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A basal actinopterygian ichthyofauna from the Scottish Lower Coal Measures Formation:
Westphalian A (Bashkirian).
Francis M. Elliott
Scottish Universities Environmental Research Centre (SUERC), Rankine Avenue, Scottish
Enterprise Technology Park, East Kilbride G75 0QF, Scotland, UK.
Francis M. Elliott
Basal actinopterygians from the Scottish Lower Coal Measures Formation
1
ABSTRACT: Seven new species and one new genus of the family Haplolepidae
(Actinopterygii: Palaeonisciformes) are described from new material obtained from the
Drumgray coal shales, North Lanarkshire: Westphalian A (Bashkirian): Protohaplolepis
isabellae; Protohaplolepis limnades; Protohaplolepis traquairi; Parahaplolepis alexandrae;
Parahaplolepis elenae; Pyritocephalus youngii and Millerolepis eleionomae. The discovery
of these new taxa increases the number of haplolepid species found in Europe to 16, thus
producing a faunal count more than comparable to that of North America. This high
concentration of haplolepid remains in limnic deposits is also a strong indication that these
fish were not only adapted to a coastal paralic basin, but well-adapted to a freshwater
brackish environment. A comprehensive description of the skull roof morphology, including
a short description of some of the larger dermal bones, is given of seven new haplolepid
species obtained from the coal shale tips at Wester Bracco and Shotts in North Lanarkshire.
In consequence, a revised table of the stratigraphical distribution of the Haplolepidae in
Europe is provided. Furthermore, the new genus Millerolepis is assigned to the subfamily
Parahaplolepinae and the generic position of the problematic Haplolepis attheyi from
Newsham, Northumberland is discussed with the taxonomic position of Protohaplolepis
proposed.
KEY WORDS: Anthracite, carboniferous, Haplolepidae, Newsham, Palaeonisciformes,
Protohaplolepis, shale, stratigraphic.
2
1. Introduction
Haplolepids are small basal actinopterygian fishes of the Carboniferous period and common
in equatorial coal-forming swamp areas. The geographical distribution of these fishes
stretched from New Mexico in the west of North America to as far as the Czech Republic in
eastern Europe in areas which were positioned in equatorial regions during this period.
During the Upper Carboniferous, haplolepids ranged stratigraphically from the Namurian A
(Serpukhovian) at Loanhead in Scotland until the Stephanian B (late Kasimovian) in the
Blanzy-Montceau Basin of France.
Newberry (1856) proposed the new genus Mecolepis, including several species, for
several haplolepid fishes from the Carboniferous strata at Linton, Ohio. He noted that the
most noticeable diagnostic characters were the small size of these fish, the posterior position
of the dorsal fin and in particular the high lateral scales. Since then, several additional species
have been named solely on the diagnostic form and ornamentation of the skull roof. In 1857
Newberry realised that Mecolepis was preoccupied and proposed the new name Eurylepis,
and Newberry (1873) described several further species. However, Miller (1892) pointed out
that Eurylepis was also preoccupied and proposed the new genus Haplolepis, with Mecolepis
corrugata Newberry as the genotype, as it was the first to be described. Furthermore,
Newberry (1889) proposed that Eurylepis lineatus should be removed from the genus and
later it was placed in the genus Pyritocephalus Fritsch. However, it was not until Westoll
(1944) provided a thorough revision of the Haplolepidae that a better understanding of the
taxa and their relationships developed.
Recent studies of the Haplolepidae have increased the stratigraphical and
paleogeographical distributions of the family in general. Baird (1961) described two new
species of haplolepids from the Lower Pennsylvanian (Bashkirian) near Parrsboro, Nova
Scotia; the specimen material consisted entirely of an incomplete, macerated individual fish
which he designated Haplolepis cf. corrugata; and a partial skull which he compared with
Haplolepis aff. anglica from Newsham and later (1978) placed it in a new species,
Haplolepis (Parahaplolepis) canadensis. Stamberg (1978) with the aid of new material
revised the haplolepid Pyritocephalus sculptus Frisch from the Nýřany locality in the Plzeň
basin of the Czech Republic, and presented a more detailed description of the skull roof and
other dermal bones of the species.
Furthermore, on the basis of new faunal material obtained from Linton, Ohio, Lowney
(1980) revised the family Haplolepidae; the genus Microhaplolepis was erected to include
Haplolepis ovoidea (Newberry) and Mecolepis serratus Newberry; and Parahaplolepis was
raised from the subgeneric to the generic level to include Parahaplolepis tuberculata from
Linton. Later, Lowney (1983) described two new genera and species of haplolepids,
Protohaplolepis scotica and Blairolepis loanheadensis from the ironstones of Loanhead,
Midlothian, in which the only material available of Blairolepis loanheadensis was a single
skull roof. Also described was a new species, Parahaplolepis westolli from Newsham,
Northumberland which showed a close resemblance to Parahaplolepis tuberculata from
Linton. Two subfamilies were also recognised to reflect the distinct phylogeny within the
family, the Haplolepinae and the Parahaplolepinae; the Haplolepinae to include
Protohaplolepis, Haplolepis, and Microhaplolepis; and the Parahaplolepinae to include
Blairolepis, Parahaplolepis, and Pyritocephalus.
More recently, Huber (1992) described a new species of haplolepid, Pyritocephalus
lowneyae from the early Stephanian (Kasimovian) of central New Mexico. And Poplin
(1997) described a new species of haplolepid, Blanzyhaplolepis beckaryae (Late Kasimovian)
from Blanzy-Montceau basin, France; specimen material consisted of two small fish lacking
most parts of the head, dorsal, pectoral and pelvic fins; and despite the lack of skull roof
detail which is characteristic of the Haplolepidae, he warranted assignment of the specimens
3
to a new genus and species based on other detail which included the distinctive wide, fan-
shaped cleithrum and the characteristic structure of the fin rays.
To date, 25 species of haplolepids have been found; 13 in North America, three in
Canada, seven in Great Britain, and two in continental Europe.
The present study is aimed to give a detailed description of the skull roof morphology
of the new taxa, including an account of some of the larger dermal bones. And, using these
data, investigate phylogenic relationships which may exist between the Haplolepidae and
other closely related genera, and also within the Haplolepidae proper in order to investigate
previous hypotheses.
2. Materials and methods
2.1. Specimen preparation and study
Although the Lower Coal Measures of Scotland are rich in fish remains, no articulated
specimen of haplolepid has been collected so far. Unfortunately, complete coal measure
specimens are not as frequently found in the Lanarkshire area as they are in the Scottish
Midlothian location and in the North Staffordshire area of England. Nevertheless, a large
collection of dermal remains of at least seven different species of haplolepid have been
found; these include skull roofs, maxillae, dentaries, cleithra, clavicles, opercula, preopercula,
dermosphenotics, scales, including many of the smaller bones. Most specimens were found
well-preserved throughout the fossil beds and, in some cases, remains formed the bulk of the
faunal material.
The haplolepid material examined for this study was found in, or close to, anthracitic
shale beds of one to about ten millimetres thickness. Specimens were also obtained from a
dark carbonaceous material lying adjacent to the thin bands of anthracite and proximal to a
bed of compressed, minute bivalve molluscs of the family Aviculopectinidae. Most
specimens, however, were found in the thin bands of anthracite and in many cases much of
constituent bony material was replaced with anthracite; in this same band the remains of
juvenile fish are also to be found. Other haplolepid fossils were associated with a mass of
mixed fish remains in a fossil bed of about one millimetre thickness and of indeterminate
lateral extension. Other vertebrate material to be found in this fossil bed include the bones
and scales of small coelacanths, spines of the acanthodian Acanthodes wardi and various
elements of actinopterygians including the rhadinichthyids Rhadinichthys grossarti, R.
monensis, R. wardi, R. hancocki, the platysomid Platysomus parvulus, the eurynotiforms
Amphicentrum granulosum, and Mesolepis wardi, and several still unidentified species.
