyathochitina dispar Tau-

gourdeau

and de Jekhowsky,

1960. Nomen nudum.

Cladochitina Lange, 1967. Type species: Conochitina biconstricta

Lange, 1949. Junior

synonym

of Spinachitina

Schallreuter,

1963.

Clathrochitinella

Cramer,

1967. Type species: Clathrochitina

oblonga

Benoit and Taugourdeau,

1961. Invalid

taxon according

to the code

of Zoological Nomenclature

(no definition

given).

Combachitina

Locquin, 1976. Type species: Lagenochitina

dubia Tau-

gourdeau

and de Jekhowsky,

1960. Nomen nudum.

Coronochitina Eisenack, 1965. Type species: Coronochitina coronata

Eisenack, 1965. Junior

synonym

of Spinachitina

Schallreuter,

1963.

Cramerochitina

Locquin, 1976. Type species: Halochitina retracta Ei-

senack, 1968. Nomen nudum.

Cupulachitina Jansonius, 1967. Type species: Desmochitina elegans

Taugourdeau

and de Jekhowsky,

1960. Nomen nudum.

Cylindrochitina Schallreuter, 1963. Type species: Cylindrochitina gran-

ata Schallreuter,

1963. Junior synonym of Angochitina

Eisenack,

1931, restrict.,

1968.

Dasychitina Tsegelnyuk, 1982. Type species: Dasychitina implexa Tse-

gelnyuk, 1982. Junior

synonym

of Ancyrochitina

Eisenack,

1955a.

Deflandrochitina Locquin, 1976. Type species: Angochitina milanensis

Collinson and Scott, 1958. Nomen nudum.

Desmochitina (Pseudodesmochitina) Paris, 1981. Type species: Des-

mochitina? cocca Eisenack, 1931. This subgenus,

sometimes used at

generic rank (e.g., Schallreuter,

1983), is here included within Des-

mochitina

Eisenack, 1931, emend.

Paris, 1981.

Diabolochitina

Locquin, 1976. Type species: Conochitina

symmetrica

Taugourdeau

and de Jekhowsky,

1960. Nomen nudum.

Discochitina Tsegelnyuk, 1982. Type species: Discochitina discoides

Tsegelnyuk, 1982. Junior synonym of Ancyrochitina Eisenack,

1955a.

Earlachitina Collinson and Scott, 1958. Type species: Earlachitina la-

tipes Collinson and Scott, 1958. Junior synonym of Ancyrochitina

Eisenack, 1955a.

Edouardochitina Locquin, 1976. Type species: Angochitina communis

Jenkins,

1967. Nomen nudum.

Erinaceochitina

Locquin,

1976. Type species:

Sphaerochitina

collinsoni

Dunn, 1959. Nomen nudum.

Eurychitina

Tsegelnyuk,

1982. Type species:

Bursachitina

oviformis

Ei-

senack, 1972. Junior synonym of Bursachitina Taugourdeau, 1966.

Flascachitina

Jansonius,

1967. Type species:

Angochitina

fiasca Collin-

son and

Schwalb,

1955. Nomen nudum

(see Jansonius, 1967, p. 351).

Fustichitina

Achab, 1980. Type species: Fustichitina ventriosa

Achab,

1980. Junior

synonym of Conochitina

Eisenack, 1931, restrict.

Ei-

senack, 1955b, 1965 and restrict.

Paris, 1981.

Giraffachitina

Locquin, 1985. Type species: Giraffachitina

poignantii

Locquin, 1985. We exclude this taxon from the chitinozoans.

Gotlandochitina

Laufeld,

1974. Type species: Gotlandochitina

martins-

soni Laufeld,

1974. Junior

synonym

of Ramochitina

Sommer and van

Boekel, 1964 emend.

Guizhouchitina

Lai, 1982. Type species: Guizhouchitina

lagena Lai,

1982. Junior

synonym

of Lagenochitina

Eisenack,

1931 if the vesicle

is glabrous.

Remarks: the "reticulate"

pattern

of the holotype is an

artifact

related to pyrite

crystal casts.

