Extant Crinoidea (Echinodermata) of Singapore

Abstract

The crinoid fauna of Singaporean waters now includes approximately 39 nominal species belonging to six families, all in Order Comatulida. Seventeen of the 22 species collected during the Singapore Strait Biodiversity Workshop (May–June 2013) were previously known from the area. Of the remaining five, Cenometra bella (Colobometridae) is definitely a new record for Singapore, while the taxonomic status of the other four is uncertain. Seventeen additional species, collected almost entirely in the nineteenth and early twentieth centuries, were not represented in the 2013 survey.

Full text

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RAFFLES BULLETIN OF ZOOLOGY 2016
Extant Crinoidea (Echinodermata) of Singapore
Charles G. Messing1 & Teresa S. Tay2
Abstract. The crinoid fauna of Singaporean waters now includes approximately 39 nominal species belonging to
six families, all in Order Comatulida. Seventeen of the 22 species collected during the Singapore Strait Biodiversity
Workshop (May–June 2013) were previously known from the area. Of the remaining ve, Cenometra bella
(Colobometridae) is denitely a new record for Singapore, while the taxonomic status of the other four is uncertain.
Seventeen additional species, collected almost entirely in the nineteenth and early twentieth centuries, were not
represented in the 2013 survey.
Key words. Crinoidea, feather star, Singapore, comatulid, echinoderm
RAFFLES BULLETIN OF ZOOLOGY Supplement No. 34: 627–658
Date of publication: 29 June 2016
http://zoobank.org/urn:lsid:zoobank.org:pub:0ADC2916-DA74-4127-9A62-35E732335379
© National University of Singapore
ISSN 2345-7600 (electronic) | ISSN 0217-2445 (print)
1Nova Southeastern University Halmos College of Natural Sciences and Oceanography,
8000 N Ocean Drive, Dania Beach, FL 33004 USA; Email: messingc@nova.edu
(*corresponding author)
2Tropical Marine Science Institute, National University of Singapore, 18 Kent Ridge
Road, Singapore 119227; Email: tmstayt@nus.edu.sg
INTRODUCTION
Collections of living crinoids from Singaporean waters have
previously included 34 nominal species in six families of
Order Comatulida, many of which are widespread in the
tropical Indo-Western Pacic region. All are feather stars,
an informal term for those members of the order that shed
the postlarval stalk and take up a free existence. Comatulida
also includes taxa that retain the stalk as adults (Rouse et
al., 2013; Hemery et al., 2013). Early material was obtained
via shore collecting by German malacologist Carl Eduard
von Martens in 1862–1864 and Svend Gamel Gad, Consul
for Denmark, in 1904–1910 (Günther, 1904; Lucas, 1906),
and described by A. H. Clark (e.g., 1909a, 1931, 1941).
This paper summarises information about the Singaporean
crinoid fauna and includes material collected during the
Singapore Strait Biodiversity Workshop (SSBW) from 17
May to 5 June 2013, as well as information about species
reported only previously.
This survey collected 366 specimens belonging to
approximately 22 crinoid species at depths ranging from
just below the low tide line to 150 m. Of these, 17 were
previously collected in Singaporean waters as well. The
remaining ve include one denite new record [Cenometra
bella (Hartlaub, 1890)], and four belonging to genera that
require taxonomic revision [Comatula sp., Capillaster
cf. tenuicirrus A. H. Clark, 1912a, Decametra sp., and
Heterometra schlegelii (A. H. Clark, 1908a)]. Seventeen
other species, collected chiey by von Martens and Gad but
not during the SSBW, bring the total number of nominal
species known from Singaporean waters to approximately
39. A number of specimens collected during the SSBW
could not be assigned with certainty to named genera or
species, either because they may be juveniles or they belong
to taxa in need of taxonomic revision. They have not been
included in this paper.
Singapore lies at the western end of the Indo-Malayan
Archipelago, which also includes Indonesia, the Philippines,
Brunei, Papua New Guinea, Timor-Leste, and the islands of
Malaysia. The shallow-water (roughly <50 m depth) crinoid
fauna of this region consists of ~100 nominal species and is
the richest in the world. However, both older dredging and
trawling efforts and more recent scuba-based surveys have
recorded only ~40–55% of the fauna from any local area
within the region (Messing, 1998a). Such small numbers
relative to the entire fauna are likely due as much or more
to insufcient collecting and inadequate taxonomy as to
limited distributional ranges. Given the location of Singapore
at the margin of this rich region, the estimated 39 recorded
species is not an unexpectedly low number. Putchakarn &
Sonchaeng’s (2004) literature review recorded 39 species as
well from Thai waters but used outdated taxonomy; currently
accepted nomenclature (e.g., Messing 1998b; Rowe et al.,
1986; Rankin & Messing, 2008) reduces this number to ~31.
Similarly, Mekhova & Britayev (2012) listed 31 species (one
may be a synonym) from the Bay of Nhatrang, Vietnam.
MATERIAL AND METHODS
Specimens were obtained during SSBW via hand collecting
in shallow water or via scuba, rock dredge and beam trawl.
Specimens collected by hand were placed underwater
in Ziploc plastic bags. The majority of specimens were
preserved shortly after collection in 75% ethanol; a few were
preserved in 95% ethanol. Colour descriptions are based
on living animals unless otherwise stated. Small portions
of selected specimens were also preserved in DMSO or

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Messing & Tay: Crinoidea (Echinodermata) of Singapore
frozen. Commensals and parasites were variously preserved
in ethanol, formalin or DMSO. Morphological terminology
follows Messing (1997, 2001), Messing et al. (2000), and
Hess & Messing (2011). Figs. 1 and 2 illustrate major
components and abbreviations associated with feather star
morphology.
Repository abbreviations: BSNH—Boston Society of Natural
History, Boston, MA; MCZ—Museum of Comparative
Zoology, Harvard University, Cambridge, MA; MNB—
Museum für Naturkunde, Berlin, Germany; MNHN—
Muséum national d’Histoire naturelle, Paris; NHM—Natural
History Museum, London; USNM—National Museum of
Natural History, Smithsonian Institution, Washington DC
(=United States National Museum); NRS—Natuurhistorisch
Rijksmuseum, Stockholm, Sweden; SIO-BIC—Benthic
Invertebrate Collection, Scripps Institution of Oceanography
University of California San Diego; YPM—Yale University
Peabody Museum; ZMC—Zoologisk Museum, Copenhagen;
ZMUH—Zoologisches Museum Universität Hamburg,
Germany; ZRC.ECH—Zoological Reference Collection,
Echinoderms (Lee Kong Chian Natural History Museum,
National University of Singapore). Station alphanumerics
include abbreviations for gear used: DR—rectangular
dredge; IT—intertidal hand collection; SB, SD—scuba;
SW—snorkeling/hand collection, and TB—beam trawl.
Collection data and numbers of specimens in the USNM
were veried by online catalog searches at http://collections.
nmnh.si.edu/search/iz/.
TAXONOMIC SECTION
Table 1 lists all nominal species known from Singaporean
waters. Asterisks indicate species collected during the SSBW.
Family COMATULIDAE Fleming, 1828
Remarks. This family was previously called Comasteridae
A. H. Clark, 1908c. However, the senior name Comatulidae
Fleming, 1828, is correct (see Summers et al., 2014).
Although article 23.2 of the International Code of Zoological
Nomenclature (ICZN, 1999, p. 25) states that “the Principle of
Priority is…not intended to be used to upset a long-accepted
name”, article 23.9.1 requires that two conditions both be
met in order to maintain prevailing usage. Comasteridae
has indeed been widely and continuously used for over
50 years (article 23.9.1.2). However, the senior synonym
Comatulidae and its coordinate subfamily name Comatulinae
have been used after 1899 (articles 23.9.1.1, 36.1). A. H.
Clark (1908b) xed Comatula solaris Lamarck, 1816, as
the type of Comatula in Comatulidae but subsequently (and
incorrectly) changed the family name to Comasteridae (A.
H. Clark, 1908c). See Summers et al. (2014) for a discussion
of suprageneric taxa of Comatulidae.
Members of order Comatulida have traditionally been referred
to informally as comatulids, a term used synonymously with
feather star—those extant crinoids that shed the postlarval
stalk and take up a free existence. However, with Comatulidae
replacing Comasteridae, comatulid could refer either to a
member of the family or the order. In addition, because
recent molecular-based phylogenies (Rouse et al., 2013;
Hemery et al., 2013) incorporate stalked bourgueticrinine
crinoids into Comatulida, comatulid and feather star are no
longer equivalent. To avoid confusion, Summers et al. (2014)
recommend using comatulid for members of Comatulidae.
Feather star should be used as a non-taxonomic term for
taxa that shed the postlarval stalk.
Table 1. List of crinoid species known from Singaporean waters.
Asterisks indicate species collected during the 2013 Biodiversity
Survey.
Family Species
Comatulidae *Comatula cf. solaris
*Comatula cf. pectinata
*Comatula sp.
*Capillaster multiradiatus
Capillaster sentosus
*Capillaster cf. tenuicirrus
*Phanogenia typica
Phanogenia schoenovi
Comaster schlegelii
Comanthus parvicirrus
Anneissia bennetti
Colobometridae *Colobometra perspinosa
*Cenometra bella
*Decametra sp.
Decametra informis
Decametra mylitta
*Oligometra serripinna
*Pontiometra andersoni
Himerometridae *Himerometra robustipinna
Himerometra bartschi
Craspedometra acuticirra
Heterometra afnis
Heterometra amboinae
Heterometra bengalensis
*Heterometra cf. crenulata
Heterometra producta
Heterometra quinduplicava
*Heterometra schlegelii
Heterometra singularis
*Amphimetra cf. discoidea
*Amphimetra ensifer
Amphimetra molleri
Mariametridae *Dichrometra agellata
*Lamprometra palmata
*Stephanometra tenuipinna
*Stephanometra indica
Zygometridae *Zygometra comata
“Antedonidae” *Dorometra nana
Dorometra parvicirra

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RAFFLES BULLETIN OF ZOOLOGY 2016
Fig. 1. Feather star morphology. A, exploded view of a feather star showing bases of two rays, types of articulations and ossicle
nomenclature. Ibr1 – rst primibrachial ossicle; IIbr2 – second secundibrachial ossicle; IIbr3+4 – third and fourth ossicles of secundibrachial
series united by syzygy; br2 and br5 – second and fth brachials, respectively, of undivided arm; PII – pinnule arising from secundibrachial
series; P1 – rst exterior pinnule; Pa – rst interior pinnule; B, aboral view of centrodorsal and base of one ray of Comatulidae illustrating
abbreviations of brachitaxes (division series); Roman numerals followed by Br and an Arabic numeral identify specic brachitaxes (e.g.,
IIBr2 = secundibrachial series composed of two ossicles); Roman numeral followed by br and subscript Arabic numerals indicate specic
ossicles (e.g., IIIbr1 = rst ossicle of third brachitaxis); C, oral surface of the disk of a feather star with a central mouth (m) and marginal
anal papilla (ap); D, same of a feather star with a marginal (excentric) mouth (m) and central anal papilla (ap).

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Messing & Tay: Crinoidea (Echinodermata) of Singapore
Fig. 2. Ray branching patterns of Comatulidae. A, Comatula with
syzygies (dotted lines) at IBr2, br1+2 and br3+4. B, Capillaster
with syzygies at IIbr3+4, IIIbr2+3 and br2+3. C, Phanogenia with a
cryptosynarthry at IBr2, and syzygies at IIbr3+4, some IIIbr1+2 and
some br1+2. D, Comanthus with syzygies at II, III and IVbr3+4 and
br3+4.
Subfamily COMATULINAE Fleming, 1828
COMATULINI Fleming, 1828
Comatula Lamarck, 1816
Diagnosis. Mouth excentric in fully developed individuals;
arms usually 10 (rarely to 17 in C. pectinata, and to 20 and
rarely 27 in C. rotalaria); centrodorsal pentagonal to circular,
thin, sometimes reduced and lying within radial circlet;
cirri absent or, when present, usually only interradial; all
brachitaxes of two ossicles united by syzygy; rst syzygy
at 1+2 on undivided arms; also at 3+4 on arms arising from
II and IIIBr series; distal intersyzygial interval 2–11; combs
composed of teeth conuent with outside of pinnule and
tapering distally or not (modied from A. H. Clark, 1931;
Summers et al., 2014).
Remarks. The genus currently includes seven morphologically-
based species: C. cratera H. L. Clark, 1916, from eastern
Australia; C. micraster A. H. Clark, 1909, from the eastern
Indian Ocean to Indonesia; C. solaris Lamarck, 1816, from
tropical Australia north to Hong Kong; C. pectinata from
Sri Lanka to tropical Australia and north to Okinawa, Japan;
C. purpurea (Müller, 1843) from tropical Australia north
to the Philippines; C. tenuicirra A. H. Clark, 1912, from
Indonesia, and C. rotalaria Lamarck, 1816, from tropical
Australia and eastern Indonesia (A. H. Clark, 1931; Rowe
& Gates, 1995; Kogo, 1998). The great majority of records
are from depths shallower than 50 m, although half of the
six depth records published for C. micraster range from 73
to 110 m, and the two published records for C. tenuicirra
are 82 and 88 m (A. H. Clark, 1931).
Comatula micraster and fully developed C. rotalaria differ
from the remaining species in lacking cirri. C. rotalaria is
unique among feather stars in having exterior arms that
develop from the first pinnule and remain shorter than
interior arms. It also usually develops 20 arms, whereas other
Comatula species rarely develop more than 10. At Lizard
Island, Australia, C. rotalaria lives on sediment, with its
shorter arms arrayed vertically; it uses several bent longer
arms to prop its central calyx above the substrate (Messing
et al., 2006). A. H. Clark (1909f) rst placed C. rotalaria
in a separate genus, Validia, which he later reduced to a
subgenus of Comatula (A. H. Clark, 1918, 1931).
Morphological features of the other ve species overlap
substantially and descriptions are often confused. A. H.
Clark (1931) diagnosed both C. cratera and C. micraster
as lacking cirri. However, he then noted that ve of the
original 14 specimens on which C. cratera was based have
1–3 small cirri (A. H. Clark, 1931), and “3 or 4” of the
45 specimens from the type locality of C. micraster have
1–4 (rarely >1) delicate cirri (A. H. Clark, 1912, p. 82).
He referred to C. cratera as “merely a form of C. solaris”
but maintained use of the separate name. A small paratype
(Australian Museum cat. no. E1361) bears 10 sockets in
interradial pairs with one cirrus retained and a comb of 11
triangular teeth that taper distally.
A. H. Clark (1931) distinguished C. purpurea and C.
tenuicirra from the others on the basis of their having cirri
restricted to the interradial angles of the centrodorsal, either
singly or in pairs. However, he identied several specimens as
C. purpurea with cirri distributed more continuously around
the centrodorsal margin, as in C. pectinata. H. L. Clark (1946)
and Rowe & Gates (1995) treated C. purpurea as a junior
synonym of C. pectinata. Comatula tenuicirra supposedly
differs from C. purpurea in having more elongated cirrals
length-to-width (LW) ratio to 2.0. However, LW in the
types of C. purpurea and C. pectinata reach 1.3 and 1.5,
respectively. The few known specimens of C. tenuicirra
were collected on ne mud in 82–88 m, which might favor
more elongated cirri. Cirral proportions for the very few
specimens attributed to C. purpurea from sand and ne
mud at similar depths (88–93 m) have not been reported
(A. H. Clark, 1931).
A. H. Clark (1931) distinguished Comatula solaris from C.
pectinata chiey by its greater number of cirrals (17–24 vs.
10–15) but mentioned specimens of the former with as few
as 15–19 and the latter with up to 17. Both are described as
having both slender and robust overall forms with cirri in
a complete or incomplete marginal row. Comatula solaris
appears to differ from C. pectinata and the other conspecics
in having much longer combs with up to 30 teeth and a
discrete terminal tooth versus a comb that tapers distally.
Hoggett & Rowe (1986) used this feature to separate C.
solaris and C. micraster from the other species as two
unnamed generic groups.