By virtue of the small size of the specimens, an Olympus BM620B stereomicroscope
with WFX10 eyepieces, with or without X2 objective lenses, were used extensively
throughout this study. In addition, a Swann-Morton scalpel with a No. 25 blade was essential
for this work, especially to aid in the separation of the finely laminated layers of material
containing the fossils. However, due to the high carbon content of the specimens, dilute
hydrochloric acid could not be used to prepare the fossils for study. As an alternative, a
solution of H2O2 (100% vol.) was used, and although slower in removing the matrix which
enveloped the specimens, was found to be very effective and safe. The hydrogen peroxide
solution was used on all specimens except those found in a black carbonaceous band as the
solution tended to lift and separate the different layers of bone; these specimens could only be
prepared mechanically with the Swann-Morton scalpel. Much of the bone material obtained
is well preserved and exhibiting fine morphological detail. In addition, the bone and scale
layers of ganoine, dentine-like cosmine and the laminate isopedine are found more or less
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intact. Although not necessary for this study, with care these layers could easily be separated
if a better view of the pit-lines and the skull roof sutures are required.
Photographic images of all specimens were produced using a Kodak Z740 digital
zoom camera with two X10 macro close-up lenses connected in tandem. Camera sensitivity
was set at ISO 80 with f-number = f/8 and exposure time = 1to1/4 seconds. Line drawings
were first produced by hand and then refined using Microsoft Paint or Paint.NET.
By using Westoll’s (1944) illustrations from his monograph on haplolepids as a guide,
and by taking a measurement of the distance from the anterior margin of the skull roof to its
posterior border, an estimation of the possible length of each fish was deduced. This
assumption is based on the fact that the estimated length of a typical fish could be calculated
from the ratio of the average skull roof measurement relative to its overall length.
Concerning the parietal–dermopterotic region of the skull roof in the genera Pyritocephalus
and Parahaplolepis (also including Millerolepis in this study), Westoll (1944) postulated that
the loss of the parietals of the skull roof had caused the dermopterotics to expand medially
until they met mid-line. It is also most unlikely that natural development resulted in the
fusion of the parietal and dermopterotic regions into a single unit, since this configuration
was present in some of the oldest known taxa. I have preferred to follow an alternative
interpretation, that of Baird (1978) in that the parietals had simply developed lappets to
compensate for the loss of the dermopterotics. Thus, the single bone formed will be named
the parietal throughout this study.
Other species of haplolepids (Table1) were used for a comparison. Also shown are the
geographical locations where these fossils were found.
2.2. Systematic palaeontology
Class Actinopterygii Woodward, 1891
Subclass Actinopteri E.D. Cope, 1871
Family Haplolepidae Westoll, 1944
Subfamily Haplolepinae Lowney, 1983
Genus Protohaplolepis, Lowney, 1983
Diagnosis. A haplolepid with a short, broad skull roof; dermopterotics and parietals
separate; posterolateral lappets absent; extrascapulars and posttemporals meeting at midline;
maxilla with a tall, triangular expansion and quadratojugal possibly present; ventral lateral
line absent.
Protohaplolepis isabellae, sp. nov.
(Figs 1, 8a, 9b(i))
Holotype. GLAHM 152369. Part and counterpart (Fig. 1b).
Paratype. GLAHM 152368. Part and counterpart (Fig. 1a).
Locality and horizon. Anthracitic bands in shale from the Drumgray coal, Ardenrigg No.6
Mine, Wester Bracco, North Lanarkshire [NS 8265 6566].
Etymology. The first Spanish queen regnant and a key character in the Reconquista, the
Spanish Inquisition.
Diagnosis. Skull roof in the form of an equilateral triangle; dermopterotics and
parietals separate, no posterolateral lappets; parietals small and square; posterior margin not
embayed; anterior margin of frontals tapered, lateral margin convex; pineal macula strongly
marked; transverse suture V-shaped; anterior pit-lines confined to the parietals; skull roof
ornamentation of flat ridges. Maxilla with tall, triangular postorbital expansion, notched area
5
at optic margin; suborbital process the same length as expansion; maxillary dentary with row
of small, close-set, conical and sharp teeth along the whole margin; ornamentation as skull
roof. Cleithrum ventral pit-line absent. Dentary deep, teeth identical to those of the maxilla;
ornamentation of longitudinal rugae and troughs; articular present.
Discussion. The skull roof outline resembles very closely that of Protohaplolepis
scotica from Loanhead but the anterior margin has no embayment for the reception of the
postrostral and there is no embayment at the posterior margin. The extrascapulars and
posttemporals do not meet midline. The frontals are slightly larger than the parietals and
more or less quadrilateral in form; they are longer than wide, and taper from about level with
the clearly marked pineal macula to their most anterior extremity; the pineal macula being
situated somewhat closer to the anterior margin than midpoint. The small parietals are almost
square and about half the length and width of the frontals. The dermopterotics are trapezoid
in form and separated laterally from the parietals. The anterior pit line and the middle pit line
are clearly visible and resemble those of Microhaplolepis from Linton, however, a posterior
pit line has not been observed on any specimens. The transverse suture separating the frontal
from the parietal and dermopterotic is V-shaped and not arched at the dermopterotic as in P.
scotica (compare Figs. 8a and 8i).
The ornamentation over most of the skull roof is a pattern of terraced areas of smooth,
flat, lustrous ridges separated by sharp grooves as in H. corrugata and P. scotica. This
ornamentation runs more or less parallel with the lateral and posterior margins, occasionally
forming a swirling pattern, especially near the posterior margin of the parietals. Anteriorly
and medially encircling the pineal macula, the ornamentation tends to small irregular-shaped
tubercles; these tubercules which may extend as far back as the posterior margin of the
parietals (Figs. 1c,1d).
The most frequently found remains of haplolepids at Wester Bracco are of this small
fish, where several maxillae and dentaries have been found in slates containing skull roofs
and other material of this species.
The maxilla of Protohaplolepis isabellae (Fig. 9b(i)) has a tall, triangular postorbital
expansion, similar to that of H. corrugata from Linton and P. scotica from Loanhead. The
suborbital process is approximately the same length as the postorbital expansion, the width of
the process remaining more or less constant along its length except at the ramus where it is
clavate distally, The dentary margin of the maxilla has a row of small, close-set, conical and
sharp teeth located along the whole margin. Ornamentation is of flat ridges and sharp
grooves, a quadratojugal, however, has not been observed on any maxillae. Maxillae from
Wester Bracco have a small notched area at the optic margin of the postorbital expansion, a
characteristic which may possibly separate Wester Bracco haplolepids from Loanhead and
Linton material. The cleithrum is similar to (Fig. 9a(v)) in which the ornamentation is of
strong, flat ridges with the ventral pit line absent. The dentary (Fig. 10a(i)) is deep and armed
with teeth, which are identical to those of the maxilla, along the whole margin. The surface is
ornamented with strong longitudinal rugae and troughs, except in the area of the articular
where the ornamentation is of flat rugae.
Approximate total length of adult fish about 45mm.
Protohaplolepis limnades, sp. nov.
(Figs 2, 8c)
Holotype. GLAHM 152371 (Fig. 2a).
Locality and horizon. Anthracitic shale from the Drumgray coal, Ardenrigg No. 6 Mine,
Wester Bracco, North Lanarkshire [NS 8265 6566].
Etymology. In Greek mythology, the Limnades or Limnatides were a type of naiad who lived
in lakes.
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Diagnosis. Skull roof trapezoid in form; dermopterotics and parietals separate,
posterolateral lappets absent; parietals square slightly less than length of frontals; anterior
margin of frontal rounded, lateral margin convex; posterior margin of skull roof not embayed;
transverse suture V-shaped; anterior pit-lines confined to the parietals; pineal macula strongly
marked, located midpoint of frontals; skull roof ornamented with flat ridges.