Halochitina

Eisenack,

1968. Type species:

Pterochitina

retracta

Eisen-

ack, 1955b. Junior

synonym

of Pterochitina

Eisenack,

1955a.

Haplochitina

Grignani

and Mantovani,

1964. Type species: Haplochi-

tina omdoulensis

Grignani

and Mantovani,

1964. Junior

synonym

Sphaerochitina

Eisenack, 1955a.

Helicochitina

Locquin, 1976. Type species:

Helicochitina

viticula Loc-

quin, 1976. Nomen nudum.

Iberichitina

Jansonius,

1967. Type species: Clathrochitina carmenchui

Cramer,

1964. Nomen nudum.

Idiochitina

Tsegelnyuk,

1982. Type species: Idiochitina

platycera

Tse-

gelnyuk, 1982. Junior

synonym

of Ancyrochitina

Eisenack, 1955a.

Illichitina Collinson and Schwalb, 1955. Type species: Illichitina cro-

talum Collinson and Schwalb, 1955. Remarks:

the authors of this

genus later considered it to be a synonym

of Cyathochitina

Eisenack,

1955b (see Taugourdeau

et al., 1967, p. 62). Normally

Illichitina has

the anteriority

(16 May 1955, instead of 12 December 1955 for

Cyathochitina)

but for stability of the taxonomy and because the

definition was too broad,

we follow the decision of CIMP

(see Tau-

gourdeau

et al., 1967, p. 62) and do not retain Illichitina.

Jansoniuchitina

Locquin, 1976. Type species: Kalochitina cf. inflata

(Taugourdeau,

1961) in Jansonius,

1964, pl. 2, fig. 23. Nomen nu-

dum.

Jenkinochitina

Paris, 1981. Type species: Conochitina oelandica Eisen-

ack, 1955b. Junior

synonym

of Euconochitina

Taugourdeau,

1966.

Labrochitina

Locquin, 1976. Type species: Conochitina

elegans Eisen-

ack, 1931. Nomen nudum.

Lachkarichitina

Locquin, 1976. Type species: Cyathochitina

elongata

Bouche, 1965. Nomen nudum.

Lambdachitina

Lakova, 1986. Type species: Lambdachitina

coronata

Lakova, 1986. Junior

synonym of Angochitina

Eisenack, 1931 re-

strict.

Eisenack,

1968.

Leiochitina

Locquin, 1976. Type species: Cyathochitina

elenitae Cra-

mer, 1964. Nomen nudum.

Leiochitina Tsegelnyuk, 1982. Type species: Lagenochitina

elegans

Beju and Danet, 1962. Junior

synonym of Lagenochitina

Eisenack,

1931.

Ligulachitina

Locquin,

1976. Type species:

Rhabdochitina

virgata

Tau-

gourdeau,

1961. Nomen nudum.

Lissochitina

Tsegelnyuk,

1982. Type species: Sphaerochitina

resupina

(Dicevichius, 1971). Junior synonym of Sphaerochitina

Eisenack,

1955a

Macrostomachitina

Taugourdeau,

1965. Type species: Lagenochitina

macrostoma

Taugourdeau

and de Jekhowsky,

1960. Nomen nudum;

see Jansonius

(1967, p. 352).

Mirachitina

Eisenack,

1931. Type species:

Mirachitina

quadrupedis

Ei-

senack, 1931. No longer included

in the chitinozoans.

Monicachitina

Locquin, 1976. Type species: Cyathochitina

striata Ei-

senack, 1937. Nomen nudum.

Monilichitina Locquin, 1976. Type species: Desmochitina sommeri

Lange, 1952. Nomen nudum.

Mucrochitina Locquin, 1976. Type species: Lagenochitina esthonica

Eisenack, 1955b. Nomen nudum.

Mycetochitina Locquin, 1976. Type species: Mycetochitina hypha Loc-

quin, 1976. Nomen nudum.

Nanochitina

Nestor,

1994. Type

species

Nanochitina nana

Nestor,

1994.

Regarded

as a junior synonym

of Bursachitina

Taugourdeau,

1966.

Nematochitina Locquin, 1976. Type species: Ancyrochitina longicornis

Taugourdeau

and Jekhowsky, 1960. Nomen nudum.