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The following describes three recognisable taxa collected
during the SSBW.
Comatula cf. solaris Lamarck, 1816
(Fig. 3A–C)
Diagnosis. Comatula with 10 arms; cirri up to XXV, 25,
forming complete or partial marginal row; combs occupying
approximately distal third or more of proximal pinnules,
composed of up to 24 tall, crowded, triangular teeth; comb
usually tapering distally but terminal tooth remaining distinct;
teeth sometimes remaining tall to tip (modied from A. H.
Clark, 1931).
Remarks. Specimens are attributed to C. cf. solaris only
tentatively. The largest has R = ~100 mm, considerably
smaller than fully developed specimens of this species
collected elsewhere. Cirri are chiefly XIV–XVI, 12–14
with LW of longest cirrals <1.5. A small specimen has cirri
XI, 12 with LW to 1.5. The type specimens of C. solaris
(MNHN EcCs1009, 1010) were collected along the western
or northwestern coast of Australia (Freycinet, 1815; A. H.
Clark, 1931).
Colour. (Includes only those specimens attributed to this
taxon following eldwork) Yellow with pinnules white with
purple or maroon lateral blotches or stripe; uniformly dark
purple with yellow pinnule tips, or banded pale and darker
lavender or purple with pinnules yellow or pale orange,
yellow cirri, and rusty orange disk and ambulacra.
Local depth range. 11.7–125 (possibly 136) m.
Ecology. Substrates recorded during the SSBW include
rocks >20 cm, laterite rock and gravel, rocky, gravel, sandy,
and muddy with gravel and dead shells. A. H. Clark (1931)
listed only two substrate records for this species: coral mud
and mud. Messing et al. (2006) attributed one specimen to
this species, found under a small piece of rubble between
12 and 18 m depth on a sediment bottom between reefs at
Lizard Island, Australia. The specimen had nine of its arms
coiled over its oral surface and one arm extended along the
sediment surface.
Material examined. (Includes only those specimens
attributed to this taxon following eldwork) sta. 5313TB2,
E of Pulau Seringat, start 01°14.009’N, 103°54.095’E, end
01°13.881’N, 103°53.837’E, 70.0–85.3 m, 17 May 2013
(1; SIO-BIC E6567); no data (3 specs.); sta. TB16, outside
Eastern Boarding Ground A, 01°13.537’N, 103°53’793’E,
89.5–98.0 m, 21 May 2013 (1; ZRC.ECH.0386); sta.
TB17, Eastern Holding, 01°13.816’N, 103°54.060’E.
86.7–90.9 m, 21 May 2013 (1; ZRC.ECH.0358); sta. TB28,
Singapore Port Limit near Eastern Boarding Ground A,
01°13.181’N, 103°52.900’E, 94.3–97.6 m, 22 May 2013
(5; ZRC.ECH.0524, ZRC.ECH.0525, ZRC.ECH.0522,
ZRC.ECH.0527, ZRC.ECH.0528); sta. TB29, Singapore
Port Limit near Eastern Boarding Ground A, 01°13.036’N,
103°52.820’E, 98–103 m, 22 May 2013 (2; ZRC.ECH.0363,
ZRC.ECH.0523); sta. TB30, Marina Barrage, outside Marina
Bay, 01°16.186’N, 103°52.375’E, 17.1–19.1 m, 22 May
2013, (1; ZRC.ECH.0615); sta. TB69, near Pulau Sudong and
Pulau Semakau, 01°13.155’N, 103°43.880’E, 17.9–18.9 m,
25 May 2013 (1; ZRC.ECH.0517); sta. TB96, near Eastern
Bunkering A, 01°18.140’N, 104°04.221’E, 22.4–25.1 m, 28
May 2013 (2; ZRC.ECH.0455); sta. DR111, outside Eastern
Boarding Ground A, 01°12.989’N, 103°53.062’E, 125–136
m, 29 May 2013 (2; ZRC.ECH.0529, 3; ZRC.ECH.0368);
sta. TB142, E Johor Strait, 01°17.838’N, 104°04.157’E,
28.7–28.8 m, 31 May 2013 (ZRC.ECH.0372); sta. SD145,
W of Pulau Hantu, no lat., long, 11.7 m, 1 June 2013 (1;
ZRC.ECH.0518); sta. DR160, Eastern Boarding Ground A,
01°13.584’N, 103°53.798’E, 92.5–97.5 m, 3 June 2013 (2;
ZRC.ECH.0486, ZRC.ECH.0530); sta. DR161, beside St
John’s Island, 01°12.843’N, 103°51.449’E, 41.2–44.4 m, 3
June 2013 (1; ZRC.ECH.0373).
Material previously collected at Singapore. ZMUH (1),
NHB (2), no data (see A. H. Clark, 1931).
Comatula cf. pectinata (Linnaeus, 1758)
(Fig. 3D–F)
Diagnosis. Comatula with 10 arms (rarely to 12; a few
specimens attributed to this species have 16–17 arms); IIBr
series 2(1+2), when present; cirri up to XX, 17 (usually no
more than XVI, 15), forming complete or partial marginal
row but not restricted to interradial angles; arms broad
basally and tapering rapidly distally, or long, slender and
evenly tapered; comb occupying less than distal third of most
proximal pinnules, composed of 12–16 rounded triangular
teeth, with bases of successive teeth separated; distalmost
teeth reduced so that comb tapers to a blunt tip (modied
from A. H. Clark, 1931).
Remarks. Specimens are attributed to C. cf. pectinata only
tentatively. The largest has R = ~80 mm, much smaller
than fully developed specimens of this species collected
elsewhere. Cirri are XIV–XVIII, 10–16, with LW of
longest cirrals 1.2–1.4. Combs are distinctly different than
those of Singapore specimens attributed to C. cf. solaris.
One specimen has 12 arms with two IIBr2(1+2). The type
specimen of C. purpurea (ZMB) was collected along the
western or northwestern coast of Australia (Freycinet, 1815,
A. H. Clark, 1931), whereas Linnaeus (1758) gave the type
locality for his Asterias pectinata as “Indian seas” (“in mare
Indico”), which could be anywhere in the Indian Ocean or
East Indies.
Colour. White or pale yellow with a pair of dark brown or
red-brown aboral arm stripes, centrodorsal yellow or yellow
orange, disk dark maroon, pinnules white with lateral brown
stripe or maroon articulations, often with bright red-brown
ambulacra and yellow tips; yellow or pale yellow-brown
with paler midaboral arm stripe.
Local depth range. 11.7–125 (possibly 141) m.
Ecology. Substrates recorded during the SSBW include silt
and gravel, laterite rock and gravel, sandy, and rocky. One

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Messing & Tay: Crinoidea (Echinodermata) of Singapore
Fig. 3. Comatula species. A–C, Comatula cf. solaris. A, aboral view; (SIO-BIC E6567); B, aboral view; (ZRC.ECH.0386); C, detached
oral pinnule comb. D–F, Comatula cf. pectinata. D, aboral view; (ZRC.ECH.0387). E, aboral view; (SIO-BIC E6532); F, Oral pinnules.
G–H, Comatula sp.; G, Aboral view; (5314-TB2-089); H, Oral pinnules. Scale bars = 1 mm.

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specimen had a black and pale yellow-white Ophiomaza
ophiuroid. Substrates mentioned in A. H. Clark (1931)
include shells, sand, lithothamnion, coral sand, pebbles
and rock. Specimens attributed to C. pectinata are widely
recorded from the Indo-western Pacic (A. H. Clark, 1931;
Rowe & Gates, 1995), and as cryptic during the day with
arms extending from reef interstices at night (Meyer, 1986;
Messing, 1998).
Material examined. Sta. 5314TB1, E of Pulau Sentosa,
start 01°14.730’N, 103°53.870’E, end 01°14.944’N,
103°53.890’E, 27.8–33.8 m, 17 May 2013 (1; ZRC.
ECH.0532); sta. 5314TB2, start 01°14.924’N, 103°53.730’E,
end 01°14.808’N, 103°53.528’E, 24.4–25.4 m, 17 May 2013
(2; ZRC.ECH.0509, ZRC.ECH.0510); sta. TB15, Eastern
Fairway, 01°16.300’N, 103°55.226’E, 21.5–23.8 m, 21
May 2013 (1; SIO-BIC E6540); sta. TB16, outside Eastern
Boarding Ground A, 01°13.537’N, 103°53.793’E, 89.5–98.0
m, 21 May 2013, (3; SIO-BIC E6533, SIO-BIC E6532,
ZRC.ECH.0387); sta. TB28, Singapore Port Limit near
Eastern Boarding Ground A, 01°13.181’N, 103°52.900’E,
94.3–97.6 m, 22 May 2013 (1; ZRC.ECH.0526); sta. TB29,
Singapore Port Limit near Eastern Boarding Ground A,
01°13.036’N, 103°52.820’E, 98–103 m, 22 May 2013 (1;
ZRC.ECH.616); sta. TB30, Marina Barrage, outside Marina
Bay, 01°16.186’N, 103°52.375’E, 17.1–19.1 m, 22 May
2013, (1; ZRC.ECH.0521); sta. TB69, near Pulau Sudong
and Pulau Semakau, 01°13.155’N, 103°43.880’E, 17.9–18.9
m, 25 May 2013 (1; ZRC.ECH.0367); sta. DR111, outside
Eastern Boarding Ground A, 01°12.989’N, 103°53.062’E,
125–136 m, 29 May 2013 (1; ZRC.ECH.0519); sta. SD145, W
of Pulau Hantu, no lat., long., 11.7 m, 1 June 2013 (1; ZRC.
ECH.0520); sta. TB158, Singapore Port Limit, Near Southern
Fairway off Kusu Island, 01°12.236’N, 103°52.116’E, 110–
141 m, 3 June 2013 (1; ZRC.ECH.0485); sta. DR161, beside
St John’s Island, 01°12.843’N, 103°51.449’E, 41.2–44.4 m,
3 June 2013 (3; ZRC.ECH.0511).
Material previously collected at Singapore. NHM (1)
(Carpenter, 1888; A. H. Clark, 1931); USNM 36259 (1),
E1084 (2), Svend Gad; E3129, on sand bank, Johore Strait
(1) (A. H. Clark, 1931); ZMC, Svend Gad (+76) (A. H.
Clark, 1931). As C. purpurea USNM E1085, Svend Gad
(1)(A. H. Clark, 1931).
Comatula sp.
(Fig. 3G, H)
Diagnosis. Comatula with 10 arms; centrodorsal very thin
with cirrus sockets usually conned to one side (sometimes
in most or all interradial angles); cirri III–VIII (rarely XI),
to 14 (chiey 12–13), more slender than in previous two
species; LW of longest cirrals 1.5–2.5; combs occupying up
to approximately distal third of proximal pinnules, of up to
25 tall, crowded, triangular teeth; comb tapering distally but
terminal tooth distinct.
Remarks. This species is similar to C. cf. solaris but with
fewer, more slender cirri, chiey conned to one side of a
thinner centrodorsal, even in specimens of similar ray length
and centrodorsal diameter. Based on published diagnostic
characters, it is not clear to which if any named Comatula
species it should be assigned. As noted above, cirri in named
species may occur in a complete or incomplete ring or be
restricted to the interradial angles. However, none have been
described as having cirri chiey restricted to one side of
the centrodorsal. One specimen was collected together with
C. cf. pectinata, reducing the likelihood of environmental
conditions contributing to the arrangement of the cirri.
Colour. Orange-brown with a paler orange mid-aboral arm
stripe and pinnules white with purplish-brown mottling; pale
gray-brown with hint of green and some distal arms yellow.
Local depth range. 23.8–67.9 m (possibly 21.5–79.3 m).
Ecology. Substrates recorded during the SSBW are mud,
silt, and gravel.
Material examined. Sta. 5314TB1, E of Pulau Sentosa,
start 01°14.730’N, 103°53.870’E, end 01°14.944’N,
103°53.890’E, 27.8–33.8 m, 17 May 2013 (3; ZRC.
ECH.0507, ZRC.ECH.0531, ZRC.ECH.0508); sta. 5314TB2,
start 01°14.924’N, 103°53.730’E, end 01°14.808’N,
103°53.528’E, 24.4–25.4 m, 17 May 2013 (1; ZRC.
ECH.0533); sta. 5313TB3, Eastern Boarding Ground A,
beside Eastern Holding B, start 01°14.079’N, 103°54.165’E,
end 01°13.932’N, 103°53.811’E, 67.9–79.3 m, 17 May 2013
(7; ZRC.ECH.0500 to 0505, ZRC.ECH.0506); sta. TB5,
Beside Sebarok, 01°10.533’N, 103°46.512’E, 63.8–64.1
m, 20 May 2013 (1; ZRC.ECH.0351); sta. TB15, Eastern
Fairway, 01°16.300’N, 103°55.226’E, 21.5–23.8 m, 21
May 2013 (1; ZRC.ECH.0360); sta. DR57, around Tanah
Merah, 01°16.297’N, 103°57.677’E, 46.2 m, 24 May 2013
(1; ZRC.ECH.0388); sta. TB58, around Tanah Merah,
01°16.808’N, 103°58.246’E, 38.7–39.9 m, 24 May 2013
(1; ZRC.ECH.0361); no data (1 spec.)
CAPILLASTERINI A. H. Clark, 1909b
Capillaster A. H. Clark, 1909b
Diagnosis. Mouth excentric in fully developed individuals;
up to 110 arms; cirri in 1–2 marginal rows (absent in C.
macrobrachius); IBr series united by synarthry; IIBr 2 or
4(3+4); IIIBr and beyond 3(2+3); rst syzygy at 3+4 on
arms arising from IBr, at 2+3 on arms arising from IIBr
and beyond; distal intersyzygial interval 4–27; distalmost
pinnule comb on P3–P21 (in C. tenuicirrus at intervals as
far as mid-arm); comb teeth single, triangular, conuent
with outer edge of pinnule; comb not tapering signicantly
distally (Summers et al. 2014).
Capillaster multiradiatus (Linnaeus, 1758)
(Fig. 4A, B, D)
Diagnosis. Capillaster with usually 15–25 arms and 15–28
(usually 20–24) cirrals; middle and distal cirrals short, broader
than long (modied from A. H. Clark, 1931).

634
Messing & Tay: Crinoidea (Echinodermata) of Singapore
Fig. 4. Capillaster species. A, B, D, Capillaster multiradiatus. A, aboral view. B, cirrus (both SIO-BIC E6563). D, middle cirrals; (ZRC.
ECH.0474); C, E, Capillaster cf. tenuicirrus. C, aboral view; (ZRC.ECH.0350); E, middle cirrals; (SIO-BIC E6556). Scale bars = 1 mm.
Remarks. Capillaster multiradiatus differs from C. sentosus
(below) in being smaller with fewer arms, and having
shorter, less robust cirri of fewer cirrals. The two are easily
distinguished wherever they have been observed in situ
together (Messing, 1998b), but it is not clear how smaller,
incompletely developed specimens of C. sentosus can be
distinguished from C. multiradiatus. A. H. Clark (1931)
noted several “typical” C. sentosus specimens from Singapore
with 57 to 100 arms, but also described a smaller specimen
with 35 arms as “practically intermediate” between the two
species. Specimens collected in Singapore were chiey small,
with at most 27 arms (chiey 19–23) and ray lengths 55
mm at most. Several small specimens have 10 arms with
ray length as little as 15 mm.
Colour. Entirely white or with proximal rays pale yellow,
or entirely pale yellow with white pinnules and dark brown
or black ambulacra. Elsewhere, colors are widely variable
(Messing, 1994, 2007, unpublished data).
Local depth range. 22.7–125 (possibly 22.4–136) m.
Ecology. All specimens were collected during the SSBW
via beam trawl or rectangular dredge. Habitats recorded
included laterite rock, rocky, gravel, mud, or sandy, with
two stations recording mud, two recording clay and one with
wood, charcoal, rock and mud. Capillaster multiradiatus
is a common reef-dweller elsewhere in the tropical Indo-
Western Pacific. At Madang, Papua New Guinea, it is
cryptic or semicryptic during the day with arms extended
from sponges or foliaceous or branching corals and occurs