Discussion. Complete skull roofs are frequently found of this relatively large
haplolepid. In outline the skull roof of P. limnades resembles that of P. scotica. In P.
limnades, however, the skull roof is much wider and the anterior margin has no embayment
for the reception of the postrostral. The broad anterior border of the frontals gives the
specimen a very robust, near quadrate appearance.
Frontals are bulky and more or less quadrilateral in form, the parietals are square-
shaped and about half the overall size of the frontals. The dermopterotics which are separated
laterally from the parietals are slightly larger and trapezoid in form. The pineal macula is
clearly seen in all specimens and located in the centre of the frontals. The posterior margin of
skull roof is rectilinear and not embayed, and the extrascapulars and posttemporals do not
meet midline. The anterior pit line and the middle pit line are clearly visible and resemble
those of Microhaplolepis, however, a posterior pit line has not been observed in any
specimens. The transverse suture separating the frontal from the parietal and dermopterotic is
V-shaped and similar to that found in P. scotica .
The ornamentation over the whole skull roof is a very strong combination of deep,
sharp trenches and flat, lustrous ridges. This pattern runs more or less parallel with the lateral
and posterior margins but tending to localised swirls anteriorly.
Approximate total length of fish about 68mm.
Protohaplolepis traquairi, sp. nov.
(Figs 3, 8g)
Holotype. GLAHM 152375 (Fig. 3a).
Locality and horizon. Shale from the Drumgray Coal, Calderhead No.3 Mine, Shotts, North
Lanarkshire [NS 8775 6139]. To date a single skull roof and a few dermal elements and
scales are the only haplolepid remains found at this site.
Etymology. In honour of the Scottish naturalist and palaeontologist, Ramsay Heatley
Traquair (1840-1912) for his contribution to palaeoichthyology.
Diagnosis. Skull roof shape of an isosceles trapezoid; dermopterotics and parietals
separate, posterolateral lappets absent; parietals square; anterior margin of frontals rounded
with two knurled areas, lateral margin rectilinear; posterior margin not embayed; transverse
suture sinusoidal; anterior pit-lines confined to parietals; pineal macula strongly marked,
located midpoint of frontals; skull roof ornament of flat ridges.
Discussion. In outline the skull roof of P. traquairi resembles that of Haplolepis
attheyi but is somewhat wider, the anterior margin more round than tapered. The frontals are
bulky and more or less quadrilateral in form. The parietals are almost square and a little more
than half the length and width of the frontals. The dermopterotics are separated laterally from
the parietals, they are trapezoid in form with two knurled areas along each anterolateral
margin. The posterior margin is not embayed but rectilinear, and the scapulars and
posttemporals do not meet midline. The pineal macula is very clearly defined as in P.
canadensis. The transverse suture which separates the frontal from the parietal and
dermopterotic and is sinusoidal in shape. The anterior pit line and the posterior pit line are
clearly visible and resemble those of H. attheyi, the middle pit line is present but is almost
obscured by the strong overlapping ornamentation of the skull roof.
The ornamentation over the whole skull roof is a combination of deep sharp trenches
and flat, lustrous ridges running in a more or less anteroposterior direction on the frontals
7
except where it encircles the pineal macula. These flat ridges also encircles two knurled areas
which are located along the anterior margin and two located along the anterolateral borders of
each dermopterotic. The posterior margin of the skull roof is, however, somewhat straight
along its whole length and the general trend in pattern of the ornamentation is to run parallel
with this margin across the parietals and dermopterotics. Approximate total length of fish
about 70 mm.
Subfamily Parahaplolepinae, Lowney, 1983
Genus Parahaplolepis, Westoll, 1944
Diagnosis. A haplolepid in which the dermopterotics and parietals are not separate;
the anterior pit line extends onto the frontal from the parietal; posterior margin of skull roof
deeply embayed for the reception of the extrascapulars and posttemporals, the latter two pairs
of bones meeting in midline; skull roof ornament of broad raised rugae or low tubercles;
maxilla (in the one species where it is known) with tall posterior expansion and a
quadratojugal present; ventral lateral line present.
Parahaplolepis alexandrae, sp. nov.
(Figs 4, 8b, 9b(ii), 10b(i))
Holotype. GLAHM 152370 (Fig. 4a).
Locality and horizon. Carbonaceous shale from the Drumgray coal, Ardenrigg No.6 Mine,
Wester Bracco, North Lanarkshire [NS 8265 6566].
Etymology. The species is named after Alexandra, a title or epithet given to the Greek
goddess Hera.
Diagnosis. Skull roof triangular in form; dermopterotics and parietals not separate;
posterolateral lappets present; anterior margin of frontals rounded, lateral margin convex;
posterior margin of skull roof deeply embayed; transverse suture sinusoid; anterior pit-line
crosses into frontal; pineal macula faint, located midpoint of frontals; skull roof ornamented
with large, round tubercles. Dermosphenotic tetrahedral in form, ornamented with round and
elongate tubercles. Maxilla with large, rounded posterior expansion; suborbital ramus longer
than posterior expansion; ornamentation of large tubercles; dentary margin with small, sharp
conical teeth occupying posterior two-thirds of the margin only.
Discussion. The skull roof is in the form of an equilateral triangle, its anterior margin
rounded and the posterior margin deeply embayed to receive the extrascapulars and
posttemporals which meet midline. In outline it resembles that of P. canadensis and P.
anglica with the rounded anterior margin. However, the outline of P. alexandrae is much
wider and in P. tuberculata and P. westolli the anterior margins are shouldered.
The frontals are somewhat triangular in form, their length being almost twice the width;
along the anterior margin they are rounded and the lateral margins are convex, similar to that
shown in P. canadensis. The pineal macula, which is faintly marked as in P. anglica and P.
tuberculata, is positioned midpoint of the frontals. The parietals are quadrilateral in shape
and approximately the same size as the frontals.
The sculpture of the skull roof is strongly developed and consists of rounded
tubercles on each of the frontals and transverse rows of merged tubercles on the parietals
similar to that in P. canadensis and P. tuberculata. The posterolateral lappets are angular at
their margins and ornamented with only a few tiny grooves and pores. Normally the positions
of the mid-sagittal suture, transverse suture and pit lines are not clearly discernible in this
species (Figs. 2a, 2b). This detail, however, is clearly shown in material which has been
subject to some form of erosion and which has resulted in the reduction or complete removal
the ganoine layer. Diagram (Fig. 8b) was produced from the study of this material which
8
indicates that the transverse suture is sinusoidal in form and passes diagonally forward and
outward from the mid-sagittal suture in a manner similar to that in P. canadensis. The
anterior pit line can be clearly seen to cross the transverse suture, the middle pit line is
present, however, a posterior pit line has not been observed in any specimens.
Other dermal remains found in the same piece of material as the skull roof of
Parahaplolepis alexandrae include a dermosphenotic (Fig. 10b(i)) which is large bone,
tetrahedral in form and ornamented with round and elongate tubercles. Several maxillae of
this species have also been found, the example in (Fig. 9b(ii)) is shown to be ornamented
with large tubercles, the suborbital ramus is almost two and a half times longer than the
rounded posterior expansion. The dentary margin has a row of small, sharp conical teeth
which are set a short distance apart and which occupy only the first two-thirds of the margin
with the remaining length edentulate. A quadratojugal has not been observed on any
specimens.
Approximate total length of fish about 63mm.
Parahaplolepis elenae, sp. nov.
(Figs 5, 8e)
Holotype. GLAHM 152373 (Fig. 5a).
The holotype is at present the only known specimen. Part and counterpart.
Locality and horizon. Fossil ostracod-rich shale from the Drumgray coal, Ardenrigg No.6
Mine, Wester Bracco, North Lanarkshire [NS 8265 6566].