569

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JOURNAL OF PALEONTOLOGY,

V. 73, NO. 4, 1999

Oochitina Tsegelnyuk, 1982. Type species: Oochitina

fugax Tsegel-

nyuk, 1982. Junior

synonym

of Ancyrochitina

Eisenack, 1955a.

Orochitina

Tsegelnyuk,

1982. Type species: Orochitina

inflata

Tsegel-

nyuk, 1982. Junior

synonym

of Angochitina

Eisenack, 1931 restrict

1968.

Pallachitina Costa, 1970. Type species: Pallachitina wilhelmi

Costa,

1970. Junior

synonym

of Bursachitina

Taugourdeau,

1966.

Palenchitina

Schweineberg,

1987. Type species: Palenchitina

pisuer-

gensis Schweineberg,

1987. Junior

synonym

of Ancyrochitina

Eisen-

ack, 1955a.

Parachitina

Eisenack, 1937. Type species: Parachitina

curvata Eisen-

ack, 1937. Incertae sedis (see Jansonius, 1967, 1970). No longer

in-

cluded in the chitinozoans.

Parvichitina

Locquin, 1976. Type species: Conochitina

vasculiformis

Bouch6, 1965. Nomen nudum.

Phiolachitina

Montenari and Maass, 1996. Type species:

Phiolachitina

silvanegratica

Montenari and Maass, 1996. Not included

in the chi-

tinozoans.

Poteriochitina

Legault,

1973a.

Type species:

Poteriochitina

briarca Le-

gault, 1973a.

Junior

synonym

of Eisenackitina

Jansonius,

1964.

Poumochitina

Locquin,

1976. Type species:

Ancyrochitina

multiradiata

Eisenack,

1959. Nomen nudum.

Retrochitina

Locquin, 1976. Type species: Halochitina

retracta Eisen-

ack, 1955b. Nomen nudum.

Rhizochitina

Tsegelnyuk,

1982. Type

species:

Rhizochitina

laufeldi

Tse-

gelnyuk, 1982. Junior

synonym

of Ancyrochitina

Eisenack,

1955a.

Sclerochitina

Tsegelnyuk,

1982. Type species: Conochitina

intermedia

Eisenack,

1955a. Junior

synonym

of Belonechitina

Jansonius,

1964.

Solenochitina

Tsegelnyuk,

1982. Type species: Solenochitina

fistulata

Tsegelnyuk,

1982. Junior

synonym of Conochitina

Eisenack, 1931,

emend.

Paris, 1981.

Spathachitina

Costa, 1970. Type species: Spathachitina

cruzi Costa,

1970. Junior

synonym

of Conochitina

Eisenack,

1931, emend.

Paris,

1981

Steneyochitina

Zaslavskaya,

1980. Type species:

Steneyochitina

ovatoe-

longata Zaslavkaya,

1980. Junior

synonym of Spinachitina

Schall-

reuter,

1963.

Stephanochitina Grignani

and

Mantovani,

1964. Type species:

Stephan-

ochitina africana Grignani

and Mantovani,

1964. Probably

a junior

synonym of Angochitina

Eisenack, 1931, but the diagnoses and il-

lustration

of the type material

do not allow a definite statement.

Striatolagenochitina

Schallreuter,

1981. Type species: Striatolageno-

chitina clava Schallreuter,

1981. Junior

synonym of Lagenochitina

Eisenack, 1931.

Subulochitina

Locquin, 1976. Type species: Acanthochitina secunda

Schallreuter,

1963. Nomen nudum.

Taugourdochitina

Locquin,

1976. Type species: Conochitina micracan-

tha Eisenack,

1931. Nomen nudum.

Togachitina

Wood, 1994. Type species: Togachitina

eamesi Wood,

1994. Junior

synonym

of Pellichitina

Achab,

Asselin, and Soufiane,

1993

Trochochitina

Miller, 1976. Type species Trochochitina radiata Miller

1976. Nomen nudum.

Urnichitina

Locquin,

1976. Type species:

Desmochitina rhenana Eisen-

ack, 1939. Nomen nudum.