635
RAFFLES BULLETIN OF ZOOLOGY 2016
no shallower than 8 m. In >25 m, it may be completely
exposed on octocoral fans or whips and usually forms an
irregular radial fan with several arms curled. At Palawan
Island, Philippines, it was found during the day in 17–20
m exposed on corals with arms coiled, and semicryptic in
a sponge with arms in a multidirectional posture. Pinnules
along each arm orient in a single plane rather than in a
multidirectional posture (Messing, 1994, 2007). At Palau,
however, it is cryptic during the day and semicryptic at
night among coral branches or in crevices with arms forming
monoplanar arm fans in as little as 1 m (Meyer & Macurda,
1980; Messing, 2007). This distinctive habit suggests that
specimens identied as C. multiradiatus should be treated
as tentative pending revision.
Material examined. Sta. 5314-TB1, start 01°14.730'N,
103°53.870'E, end 01°14.944'N, 103°53.890'E, 27.8-33.8 m,
17 May 2013 (SIO-BIC E6563); sta. TB16, outside Eastern
Boarding Ground A, 01°13.537’N, 103°53.793’E, 89.5–98.0
m, 21 May 2013 (1; ZRC.ECH.0357); sta. TB28, Singapore
Port Limit, Eastern Boarding Ground A, 01°13.181’N,
103°52.900’E, 94.3–97.6 m, 22 May 2013 (2; SIO-BIC
E6534, ZRC.ECH.0370); sta. TB58, around Tanah Merah,
01°16.808’N, 103°58.246’E, 38.7–39.9 m, 24 May 2013
(1; ZRC.ECH.0374); sta. TB73, South of Pulau Semakau,
01°11.282’N, 103°46.632’E, 24.6–29.8 m, 25 May 2013
(specimen discarded); sta. TB97, near Eastern Bunkering
A, 01°18.425’N, 104°04.607’E, 22.4–22.7 m, 28 May
2013 (4; SIO-BIC E6545); sta. TB98, Eastern Bunkering
A, 01°18.938’N, 104°05.312’E, 30.2–33.6 m, 28 May 2013
(4; SIO-BIC E6543); sta. TB109, Eastern Boarding Ground
A, 01°13.045’N, 103°52.943’E, 111–114 m, 29 May 2013
(1; ZRC.ECH.0446); sta. DR111, outside Eastern Boarding
Ground A, 01°12.989’N, 103°53.062’E, 125–136 m, 29 May
2013 (1; ZRC.ECH.0447, 4; ZRC.ECH.0456); sta. TB141,
East Johor Strait, 01°17.725’N, 104°04.363’E, 28.3–28.4 m,
31 May 2013 (3; ZRC.ECH.0471); sta. TB142, East Johor
Strait, 01°17.838’N, 104°04.157’E, 28.7–28.8 m, 31 May
2013 (10; ZRC.ECH.0474).
Material previously collected at Singapore. USNM 35026
(1), E.1086 (1), ZMC (26), Svend Gad (in A. H. Clark, 1931);
MNB 2455 (1), Prof. Eduard von Martens (in A. H. Clark,
1931); NHM[?] (1), Prof. Charles Stewart (in Carpenter,
1888, A. H. Clark, 1931).
Capillaster sentosus (Carpenter, 1888)
Diagnosis. Large, robust Capillaster with up to 110 arms
(usually > 60); cirri to 40 mm long, of up to 40 cirrals;
longest cirrals with LW no greater than ~1.3; distal cirrals
short. (A. H. Clark, 1931).
Remarks. Capillaster gracilicirrus A. H. Clark, 1912, which
is known from only ve specimens collected off East Java,
Indonesia, differs only in having longest cirrals with LW
2.0 and distal cirrals with LW ~1.0 (A. H. Clark, 1912).
A. H. Clark (1931) attributed a small 17-armed specimen
from Banda, Indonesia, to C. sentosus, apparently because
it has three IVBr series, which are rare in C. multiradiatus.
Material previously collected at Singapore. ZMC (12
specimens), Svend Gad (A. H. Clark, 1909a, 1931).
Capillaster cf. tenuicirrus A. H. Clark, 1912a
(Figs. 4C, E; 5)
Diagnosis. Similar to C. multiradiatus, but with proportionately
longer cirrals (fewer cirrals for a given cirrus length); distal
cirrals often as long as or slightly longer than wide; small
erect or hooked aboral spine on distal cirrals, and smaller
cirrus-free aboral pole for a given centrodorsal diameter
(Fig. 5).
Remarks. A. H. Clark (1931) distinguished C. tenuicirrus
from C. multiradiatus solely on the “elongated and slender
cirri in which the distal segments from the tenth or eleventh
onward are very slightly longer than broad” (p. 209).
Although this is thin evidence on which to distinguish a
species, several specimens collected during the SSBW
appear to t the published description of C. tenuicirrus.
The distinguishing characters are chiey relative, e.g., for
a cirrus length of 17 mm, C. cf. tenuicirrus has 23–25
cirrals and C. multiradiatus from Singapore 27–28; the
centrodorsal diameter to aboral pole diameter ratio is 1.3–1.4
in C. multiradiatus and chiey 1.5–1.9 (1.4 in one smaller
specimen) in C. cf. tenuicirrus. Color is also distinctive (see
below). Specimens of both were collected at the same station,
and although some specimens of C. cf. tenuicirrus are larger
than any attributed to C. multiradiatus, some size overlap
exists, suggesting that the distinctions are neither ecological
nor ontogenetic, and C. multiradiatus gets larger elsewhere
(A. H. Clark, 1931; Messing, unpublished observations).
However, it is unclear if specimens distinguished here as C.
cf. tenuicirrus represent a separate taxon. Also, the Singapore
specimens were collected in substantially shallower water
than the type series of C. tenuicirrus (82–118 m) (A. H.
Clark, 1931).
Colour. Uniformly rich red-purple or dark purple; one
specimen with a yellow centrodorsal.
Local depth range. ~22–28 m.
Ecology. All specimens were collected via beam trawl.
Habitats recorded included clay, one with wood, charcoal,
rock, and mud, and one very muddy with gravel, and dead
shells.
Material examined. Sta. TB97, near Eastern Bunkering A,
01°18.425’N, 104°04.607’E, 22 m, 28 May 2013 (1; SIO-
BIC E6544); sta. TB141, East Johor Strait, 01°17.725’N,
104°04.363’E, 28 m, 31 May 2013 (1; SIO-BIC E6556);
sta. TB142, East Johor Strait, 01°17.838’N, 104°04.157’E,
28.7–28.8 m, 31 May 2013 (2; SIO-BIC E6551, 1; SIO-
BIC E6550).

636
Messing & Tay: Crinoidea (Echinodermata) of Singapore
PHANOGENINI White & Messing
(in White et al. 2001)
Phanogenia Lovén, 1866
Diagnosis. Mouth central in fully developed individuals; up
to 170 arms; cirri absent or in 1–2 marginal rows; IBr series
united by cryptosynarthry or synarthry; IIBr chiey 4(3 + 4);
subsequent brachitaxes chiey 2(1+2); IIIBr and following
axils often bearing one brachitaxis and one undivided arm,
alternating on successive axils; rst syzygy at 3+4 on arms
arising from IBr, at 1+2 on arms arising from subsequent
brachitaxes; distal intersyzygial interval 3–4; pinnule combs
at intervals to near arm tip; comb teeth tall, triangular to
spade-shaped, conuent with outer edge of pinnule; proximal
tooth saucer-like and transverse; terminal tooth discrete
(Messing, 1998b, 2001; Summers et al., 2014).
Phanogenia typica Lovén, 1866
(Fig. 6)
Diagnosis. Phanogenia with the centrodorsal reduced,
pentagonal or stellate, and lacking cirri in all but the
smallest specimens; combs typically coiled; number of teeth
on P1 widely variable, 10–29; arms detach easily; texture
extremely sticky/adhesive due to numerous ne spines on
pinnules; color pattern usually including at least a broken
dark aboral arm stripe.
Remarks. The type species, P. typica, rst collected at New
Harbour, Singapore, by Capt. Albert Vestöö and described
by Lovén (1866), was long treated as a junior synonym
of the Australian endemic Comaster multidus (Müller,
1841) (A. H. Clark, 1931). The latter shares with P. typica
a reduced centrodorsal and few or no cirri, but otherwise
differs in having massive ray bases, a pavement of small
plates aborally between adjacent ray bases; no syzygy at
br1+2, and a completely different comb form. Messing
(1998b) resurrected Phanogenia for most species placed in
Comaster by A. H. Clark (1931), recognised P. typica as
distinct, and distinguished the type specimen from P. gracilis,
the other Phanogenia with a reduced centrodorsal bearing
few rudimentary or no cirri, on the basis of its signicantly
longer pinnule combs: 24–29 teeth on P1, and rarely fewer
than 10 teeth on brachial pinnules. Similarly large or larger
specimens attributed to P. gracilis had P1 with 10–16 teeth
and almost always <10 teeth on subsequent pinnules. The
two species had been distinguished (as Comaster multidus
and C. gracilis) on various grounds in several studies
(e.g., Meyer & Macurda, 1980; Zmarzly, 1985; Messing,
1998a). Owen et al. (2009) examined a large number of
specimens from across the Indo-western Pacic and found
two morphotypes—“stunted” with up to ~120 arms usually
<12 cm long usually at depths of 2–5 m, and “large” with
usually <60 arms to 25 cm long in >6 m. Their molecular
phylogeny returned three clades with no areal congruity and
with the two morphotypes scattered among all three clades.
They treated all specimens as P. gracilis (none came from
Singapore).
The SSBW retrieved the first long-combed specimens
recognised since the species was described. However,
specimens with short combs, collected on the same reefs,
are otherwise morphologically identical, and may even
exhibit the same color pattern. As a result, all are treated
here as P. typica.
Phanogenia typica appears to drop its few juvenile cirri
and increase arm number rapidly. One small specimen from
Singapore (ZRC.ECH.0380) with only 21 arms, ray length
~65 mm, and the elongated ray ossicles characteristic of
most juvenile feather stars, has a pentagonal centrodorsal
1.2 mm across that is raised above the surrounding radials
and rises to low central apex (a vestige of the attachment
site for the postlarval stalk); it has 9 functional cirrus sockets
(3 cirri remain), and traces of obsolete sockets on the aboral
pole. Another small specimen (sta. TB69; discarded) has
a centrodorsal of the same diameter, already attened and
sunken, with cirri reduced to 10 buds, and 57 arms (ray
length ~50 mm), including eight regenerating from a single
brachitaxis. The largest specimens examined have 70–80
arms with ray length ranging from 55 to 155 mm.
Colour. In situ: gray, orange, pale green, or black, usually
with beaded pinnules. Detail: rays mottled, blotched or
Fig. 5. Comparison of Capillaster multiradiatus (solid circles) and
Capillaster cf. tenuicirrus (open diamonds) specimens. A, number
of cirri versus ratio of centrodorsal base diameter to centrodorsal
aboral pole diameter; B, number of cirrus segments (cirrals) versus
cirrus length (mm).

637
RAFFLES BULLETIN OF ZOOLOGY 2016
Fig. 6. Phanogenia typica. A, aboral view; (ZRC.ECH.0378); B, long oral pinnule comb (ZRC.ECH.0401); C, in situ (not collected).
Scale bars = 1 mm.

638
Messing & Tay: Crinoidea (Echinodermata) of Singapore
spotted throughout or just proximally, with distal arms
more or less a solid color; white and either charcoal gray,
orange, dark brown or maroon; orange or yellow and black
or maroon; usually with darker pigment producing at least
a broken midaboral stripe. Darker pigment sometimes
dominant, reducing paler color to mottling or spots. Dark
sides of brachials may produce a pair of pale stripes anking
the dark midaboral stripe. Pinnules usually beaded the same
color as the rays: charcoal gray and white, yellow and orange,
orange and black or maroon; some or all pinnules may be
all white or pale yellow; tips rarely darker. Gonads pink,
tan or white. Disk white or dark gray.
Local depth range. 3.3–18.0 m.
Ecology. Semicryptic, with centrodorsal hidden in a crevice or
under a ledge and arms extended in a multidirectional posture
(Meyer & Macurda, 1980). Specimens are particularly sticky
due to numerous ne spines on pinnules. Arms detach easily.
Material examined. Sta. SD25, Southwest St John’s Island,
01°12’51”N, 103°50’57”E, 6.8–16 m, 22 May 2013 (4;
ZRC.ECH.0378, ZRC.ECH.0380, ZRC.ECH.0395, ZRC.
ECH.0397); sta. SD40, West Pulau Semakau, 01°12.389’N,
103°45.24’E, 3.3–7.3 m, 23 May 2013 (5; ZRC.ECH.0399,
ZRC.ECH.0401, SIO-BIC E6542, ZRC.ECH.0402, ZRC.
ECH.0403); sta. SD45, channel between Lazarus and St
John’s Islands, 01°13’12”N, 103°51’11”E; 16.2 m, 23 May
2013 (1; SIO-BIC E6541); sta. TB69, near Pulau Sudang
and Pulau Semakau, 01°13.155’N, 103°43.880’E, 17.9–18.9
m, 25 May 2013 (2; discarded).
Material previously collected at Singapore. NRS (3
specimens), New Harbour, shallows and muddy places,
Capt. Albert Vestöö (as Phanogenia typica, Lovén 1866);
ZMC (2 spec.), Svend Gad (as Comaster gracilis in A. H.
Clark, 1909a, 1931).
Phanogenia schoenovi (A. H. Clark, 1918)
Remarks. A. H. Clark (1918) described this species as
Comaster schoenovi from a single specimen collected off
the east coast of China (ZMC). Only two specimens are
known. This species differs from P. typica and P. gracilis
in having a complete ring of well-developed cirri around
the centrodorsal margin. It is likely a junior synonym of P.
fruticosus (A. H. Clark, 1911a), as it differs only in minor
variations in the number and proportions of cirrus segments.
Material previously collected at Singapore. ZMC (1
specimen), no collector named (as Comaster schoenovi in
A. H. Clark, 1931).
COMASTERINI A. H. Clark, 1908c
Comaster Agassiz, 1836
Diagnosis. Mouth excentric in fully developed individuals;
up to 180 arms; centrodorsal small, discoidal or pentagonal;
cirri absent or present; aboral surface with irregular plates
between bases of adjacent rays; IBr united by synarthry; IIBr
series usually 4(3+4); IIIBr usually of 2 ossicles exteriorly
and 4(3+4) interiorly; rst syzygy on undivided arms always
3+4; distalmost pinnule comb on at least P3, sometimes at
intervals to P14; combs arising gradually and tapering to a
sharp point distally or with a discrete terminal tooth; comb
teeth paired, erect, well separated; pairs of teeth of more or
less equal size, each conuent with its edge of the pinnular,
and sometimes joined to form a transverse bar (Messing,
1998b, 2001).
Remarks. Previous to the revision by Messing (1998b),
species in this genus were chiey referred to Comanthina A.
H. Clark, 1909 (A. H. Clark, 1931; Hoggett & Rowe, 1986).
Comaster schlegelii (Carpenter, 1881)
Remarks. Hoggett & Rowe (1986) distinguished C. nobilis
(Carpenter, 1888) as a separate species, but the two overlap
enough to restore it to synonymy under C. schlegelii,
following A. H. Clark (1931).
Material previously collected at Singapore. ZMC (2
specimens), Svend Gad [as Comanthus (Comanthina) nobilis
in A. H. Clark, 1909a].
Comanthus A. H. Clark, 1908a
Diagnosis. Mouth excentric in fully developed individuals; up
to 75 arms; centrodorsal circular to pentagonal; cirri present
in one row or absent; IBr2 united by synarthry; IIBr and
subsequent brachitaxes 2 or 4(3+4); rst syzygy at 3+4 on
all undivided arms; distal intersyzygial interval 4; distalmost
pinnule comb at intervals sometimes reaching near arm tip;
comb terminating in large discrete tooth; proximal tooth
transverse, saucer-like; primary comb teeth conuent with
exterior edge of pinnulars; smaller secondary tooth present
or not (Summers et al., 2014).
Remarks. Several Comanthus species are widespread in
the eastern tropical Indo-western Pacic region, but only
C. parvicirrus has been reported from Singaporean waters.
Comanthus wahlbergii (Müller, 1843) has been recorded as
far west as South Africa, but not from Singapore.
Comanthus parvicirrus (Müller, 1841)
Material previously collected at Singapore. USNM E1087
(syntype, 1 specimen); ZMC (6); Svend Gad, 16 April 1907
(as Comaster tenella A. H. Clark, 1931).—ZMC (1), Svend
Gad [as Comanthus (Comanthus) rotalaria (Lamarck, 1816)
in A. H. Clark, 1909a, and Comanthus timorensis (Müller,
1841) in A. H. Clark, 1931].—USNM 34996 (4); ZMC
(41), Svend Gad, 17 June 1904 to 23 October 1910 [as
C. (C.) rotalaria and C. rotalaria in A. H. Clark, 1909a),
and Comanthus parvicirrus (Müller, 1841) (in A. H. Clark,
1931)].