Etymology. A Spanish variant of the Greek name Helena meaning “shining light” or “bright
one” referring to the lustrous nature of the skull ornamentation.
Diagnosis. Skull roof triangular in form; parietals without dermopterotics, posterior
lappets present; anterior margin of frontals rounded, lateral margin concave; posterior margin
of skull roof deeply embayed; transverse suture sinusoidal; anterior pit-line crosses into
frontal; pineal macula strongly marked, positioned midpoint of frontals; skull roof
ornamentation of rugae and tubercles.
Discussion. The general outline of the skull roof of Parahaplolepis elenae is in the
form of an isosceles triangle with the posterior margin slightly embayed to receive the
extrascapulars and posttemporals which do not meet midline. The long, narrow skull roof
resembles that of P. canadensis and P. anglica, with its rounded anterior margin and concave
lateral borders of the frontals, but differs from P. westolli which has a distinctly shouldered
anterior margin.
The length of the frontals are almost twice the width with the lateral margins concave
and similar to that found in P. canadensis; the clearly defined pineal macula is also similar to
that found in P. canadensis and is located midpoint of the frontals. The parietals are more or
less triangular in form and about two-thirds the size of the frontals. The transverse suture
passes forward and outward in a gentle curve from the mid-sagittal suture to about half its
distance, then abruptly altering direction at the point where the anterior pit line crosses into
the frontal from the parietal, to almost 90 degrees relative to the mid-sagittal suture. The
anterior pit line is clearly seen and crosses the transverse suture as previously mentioned; the
middle pit line is present but difficult to see, and a posterior pit line has not been observed.
The sculpture of the skull roof is very strongly developed, the direction of which is
remarkably similar to that of P. canadensis and consists of long rugae and rounded tubercles
on each of the frontals and long, less strongly marked rugae running more or less axially on
the parietals. On the frontals the ornamentation of is of strong, elongate tubercles running
anteroposteriorly and not transversely as in P. anglica. The posterolateral lappets are angular
at their margins and ornamented with broad, flat rugae.
Approximate total length of fish 63 mm.
9
Genus Pyritocephalus, Fritsch, 1895
Diagnosis. A haplolepid with paired skull roof fenestrations, mostly surrounded by
frontals, parietals, and dermosphenotics; dermopterotics not present and parietals meeting
midline; ornament of head bones of fairly regularly arranged terraced rugae; scales, smooth
except for a few linear grooves near the anterior margin, without denticulations on the
posterior border, peg-and-socket articulations probably absent; ventral lateral line present,
represented by grooves on cleithrum and scales of venter; pit-line grooves completely
developed.
Pyritocephalus youngii, sp. nov.
(Figs 6, 8f, 9a(iv))
Holotype. GLAHM 152374 (Fig. 6a). Part and counterpart.
Locality and horizon. Anthracitic shale in from the Drumgray coal, Ardenrigg No.6 Mine,
Wester Bracco, North Lanarkshire [NS 8265 6566].
Etymology. Named after the geologist John Young (1823-1900), in recognition of his
services to palaeontology by his researches into the Carboniferous fossils of the West of
Scotland.
Diagnosis. Skull roof approximates the shape of an isosceles triangle; anterior margin
of frontals with small indentation at the extremity, lateral margin slightly convex and tapering
towards the anterior margin; posterior margin deeply embayed; transverse suture not present;
pineal macula faintly marked, located close to anterior margin of frontals; orbital fenestrae
present; skull ornamentation of fine ridges. Dentary moderately deep; teeth large, conical,
slightly incurved; ornamentation of flat ridges, tubercles and longitudinal grooves. Cleithrum
small, almost square-shaped; anterior margin near straight; ventral pit line present;
ornamentation of flat ridges. Scales small; much taller than wide, without anterodorsal
process; ornamentation smooth.
Discussion. The frontals are very much larger and the parietals much smaller than
other Pyritocephalus species, however the pattern of ornamentation on the frontals is
remarkably similar to that found in the type species, Pyritocephalus sculptus Fritsch (1895)
from Nýřany. In Pyritocephalus youngii the frontals are large and expanded and tapering
from a point roughly level with the pineal macula to the anterior margin, anterior margin
slightly indented where it contacts the postrostral. Parietals reduced to narrow, curved
extensions bordering the posterior margins of the temporal fenestrae which are rounded as in
P. sculptus (compare Figs. 8(f) and 8(l)); posterior margin of parietals very deeply embayed
for the reception of the posttemporals; the extrascapulars are most likely very small paired
elements, each completely surrounded by the parietals and posttemporals, and, as a
consequence of their small size, the posttemporals only would meet in the middle line.
Supraorbital vacuities large and ovate with a smooth tympanic-like membrane as in P.
sculptus. Mid-sagittal suture visible, frontoparietal suture not apparent although
ornamentation has a natural break where suture line would be positioned. Middle pit lines
present but difficult to determine; anterior and posterior pit lines not observed.
Ornamentation of skull roof consists of long, fine ridges separated by deep troughs of roughly
the same width; ridges arranged in a concentric or semiconcentric pattern on frontals and in
region between fenestrations.
Other dermal remains found in the same piece of material as the skull roof of
Pyritocephalus youngii include a cleithrum a dentary, and some scales. The cleithrum is
small and almost square-shaped (Fig. 9a(iv)) compared with that of other haplolepids;
anterior margin almost straight and not curved where it connects with the clavicle;
10
ornamentation is of flat ridges running more or less parallel with ventral and posterior
borders; ventral pit line observed mid-way along ventral margin. The dentary is moderately
deep, ornamentation is of a strong, flat ridges separated by four or five longitudinal grooves,
the pattern breaking into broad, flat tubercles near the dentary border. Form of the dentary is
similar to Fig. 10a(ii) but teeth large, conical and slightly incurved forwards with each tooth
very close to the one next. Scales small; much taller than wide, without anterodorsal process;
ornamentation smooth with peg and socket articulation.
Approximate total length of fish about 40mm.
Genus Millerolepis gen. nov.
Diagnosis. A haplolepid with skull roof in the form of an isosceles triangle; parietals
without dermopterotics; parietals extending outwards and backwards; posterolateral lappets
absent; anterior margin of frontals tapered, lateral margin planate, posterior margin deeply
embayed; extrascapulars and posttemporals meeting at midline: transverse suture near
straight and oblique; anterior and posterior pit-lines absent; pineal macula faintly marked,
positioned close to anterior margin; longitudinal rugae on frontals; skull roof ornamented
with rugae and large tubercles.
Holotype. Millerolepis eleionomae, sp. nov.
Etymology. The genus is named after Hugh Miller (1802–1856) the self-taught Scottish
geologist and writer.
Millerolepis eleionomae, sp. nov.
(Figs 7, 8d)
Holotype. GLAHM 152372 (Fig. 7a).
The holotype is at present the only known specimen. Part and counterpart
Locality and horizon. Fossil ostracod-rich shale from the Drumgray coal, Ardenrigg No.6
Mine, Wester Bracco, North Lanarkshire [NS 8265 6566].
Etymology. The species is named after marsh and wetland naiads from Greek mythology.
Diagnosis. As for genus, and can be identified immediately by the almost straight,
longitudinal rugae which run half the length of the frontals.
Discussion. Millerolepis eleionomae has a Parahaplolepis type skull roof, that is, the
presence of parietals without dermopterotics but without the posterolateral lappets. However,
further association with the genus Parahaplolepis cannot be established for the reason that
the anterior pit-lines which may cross from the parietals into the frontals are not observed.
Removal of the dermal ganoine may reveal pit-lines and thus help determine any possible
relationship with that genus, however, to undertake such an action would cause undesirable
damage to the specimen. Nonetheless, in Millerolepis the ornamentation at the posterolateral
corner does not run parallel with the margin of the bone as in some species of
Parahaplolepis, but terminates at the margin in a similar manner to that of Protohaplolepis in
general. Millerolepis differs also from the other Scottish haplolepids, Protohaplolepis and
Blairolepis as both genera have separate dermopterotics and parietals.