Virgilochitina

Tasch and

Hutter,

1978. Type species:

Virgilochitina

kan-

sasensis Tasch and Hutter,

1978. Junior

synonym of Lagenochitina

Eisenack,

1931.

Vitreachitina

Nestor, 1994. Type species: Sphaerochitina

vitrea Tau-

gourdeau, 1962. Regarded

as a junior synonym of Euconochitina

Taugourdeau,

1966 because the wall thickness

is not used as a dis-

criminate character

in the present

classification.

Discussion.-Locquin's document

(1976), including

new chitinozoan

genera and distributed to some chitinozoan workers

by this author,

not registered

in the official record for French

publications

in the Bib-

liotheque

Nationale de France.

Concerning

valid publications,

the In-

ternational

Code of Zoological

Nomenclature

(third

edition, 1985) stip-

ulates:

Article 8a(i) "it must be issued for the purpose

of providing

permanent

scientific record." We consider that this requirement

and

point (i) of Article 13a of the code are not fulfilled in Locquin's

doc-

ument

(1976). Therefore,

we consider the taxa described

in this docu-

ment as nomina

nuda,

like the taxa described

in unpublished

theses.

Four new genera,

Grahnichitina,

Nanochitina, Retiachitina,

and Ser-

icochitina,

have been erected

recently

by Geng et al. (1997). Because

they were published

after the submission

of our manuscript,

it was not

possible to include

them in our multivariate

analysis

and

therefore,

they

are not discussed

herein.

It should be noted that Nanochitina

Geng et

al., 1997 is an homonym

of Nanochitina

Nestor, 1994. However,

if the

synonymy

of Nanochitina

Nestor,

1994 with

Bursachitina

Taugourdeau,

1966 is accepted,

then the name Nanochitina can be used again as a

generic

name.

570

Ordovician chitinozoans of the Miaopo Formation at Zhenjin, Upper Yangtze Platform, South China

Article

Oct 2023

Peri-Gondwanan acritarchs and chitinozoans from the Lower-Middle Ordovician Lashkarak Formation in the Alborz Mountain Ranges, northern Iran: Regional stratigraphical significance and palaeogeographical implications

Article

May 2023

The Lashkarak Formation (Lower-Middle Ordovician) in the Gerdkuh locality, 10 km west of Damghan city, northern Iran has been found to contain acritarchs and chitinozoans. This study aimed to understand these chitinozoan and acritarch successions as well brachiopods in this part of the Alborz Mountains, in a novel manner. Ninety-Seven surface samples from this succession were collected and analysed. Thirty samples yielded well-preserved palynomorph taxa such as acritarchs, chitinozoans, and scolecodonts, as well as graptolite remains. In total, 53 taxa were identified from acritarchs (38 species from 21 genera) and chitinozoans (15 species from 10 genera). Although scolecodonts and graptolite remains were also observed, they were not studied in detail. The palynological analyses revealed the presence of several diagnostic acritarchs in the Lashkarak Formation, including Vulcanisphaera simplex, Arbusculidium filamentosum, Coryphidium bohemicum, Dactylofusa velifera, Striatotheca mutua, Arkonia virgata, and Orthosphaeridium ternatum. These acritarchs allowed recognition of five acritarch assemblage zones. Similarly, seven chitinozoan biozones were recognised, including Eremochitina brevis, Desmochitina ornensis, Belonechitina henryi, Cyathochitina protocalix, Cyathochitina calix, Siphonochitina formosa, and Laufeldochitina clavata. These findings confirm the inclusion of the Alborz Mountains in the peri-Gondwana palaeoprovince during the Early-Middle Ordovician. The co-occurrence of the acritarch and chitinozoan taxa with previously identified brachiopods allowed for the establishment of a more detailed Early-Middle Ordovician biozonation, demonstrating their potential usefulness for global chronostratigraphy. Based on palynological and brachiopod assemblages, a shallow marine environment of inner shelf setting is suggested for the Early-Middle Ordovician at the Gerdkuh locality. Moreover, in this study, four new morphotype species were erected, consisting of one new chitinozoan (Cyathochitina gerdkuhensis sp. nov.) and three new acritarchs (Baltisphaeridium razii sp. nov., Navifusa alborzensis sp. nov., and Orthosphaeridium iranense sp. nov). However, Othosphaeridium cf ternatum. was left with open nomenclature.