639
RAFFLES BULLETIN OF ZOOLOGY 2016
Anneissia Summers, Messing & Rouse, 2014
Diagnosis. Mouth excentric in fully developed individuals;
up to 120 arms; centrodorsal circular, large and thick; cirri
always present; IBr2 united by synarthry; IIBr and beyond
all 4(3+4); rst syzygy at 3+4 on all undivided arms; distal
intersyzygial interval 4, occasionally 5; distalmost pinnule
comb on P2 to P5, tapering distally to a sharp point; teeth
erect, non-conuent (Summers et al., 2014).
Remarks. Phylogenetic trees derived from molecular data
and supported by morphological distinctions (Summers et al.
2014) split the former genus Oxycomanthus into two separate
groups of species. One group, characterised by a reduced
centrodorsal with relatively few or no cirri, falls out within a
clade of Clarkcomanthus species. Because this group includes
the type species of Oxycomanthus—Comanthus (Vania)
parvicirra ß comanthipinna Gislén, 1922—the remaining
species formerly included in Oxycomanthus required a
new generic epithet; hence, Anneissia, named for crinoid
researcher Anne Hoggett.
Anneissia bennetti (Müller, 1841)
Remarks. This species was previously treated as Comanthus
bennetti (e.g., A. H. Clark, 1931, Meyer & Macurda, 1980)
and Oxycomanthus bennetti (e.g., Hoggett & Rowe, 1986;
Rowe et al. 1986; Kogo, 1998).
Material previously collected at Singapore. ZMUH (1
specimen), no collector (as Actinometra bennetti in Carpenter,
1882, 1888, and Comanthus bennetti in A. H. Clark, 1909,
1931).
Family COLOBOMETRIDAE A. H. Clark, 1909c
Diagnosis. Some or all cirrals with aboral transverse ridge,
commonly serrate or tuberculate, or with transverse row of
2 or 3 tubercles or spines; distal (rarely all) spines often
single; radial articular facet steep, separated along interradial
margin; interarticular ligament fossae moderate and triangular
to large and high, separated by wide and shallow midradial
furrow (except in Cyllometra); adoral muscle fossae small
and vestigial to low, slightly curved along adoral margin;
arms 10 to >80; brachitaxes 2 or 4(3+4); rst syzygy on
undivided arms at 3+4; proximal brachials sometimes with
lateral processes; one or more proximal pinnules (usually Pa)
may be absent; some genera with pinnulars broadened over
gonads (modied from Hess & Messing, 2011).
Remarks. The family as currently construed includes
genera with individual characters that diverge from other
confamilials, suggesting that the family may not represent
a monophyletic clade, e.g., Pontiometra has a greatly
elongated rst exterior pinnule and apparently distinctive
radial articular facets (A. H. Clark, 1921), whereas Cyllometra
has interradial ridges and a small radial pit on the adoral
centrodorsal surface, the radial interarticular ligament fossa
with a narrow median ridge, and muscle fossae uniquely tall
(Hess & Messing, 2011).
Recent molecular phylogenies have placed Colobometridae
somewhat differently relative to closely related families.
Hemery (2011) returned eight terminals representing six
taxa in four genera (Oligometra, Decametra, Cyllometra,
Colobometra) as a clade sister to Stephanometra
(Mariametridae), and this clade sister to a clade composed
of Himerometridae, Zygometridae, and other Mariametridae.
The colobometrid Iconometra anisa returned separately,
nested within a clade of Indo-Pacific “antedonids” and
sister to Aporometridae. Subsequently, Hemery et al. (2013)
returned three of the colobometrid terminals as a clade sister
to a similar Mariametridae/Himerometridae/Zygometridae
clade, but omitted Stephanometra and Iconometra from the
analyses. Rouse et al. (2013) returned two colobometrid
terminals (Colobometra, Cenometra) as a clade sister to a
Stephanometra/Lamprometra clade, and this combined clade
as sister to a clade including Himerometridae, Zygometridae
and the mariametrid Liparometra.
Colobometra A. H. Clark, 1909d
Diagnosis. Proximal cirrals with distal aboral fringe of
spines; middle and distal cirrals with paired spines; arms
10; Pa present or absent (Hess & Messing, 2011).
Remarks. As with Zygometra (see below), most if not all of
the six nominal species currently recognised in Colobometra
by A. H. Clark (1947) are distinguished largely by size-
related features and may be synonyms. Only C. arabica A.
H. Clark, 1936a, described from the Red Sea, occurs outside
the range recorded for the other ve: Fiji through tropical
Australia to Sri Lanka and north to Okinawa, Japan (A. H.
Clark, 1947; Fishelson, 1974; Kogo, 1998).
Colobometra perspinosa Carpenter, 1881
Diagnosis. The largest species of Colobometra. Cirri of
53–65 cirrals; P3 slightly longer and larger than P2; following
pinnules to P8 or P9 similar to P3, slightly decreasing in length;
arms 120–150 mm long (A. H. Clark, 1947).
Remarks. Colobometra previously collected at Singapore was
recorded as C. vepretum A. H. Clark, 1909a. Subsequently,
A. H. Clark (1936) recorded intermediate specimens between
C. perspinosa and C. vepretum, referring to them as probably
representing “the same specic type,” but then (A. H. Clark,
1947) treated the latter as C. perspinosa var. vepretum. The
differences between the two—relative stiffness of P1 and
proportions of some cirrals—are minor, and all Colobometra
collected from Singapore so far are treated here as C.
perspinosa. Two specimens were collected during the SSBW.
Colour. White with a few dark pinnules, or white with a
broad dark chocolate aboral stripe, broadened as dark bands
on middle and distal arms; cirri chiey dark chocolate;
pinnules white or chocolate. At Madang, Papua New Guinea,
C. perspinosa is typically dark maroon or red-brown (black
in situ) with a paler aboral stripe and cirri; its pinnules may
have orange tips (Messing, unpublished).

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Messing & Tay: Crinoidea (Echinodermata) of Singapore
Fig. 7. A, Pontiometra andersoni in situ; B, Cenometra bella, centrodorsal, bases of cirri and bases of two rays; (ZRC.ECH.0467). C, D,
F, Oligometra serripinna; C, specimen on ellisellid octocoral; (ZRC.ECH.0405); D, cirrus, with middle cirrals bearing transverse ridge;
(ZRC.ECH.0381). F, proximal pinnules with P1 at right, showing carination on large P2; (ZRC.ECH.0381). E, G, Decametra sp. (ZRC.
ECH.0476); E, middle cirrals showing paired low tubercles; G, proximal pinnules with P1 at right, with P2 bearing rim of spines on middle
pinnulars and weak carination on distal pinnulars. Scale = 1 mm.

641
RAFFLES BULLETIN OF ZOOLOGY 2016
Ecology. Clings to usually fan-shaped octocorals with its
ten arms arrayed in a planar or shallow-bowl-like radial fan
(Meyer & Macurda, 1980).
Material examined. Sta. SD54, SW Kusu Island, 01°13.9’N,
103°52’E, depth not recorded, max. depth 7.8 m, 24 May
2013 (1; ZRC.ECH.0407); sta. SD151, SW Kusu Island,
01°13.9’N, 103°52’E, depth not recorded, max. depth 19.6
m, 3 June 2013 (1; ZRC.ECH.0484).
Material previously collected at Singapore. USNM 35313
(1 specimen), ZMC (1), Svend Gad, 17 June 1904 (as
Colobometra vepretum in A. H. Clark, 1909a); MNB 6379
(1), Eduard von Martens (as C. vepretum in A. H. Clark,
1912c, with incorrect catalogue no. 5351).
Cenometra A. H. Clark, 1909d
Diagnosis. As many as 40 arms; brachitaxes of 2 ossicles,
with adambulacral anges; second pinnule large, stout, and
curved (Hess & Messing, 2011).
Remarks. A. H. Clark (1947) distinguished four species of
Cenometra on the basis of variations in the development of
carination on the basal pinnulars of the proximal pinnules,
although Gislén (1940) suggested that the differences were
age-related. A. M. Clark & Rowe (1971, p. 19) stated that
C. cornuta and C. herdmani “should be considered as
synonyms” of C. bella and maintained only C. emendatrix
from the western Indian Ocean as distinct. However, they
distinguished all four in their key.
Cenometra bella (Hartlaub, 1890)
(Fig. 7B)
Colour. Zebra-banded yellow and dark chocolate.
Ecology. The single collected specimen was found clinging
to an antipatharian whip.
Material examined. Sta. SD133, south of Kusu Island, no
lat., long., 11 m, 31 May 2013 (1; ZRC.ECH.0467).
Decametra A. H. Clark, 1911c
Diagnosis. Proximal cirrals with transverse aboral ridge,
becoming paired spines or tubercles, or rarely a single spine
distally; arms 10; rst interior pinnule (Pa) absent; second
pinnule (P2) rounded or rounded triangular in cross section
(prismatic); distal ends of pinnulars uniformly spinose or
smooth (Hess & Messing, 2011).
Remarks. The published distinction between Decametra
and Oligometra (A. H. Clark (1947) is minor, and it is not
clear that the two should remain separate (compare diagnosis
above with that of Oligometra below). In addition, A. H.
Clark (1947) diagnosed Decametra as having distal ends of
P2 pinnulars uniformly spinous but described D. parva (A. H.
Clark, 1912e) as having spines at the prismatic corners of the
pinnulars, D. mollis (A. H. Clark, 1909f) as having projecting
outer corners, and D. arabica A. H. Clark, 1912d, as having
the distal angles produced as in Oligometra serripinna.
Similarly, his generic diagnosis refers to distal cirrals with
paired spines or tubercles or rarely a single spine, but he
described three species [D. studeri (A. H. Clark, 1909d),
D. brevicirra (A. H. Clark, 1912d), D. modica A. H. Clark,
1911c] as having 4–6 cirrals preceding the penultimate with
a single spine. He recognised 16 species but noted that: “…
specic lines within the genus Decametra are difcult to
draw, and the present interpretation of specic limits must
be regarded as largely tentative” (p. 172). He suggested that
a number of species, e.g., D. informis (Carpenter, 1888), D.
modica and D. taprobanes (A. H. Clark, 1909g), D. arabica
and D. alaudae A. H. Clark, 1911c, might prove conspecic.
Hemery (2011) returned this genus as a paraphyletic clade
including representatives of three other colobometrid genera.
?Decametra sp.
(Fig. 7E, G)
Remarks. Specimens collected during the SSBW are very
tentatively attributed to Decametra and may prove instead to
be Oligometra. All are small; the largest has ray length 35
mm. Most conform to Decametra in having paired tubercles
or spines on one or a few distal cirrals and Pa uniformly
absent. However, the paired tubercles chiefly appear as
stronger ends of a weak transverse ridge, and the latter feature
may be a function of small size (ray length <20 mm). As
in Oligometra, one or few distalmost cirrals preceding the
opposing spine bear a single aboral spine, and pinnulars of
P2 often bear a spine at the distal corner or corners.
Colour. Dark or pale purple, maroon, or reddish-purple,
sometimes with white arm tips, or yellow with maroon
articulations; cirri white, bluish-gray, or both; pinnules
sometimes blue.
Local depth range. 18–125 m (possibly 15–136 m).
Ecology. One specimen was recovered clinging to a hydroid.
Bottom data recorded for dredge and trawl stations include
clay, silt, mud, gravel and rocks.
Material examined. Sta. DR14, Eastern Fairway,
01°16.835’N, 103°55.284’E, 15.8–18.0 m, 21 May
2013 (1; ZRC.ECH.0359); sta. TB17, Eastern Holding,
01°13.816’N, 103°54.060’E, 86.7–90.9 m, 21 May 2013 (1;
ZRC.ECH.0365); sta. TB28, Singapore Port Limit, Eastern
Boarding Ground A, 01°13.181’N, 103°52.900’E, 94.3–97.6
m, 22 May 2013 (1; ZRC.ECH.0369); sta. TB96, near Eastern
Bunkering A, 01°18.140’N, 104°04.221’E, 22.4–25.1 m,
28 May 2013 (1; ZRC.ECH.0444); sta. TB97, near Eastern
Bunkering A, 01°18.425’N, 104°04.607’E, 22.4–22.7 m, 28
May 2013 (3; ZRC.ECH.0439); sta. DR111, outside Eastern
Boarding Ground A, 01°12.989’N, 103°53.062’E, 125–136
m, 29 May 2013 (1; ZRC.ECH.0457); sta. TB142, East Johor
Strait, 01°17.838’N, 104°04.157’E, 28.7–28.8 m, 31 May
2013 (2; ZRC.ECH.0476).

642
Messing & Tay: Crinoidea (Echinodermata) of Singapore
Decametra informis (Carpenter, 1888)
Diagnosis. Decametra with cirri 7 mm long with 14–18
segments; P1 and P2 of 10–12 segments, with distal edge of
distalmost pinnulars with small tufts of spines; P2 longer and
stouter than P1; arms 30–40 mm long (A. H. Clark, 1947).
Remarks. A. H. Clark (1947) noted that this species,
previously also known from the Philippines, and D. modica,
known from east Africa to the Maldives and possibly Sri
Lanka, may be synonyms.
Material previously recorded from Singapore. MNB 5353
(1) Prof. Edouard von Martens (A. H. Clark, 1912c, 1947).
Decametra mylitta A. H. Clark, 1912e
Diagnosis. Decametra with cirri 10–11 mm long with 21–23
cirrals; all cirrals markedly broader than long; P2 9 mm long
with 17 segments, much longer and stronger than small weak
P1; P3 of 14 segments, resembling P2 but about two-thirds as
long; arms 55–75 mm long (A. H. Clark, 1947).
Remarks. A. H. Clark (1947) noted that this species,
previously also known from the Philippines, Hong Kong
and possibly Borneo, and D. mollis, known from the Persian
Gulf and Pakistan to the Maldives, are likely synonymous.
Material previously recorded from Singapore. No
repository given (1), Svend Gad (A. H. Clark, 1947).
Oligometra A. H. Clark, 1908b
Diagnosis. Cirrals with transverse aboral ridge; arms 10; rst
interior pinnule present or absent; second pinnule enlarged,
stiff, prismatic, with distal ends of pinnulars produced as
broad spine, ange, or tuft of spines (Hess & Messing, 2011).
Remarks. Hemery (2011) returned Oligometra serripinna,
macrobrachius A. H. Clark, 1936b and Oligometra carpenteri
(Bell, 1884) seperately in a clade including representatives
of four colobometrid genera, with O. carpenteri as basal.
P2 in O. carpenteri, with its uniquely broadened and keeled
segments, differs substantially from that of both O. serripinna
and all other colobometrids (A. H. Clark, 1947).
Oligometra serripinna (Carpenter, 1881)
(Fig. 7C, D, F)
Diagnosis. Oligometra with segments of P2 mostly longer
than, or at least as long as, broad, with distal ends of
prismatic ridges produced or with one or more spines (A.
H. Clark, 1947).
Remarks. A. H. Clark (1947) recorded O. serripinna
as occurring from the Red Sea and eastern Africa to the
Philippines, Indonesia, and as far north as Hong Kong. He
recognised three “true geographical races or subspecies” (p.
216) from outside this range: O. s. chinensis (A. H. Clark,
1918) (Fujian, China) with P2 not greatly enlarged, delicate
distally, with distal pinnulars twice as long as broad or longer,
pinnule prole serrate in distal half, proximal pinnules with
second-fourth segments narrowly carinate, and cirri relatively
long and slender with up to 24 segments; O. s. electrae A. H.
Clark, 1913 (Eritrea), as ornate, with extravagantly developed
processes on proximal pinnules, and O. s. caledoniae A.
H. Clark, 1911b (New Caledonia and Tonga), with distal
ends of pinnulars of P2 weakly produced and spinous, and
distal ends of following pinnules not produced. It is unclear
whether any of these or his other named local varieties have
any validity, e.g., the single specimen of O. s. electrae was
collected only about 250 km north of fragmentary material
attributed to one of his local varieties, O. s. occidentalis A. H.
Clark, 1911c (southern Red Sea to Mauritius). Kogo (1998)
treated specimens that represented the rst records from Japan
as Oligometra chinensis, although he described the cirri as
rather stout, “proximal pinnul[ar]s mostly about as long as
broad” (p. 82) and did not mention the pinnule carination
described by A. H. Clark (1947) for O. s. chinensis. The
species has since been recorded, as Oligometra serripinna,
from tropical Australia (Houtman Abrolhos WA to Tweed
River NSW) (Rowe & Gates (1995), Palau (Meyer &
Macurda, 1980; Messing, 2007) and Rarotonga, Cook Islands
(USNM E 38906, http://collections.USNM.si.edu/search/iz/
downloaded 11 September 2014).
Specimens from Singapore vary considerably and exhibit
features of both O. s. serripinna and O. s. chinensis. Proximal
pinnulars of P1 may be distinctly carinate or not. The second
pinnule may have proximal pinnulars weakly carinate or not,
and middle pinnulars with no distal projection or with a well-
developed sometimes nely spinose triangular projection,
sometimes on both interior and exterior distal corners of
pinnulars. Distal pinnulars of P2 may be distinctly longer
than wide or about as long as wide in the same specimen.
Pa may be absent on some rays or uniformly present. Cirri
are stout, of up to 20 cirrals, with the transverse aboral ridge
reduced to a single small spine only on the distal 1–2 cirrals
preceding the opposing spine. The brachials are smooth or
somewhat everted. The specimens collected at Singapore
during the SSBW are thus treated simply as Oligometra
serripinna.
Colour. Arms usually variously banded or blotched: 1) white
with large dark maroon blotch on each brachial bordered
with orange and chiey orange distally, 2) with numerous
red-purple blotches; 3) three to four large chocolate blotches
bordered by yellow blend into broad chocolate arm stripe that
gradually covers arm; 4) banded golden brown and white with
some maroon aborally; 5) white with dark chocolate spots
proximally, becoming short dark bands on middle and distal
arms; 6) white with purple bands, or 7) all purple. Pinnules
white, chocolate, banded white and maroon or dark chocolate,
or white with red-purple blotches arranged in curved lines
spanning several adjacent pinnules. Centrodorsal white; cirri
white proximally, light maroon distally or with pale maroon
adoral spot; disk mottled white and maroon, with maroon
areas bordered by olive.