The outline of the skull roof of Millerolepis eleionomae is similar to that of
Haplolepis corrugata, though the shape of the former species is longer and narrower and
tapers at the anterior border rather than being shouldered. The frontals are almost twice as
long as broad with the lateral borders near straight for much of their length, and the anterior
border tapering to a point; the pineal macula is faintly marked as in P. anglica and P.
tuberculata and lies slightly closer to the anterior margin of these bones than midpoint. The
parietals are almost the same size as the frontals, quadrilateral in shape and extend outwards
and backwards, and are deeply embayed for the reception of the extrascapulars and
11
posttemporals which probably meet midline in much the same way as Protohaplolepis
scotica (see Lowney, 1983, p.71 Fig. 4b). The shape and direction of the transverse suture is
not particularly pronounced or clear, it can, though, be traced from the lateral margin of the
skull roof to the mid-sagittal suture where it is seen to be steeply inclined and to follow a
more or less linear path as it separates the frontals from the parietals. The anterior and
posterior pit lines are not observed, and the existence of the middle pit lines is also not very
clear but there are markings in one area which seems to suggest they may possibly be present.
The sculpture of the skull roof is strongly developed and consists anteriorly of short
rugae and small tubercles which are also found in the area of the pineal macula. Two or three
strong, longitudinal rugae commence proximal to the anterior margin and continue for half
the length of the frontals without diverging. The frontals are, however, ornamented with short
rugae and large, irregular-shaped and slightly raised tubercles mostly originating from about
level with the terminations of the longitudinal rugae and continuing to as far as the posterior
margin.
Approximate length of fish about 58mm.
3. Remainder of material
Due to the rather unique morphology and osteology of the haplolepid elements, identification
of their dermal bones and scales was not difficult to determine. For that reason, and
regardless of the fragmented nature of the specimens, these elements could not be confused
with those of other actinopterygians from the Lower Coal Measures of Scotland. A brief
description and interpretation of some of the remains are given below.
The cleithra (Fig. 9a) are typically haplolepid in ornamentation and form. That is,
compared with the cleithra of other basal actinopterygians they are large for the size of the
fish, broader ventrally and, without exception, strongly ornamented with flat ridges and
grooves along the anterior, posterior and ventral borders. In addition, the existence of a
ventral lateral line is evident by the presence of a pit line close to the ventral margin of the
bone. These pit lines are not found on all cleithra and the angle which they occupy on these
bones can vary considerably in different species. The cleithrum (Fig. 9a(i)) indicating the
presence of a ventral lateral line is similar to that of P. tuberculata from Linton and is usually
associated with the remains of P. alexandrae. There are several similar cleithra to that of
(Fig. 9a(v)) in which the ventral pit line is absent, the only difference being the size of the
bone and the direction in ornamentation which can vary. The small square-shaped cleithra
(Fig. 9a(iii) and 9a(iv)) also exhibiting ventral pit lines are from Pyritocephalus; the smaller
one belongs to Pyritocephalus youngii.
All maxillae (Fig. 9b) encountered so far have a greatly modified postorbital
expansion similar to that found in P. tuberculata and H. corrugata from Linton and P.
scotica from Loanhead. The teeth along the dentary margin are strong, conical and sharp; the
size of which can vary quite considerably within species. Ornamentation on the maxillae is
usually of broad terraced rugae running parallel with the dorsal and ventral margins. A
quadratojugal has not been observed on any specimen.
The small maxilla with the triangular-shaped postorbital expansion (Fig. 9b(i)) is usually
associated with P. isabellae; also to be found are much larger, almost identical maxillae with
a similar triangular-shaped expansion; the teeth are large and conical and the notched area
may be located close to the apex of the expansion, or further along the optic margin. The
tuberculated maxilla (Fig. 9b(ii)) is usually associated with remains of P. alexandrae.
The preopercula (Fig. 9c) are of the typical haplolepid type in which the expanded
anterodorsal part does not continue over the orbit as in normal palaeoniscids but remains
12
posterior to it. All specimens found are very similar in shape to the preoperculum found in H.
corrugata from Linton and of P. scotica from Loanhead: lunate poster margin; anterior
margin notched anterodorsally at the point of contact with the suborbital and anteroventrally
for the maxilla; ornamentation is of a rather complex pattern in which both horizontal and
vertical pit lines can be clearly observed.
The clavicles (Fig. 9d) are large for the size of the fish, triangular in form and
ornamented with a strong “groove and terrace” pattern. The direction of this ornamentation,
which is a continuation of the same pattern from the cleithrum, runs mostly parallel with the
anterior margin of the bone. The ventral margin, however, may be smooth or strongly
denticulated as in (Fig. 9d(iii)).
The opercula and subopercula (Fig. 9e) are large plates which can be ovoid, square or
irregular in outline. The ovoid operculum (Fig. 9e(i)) is very similar that found in
Parahaplolepis scotica from Loanhead and the irregular shaped suboperculum (Fig. 9e(vi)) is
similar to the bone found in Microhaplolepis ovoidea from Linton. The ornamentation of
most opercula is of a strong flat rugae running more or less parallel with the plate margins,
but it can be almost smooth with a few concentric grooves as in (Fig. 9 e(iv)). The flat rugae
of the subopercula on the other hand, tends to run dorsoventrally and form small tubercles or
striations at the centre of the plate.
The dentaries are extremely deep in some specimens and usually have a very strong
ornamentation of well-marked, longitudinal rugae; occasionally they exhibit an
ornamentation with flat ridges and grooves as found in Pyritocephalus youngii (Fig. 10a(ii)).
The articular is clearly observed in most specimens, in some instances detached and missing.
The teeth, irrespective of size, are strong, conical and sharp and vary considerably in
arrangement from being very close together or with a short space between each tooth. The
dentary (Fig. 10a(i)) is often associated with the remains of P. isabellae and the large
dentaries (Figs. 10a(iii) and 10a(iv)) which show different aspects of a dentary most likely to
belong to P. limnades.
The dermosphenotics of these haplolepids (Fig.10b) are stout and usually ornamented
with a pattern similar to that found on the skull roof. This may be an ornamentation of strong
terraced rugae running parallel with the medial and distal borders of the bone or with low
rounded tubercles similar to that of P. tuberculata from Linton or as in P. alexandrae (Fig.
10b(i)).
Very little information concerning the morphological detail of the nasals of these fish
is known due to the fact that they are not commonly found, though this may be due to their
small size or that they do not preserve very well. The two figures (Fig. 10c) appear to exhibit
an arched contour at their lower margins which may correspond to the anteromesial openings
found in the nasals of haplolepids.
The supracleithra and postcleithra are commonly met with and are ovoid in form and
ornamented with strong, concentric, flat ridges and grooves. The posterior margin is strongly
denticulated in some specimens.
The scales (Fig. 10c) of these fish, especially the high diagnostic lateral scales, are a
feature which can vary quite considerably in their specific osteology: the anterior lateral
scales may be four or five times as high as wide; usually lustrous and completely smooth or
with diagonal grooves, punctuations or ridges, the ridges often indicating wear on the
otherwise smooth surface; posteriorly with or without fine, coarse or blunt denticulations;
“peg and socket” articulation on some types of scale, absent from others, the peg being
narrow or broad, depending on species; anterodorsal corner of scales for most species is
curiously drawn out and extended, on certain scales this characteristic may be absent; lateral
line and accessory lateral line evident by deep, near horizontally orientated pits and grooves
high up on the scale. The osteological and histological detail of the scales of this family is in
13
fact very complex, not quite what the English translation of their latin name suggests “haplo”
and “lepis”, or simple scale.
Infraorbitals, posttemporals and suborbitals of haplolepids are also commonly found;
however, identification of many smaller elements could not be given with complete certainty.