Chitinozoan response to the ‘Kellwasser events’: population dynamics and morphological deformities across the Frasnian–Famennian mass extinction

Article

May 2024

Fossil (zoo)plankton dynamics during Devonian ocean‐anoxic and extinction events can shed light on the palaeoceanographic and geochemical processes that shaped the middle Palaeozoic biosphere. However, datasets on (Upper) Devonian marine palynology, illustrating such dynamics, remain underexplored. The type section of the Sweetland Creek Shale in Iowa (USA) offers a detailed conodont zonation for the upper Frasnian and across the Frasnian–Famennian boundary, records the Upper and Lower Kellwasser events and has pristine preservation of organic material, making this an ideal section to study the effects of this catastrophic event on chitinozoan zooplankton populations. A total of 3998 specimens were recovered, imaged and classified into 12 distinct species, 10 of which were previously unknown. This study demonstrates the unrealized potential of chitinozoans as a regional biostratigraphic tool in the Upper Devonian. The Lower Kellwasser Event is characterized by a drop in chitinozoan abundance and the run up to the Upper Kellwasser Event marks a period of rapid species turnover rates. Interestingly, every assemblage in this interval is nearly monospecific. Patterns of changing spine morphologies in Fungochitina pilosa , Ramochitina sp. A and Saharochitina sp. A are herein explored as potential ecophenotypic expressions. We identify Angochitina monstrosa as a new disaster species. The discovery of two teratological chitinozoans specimens, in combination with the presence of the disaster species Angochitina monstrosa and deformation in contemporaneous conodonts, supports our previous discovery that marine teratology is a feature of many Palaeozoic extinction events, possibly triggered by the injection of hydrothermal brines into the ocean.

The biostratigraphy and palaeobiogeography of Cambrian and Ordovician acritarchs and chitinozoa from the Simeh-Kuh, NW Damghan City, the Alborz Mountains, northern Iran

Article

Apr 2024

A new chitinozoan assemblage from the Middle Devonian Los Monos Formation (sub-Andean basin, southern Bolivia) and its biozonal implications for Western Gondwana

Article

Full-text available

Apr 2024
PLOS ONE

Chitinozoans recovered from one section of the Middle Devonian Los Monos Formation in the TCB X-1001-Tacobo borehole, sub-Andean basin of Bolivia, have been analysed. Eleven from the eighteen processed cutting samples yielded specimens that allowed taxo-nomic study. Eleven genera and thirty-five chitinozoan species were identified from the Los Monos Formation with four of them recorded for the first time in Western Gondwana. Ancyr-ochitina biconstricta, Ancyrochitina parisi, Angochitina galarzae and Ramochitina boliviensis are among the most relevant taxa restricted to Western Gondwana that support the affinity with this paleocontinent. One new species, Lagenochitina tacobensis sp. nov. is described, and Ramochitina candelariaensis sp. nov. (n. n.) is formally erected. The chitinozoan assemblage reinforces the late Eifelian-middle Givetian age previously proposed by organic-walled phytoplankton and miospores for this section of the TCB X-1001-Tacobo borehole. A new local chitinozoan biozonation based on the chitinozoan assemblages is proposed and a revision of the current chitinozoan biozonation for Western Gondwana and Bolivia is recommended.

Middle–Late Silurian and Early Devonian Chitinozoans from the Chacoparaná Basin, Salta Province, Argentina

Article

Apr 2024
Ameghiniana

The first chitinozoan assemblages from the middle–late Silurian and Early Devonian strata of the Copo Formation in the Rivadavia borehole, Salta province, Argentina, are described. The studied interval was considered deposited in an offshore shelf environment and composed of micaceous dark-gray shales with pyrrhotite intercalated with fine-grained quartzitic sandstones. Thirty-nine core samples were processed, and eleven yielded chitinozoan specimens that allowed taxonomic classification. Seven genera and thirteen species were identified; four were retained in open nomenclature, and the new species Cingulochitina chacoparanaense sp. nov. is erected. Three chitinozoan assemblages were recognized: CAI of a middle–late Silurian age, CAII of a late Silurian age, and CAIII of a late Lochkovian (Early Devonian) age. A new upper Lochkovian chitinozoan concurrent range biozone of Cingulochitina striata and Ancyrochitina asterigis is proposed for northwestern Argentina. The chitinozoan assemblages support Gondwanan affinities from the middle Silurian to Early Devonian of the Chacoparaná Basin.