643
RAFFLES BULLETIN OF ZOOLOGY 2016
Local depth range. Subtidal to 24.6 (possibly 29.8) m.
Ecology. On octocorals, including red ellisellid whip.
Material examined. Sta. SD25, SW of St John’s Island,
no lat., long., 7.6 m, 22 May 2013 (6; ZRC.ECH.0379,
ZRC.ECH.0381, ZRC.ECH.0382, ZRC.ECH.0384, ZRC.
ECH.0385, ZRC.ECH.0396); sta. SD54, SW of Kusu
Island, 01°13.9’N, 103°52’E, 7.8 m, 24 May 2013 (3;
ZRC.ECH.0409, ZRC.ECH.0405, ZRC.ECH.0408); sta.
TB73, S of Pulau Semakau, 01°11.282’N, 103°46.632’E,
24.6–29.8 m, 25 May 2013 (discarded); sta. SD84, SW of
Pulau Tekukor, 01°13.8’N, 103°50.25’E, 8 m, 27 May 2013
(1; ZRC.ECH.0429); sta. IT93, Pulau Jong, 01°12.901’N,
103°47.194’E, <1 m, 28 May 2013, hand collection
(discarded); sta. TB113, Southern Fairway, S of Sisters’
Islands, 01°12.001’N, 103°50.261’E, 29.3–30.5 m, 29 May
2013 (1; ZRC.ECH.0453); sta. SB132, S of Kusu Island, no
lat., long., 8 m, 31 May 2013 (discarded).
Material previously collected at Singapore. ZMC (75?),
shallow water, Svend Gad; USNM (2) 36265, E1072) (A.
H. Clark, 1947).
Pontiometra A. H. Clark, 1907b
Diagnosis. Adoral side of centrodorsal with irregular,
radiating, coelomic furrows; cirri with up to 80 cirrals;
proximal cirrals with distal aboral spinose edge; middle
cirrals with paired spines; distal cirrals with single spine;
to 120 arms; all brachitaxes of 2 ossicles. P1 on exterior
undivided arms much longer than those following (Hess &
Messing, 2011).
Pontiometra andersoni (Carpenter, 1889)
(Fig. 7A)
Remarks. Pontiometra andersoni is the only species in
the genus. It is easily recognised by its large size, many
arms arrayed in a parabolic fan, very long cirri that elevate
it above the substrate, and rst pinnule on each arm much
longer than those following. It is soft relative to most other
local crinoids and sheds its arms easily.
Colour. Pale, creamy tan or white with short brown arm
bands; one specimen with pair of faint tan aboral stripes
anking midaboral white stripe; pinnules pale creamy tan
either with few or many brown pinnules, few dark brown
pinnules forming 1–2 short irregular concentric bands on
rays, or with brown bands on successive pinnules form
stripes parallel to arm; one specimen each with pinnules
and ambulacra dark brown, rays pale orange and white, or
entirely white. Cirri pale creamy tan; disk with brown spots.
Local depth range. 3–39.5 (possibly 40.2) m.
Ecology. Perches fully exposed on rock or coral pinnacles
and sponges with arms arrayed in a parabolic fan (Meyer
& Macurda, 1980).
Material examined. Sta. SD45, channel between Lazarus
and St John’s Is., 01°13’21”N, 103°51’02”E, max. depth
16.2 m, 23 May 2013 (1; ZRC.ECH.0404); sta. TB73, S
of Pulau Semakau, 01°11.282’N, 103°46.632’E, 29.8–24.6
m, 25 May 2013 (2; ZRC.ECH.0415, ZRC.ECH.0416); sta.
SD66, W patch reef, Pulau Hantu, 01°13.6’N, 103°44.8’E, 3
m, 25 May 2013 (1; ZRC.ECH.0419); sta. TB69, near Pulau
Sudong and Pulau Semakau, 01°13.155’N, 103°43.880’E,
17.9–18.9 m, 25 May 2013 (1; discarded); sta. TB71, S
of Pulau Hantu, 01°13.157’N, 103°44.642’E, 21.1–22.6
m, 25 May 2013 (1; discarded); sta. SD133, S of Kusu
Island, 01°13’13”N, 103°51’38”E, max. depth 11 m, 31
May 2013 (1; ZRC.ECH.0468); sta. SD151, SW of Kusu
Island, 01°13.9’N, 103°52’E, max. depth 19.6 m; 3 June
2013 (2; ZRC.ECH.0482, ZRC.ECH.0483); sta. SD167,
SW of Pulau Jong, 01°12’51”N, 103°47’07”E, max. depth
15.4 m, 4 June 2013 (1; ZRC.ECH.0492); sta. TB187, near
Rafes Lighthouse, 01°09.239’N, 103°44.674’E, 39.5–40.2
m, 5 June 2013, trawl (1; ZRC.ECH.0498).
Material previously collected at Singapore. USNM 36264
(1 specimen), ZMC (4), Svend Gad (in A. H. Clark, 1909a,
1947); MNB 5351, 5372 (2 cirri and a visceral mass), Eduard
von Martens (in A. H. Clark, 1912c); Rafes Museum (1),
1899, no collector (in A. H. Clark, 1934).
Family HIMEROMETRIDAE A. H. Clark, 1908a
Diagnosis. Centrodorsal aboral apex broad and at, depressed
or deeply concave; extant genera with cirrus sockets without
distinct sculpturing, basal rosette but no basal rods, and adoral
surface of centrodorsal with interradial ridges and paired,
Y-shaped, or radiating coelomic furrows (also on aboral
surface of radials); cirrals with or without aboral tubercle
or spine; radial articular facet moderately sloping to very
steep; interarticular ligament fossae large and high; adoral
muscle fossae low, curved along adoral edge and more or
less continued along part of midradial furrow; radial cavity
large; IBr2 united by synarthry; following brachitaxes of
either 2 or 4 ossicles; rst arm syzygy at 3+4; brachials of
undivided arms often extremely short, often discoidal; one
or more proximal pinnules enlarged (modied from Hess
& Messing, 2011).
Remarks. Relationships within and among Himerometridae,
Zygometridae, Colobometridae and Mariametridae remain
to be clarified (see under Colobometridae above and
Mariametridae and Zygometridae below).
Himerometra A. H. Clark, 1907b
Diagnosis. Himerometridae with proximal pinnules
decreasing in length and stoutness from the most proximal
(on the brachitaxes) to P3; brachitaxes strongly rounded
aborally and well separated; usually more than 25 arms;
IIIBr series usually 4(3+4) on the outside and 2 on the inside
of each IIBr series.
Remarks. A. H. Clark (1941) distinguished six species in two
groups: H. robustipinna (Carpenter, 1881), H. magnipinna A.

644
Messing & Tay: Crinoidea (Echinodermata) of Singapore
H. Clark, 1908d, H. sol A. H. Clark, 1912d, and H. martensi
(Hartlaub, 1890) with stout proximal pinnules composed
chiey of short pinnulars lacking any carination, and H.
bartschi A. H. Clark, 1908d, and H. persica A. H. Clark,
1908e, with long, slender, distally agellate and proximally
carinate proximal pinnules.
Himerometra robustipinna (Carpenter, 1881)
Diagnosis. Himerometra with enlarged proximal pinnules
stout with all or most pinnulars broader than long, or as
broad as long, no carination, and with distal margins of
proximal pinnulars swollen and everted or not.
Remarks. Himerometra magnipinna is here considered a
junior synonym of H. robustipinna; the only characters
on which A. H. Clark (1941) distinguished them (length
and number of component pinnulars of enlarged proximal
pinnules) overlap substantially, as do their ranges. The two
known specimens of H. sol appear to be slightly more robust
variants of H. robustipinna but were collected in the Maldive
Islands, whereas the westernmost record of H. robustipinna
[recorded as its putative synonym, H. kraepelini (Hartlaub,
1890)] is Sri Lanka. A. H. Clark (1941) distinguished
H. martensi (Hartlaub, 1890) as having distal margins of
enlarged proximal pinnules projecting abruptly beyond the
bases of succeeding pinnulars (but not overlapping) and
armed with numerous ne spines (restricted to distal pinnulars
in large specimens), and distal ends of proximal brachials
strongly produced and everted. However, examination of
several specimens collected by Svend Gad at Singapore
(the type locality) and identied as H. martensi by A. H.
Clark (USNM 36136, E1080), while exhibiting pinnulars of
large proximal pinnules with distal margins thickened and
projecting on one side, and brachials with everted distal
margins, revealed no ne spines (numerous or otherwise)
on pinnulars of enlarged proximal pinnules. The variations
in these specimens and those collected during the SSBW
fall well within the range of variation of H. robustipinna.
Himerometra martensi is thus considered a junior synonym
of H. robustipinna.
Colour. Rays orange or pale red; pinnules and ambulacra
red or dark red; or entirely red.
Local depth range. <1.0–20.6 (possibly 22.6) m.
Ecology. Perches fully exposed on corals, rocks, sponges
or octocorals with arms arrayed in a parabolic or radial fan;
often with arms curled meridionally inward. Symbionts
recorded during the SSBW were Periclimenes commensalis
(sta. SD89) and Allogalathea elegans (sta. 133).
Material examined. Sta. SD25, SW of St. John’s Island,
01°13’02”N, 103°50’48”E, 6.8 m, 22 May 2013 (3; ZRC.
ECH.0390, ZRC.ECH.0377, ZRC.ECH.0383); sta. DR70,
near Pulau Sudong and Pulau Semakau, 01°13.134’N,
103°44.283’E, 20.6–22.6 m, 25 May 2013 (1; ZRC.
ECH.0420); sta. TB69, near Pulau Sudong and Pulau
Semakau, 01°13.155’N, 103°43.880’E, 17.9–18.9 m, 25
May 2013 (9; discarded); sta. IT81, Big Sister’s Island,
~ 01°12’51”N, 103°49’56”E, <1 m, 26 May 2013, hand
collection (1; discarded); SD89, S of Small Sister’s
Island, 01°12.9’N, 103°49.88’E, 9–10 m, 27 May 2013
(1; discarded); sta. SD133, S of Kusu Island, 01°13’13”N,
103°51’38”E, max. depth 11 m, 31 May 2013 (1; discarded);
sta. IT140, Pulau Tekukor, 01°13.899’N, 103°50.265’E, <1
m, 31 May 2013, hand collection (1; discarded).
Material previously collected at Singapore. Raffles
Museum (1), 1899, no collector (as Himerometra magnipinna
in A. H. Clark, 1934); MNB 5373 (1 specimen), Straits
Settlements, von Martens (as Antedon martensi in Hartlaub,
1890, 1891; and in A. H. Clark, 1941); USNM 35968 (2),
36136 (6), 36176 (1), E1080 (1); ZMC (21?), Svend Gad
(as H. crassipinna in A. H. Clark, 1909a, as H. martensi
in A. H. Clark, 1941); BSNH (18), no collector (in A. H.
Clark, 1909a, 1941); MCZ 59 (1), 289 (1), no cat. no. (1),
no collector (as H. martensi in A. H. Clark, 1909a, 1941);
Rafes Museum (1), no collector (as H. martensi in A. H.
Clark, 1934, 1941); YPB (1) no collector (as H. martensi in
A. H. Clark, 1941); NHM (1), Pulau Obin (as H. martensi
in A. H. Clark, 1913, 1941).
Himerometra bartschi A. H. Clark, 1908d
Diagnosis. Himerometra with enlarged proximal pinnules
long, slender, distally agellate; proximal pinnulars carinate
(A. H. Clark, 1941).
Material previously collected at Singapore. ZMC (1
specimen), Svend Gad (in A. H. Clark, 1909a, 1941).
Craspedometra acuticirra (Carpenter, 1882)
Diagnosis. Himerometridae with cirri long, nearly straight
or slightly curved, tapering gradually to sharp tip; of 40–60
cirrals; distal cirrals much longer than broad and without
aboral processes; no opposing spine; terminal claw nearly
straight; P2 longer and stouter than more proximal pinnules
(modied from A. H. Clark, 1941).
Remarks. Craspedometra is a monspecific genus that
includes only C. acuticirra.
Material previously collected at Singapore. MNHN no
cat. no. (1 specimen), M. Maidron, 1884 (A. H. Clark,
1911b); ZMC no cat. no. (1), Svend Gad (in A. H. Clark,
1909a, 1941).
Heterometra A. H. Clark, 1909d
Diagnosis. Centrodorsal hemispherical to discoidal with at
aboral apex; adoral side with radiating coelomic furrows
in paired depressions; arms 10–48; brachitaxes of 2 or 4
ossicles; ray bases separated or laterally apposed; proximal
pinnules increasing in length and stoutness to P3; pinnulars
smooth, carinate or distally spinose, or anged (Hess &
Messing, 2011).

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RAFFLES BULLETIN OF ZOOLOGY 2016
Remarks. Heterometra currently includes 27 named species,
16 of which were described by A. H. Clark. Of the latter, ten
were described from fewer than ve specimens each (i.e., H.
astyanax A. H. Clark, 1941, H. ater (A. H. Clark, 1911c), H.
ora (A. H. Clark, 1913), H. gravieri A. H. Clark, 1911c,
H. joubini A. H. Clark, 1911c, H. madagascarensis (A. H.
Clark, 1911c), H. parilis (A. H. Clark, 1909h), H. producta
(A. H. Clark, 1908a), H. sarae A. H. Clark, 1941, and H.
schlegelii (A. H. Clark, 1908a)) (A. H. Clark, 1941). A. H.
Clark (1941) wrote that many of the characters (i.e., cirri,
pinnules, and arms) are highly variable and overlap those of
the other himerometrid genera to varying degrees, and that
members of the genus are recognised chiey because they
do not fall within any of the other himerometrid genera.
Hemery (2011) returned two terminals in two separate clades
(Heterometra crenulata among several Himerometridae and
Heterometra sp. within Mariametridae), so it is possible that
the genus will be dismantled.
Many species are differentiated on the basis of minor
morphological differences, and A. H. Clark (1941) admitted
that some species may intergrade (e.g., H. producta and
H. propinqua (A. H. Clark, 1912e)) and that “species of
Heterometra are among the most difcult of all comatulids
to identify” (p. 227). Clark & Rowe (1971) also pointed out
inconsistencies between A. H. Clark’s keys and descriptions.
As an example, one of the primary dichotomies in A. H.
Clark’s (1941, pp. 230–231) key to the species of Heterometra
is: basal segments of the enlarged proximal pinnules with
versus without prominent thin carinate processes or keels
on the side toward the arm tip. However, the character is
almost identical in the holotypes of H. schlegelii (ZMC cat.
no. CRI–41) in the group with keels and H. producta (ZMC
cat. no. CRI-34) in the group without, although the distal
ends of the distal pinnulars bear a few spines in H. producta
(C.G. Messing, personal observations).
Multiple specimens collected during the SSBW cannot be
satisfactorily identied to species, either because of their
small size or lack of denitive characters, and some are
only tentatively identied as Heterometra; they have not
been included herein. Identications to the species level
are also tentative.
Heterometra afnis (Hartlaub, 1890)
Diagnosis. Heterometra with enlarged proximal pinnules
smooth with proximal pinnulars carinate; P2 the largest and
longest pinnule; cirri of up to 30 cirrals; few cirrals slightly
longer than broad; distal cirrals with small aboral spines;
arms 15–18, 65–120 mm long, composed of wedge-shaped
brachials (A. H. Clark, 1941).
Material previously recorded from Singapore. USNM
E1082 (1), ZMC (2?), Svend Gad (A. H. Clark, 1941).
Heterometra amboinae (A. H. Clark, 1912d)
Diagnosis. Heterometra with brachials distinctly wedge-
shaped with ends never quite parallel, and not exceedingly
short; enlarged proximal pinnules smooth, with proximal
pinnulars keeled; cirri of 28–40 (usually 30–35) subequal
cirrals; all cirrals about twice as broad as long; arms 13–23
(usual 17–19), 105–180 mm long; P2 and P3 of 26–31
segments; P3 usually longer than P2 (A. H. Clark, 1941).
Material previously recorded from Singapore. ZMC (1),
Svend Gad, 12 December 1906 (A. H. Clark, 1941).
Heterometra bengalensis (Hartlaub, 1890)
Diagnosis. Heterometra with brachials beyond the proximal
fourth of the arms exceedingly short, discoidal, with ends
parallel; distal ends of proximal brachials produced and
everted; IIIBr series absent; cirri of 22–31 (chiey <30)
cirrals, 13–22 mm long; longest cirrals somewhat longer than
broad; arms 11–18, 50–100 mm long; P2 and P3 similar, 9
mm long, of 24 pinnulars, or P3 is somewhat smaller than P2.
Remarks. A. M. Clark (in Clark & Rowe, 1971, p. 12)
suggested that the specimens from Singapore in the NHM
identied by A. H. Clark “may be referable rather to H.
singularis.”
Material previously recorded from Singapore. USNM
E1073 (1), E1079 (5), ZMC (15?), Svend Gad; NHM (2),
13 m, 12 December 1898; Rafes Museum (1), New Harbor,
15 m, 31 July 31 1899 (A. H. Clark, 1941).
Heterometra cf. crenulata (Carpenter, 1882)
(Fig. 8A, C)
Diagnosis. A highly variable Heterometra with enlarged,
strongly prismatic proximal pinnules; distal portion of
prismatic ridges on each pinnular raised into conspicuous
broad rounded triangular processes; pinnule proles strongly
serrate with ends of teeth broadly rounded (A. H. Clark, 1941).
Remarks. Specimens identied as H. crenulata have the
enlarged proximal pinnules moderately to strongly prismatic
with the distal ends of the ridges, especially the abambulacral
ridge facing the arm tip, bearing a nely spinose projection
that gives the pinnule a serrate prole. In some middle
pinnulars the spines form a short partial rim across the distal
margin facing the arm tip. The distal cirrals bear an aboral
carina or longitudinally attened, distally-directed spine; the
spine may be blunt or sharp and the carina may be divided
into 2–3 teeth. Low synarthrial tubercles are present, and at
least some of the short middle brachials have projecting distal
margins. Small specimens with at least some projection of
the distal corners of the pinnulars on the proximal pinnules
have been placed here; their cirri are substantially more
delicate with longer, more slender cirrals, but retain an
aboral spine or carina.
Colour. Red-orange, yellow-orange, pinkish-red, reddish-
purple, pink, often with paler or white pinnules; rays often
banded, e.g., rays yellow-orange with pale tan-yellow bands
and white pinnules; pale purple or white with darker arm
bands; dull reddish-purple with white bands; creamy yellow