Furthermore, the gulars from these fish have not been identified so far, it may be that this
type of fossilisation does not favour their preservation.
4. Cladistic analysis.
The variation in skull roof morphologies in the Haplolepidae has for many years been used as
an aid in the determination of taxonomic classification within the family. A phylogenetic
analysis was thus conducted in order to establish a hypothetical relationships which may have
existed between the haplolepids and different, though closely related, lower actinopterygians.
The information was then used to ascertain the possible taxonomic placements for the new
genus Millerolepis eleionome and the problematic Haplolepis attheyi from Newsham.
Morphological data were obtained from detailed illustrations in Traquair (1914),
Moy-Thomas and Bradley Dyne (1938), Gardiner (1989) and from personal material. A list
of 18 characters with a maximum of five states was created (Table 3) and, with the
assumption that all characters are valid for all taxa, the information was used to construct a
data matrix (Table 4). All analyses were conducted using the phylogenic package Mesquite
Version 3.0 and applying a heuristic search to create the most parsimonious trees, and with
all characters unordered and given equal weight. The hypothesis was also tested using TNT
Version 1.1 which generated similar results.
In order to establish relationships within the Haplolepidae and Canobius-Mesopoma-
Rhadinichthys complex, a homologous hypothesis was produced using 32 taxa from fossil
localities in Scotland and England. This tree was rooted to the genus Canobius since Westoll
(1944) hypothesised that Canobius, due to the close resemblance in its skull roof to the most
generalized species of Haplolepis, could have an ancestral lineage with the Haplolepidae.
This analysis excluded Haplolepis attheyi due to missing detail from the original specimen,
however, a second cladogram using 13 haplolepid taxa, including Haplolepis attheyi, was
generated with the phylogenic tree rooted to a hypothetical outgroup.
Figure 12 clearly illustrates a common relationship within the Haplolepidae and other
lower actinopterygians. This can also be shown by examination of the skull roof of Canobius
ramsey which reveals several features which in form and structure are remarkably similar to
that of a haplolepid, an observation which was also noted by Westoll (1944). This is
especially true as regards the resemblance of the skull roof to that of the genus
Protohaplolepis, albeit without the pineal macula. On the other hand, concerning the skull
roof of Canobius elegantulus, although the morphological detail is basically similar to that of
Canobius ramsey, the dermopterotics extend in a forward direction and terminate close to the
anterior margin of the frontals. This is also a feature prevalent in the genus Mesopoma, the
known nearest relative of Canobius, and by virtue of the mode of jaw suspensorium in
Mesopoma, is also known to be closely related to the Rhadinichthyids. Thus, and in
agreement with the cladistics results, the Canobius elegantulus line does not appear to
produce a distinct haplolepid phylogeny. However, the results do indicate there is a possible
lineage with Canobius ramseyi to the Haplolepidae, and as such presents the Haplolepidae as
paraphyletic with two monophyletic groups:
(1) The clade representing the subfamily Haplolepinae (Lowney 1983) is
composed of the haplolepids: Protohaplolepis scotica; P. isabellae; with P.
limnades and P. traquairi forming closely related sister taxa.
14
(2) The clade representing the subfamily Parahaplolepinae (Lowney 1983)
contains the haplolepids: Parahaplolepis anglica; P. westolli; sister taxa P. elenae
and P. alexandrae; Millerolepis eleionome; Blairolepis loanheadensis; and sister
taxa Pyritocephalus youngii and P. rudis.
Figure 13 shows a possible relationship with haplolepids from the United Kingdom which are
all referred to in this study, and, bearing in mind the missing character data, including the
position of Haplolepis attheyi within the Haplolepinae. Again, two monophyletic groups are
depicted within the Haplolepidae:
(1) The Haplolepinae in which all taxa are as in Figure 12.
(2) The Parahaplolepinae which, in this case has a slightly different arrangement
from Figure 12 and contains: Millerolepis eleionome; sister taxa Pyritocephalus
youngii and P. rudis; Parahaplolepis elenae; P. alexandrae; P. westolli; with
sister taxa Blairolepis loanheadensis and Parahaplolepis anglica.
In effect, the analyses clearly show that the subfamilies Haplolepinae and the
Parahaplolepinae most likely evolved in parallel with each another and that the genus
Millerolepis eleionome should be placed within the latter subfamily. Also indicated in the
analyses is that Haplolepis attheyi should be positioned within the Haplolepinae and possibly
renamed Protohaplolepis attheyi. And, furthermore, the study also implies that the separate
parietals and dermopterotics found in many genera are a homologous trait, with the loss of
the dermopterotics being a derived synapomorphyic character state.
5. Discussion
5.1. Associated fauna
As regards the strata where haplolepid fossils are to be found, it is interesting to note that the
ostracod Beyrichia arcuata is always present in large numbers. For that reason it is possible
that these crustaceans served as a food source for these fish and most likely other small
actinopterygians. Very little is known of the diet of haplolepids, although the large, sharp,
conical teeth found on most haplolepid dentaries and maxillae do suggest a diet of small fish
and invertebrates. Also worth noting is the association of haplolepid remains with the
brachiopod Lingula mytiloides and the serpulid worm Spirorbis carbonarius; the fossils of
these invertebrates, although abundant at times, are not always present. Haplolepid fossils are
also found close to, but have never been found within the Anthracomya or Carbonicola
mussel beds. These bivalves are commonly met with in bands of several centimetres in
thickness, and where an assortment of fish remains are frequently found trapped between the
closely-spaced mussels.
There is, however, a noticeable near complete absence of large predator fishes in the
haplolepid bearing strata. Fossils of the larger coelacanths, rhizodonts and elasmobranchs,
which may be found in quantity a few centimetres above and below the thin haplolepid beds
are very rare in these rocks. Westoll (1944, p.106) however, mentioned that large baphetids
were often associated with haplolepids, and that these tetrapods were practically confined to
known haplolepid yielding localities. In fact, the remains of a large tetrapod, most probably
Loxomma rankini, are found in close proximity to the haplolepid stratum in the shales at
Wester Bracco, the very nature of the shale tips makes the exact distance from the haplolepid
stratum difficult to measure.
Unlike most other actinopterygians encountered in the Lower Coal Measures of
Scotland, the skull roofs of haplolepids are normally found with the cranial dermal plates still
15
articulated; this occurrence is most likely the result of ankylosis along the suture lines, though
occasionally specimens are found which have separated along the mid-sagittal or other
suture, but this is not a very common occurrence. In many instances, however, skull roofs are
found in a state in which the complete assemblage has folded over on itself before
fossilization. This condition and the fragmentary nature of the material in general suggests
that these fish could not have been buried rapidly after death but were subjected to a
moderate form of water movement which carried the remains a relatively short distance. It is
also possible that the dead fish floated for a length of time in a fine, briny silt in a low energy
environment, and as decay gradually set in, this would allow the various dermal elements to
become disarticulated, but not scattered. Eventually, and due to the large density gradient, the
suspension and its contents settled to form a very thin band of material, typical of that found
in the Lanarkshire coalfield shale beds. This is evident by the fact that disarticulated scales
are found en masse and accompanied with head bones apparently from the same individual
are not an uncommon find. It is of course also possible that scavengers may have fed on the
decaying fish and left the bones and scales slightly disturbed but undamaged before burial.
5.1. Biostratigraphical and geographical distribution
The discovery of a number of new species of haplolepid in association with other freshwater
fish fauna in the Westphalian A (Bashkirian) of the Midland Valley of Scotland has helped to
fill a gap in the continuity of the chronological history of the Haplolepidae in Europe.
Although these new taxa are stratigraphically younger than the previously known specimens
from the Scottish Namurian (Lowney, 1983), they are also to be found in a stratigraphic
horizon equivalent to the earliest haplolepid recorded from the North American continent,
Parahaplolepis canadensis from Parrsboro, Nova Scotia.