几丁虫研究现状及展望 [Chitinozoan study: review and prospect]

Article

Nov 2023

几丁虫是古生代海洋中一类重要的微体生物化石, 迄今已有近百年的研究历史。作为一类有效的生物地层工具, 几丁虫在奥陶纪和志留纪生物地层研究中发挥着重要作用, 为早古生代油气-矿产资源勘探提供可靠的地层对比资料, 还为一些重大地质-环境-生物事件的全球对比提供可靠依据, 特别是那些缺乏笔石和牙形类的地层。然而, 随着现代古生物学的快速发展以及几丁虫资料的不断积累, 几丁虫研究目前正遭遇着瓶颈期, 主要体现在: (1)受制于有限的技术手段及尚未形成规范的研究标准, 不少早期建立的几丁虫分类单元存在着明显的问题, 如描述简单、展示标本过少、光学显微成像无法很好地揭示壳表的形态特征等, 使得后期相关属种的鉴定存在争议; (2)在全球古生物数据不断被数字化和可视化的进程中, 几丁虫相关工作进展迟缓。目前尚未能对全球的几丁虫数据进行有效汇总, 影响了几丁虫宏演化及生物地层学研究, 同时也使得几丁虫古生物地理学与古生态学这类薄弱研究环节一直未能形成突破; (3)几丁虫的生物学属性近来虽有进展, 但仍有争论, 亟待寻求新的证据及思路以解决这一问题。为了能有效地解决这些问题, 促进几丁虫学科的持续发展, 建立一个涵盖系统分类、鉴定特征、标本影像、定量数据、产地、层位、剖面及文献出处等多维度信息的几丁虫开源数据库正逢其时。相关从业人员均可对数据进行检索、录入、厘定、导出及分析研究, 切实增进几丁虫数据的可用性和便捷性。在进行数据库建设的同时, 运用一系列高新技术手段, 逐步对早前建立的信息不完备的、或有争议的几丁虫进行再研究, 完善其形态学特征, 对争议属种进行厘定。该研究不仅有利于推动基于大数据的几丁虫古生物学研究, 为数据驱动的基础研究新范式提供典型案例, 还将有效促进以几丁虫为代表的微体化石的学科发展, 最终提升我国在这一领域的国际学术影响力。

Ordovician chitinozoans and review on basin stratigraphy, biostratigraphy and paleobiogeography of northern Argentina along the Proto-Andean margin

Article

Aug 2023

Subchapter 3C - Chitinozoans [In: Gradstein et al., The Geologic Timescale 2020]

Chapter

Nov 2020

Anthony Butcher

Chitinozoans are Paleozoic marine organic-walled microfossils of unknown animals thought to be egg cases. The bottle-, flask-, or urn-shaped vesicles are important for Ordovician through Devonian biostratigraphy.

On future directions of Ordovician chitinozoan research

Article

Full-text available

Jan 2023
EST J EARTH SCI

Chitinozoan stratigraphy in the Ashgill and Llandovery

Article

Full-text available

Jan 1988

Yngve Grahn

There is little published information on chitinozoan faunas from sections with continuous sedimentation across the Ordovician-Silurian boundary. Most boundary sections from which chitinozoans have been described include a hiatus. To aid determination of the extent of any hiatus, the ranges of thirty-one diagnostic chitinozoan species from Ashgill and Llandovery strata are documented, with reference to the British standard graptolite zonation. The composition of the chitinozoan faunas at the Ordovician-Silurian boundary is discussed, and the influence of ecological factors is assessed. -Author

Les Chitinozoaires

Article

Full-text available