646
Messing & Tay: Crinoidea (Echinodermata) of Singapore
with white bands; pink and white banded; white with broad
light purple bands or with pale orange bands, or pale orange
with white and pale red bands. Bands may be restricted to
proximal or distal arms. Ambulacral tissue often darker (red,
maroon or purple) with dark color sometimes restricted to
more darkly-colored arm bands.
Local depth range. 22.7–125 (possibly 22.4–136) m.
Ecology. All specimens identied as H. crenulata were
trawled or dredged on a variety of bottoms, including rocks,
gravel, dead shells, shell fragments, coral rubble, laterite
rock, sand, smelly sand, silt, mud, clay, sticky clay, big
lumps of clay, reddish marine clay, and sponge, in various
combinations.
Material examined. Sta. DR1, Rafes reserve near Rafes
Lighthouse, 01°10.125’N, 103°45.419’E, 38.3–38.5 m, 20
May 2013 (2; ZRC.ECH.0352, 1; ZRC.ECH.0353, 1; ZRC.
ECH.0355); sta. 5313TB3, Eastern Boarding Ground A,
beside Eastern Holding B, start 01°14.079’N, 103°54.165’E,
end 01°13.932’N, 103°53.811’E, 67.9–79.3 m, 17 May
2013 (1; ZRC.ECH.0617); sta. TB15, Eastern Fairway,
01°16.300’N, 103°55.226E, 21.5–23.8 m, 21 May 2013,
Beam trawl, (1; ZRC.ECH.0364); sta. TB16, outside Eastern
Boarding Ground A, 01°13.537’N, 103°53.793’E, 89.5–98.0
m, 21 May 2013 (2; ZRC.ECH.0362, ZRC.ECH.0366); sta.
TB28, Singapore Port Limit, Eastern Boarding Ground A,
01°13.181’N, 103°52.900’E, 94.3–97.6 m, 22 May 2013 (2;
ZRC.ECH.0371, ZRC.ECH.0389); sta. TB73, S of Pulau
Semakau, 01°11.282’N, 103°46.632’E, 24.6–29.8 m, 25 May
2013 (1; ZRC.ECH.0424); sta. TB96, near Eastern Bunkering
A, 01°18.140’N, 104°04.221’E, 22.4–25.1 m, 28 May 2013
(3; ZRC.ECH.0442); sta. TB97, near Eastern Bunkering A,
01°18.425’N, 104°04.607’E, 22.4–22.7 m, 28 May 2013
(1; ZRC.ECH.0441); sta. DR111, outside Eastern Boarding
Ground A, 01°12.989’N, 103°53.062’E, 125–136 m, 29
May 2013 (1; ZRC.ECH.0448); sta. TB127, beside Eastern
Boarding Ground A, 01°12.974’N, 103°52.960’E, 113–128
m, 30 May 2013 (1; ZRC.ECH.0466); sta. TB129, beside
Eastern Boarding Ground A, 01°12.783’N, 103°52.200’E,
66.5–74.7 m, 30 May 2013 (1; ZRC.ECH.0460); sta. TB142,
East Johor Strait, 01°17.838’N, 104°04.157’E, 28.7–28.8
m, 31 May 2013 (1; ZRC.ECH.0472); sta. DR161, beside
St John’s Island, 01°12.843’N, 103°51.449’E, 41.2–44.4
m, 3 June 2013 (3; ZRC.ECH.0488, ZRC.ECH.0489,
ZRC.ECH.0490); sta. DR174, next to Eastern Boarding
Ground A near Kusu Island, 01°12.202’N, 103°52.178’E,
79.6–135 m, 4 June 2013 (1; ZRC.ECH.0494); sta. DR183,
beside Rafes Lighthouse, 01°09.652’N, 103°44.908’E,
39.7–42.1 m, 5 June 2013 (1; ZRC.ECH.0495, 3; ZRC.
ECH.0496, 1; ZRC.ECH.0497); TB185, next to Pulau
Senang, 01°09.942’N, 103°43.458’E, 24.5–24.3 m, 5 June
2013 (4; ZRC.ECH.0499).
Material previously recorded from Singapore. ZMC (6),
Svend Gad (A. H. Clark, 1941).
Heterometra producta (A. H. Clark, 1909a)
Diagnosis. Heterometra with enlarged proximal pinnules
rather slender, becoming agellate distally; basal segments
sharply carinate; pinnulars from the third onward with entire
distal end somewhat produced and overlapping; outer portion
of prismatic ridges produced into a blunt spine directed
obliquely forward; cirri of 23–26 cirrals; longest cirrals with
LW 1.5; distal cirrals with LW ~1.0; arms 10–13, 50 mm
long (A. H. Clark, 1941).
Material previously recorded from Singapore. ZMC (1),
Svend Gad (A. H. Clark, 1941).
Heterometra quinduplicava (Carpenter, 1888)
Diagnosis. Heterometra with cirri of 25–36 (usually ~30)
subequal cirrals about as long as broad; distal cirrals at least
weakly carinate but aboral spines or tubercles absent; enlarged
proximal pinnules slender, smooth, with basal pinnulars more
or less abruptly rounded, sharpened, or obscurely carinate on
side toward arm tip; arms 10–26 (usually 15–20), 60–145
mm long; brachials very short (A. H. Clark, 1941).
Material previously recorded from Singapore. ZMC (2),
Svend Gad (A. H. Clark, 1941).
Heterometra schlegelii (A. H. Clark, 1908a)
(Fig. 8B, D)
Diagnosis. Heterometra without IIIBr series; distal brachials
exceedingly short and discoidal; distal margins of middle
brachials everted; radials with beads along distal margin;
brachitaxes laterally flattened; cirri ~20 mm long with
usually 30–35 cirrals; longest cirrals about as long as broad;
distal cirrals with LW ~1.3; aboral cirral spines long, sharp,
beginning abruptly; arms 12–13 (possibly to 20?), 70–85
mm long; proximal pinnules with prominent thin carinate
extensions or keels on the side toward the arm tip (modied
from A. H. Clark, 1941).
Remarks. Several specimens referred to H. schlegelii agree
with the diagnosis, key, and description in A. H. Clark
(1941). The holotype (ZMC cat. no. CRI-41) is similar but
appears somewhat more slender. The Singapore specimens
differ chiey in having more arms—up to either 19 or 20.
Colour. Orange with dark brown articulations. Live colour
was not recorded for specimen ZRC.ECH.0513; it is pinkish
gray with dark purple articulations in alcohol. ZRC.ECH.0434
is similar to the other two but with slightly more slender
rays and a different color pattern: ray bases and cirri white;
rays orange-brown; pinnules white with purple bases, some
pinnules banded purple and white.
Ecology. Specimens were trawled or dredged. Substrates
recorded were sandy and laterite gravel.

647
RAFFLES BULLETIN OF ZOOLOGY 2016
Material examined. Sta. TB73, S of Pulau Semakau,
01°11.282’N, 103°46.632’E, 24.6–29.8 m, 25 May 2013
(1; ZRC.ECH.0417, 3; ZRC.ECH.0512, 1; ZRC.ECH.0513);
sta. DR90, Southern Fairway near St John’s Island,
01°12.942’N, 103°51.946’E, 48.3–49.7 m, 27 May 2013
(1; ZRC.ECH.0432); sta. TB92, Southern Fairway near
St John’s Island, 01°12.926’N, 103°51.647’E, 39.5–49.9
m, 27 May 2013 (2; ZRC.ECH.0434, ZRC.ECH.0435);
sta. TB113, Southern Fairway, S of Sisters’ Island,
01°12.001’N, 103°50.261’E, 29.3–30.5 m, 29 May 2013
(1; ZRC.ECH.0452); sta. DR125, beside Sisters’ Island,
01°12.416’N, 103°49.858’E, 25.3–30.8 m, 30 May 2013
(1; ZRC.ECH.0465).
Heterometra singularis A. H. Clark, 1909g
Diagnosis. Heterometra with brachials distinctly wedge-
shaped with ends never quite parallel and not exceedingly
short; enlarged proximal pinnules smooth, with proximal
pinnulars keeled; cirri of 36–39 cirrals, about 35 mm long;
longest cirrals about as long as broad and distal cirrals
slightly broader than long with conspicuous aboral spines;
arms 12–20, 90–150 mm long; P2 largest pinnule; P1 and
P3 equally long (A. H. Clark, 1941).
Material previously recorded from Singapore. ZMC (1),
Svend Gad (A. H. Clark, 1941).
Amphimetra A. H. Clark, 1909d
Diagnosis. Himerometridae with centrodorsal low
hemispherical to discoidal; adoral side with radiating
coelomic furrows; exposed surface of radials low, but higher
in small species; arms 10; rare individuals with more than 10
arms have IIBr2; proximal pinnules only slightly enlarged
(Hess & Messing, 2011).
Remarks. Hess & Messing (2011) maintained Amphimetra
within Himerometridae in part because of the radiating
coelomic furrows on the adoral surface of the centrodorsal
rather than an undivided coelomic impression as in
Mariametridae. However, molecular data (Hemery, 2011)
place Amphimetra within a clade consisting of several
mariametrids (Lamprometra and Mariametra species) and
Heterometra sp., separate from other himerometrids. Rare
specimens with greater than ten arms have IIBr of two
ossicles as in Mariametridae, rather than both 2 and 4(3+4)
as in Himerometridae.
A. H. Clark (1941) recognised six species-level taxa within
the genus, but acknowledged that four intergrade (A.
pinniformis, A. molleri, A. tessellata, A. spectabilis), and he
distinguished the other two, A. ensifer and A. laevipinna,
chiey on size-related features and the extent of development
of synarthrial tubercles (see Clark & Rowe, 1971). Thus, the
number of valid taxa and the placement of the genus both
remain to be determined.
Amphimetra cf. discoidea (A. H. Clark, 1908d)
Diagnosis. Medium to large Amphimetra with cirri moderately
stout and straight proximally, becoming more slender and
curved distally, of 34–51 cirrals; longest cirrals about as long
as broad; distal cirrals with short dorsal spines or pointed
tubercles; arms 110–200 mm long; prominent sharp-pointed
synarthrial tubercles present (A. H. Clark, 1941).
Remarks. A. H. Clark (1941) treated A. discoidea as a
geographic race, as A. tessellata discoidea, but wrote (p.
381): “Whether discoidea should be recognised as a species
distinct from tessellata, or as a geographical race, or perhaps
merely as a form, is at the present time simply a matter of
personal opinion. Although when they are typically developed
tessellata and discoidea are very different in appearance, they
certainly intergrade. The ranges of the two types overlap,
though generally speaking tessellata is characteristic of the
region from the Sunda Islands to the Moluccas and southward
along the coast of Western Australia, while discoidea is
equally characteristic of the region from the Philippines
to Singapore and eastern and northern Australia as far as
the Aru Islands.” His photographic plate legends indicate
both A. discoidea (pl. 39, gs. 178, 182) and A. tessellata
discoidea (pl. 40, g. 188).
The single small specimen collected during the SSBW
agrees with the published description of A. discoidea and
is similar to a specimen previously collected at Singapore.
It has cirri straight proximally and low conical synarthrial
tubercles. Cirri are XVII, 27–28; the proximal pinnules
chiey have 14 pinnulars but vary in relative lengths: P1
is more slender than those following but may be about as
long. Middle brachials are wedge-shaped but more distal
brachials become more discoidal as in A. H. Clark’s (1941)
description. A. H. Clark included a specimen collected at
Singapore by Svend Gad in his description of A. formosa
(since synonymized under A. discoidea), which he described
as having distal pinnulars of the proximal pinnules with
“slightly thickened edges vaguely suggesting an approach
to the conditions found in Heterometra crenulata” (A. H.
Clark, 1941, p. 378)—a feature also present in the specimen
collected during the SSBW.
Colour. Rich purple aborally with purple and white pinnules;
ambulacral side of arms banded purple and white.
Ecology. Bottom recorded as gravel and dead shells.
Material examined. Sta. DR90, Southern Fairway near St
John’s Island, 01°12.942’N, 103°51.946’E, 48.3–49.7 m, 27
May 2013 (1; ZRC.ECH.0430).
Material previously collected at Singapore. ZMC (1),
Svend Gad (originally as A. formosa); Rafes Museum (1),
1899 (A. H. Clark, 1941).

648
Messing & Tay: Crinoidea (Echinodermata) of Singapore
Fig. 8. Heterometra species. A, C, Heterometra cf. crenulata. A, aboral view, (ZRC.ECH.0466); C, Proximal pinnules, with P1 at right,
showing strong spines on distal corners of pinnulars of P3; (ZRC.ECH.0352); B, D, Heterometra schlegelii; B, lateral view showing bases
of rays and cirri; (ZRC.ECH.0434); D, Proximal pinnules, with P1 at right, showing strong carination on side of pinnulars facing arm tip;
ZRC.ECH.0513. Scale bars = 1 mm (A, B).