The distribution of the Haplolepidae in Western Europe (Table 2) demonstrates the
possibility of the lateral distribution of the taxon through Europe which possibly began in the
vicinity of the Midland Valley of Scotland, spreading in the direction of Northumberland and
the English Midlands and then into continental Europe. This dispersal would coincide with a
migration of haplolepid fauna from Europe through the vast equatorial coal swamps into the
areas of Canada and the rest of North America (Lowney 1983).
5.2. The taxonomic position of Haplolepis attheyi from Newsham
Westoll (1944) based his conclusions in the taxonomic position of Haplolepis attheyi on a
single skull roof and with the ornamentation and strong dentition of a single dentary. He also
mentioned that the fin rays of the caudal fin were widely separated, segmented and with the
basal segments expanded, and that the scales were entirely smooth with the anterior ones
denticulated: detail which could be found in other haplolepid genera. However, Lowney
(1983) described a complete operculum in which the bone is shaped and ornamented as in
Protohaplolepis scotica. This description is remarkably similar to that of several operculae
found in the Lanarkshire coalfield, and which are usually associated with Protohaplolepis
material. Furthermore, Westoll did not include H. attheyi within the genus Parahaplolepis
due to the absence of a marked concavity of the posterior margin of the skull roof.
Nonetheless, it can be deduced from this study that the shape of the posterior margin of the
skull roof can be quite variable, even within a range of skull roofs of similar species; for
example, compare the posterior of the skull roof margins of Protohaplolepis isabellae and
Protohaplolepis limnades (Figs. 8a and 8c respectively).
The original specimen of H. attheyi lacked ornamentation, and consequently no
proper description was given of this feature. Nonetheless, regarding the genus
Protohaplolepis, the ornamentation of the skull roof can be either terraced with deep grooves,
tuberculated or a mixture of both of these or with longitudinal rugae, and not limited to a
terraced pattern: for instance compare the skull roof ornamentation of P. isabellae (Figs. 1a to
16
1d) and P. limnades (Figs. 2a, 2b). It is fair to say that although the facial dermal elements of
H. attheyi resemble very closely those of Haplolepis corrugata from Linton, the structure of
the skull roof, in particular the separate dermosphenotics and parietals in H. attheyi seem to
exclude it from any taxonomic connection with the genus Haplolepis. H. attheyi does,
however, possess several of the diagnostic characteristics given to both Microhaplolepis and
Protohaplolepis; the short, broad skull roof; the separate dermopterotics and parietals; and
the absence of posterolateral lappets.
The dentaries of haplolepids from the Lanarkshire coalfield seem to be exclusively a
fairly deep bone with longitudinal rugae and a well-marked angular; with the exception of
Pyritocephalus, all the teeth have been strong, conical and sharp, irrespective of size. The
size of the teeth on the dentary (but not their form) has also been shown to be a very variable
character; this most likely also applies to the maxilla. With this information regarding the
teeth we can look at the illustration of H. attheyi in Westoll’s (1944) monograph. At the top
part of the illustration and close to the specimen, a small plate with tiny hemispherical teeth
can be seen. This tiny tooth plate has been identified as possibly belonging to the illustrated
specimen. The assumption that these hemispherical teeth belong to of H. attheyi is certainly
incorrect as this element is most likely part of the tooth palate of another common
Carboniferous fish, the eurinotiform Amphicentrum.
The diversity of faunal material incorporated in the fossils found at the Lanarkshire
coal shale tips have presented a clearer picture into an understanding and the distribution of
British Haplolepidae of which so little material is available; an assumption which most likely
applies to material concerning continental European haplolepids. Thus, after careful study of
these fossils and using information regarding the skull roof of H. attheyi given by Westoll
(1944) and the description of other material from Newsham presented by Lowney (1983), it
can be deduced that this skull roof is not of the Microhaplolepis-Haplolepis type (Lowney,
1983, p.75) rather the Microhaplolepis-Protohaplolepis type as explained above.
Finally, considering the detail of the skull roof, the comparatively deep mandible with
a strong longitudinal ornament of rugae and the shape and ornamentation of the operculum,
Haplolepis attheyi should most likely be assigned to the generic level of Protohaplolepis
Lowney.
5.3. Further notes on the Haplolepidae
At least two species of Pyritocephalus are to be found at Wester Bracco, and to date
Pyritocephalus youngii is the oldest member of the genus; this was previously attributed to
Pyritocephalus rudis (Westoll, 1944) from upper Westphalian B (late Bashkirian) material
from Newsham, Northumberland and which was described from a single skull roof.
The peculiar shape of the skull roof of P. youngii (Figs. 6a, 6b and 8f) is the result of
the enlarged frontals, reduced parietals and the large, rounded temporal fenestrae which in all
probability are primitive characteristics of the genus. If these attributes are autapomorphic,
then it is most unlikely that Pyritocephalus evolved from Parahaplolepis (Westoll 1944) or
indeed from any haplolepid ancestry.
Furthermore, the form of the temporal fenestrae in P. youngii and the extent of the
skull roof challenge a previous hypothesis. That theory is based on the assumption that the
progressive development of the fenestrae and reduction of the skull roof was due to the
enlargement of the supraorbital vacuities and which happened over a period of time (Huber
1992 p.186). However, careful examination of the osteological detail of the new material
quite clearly illustrates that when a comparison is made of different species the increase in
the area of the vacuities and the reduction in the skull roof area did not happen over a period
of time as proposed.
It is interesting to note that several other indeterminate fish remains are found in the
Lanarkshire shale tips and which exhibit some of the morphological and osteological
17
characteristics of haplolepids and other actinopterygians. For example, in one unknown taxon
the dermopterotics are absent and the parietals exhibit small fenestrae at their lateral margins;
in another, the dermal bones, including the tall scales, are strikingly similar to those found in
haplolepids albeit some diagnostic features are absent from the skull roofs. These fishes lived
in swamp areas in parallel with the haplolepids and may represent their close relatives but it
is not known whether they possess such features as the ventrally placed nostrils, reduced
branchiostegals and the reduction of fin rays which are characteristic of the Haplolepidae.
6. Conclusion
Seven new species of haplolepids from Lanarkshire coal shale tips are used as an aid to the
stratigraphic correlation and geological distribution of the Haplolepidae in Europe; and are in
agreement that the family possibly arose in Great Britain and dispersed west to North
America and east to the Czech Republic in continental Europe in a more or less simultaneous
movement.
This work also supports the supposition that the fossilised remains of these fish are
more common in Great Britain and continental Europe than previously estimated. This
assumption is based on the fact that although haplolepids were small, minnow-sized fish and
could quite easily be overlooked, there is a definite discrepancy in their fossil remains. This
discrepancy is possibly due to the preference of haplolepids to inhabit quiet, shallow, waters
as these areas would be relatively free from the larger predators which frequented the deeper
parts. The result, therefore, of living in this type of environment was to limit the distribution
of their fossilised remains to a few localised bands of material which in most instances is only
a millimetre or so in thickness, as found in the Lanarkshire coalfield. This presupposition
may not only apply to the coal measures of Scotland but also to the large coal fields of
England where these small fish may have possibly been overlooked in the past.
Additionally, and as a result of the examination of this new material it is shown that
the area of the supraorbital vacuities and the reduction of the skull roof in the genus
Pyritocephalus did not happen gradually over a period of time as previously thought. The
new findings suggest that these features are most likely the result of apomorphic homology of
the genus.
The study also indicates that the new genus Millerolepis eleionome should be placed
with the Parahaplolepinae, and that the problematic Haplolepis attheyi from Newsham,
should (tentatively) be assigned to the generic level of Protohaplolepis within the subfamily
Haplolepinae.
7. Acknowledgements
I am extremely grateful to Ramsey and William Kerr, owners of Wester Bracco Farm, for
allowing me unlimited access to the shale tips. Many thanks to Tony Fallick, Josanne Newton
and Jason Newton for their helpful comments and grammatical corrections to this paper, and
special thanks to Neil Clark for his valuable suggestions during its preparation.