649
RAFFLES BULLETIN OF ZOOLOGY 2016
Amphimetra ensifer (A. H. Clark, 1908a)
(Fig. 9A, B)
Diagnosis. Medium to small Amphimetra with synarthrial
tubercles extravagantly developed and produced; cirri 23–30
mm long, with usually 30–35 cirrals; longest cirrals usually
slightly longer than broad; arms 80–120 mm long (A. H.
Clark, 1941).
Remarks. All of the larger specimens collected during
the SSBW have the very strongly developed synarthrial
tubercles diagnostic of this species. Two smaller specimens
collected with the larger specimens have less developed
tubercles that are still larger than those of A. cf. discoidea
above. The larger specimens have longest cirrals broader
than long, similar to those described by A. H. Clark (1941)
for A. tessellata as “from nearly twice as broad as long to
nearly as long as broad.” Only the smaller specimens have
cirrals slightly longer than broad, as described for A. ensifer.
Until recently, A. ensifer was only known from Singapore.
Messing (1998a) mentioned A. ensifera/laevipinna (following
AM Clark & Rowe’s [1971] spelling of A. ensifera) from
the Sulu Sea and noted that “large and small specimens of
Amphimetra collected in the Sulu Sea survey key out as A.
ensifera and A. laevipinna, respectively. Both occur in the
same habitat (sometimes together)—clinging to isolated
arborescent cnidarians or sponges on mud bottoms—and
clearly represent a single species” (p. 190). Mekhova &
Britayev (2012) recorded two specimens from Nhatrang
Bay, Vietnam (South China Sea). They also attributed three
specimens to A. cf. tessellata, distinguishing them on the
basis of prominently developed (A. ensifera) vs. “purely
developed” (A. cf. tessellata) synarthrial tubercles (p. 461),
although they noted a personal communication from one of
us (CGM) indicating that the two should be considered a
single species. Although A. tessellata is the senior name, I
retain A. ensifer herein because the specimens were collected
from the Singapore type locality, and the status of the various
Amphimetra species remains to be determined.
Fig. 9 illustrates variations in the development of synarthrial
tubercles between a large and small specimen attributed to
A. ensifer taken at the same station.
Colour. White with darker or dark brown ambulacra, the dark
color sometimes restricted to short arm bands); centrodorsal
and sometimes arm bases may be bright pale yellow; cirri
pale purple, sometimes darker distally; some pinnules with
pale yellow tips; one specimen with proximal arms pale
lavender; a small specimen pale yellow with short purple
arm bands.
Local depth range. 25.3–28.8 m (possibly 24.6—30.8 m).
Ecology. Substrates recorded for trawled and dredged
specimens include very muddy, gravel, dead shells; laterite
gravel and sand; sandy, and rocky.
Material examined. Sta. TB73, S of Pulau Semakau,
01°11.282’N, 103°46.632’E, 24.6–29.8 m, 25 May 2013
(8; ZRC.ECH.0422); sta. TB113, Southern Fairway, S of
Sisters’ Island, 01°12.001’N, 103°50.261’E, 29.3–30.5
m, 29 May 2013 (1; ZRC.ECH.0451); sta. DR125, beside
Sisters’ Island, 01°12.416’N, 103°49.858’E, 25.3–30.8 m,
30 May 2013 (5; ZRC.ECH.0459); sta. TB142, East Johor
Strait, 01°17.838’N, 104°04.157’E, 28.7–28.8 m, 31 May
2013 (2; ZRC.ECH.0473).
Material previously collected at Singapore. USNM 36197
(1), 36260 (1), 36261 (1), E1083 (5), ZMC (?55), Svend Gad;
NHM (7), 13 m, 12 December 1898 (A. H. Clark, 1941).
Amphimetra molleri (A. H. Clark, 1908a)
Diagnosis. Amphimetra with cirri stout, curved throughout, of
24–50 short subequal cirrals with LW 0.3–0.5; aboral spines
developed proximal to eighth cirral; arms to 150 mm long;
P2 with 18–21 pinnulars (A. H. Clark, 1941).
Material previously recorded from Singapore. NHM (1),
13 m, 12 December 1898; USNM E1081 (1), ZMC (8?),
Svend Gad (A. H. Clark, 1941).
MARIAMETRIDAE A. H. Clark, 1909e
Diagnosis. Centrodorsal with interradial ridges and undivided
coelomic impression in each adoral radial area; cirrals fewer
than 40 (up to 80 in Oxymetra); radial articular facet steep;
interarticular fossae large and high; adoral muscle fossae low,
curved along adoral edge and midradial furrow; brachitaxes
always of 2 ossicles joined by synarthry; usually fewer than
40 arms (to 51 in Oxymetra) (Hess & Messing, 2011).
Remarks. In recent molecular phylogenetic reconstructions,
Hemery et al. (2013) returned a monophyletic Mariametridae
as sister to a clade composed of Himerometridae and
Zygometridae. Hemery (2011) also found a chiefly
monophyletic Mariametridae but also including the
himerometrids Amphimetra spectabilis (see discussion under
Amphimetra above) and a Heterometra sp. (Heterometra
crenulata returned with other Himerometridae). However,
Rouse et al. (2013) returned the family as paraphyletic,
with two mariametrid sister terminals (Stephanometra,
Lamprometra) as sister to a pair of colobometrid terminals,
and this entire clade sister to another composed of the
mariametrid Liparometra as sister to a Himerometridae/
Zygometridae clade. Thus, the status and diagnosis of this
family remain to be conrmed.
Dichrometra A. H. Clark, 1909
Diagnosis. Mariametridae with cirri of fewer than 40 cirrals;
brachitaxes separated laterally and smooth; P3 the longest
and largest proximal pinnule (Hess & Messing, 2011).
Remarks. See comments about the status of this genus
under Lamprometra below. A. H. Clark (1941) recognised
seven species distinguished on the basis of slight differences,
chiey variations in length-to-width proportions of cirrals
and relative lengths of proximal pinnules, and wrote that D.

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Messing & Tay: Crinoidea (Echinodermata) of Singapore
agellata, D. tenuicirra, and D. afra were “probably merely
local varieties of the same form” (p. 537). The status of all
seven remains to be determined.
Dichrometra agellata (Müller, 1841)
(Fig. 9C)
Diagnosis. Dichrometra with longest proximal cirrals about
as long as broad or slightly longer; distal cirrus segments as
broad as long or broader, with usually short aboral spines;
brachitaxes and arm bases more or less rugged or rugose
due to more or less marked synarthrial tubercles; proximal
pinnules markedly unequal in size, but none especially
enlarged; P3 longest and stoutest, 9–18 mm long, with 21–38
(usually 25–30) stout cylindrical pinnulars; P2 7.5–12 mm
long, with 18–27 (usually about 25) pinnulars; P1 small,
weak, 4.5–11 (usually 8–9) mm long, with up to 28 pinnulars;
arms 14–40 (averaging about 30), 65–150 (averaging about
110) mm long (A. H. Clark, 1941).
Remarks. Some specimens collected during SSBW approach
Liparometra in having P2 and P3 the same or almost the
same length on some arms. One specimen has pinnulars of
enlarged oral pinnules longer than wide as described for D.
ciliata A. H. Clark, 1912d, but has synarthrial tubercles as
in D. agellata.
Colour. Rays uniformly dark chocolate, maroon to almost
black, sometimes with few short white, cream or gray bands
on arms, or tan-beige with short white bands and with pinnules
brown or banded brown and white, with orange tips, or rays
banded gray and orange; cirri pale orange-brown.
Ecology. Clinging under ledges and in crevices with arms
curled during the day. Commensals include Ophiomaza
sp. (Ophiuroidea), Periclimenes commensalis (Crustacea,
Decapoda) and unidentied myzostomes. The single trawled
specimen (ZRC.ECH.0425), recorded as taken on a sandy
bottom, was identied as Dichrometra sp.
Local depth range. ~3–24.6 (possibly 29.8) m.
Material examined. Sta. SD25, SW of St John’s Island,
no lat., long., 7.6 m, 22 May 2013 (3; ZRC.ECH.0391,
ZRC.ECH.0393, ZRC.ECH.0394); sta. SD56, S of Pulau
Jong, 01°12.55’N, 103°47.2’E, 17 m, 24 May 2013 (1;
ZRC.ECH.0411); sta. SD66, W patch reef of Pulau Hantu,
01°13.6’N, 103°44.8’E, 3 m, 25 May 2013 (1; ZRC.
ECH.0418); sta. TB73 , S of Pulau Semakau, 01°11.282’N,
103°46.632’E, 24.6–29.8 m, 25 May 2013 (1; ZRC.
ECH.0425); sta. IT95, Rafes Lighthouse, no lat., long., no
depth, 28 May 2013 (1; ZRC.ECH.0437). Two additional
specimens identified in the field and discarded were
collected at sta. SD89, S of Small Sister’s Island, 01°12.9’N,
103°49.88’E, 14.7 m, 27 May 2013.
Material previously recorded from Singapore. USNM
35238 (1), ZMC (?5), Svend Gad; NHM (5), Pulau Obin;
[no collection identied] (1), Dr. Th. Mortensen, 1 June
1900 (A. H. Clark, 1941).
Lamprometra A. H. Clark, 1913
Diagnosis. Mariametridae with centrodorsal thin, discoidal;
radials partly or completely concealed by centrodorsal; cirrus
sockets restricted to centrodorsal margin, not encroaching
on broad aboral pole; brachitaxes separated or in close
lateral apposition; brachitaxis ossicles usually thickened
laterally, producing characteristically apposed flattened
margins, sometimes weakly crenulate, or weakly thickened
with margins not apposed; cirri of <35 cirrals; distal cirrals
smooth or bearing aboral carination that may develop into a
low triangular spine; P1, P2 and sometimes P3 with reduced
ambulacral groove; P2 largest, tapering to nely agellate tip;
pinnulars barely longer than broad; articular facets normally
developed (Rankin & Messing, 2008).
Remarks. Distinctions between Lamprometra, Liparometra
and Dichrometra are based only on variations in relative
length and strength of the proximal three oral pinnules. These
are variable characters, and Gislén (1922) and H. L. Clark
(1938) questioned whether the three should remain distinct.
A. H. Clark (1941) acknowledged that some specimens
could not be assigned to genus based on oral pinnule form,
though he maintained them as separate genera, and Rankin
& Messing (2008) described intermediate specimens. Among
specimens collected during the SSBW, one had P2 only
slightly longer than P3, another had one arm at least with P3
as long as or longer than P2, and a third had one P1 almost
as long as P2. The three genera are maintained as distinct
here pending detailed taxonomic revision. Lamprometra is
currently treated as monotypic (Rankin & Messing, 2008).
Lamprometra palmata (Müller, 1841)
Diagnosis. Same as for genus.
Remarks. Lamprometra palmata as currently recognised
is an extremely variable species with at least 17 synonyms.
A. H. Clark (1941) reduced the number to two species—L.
klunzingeri (Hartlaub, 1890) from the Red Sea and western
Indian Ocean, and L. palmata with two subspecies, L. p.
palmata and L. p. gyges (Bell, 1884), both with broad
and broadly overlapping Indo-western Pacic ranges—but
Rankin & Messing (2008) united them all as L. palmata
based on overlapping characters. Several specimens collected
during the SSBW were identified as L. palmata form
brachypecha, which was originally described as a distinct
species (Lamprometra brachypecha H. L. Clark, 1915) and
is characterized by shorter arms, a color pattern including
pale green blotches, spots or bands, and an enormously
enlarged P2. However, the form of P2 and the color pattern
do not uniformly occur together, and Rankin & Messing
(2008) treated it as an infrasubspecic variant of L. palmata.
Colour. Widely variable, ranging from one color (e.g.,
purplish- or dark brownish-black) to variously banded, often
concentrically, e.g., white with black, purplish-black, red-
purple, pale purple, yellow-orange, pale greenish-gray, gray,
gray-brown, or chocolate bands; brown and tan; white with
orange blotches and orange-brown bands, or pale purplish-

651
RAFFLES BULLETIN OF ZOOLOGY 2016
Fig. 9. A, B, Amphimetra ensifer; (ZRC.ECH.0459). A, large specimen in lateral view showing strongly developed conical synarthrial
tubercles. B, smaller specimen with weak synarthrial tubercles. C, Dichrometra agellata, in situ, Pulau Hantu, depth 3 m, night, not
collected. Scale bars = 1 mm.

652
Messing & Tay: Crinoidea (Echinodermata) of Singapore
gray with darker bands. Bands may short or long, crowded
or well-spaced, or restricted to middle and distal rays,
sometimes with different colors distally and with proximal
rays often paler and sometimes with darker blotches or spots,
e.g., pale grayish-orange distally and spotted gray and white
proximally; mottled light green and white with few narrow
faint tan bands and distal arms off white; proximal rays
white with light gray-brown blotches that form an irregular
broken double stripe, and middle and distal rays with short
tan and brown bands. Bands may be chiey obvious on
ambulacral surface. Articulations between brachials may be
distinctly darker. Pinnules variously banded or spotted; oral
pinnules may be colored differently than those following.
Centrodorsal and cirri may be paler or white.
Local depth range. <1–29.3 (possibly 30.5) m.
Ecology. Cryptic on reefs during the day under coral rubble
and slabs or within the reef infrastructure, in some areas in as
little as 1 m depth among branching corals among macroalgae
and seagrass. At night, perched on branching corals, large
rubble, coral rock projections or prominent coral heads or
sponges, with arms arranged in a biplanar arcuate fan, funnel
or shallow bowl. Specimens may form feeding fans during
the day under reduced light conditions, e.g., under ledges,
caves, tunnels, turbid conditions or deeper water (Stevens,
1989; Messing, 2007; Rankin & Messing, 2008). Meyer &
Macurda (1980) reported that, at Palau, they emerge within
an hour before dusk and crawl to the tops of coral perches
within ~15 min.
Material examined. Sta. SW6, St John’s Island, DRTech
pontoon at S lagoon, 01°12.928’N, 03°51.099’E, no depth,
20 May 2013 (1; ZRC.ECH.0354); sta. SD25, SW of St
John’s Island, no lat., long., 7.6 m, 22 May 2013 (1; ZRC.
ECH.0398); sta. SB67, W patch reef of Pulau Hantu,
01°13.6’N, 03°44.8’E, 15.7 m, 25 May 2013 (1; ZRC.
ECH.414); sta. IT81, Big Sister’s Island (?S side), no
lat., long., <1 m, 26 May 2013, hand collection (3; ZRC.
ECH.0426, ZRC.ECH.0427, ZRC.ECH.0428); sta. IT102,
Big Sister’s Island, no lat., long., <1 m, 29 May 2013,
hand collection (1; ZRC.ECH.0445); sta. SB132, S of
Kusu Island, no lat., long., 8 m, 31 May 2013 (1; ZRC.
ECH.0478); sta. TB113, Southern Fairway S of Sister’s
Island, 01°12.001’N, 103°50.261’E, 29.3–30.5 m, 29 May
2013 (2; ZRC.ECH.0449 as L. p. form brachypecha, ZRC.
ECH.0450); sta. DR125, beside Sisters’ Island, 01°12.416’N,
103°49.858’E, 25.3–30.8 m, 30 May 2013 (1; ZRC.ECH.0464
as L. p. form brachypecha, 10; ZRC.ECH.0461); (following
specimens identied on location as L. p. form brachypecha)
sta. SD56, S of Pulau Jong, 01°12.55’N, 103°47.2’E, 17
m, 24 May 2013 (1; ZRC.ECH.0412); sta. TB71, between
Pulau Hantu and Pulau Sudong, 01°13.157’N, 103°44.642’E,
21.1–22.6 m, 25 May 2013 (1; ZRC.ECH.0421); sta. TB73,
S of Pulau Semakau, 01°11.282’N, 103°46.632’E, 24.6–29.8
m, 25 May 2013 (1; ZRC.ECH.0423); sta. SD89, S of Small
Sisters’ Island, 01°12.9’N, 103°49.88’E, 14.7 m, 27 May
2013 (1; ZRC.ECH.0436); sta. IT95, Rafes Lighthouse, no
lat., long., <1 m, 28 May 2013, hand collection (1; ZRC.
ECH.0438); sta. SB132, S of Kusu Island, no lat., long., 8
m, 31 May 2013 (1; ZRC.ECH.0477).
Material previously recorded from Singapore. Rafes
Museum (1); MNB (1), Herr Jagor; ZMC (22), Svend Gad;
ZMC (3) Pulau Ubin, Johore Strait, Marius Jensen (A. H.
Clark, 1941).
Stephanometra A. H. Clark, 1909d
Diagnosis. Mariametridae with centrodorsal convex
discoidal with gently sloping sides, and with cirrus sockets
encroaching on aboral pole; brachitaxes well-separated;
brachitaxis ossicles bearing rounded adambulacral processes
oriented parallel or oblique to longitudinal axis of ossicle
and producing characteristically scalloped or knobbed lateral
margins; cirrals <40; distal cirrals with aboral ornamentation
ranging from prominent spine to slight carination; one or
more pairs of oral pinnules with reduced ambulacral groove,
attened articular facets, reduced tissue between pinnulars,
conical tip and with LW of middle pinnulars 1.5–4.0; P2 of
8 to 18 pinnulars (Rankin & Messing, 2008).
Remarks. Rankin & Messing (2008) revised and re-
diagnosed the genus, reducing the number of included
species from six to two.
Stephanometra tenuipinna (Hartlaub, 1890)
Diagnosis. Stephanometra with lateral margins of brachitaxis
ossicles weakly swollen or with well-rounded lateral
processes oriented parallel or obliquely to ray axis; at least
distal cirrals with prominent aboral spine; pinnulars of P1–
P4 and sometimes P5 elongated, LW 1.5–3.5, with reduced
ambulacral groove and conical terminal segment; proximal
and distal pinnular facets with elongated triangular fossae
anking ambulacral groove (Rankin & Messing, 2008).
Remarks. Rankin & Messing (2008) synonymized
Stephanometra echinus (A. H. Clark, 1908d) under this
species.
Colour. Very dark purplish black; cirri paler. Elsewhere,
rays variously banded with red, red-purple, maroon,
orange, brown or tan and usually some white; sometimes
with orange blotches; sometimes all white with red tips, or
red proximally and white distally with or without red tips.
Rarely gray proximally and deep purple distally. Brachitaxes
may be orange, dark rose, purple or maroon with white,
pink, orange or brown speckles, or with orange blotches or
with scattered pink and white areas. Mid-arm may be dark
orange-brown with numerous white or tan bands (Rankin
& Messing, 2008).
Ecology. Diurnally cryptic, curled within reef infrastructure
or deep among Acropora colony branches; perches at
night on prominent coral heads. Arms usually arrayed in
a biplanar arcuate ltration fan, or spread radially over its
perch, sometimes with upcurrent arms raised perpendicular to