Please note that this study is of a personal nature and is not funded in any way by SUERC.
8. References
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Baird, D. 1972. A haplolepid fish fauna in the early Pennsylvanian of Nova Scotia.
Palaeontology 5, 22-29.
Baird, D. 1978. Studies on Carboniferous freshwater fishes. American Museum Novitates
2641, 1-22, figs. 1-9.
Elliot, G.F. et al. eds. 1901. Fauna, flora & geology of the Clyde area. Glasgow: Local
Committee for the Meeting of the British Association.
Fritsch, A. 1893. Fauna der Gaskohle und der Kalksteineder Permformation Bohmens.
Prague 3, 1-132, figs. 189-310, pls. 91-132. (whole volume dated 1895)
Gardiner, B.G. & B. Schaeffer. 1989. Interrelationships of lower actinopterygian fishes.
Zoological Journal of the Linnean Society. 97, 135-187.
Huber, P. 1992, Pyritocephalus lowneyae n. sp., the youngest haplolepiform (Pisces:
Actinopterygii) from the Pennsylvanian of Central New Mexico. New Mexico
Bureau of Mines & Mineral Resources 138, 183-187.
Lowney, K. A. 1980a. A revision of the Family Haplolepidae (Actinopterygii,
Paleonisciformes) from Linton, Ohio, (Westphalian D, Pennsylvanian). Journal of
Palaeontology 54, 942-953.
Lowney, K. A. 1983. The earliest known (Namurian A,E1) haplolepids (Osteichthyes:
Actinopterygii). Transactations of the Royal Society of Edinburgh: Earth Sciences
74, 79-78.
Moy-Thomas, J. A. and B. A. Bradley-Dyne. 1938. The actinopterygian fishes from the
Lower Carboniferous of Glencartholm, Eskdale, Dumfriesshire. Transactions of the
Royal Society of Edinburgh 59, 437-480.
Newberry, J. S. 1857. Description of several new genera and species of fossil fishes from the
Carboniferous strata of Ohio. Proceedings of the Academy of Natural Sciences of
Philadelphia 8, 97-100.
Poplin, C. M. 1997. Le premier Haplolepiforme (Pisces, Actinopterygii) decourvert en
France (Carbonifere superieur du bassin de Blanxy-Montceau, Massif central):
Compte rendu hebdomadaire des seances de l’Academie des Sciences Paris 324 (2),
59-77.
Traquair, R. H. 1877-1914. The Ganoid Fishes of the Carboniferous Formations:
Palaeoniscidae. London: The Palaeontographical Society.
Ward, J. 1890. The Geological Features of the North Staffordshire Coal-fields, their Organic
Remains, their Range and Distribution; with a Catalogue of the Fossils of the
Carboniferous System of North Staffordshire. Transactions of the North Staffordshire
Institute of Mining and Mechanical Engineers 10, 1-180.
Westoll, T. S. 1944. The Haplolepidae, a new family of Late Carboniferous bony fishes.
Bulletin of the American Museum of Natural History 83, 1-122.
9. List of figures and captions.
Figure 1 (a) Paratype specimen of Protohaplolepis isabellae skull roof, GLAHM 152368.
(b) Line drawing of same skull roof showing ornamentation. (c) Holotype specimen of
Protohaplolepis isabellae skull roof, GLAHM 152369, showing variation in ornamentation.
(d) Line drawing of same skull roof showing ornamentation. (Scale bars = 2mm)
Figure 2 (a) Holotype specimen of Protohaplolepis limnades skull roof, GLAHM 152371.
(b) Line drawing of same skull roof showing ornamentation. (Scale bar = 2mm)
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Figure 3 (a) Holotype specimen of Protohaplolepis traquairi skull roof, GLAHM 152375.
(b) Line drawing of same skull roof showing ornamentation. (Scale bar = 2mm)
Figure 4 (a) Holotype specimen of Parahaplolepis alexandrae skull roof, GLAHM 152370.
(b) Line drawing of same skull roof showing ornamentation. Dotted line indicates path of
frontoparietal sutures. (Scale bar = 2mm)
Figure 5 (a) Holotype specimen of Parahaplolepis elenae skull roof, GLAHM 152373. (b)
Line drawing of same skull roof showing ornamentation. Left parietal repositioned with
lappet reconstruction. (Scale bar = 2mm)
Figure 6 (a) Holotype specimen of Pyritocephalus youngii skull roof, GLAHM 152374. (b)
Line drawing of same skull roof showing ornamentation and area of “tympani”. (Scale bar =
2mm)
Figure 7 (a) Holotype specimen of Millerolepis eleionomae skull roof, GLAHM 152372. (b)
Line drawing of same skull roof showing ornamentation. Dotted lines indicates path of
frontoparietal sutures. (Scale bar = 2mm)
Figure 8 Diagrams of centre part of skull roofs of Haplolepidae showing pineal macula, pit-lines,
mid-sagittal suture and oblique/transverse sutures. (not to scale)
(a) Protohaplolepis isabellae sp. nov. (b) Parahaplolepis alexandrae sp. nov. (c) Protohaplolepis
limnades sp. nov. (d) Millerolepis eleionomae sp. nov., gen. nov. (e) Parahaplolepis elenae sp. nov.
(f) Pyritocephalus youngii sp. nov. (g) Protohaplolepis traquairi sp. nov. (h) Parahaplolepis
tuberculata (after Westoll 1944) (i) Parahaplolepis scotica (after Lowney 1986) (j) Haplolepis
attheyi (after Westoll 1944) (k) Parahaplolepis canadensis (after Baird 1978) (l) Pyritocephalus
sculptus (after Westoll 1944)
Figure 9 Line drawings of various dermal elements of Haplolepidae from Wester Bracco.
(a) cleithra; (b) maxillaries; (c) preopercula; (d) clavicles; (e) opercula/subopercula. Scale
bars = 2 mm
Figure 10 Line drawings of various dermal elements and scales of Haplolepidae from Wester
Bracco.
(a) dentaries; (b) dermosphenotics; (c) nasals; (d) scales. Scale bars = 2 mm
Figure 11 (a) Haplolepis corrugata (Newberry). Reconstruction of whole fish in lateral view.
(b) H. corrugata. Reconstruction of dermal skull and shoulder girdle in lateral view. (c)
Microhaplolepis ovoidea (Newberry). Reconstruction of dermal skull in dorsal view. (d) M.
ovoidea. Reconstruction of dermal skull in ventral view. All figures modified after Westoll
(1944).
Abbreviations: A, angular; Apg, anterior paired gular; apl, anterior pit line of parietal; C,
cleithrum; Cl, clavicle; D, dentary; Dp, dermopterotic; Ds, dermosphenotic; Es,
extrascapular; F, frontal; hpl, horizontal pit line of preoperculum; Io, infraorbital; M, maxilla;
Mg, median gular; mpl, middle pit line of parietal; N, nasal; O, operculum; P, parietal; Pc,
postcleithrum; pf, pineal foramen or macula; Pm, premaxilla; Po, preoperculum; Ppg,
posterior paired gular; ppl, posterior pit line of parietal; Pr, postrostral; Pt, posttemporal; Sc,
supracleithrum; Sor, suborbital; Sop, suboperculum; vpl, vertical pit line of preoperculum.
Dashed lines indicate areas of free reconstruction.
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Figure 12 Cladogram A. The most parsimonious tree showing the relationship between the
main groups of lower actinopterygians introduced in this paper (tree length=90, consistency
index=0.4222 and retention index=0.6730).
Figure 13 Cladogram B. The most parsimonious tree showing the relationship of
Haplolepis attheyi with other Haplolepidae mentioned in this study (tree length=54,
consistency index=0.5556 and retention index=0.6757).
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