653
RAFFLES BULLETIN OF ZOOLOGY 2016
substrate (Rankin & Messing, 2008). The specimen collected
during the SSBW was exposed during the day, probably due
to low visibility and low light penetration.
Material examined. Sta. SD25, SW of St John’s Island,
01°12’51”N, 103°50’57”E, 6.8 m, 22 May 2013 (1; ZRC.
ECH.0376).
Material previously collected at Singapore. ZMC (1
specimen), Svend Gad (in A. H. Clark, 1909a).
Stephanometra indica (Smith, 1876)
Diagnosis. Stephanometra with brachitaxis ossicles weakly
swollen laterally or with thick rounded ridge-like extensions
oriented obliquely to longitudinal axis of ray; middle and
distal cirrals bearing midaboral carination, sometimes with
small spine distally; P1 slender, tapering delicately to conical
tip; P2 alone or P2 and following 1–3 pinnules composed
of elongated pinnulars with reduced ambulacral groove,
conical terminal segment, and attened articulations lacking
triangular fossae (Rankin & Messing, 2008).
Remarks. Based on numerous morphologically intermediate
specimens, Rankin & Messing (2008) placed three species
[S. spicata (Carpenter, 1881), S. oxyacantha (Hartlaub, 1890)
and S. spinipinna (Hartlaub, 1890)] in synonymy under S.
indica. They were formerly distinguished on the basis of
variations in number of stiff, spinelike proximal pinnules.
Colour. Arms appear zebra-striped; articulations black or
chocolate, sometimes bordered with brown; brachials white,
with series of gray, light and/or dark brown brachials forming
concentric bands; pinnules orange, yellow or both, or banded
white or light brown and brown, sometimes with orange tips.
Ecology. Cryptic during the day under slabs or rubble, or
within reef infrastructure. Exposed at night on coral rock
projections, prominent coral heads, and sometimes on
massive soft corals. Although the typical nocturnal posture
is a biplanar arcuate fan, individuals may also form a at
or shallow bowl-like radial fan with arms spread across the
surface of their perch (Rankin & Messing, 2008). Individuals
may actively form fans during the day, but only under
reduced light conditions, e.g., under ledges, in recesses
or caves (Meyer & Macurda, 1980), or at greater depths
(Stevens 1989).
Local depth range. 3–15.4 m.
Ecology. Symbionts collected on S. indica during the SSBW
include Harrovia sp., Allogalathea elegans, Periclimenes
commensalis and unidentified shrimp, myzostome and
scaleworm.
Material examined. Sta. SD25, SW of St. John’s Island, no
lat., long., 6 m, 22 May 2013 (1; ZRC.ECH.0392 S. indica
f. spicata); sta. SD40, W of Pulau Semakau, 01⁰12.389’N,
103°45.24’E, 7.5 m, 23 May 2013 (1; ZRC.ECH.0400);
sta. SB54, SW of Kusu Island, 01°13.9’N, 103°52’E, 7.8
m, 24 May 2013 (1; ZRC.ECH.0406); sta. SB55, SW of
Kusu Island, 01°13.9’N, 103°52’E, 4 m, 24 May 2013 (1;
ZRC.ECH.0410); sta. SD56, S of Pulau Jong, 01°12.55’N,
103°47.2’E, 3–6 m, 24 May 2013 (2; ZRC.ECH.0413 S.
indica f. oxyacantha with ophiuroid and scaleworm, ZRC.
ECH.0375); sta. SD123, St John’s Island, lagoon next to
public jetty, no lat., long., 5–13 m, 30 May 2013 (1; ZRC.
ECH.0454 S. indica f. spicata); sta. SD133, S of Kusu Island,
no lat., long., 11 m, 31 May 2013 (2; ZRC.ECH.0470 S.
indica f. spicata/oxyacantha with Periclimenes commensalis,
myzostome, scaleworm, ZRC.ECH.0469); sta. SD150, SW
of Kusu Island, no lat., long., 10.7 m, 1 June 2013 night,
(1; ZRC.ECH.0481 with Harrovia sp.); sta. SD167, SW of
Pulau Jong, no lat., long., 15.4 m, 4 June 2013 (1; ZRC.
ECH.0493 with Allogalathea elegans (2) and shrimp).
Material previously recorded from Singapore. ZMC (4),
Svend Gad; NHM (1) Pulau Ubin; Rafes Museum (1),
Blakang Mati (all as S. spicata); ZMC (1), Svend Gad;
Rafes Museum (1) (both as S. indica protectus) (A. H.
Clark, 1941).
Family ZYGOMETRIDAE A. H. Clark, 1908b
Diagnosis. Centrodorsal large; adoral side with large, paired
or V-shaped radial impressions; 1–4 marginal circlets of
sockets; radial articular facet rather at, moderately sloping
to almost vertical; adoral muscle fossae narrow, curved
bands along adoral edge and midradial furrow; up to 100
arms; IBr2 united by syzygy; II and IIIBr series usually
4(3+4); rst syzygy on undivided arms at 3+4 (modied
from Hess & Messing, 2011, to exclude Catoptometra
following Hemery, 2011).
Remarks. Zygometridae has traditionally included two
genera: Zygometra A. H. Clark, 1907a, and Catoptometra
A. H. Clark, 1908c (A. H. Clark, 1941). Hemery’s (2011)
molecular phylogeny returned Catoptometra (as C. ophiura
A. H. Clark, 1911a) separate from Zygometra species as sister
to a clade composed of Tropiometra species (Tropiometridae)
and the “antedonid” Annametra occidentalis (A. H. Clark,
1915). Molecular phylogenies in Hemery (2011) and Hemery
et al. (2013) returned Zygometra species as sister to a clade
of three himerometrids (Himerometra, Homalometra, and
Heterometra crenulata). Rouse et al. (2013) reported a
sister relationship between one terminal each of Zygometra
and Himerometra. This relationship is not surprising,
as Zygometra species differ chiefly from Himerometra
species only in having the IBr2 ossicles joined by syzygy,
a character that, in the most recent molecular reconstruction
of Comatulidae, distinguishes Comatula only at the generic
level (Summers et al. 2014).
Zygometra A. H. Clark, 1907a
Diagnosis. Same as family.
Remarks. Five of the six currently recognised species of
Zygometra [Z. microdiscus (Bell, 1882), Z. elegans (Bell,
1882), Z. comata A. H. Clark, 1911a, Z. punctata A. H.

654
Messing & Tay: Crinoidea (Echinodermata) of Singapore
Clark, 1912a, and Z. pristina A. H. Clark, 1911a] are
largely distinguished on the basis of size-related meristic
characters (e.g., numbers of arms, cirri and cirrals) and
appear to represent growth series of fewer valid species. A.
H. Clark (1941), who treated all six as distinct, admitted that
intermediate forms existed between at least Z. microdiscus,
Z. elegans and Z. comata. Only Z. andromeda A. H.
Clark, 1912b, known from a single specimen outside the
distributional ranges of the others (probably from Sri Lanka),
differs in having thickened and everted proximal ray ossicles
(A. H. Clark, 1941). Zygometra microdiscus, Z. elegans and
Z. punctata are restricted to tropical Australia and eastern
Indonesia. Zygometra comata occurs from the Mergui
Archipelago, Burma, east to the Philippines and Indonesia
and north to Sagami Bay, Japan (A. H. Clark, 1941, Kogo &
Fujita 2014). Z. pristina is known only from the Philippines.
Unlike the majority of shallow-water feather stars from the
Indo-western Pacic region, Zygometra species are often
found on sediment substrates rather than reefs (e.g., Stevens
& Connolly 2003; Messing et al., 2006).
Zygometra comata A. H. Clark, 1911a
(Fig. 10)
Diagnosis. Zygometra with moderately long cirri of usually
25–30 cirrals; usually 25–35 arms; proximal and distal edges
of brachitaxes ossicles and rst two brachials of undivided
arms plain, not thickened or everted and scalloped (A. H.
Clark, 1941).
Remarks. As noted above, the distinction between Z.
comata and at least some other Zygometra species may be
ontogenetic. The largest specimen collected has 21 arms,
ray length 70 mm; cirri XXIII with up to 33 cirrals. Small
specimens with centrodorsal diameter of ~1 mm, ray length
~20–25 mm, and as few as 18 cirrals, still have 11–13 arms,
which appears to distinguish them from Z. pristina, which is
known from a single specimen with 10 arms 50 mm long.
Colour. (in alcohol) Purple with numerous short white arm
bands; pinnules white with short distal purple band; pinkish
gray with darker purple tissue; pinkish gray with few short
darker reddish purple arm bands; cirri sometimes banded
pale pinkish gray and purple.
Local depth range. 11–125 (possibly 136) m.
Ecology. Most material was trawled or dredged with
substrates recorded as broken shell, silty; clay; rocky; clean,
big sponges, and gravel. One specimen was collected via
scuba, but no notes were taken.
Material examined. Sta. TB3, near Rafes Lighthouse,
Gusong Boarding Ground, S of Pulau Semakau, 01°10.653’N,
103°46.772’E, 40.7–40.9 m, 20 May 2013 (1; ZRC.
ECH.0356); sta. DR90, Southern Fairway near St John’s
Island, 01°12.942’N, 103°51.946’E, 48.3–49.7 m, 27 May
2013 (1; ZRC.ECH.0431); sta. TB92, Southern Fairway near
St John’s Island, 01°12.926’N, 103°51.647’E, 39.5–49.9 m,
27 May 2013 (2; ZRC.ECH.0618); sta. TB96, near Eastern
Bunkering A, 01°18.140’N, 104°04.221’E, 22.4–25.1 m,
28 May 2013 (3; ZRC.ECH.0514); sta. TB98, Eastern
Bunkering A, 01°18.938’N, 104°05.312’E, 30.2–33.6 m, 28
May 2013 (1; ZRC.ECH.0515); sta. DR111, outside Eastern
Boarding Ground A, 01°12.989’N, 103°53.062’E, 125–136
m, 29 May 2013 (5; ZRC.ECH.0516); sta. SD145, W of
Pulau Hantu, no lat., long., 11.7 m, 1 June 2013 (2; ZRC.
ECH.0479, ZRC.ECH.0480); sta. DR161, beside St John’s
Island, 01°12.843’N, 103°51.449’E, 41.2–44.4 m, 3 June
2013 (1; ZRC.ECH.0491).
Material previously collected at Singapore. USNM 36262
(1 specimen), 36263 (1); E1076 (1), Svend Gad, no dates
(in A. H. Clark, 1941).—ZMC (22), Svend Gad, 20 April
1906 to 9 January 1908 (as Zygometra uctuans in A. H.
Clark, 1909a).—NHM (1), no collector, 13 m, 12 December
1898 (in A. H. Clark, 1929, 1941).
“ANTEDONIDAE” Norman, 1865
Remarks. This nominal family was previously characterised
as having a centrodorsal cavity moderate to large; apical
cirri usually retained in large specimens; basal rosette not
sunken within radial circlet; radial cavity narrow, without
calcareous plug; radial articular facets deeply excavated with
large, thin-walled muscle fossae; very rarely more than 10
arms, and pinnules chiey cylindrical with no carination or
ambulacral plates (modied from Clark & Clark, 1967; Hess
& Messing, 2011). However, recent molecular phylogenies
clearly demonstrate that the family is polyphyletic (Hemery,
2011; Rouse et al., 2013; Hemery et al., 2013).
Fig. 10. Zygometra comata; ZRC.ERH.0514. A, Bases of three rays
showing syzygy (dotted) at middle and right-hand IBr2. Syzygy not
visible on left-hand IBr2. B, Cirrus. Scale bars = 1 mm.

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RAFFLES BULLETIN OF ZOOLOGY 2016
Dorometra A. H. Clark, 1917
Diagnosis. “Antedonidae” with cirri rarely >40; up to 17
cirrals with distal ends produced and overlapping; distal
cirrals much longer than proximal width. P3 longest and
stoutest (Hess & Messing, 2011).
Remarks. Hemery et al. (2013) returned Dorometra briseis
(A. H. Clark, 1907c), a member of the only “antedonid”
genus recorded from Singapore, within a clade including
several other “antedonid” taxa belonging to four nominal
genera, as well as Aporometra sp. (Aporometridae) and
Eudiocrinus spp. (Eudiocrinidae). (Both of these families
are monogeneric.) Phylogenetic placement of Aporometridae
varies among reconstructions (Hemery, 2011; Rouse et al.,
2013; Hemery et al., 2013), and Eudiocrinidae was formerly
placed in superfamily Mariametroidea (A. H. Clark, 1941;
Hess & Messing, 2011). All genera formerly placed in
Antedonidae require taxonomic revision.
Dorometra cf. nana (Hartlaub, 1890)
Diagnosis. Dorometra with P3 of 13–16 pinnulars, twice as
long as P1 and P2, of 8–10 pinnulars; cirri of 10–14 (usually
10–12) cirrals, 4–9 mm long; c4–7 longest, 2–3 times longer
than broad with much expanded ends; antepenultimate 1.5
times longer than broad; arms 25–60 (usually 30–45) mm
long (Clark & Clark, 1967).
Remarks. The largest specimen collected (ZRC.ECH.0455)
conforms to the diagnosis of D. nana: R ~30 mm, P1 and
P2 both ~4 mm long with 9–10 pinnulars, P3 ~8 mm long
with 19–20 pinnulars, and cirri of 14–15 cirrals with LW
of longest cirrals 2.6. However, several smaller specimens
(R < 20 mm) have P3 only about 1.5 times longer than P2
(e.g., ZRC.ECH.0487), or P2 intermediate in length between
P1 and P3 as in Dorometra parvicirra (Carpenter, 1888),
which has also been collected at Singapore. As these may
be ontogenetic variations, all specimens are treated here as
D. cf. nana.
Color.—White or pale tan with brown bands; arms purplish
black, sometimes with white distal arms, with white
centrodorsal, cirri and pinnules; yellow with brownish
pinnules; arm tips sometimes darker; disk black or mottled.
Local depth range. 22.7–125 (possibly 22.4–136) m.
Ecology. All specimens were dredged or trawled; bottoms
recorded include clay; lumps of clay; gravel; rocky; broken
shells and coral rubble; laterite gravel and sand, and mud,
gravel and dead shells. One specimen was recovered clinging
to a large verrucomorph barnacle.
Material examined. Sta. TB92, Southern Fairway near St
John’s Island, 01°12.926’N, 103°51.647’E, 39.5–49.9 m,
27 May 2013 (1; ZRC.ECH.0433); sta. TB96, near Eastern
Bunkering A, 01°18.140’N, 104°04.221’E, 22.4–25.1 m,
28 May 2013 (1; ZRC.ECH.0443); sta. TB97, near Eastern
Bunkering A, 01°18.425’N, 104°04.607’E, 22.4–22.7 m, 28
May 2013 (1; ZRC.ECH.0440); sta. DR111, outside Eastern
Boarding Ground A, 01°12.989’N, 103°53.062’E, 125–136
m, 29 May 2013 (1; ZRC.ECH.0458); sta. DR112, Southern
Fairway, S of Sister’s Island, 01°12.024’N, 103°50.170’E,
33.6–34.4 m, 29 May 2013 (1; ZRC.ECH.0455); sta. DR125,
beside Sister’s Islands, 01°12.416’N, 103°49.858’E, 25.3–
30.8 m, 30 May 2013 (2; ZRC.ECH.0462, ZRC.ECH.0463);
sta. TB142, East Johor Strait, 01°17.838’N, 104°04.157’E,
28.7–28.8 m, 31 May 2013 (1; ZRC.ECH.0475); sta.
DR161, beside St John’s Island, 01°12.843’N, 103°51.449’E,
41.2–44.4 m, 3 June 2013 (1; ZRC.ECH.0487).
Material previously collected at Singapore. ZMC (7
specimens), Svend Gad, 1906, 1907 (in A. H. Clark, 1909a,
Clark & Clark, 1967).
Dorometra parvicirra (Carpenter, 1888)
Diagnosis. Robust Dorometra with P2 intermediate in size
and number of pinnulars between P1 and P3; cirri with up
to 17 cirrals; longest cirrals not more than twice as long as
width of expanded ends; P1 with 10–15 pinnulars, P2 with
13–14 or more, and P3 with 17–19; arms 50–60 mm long
(Clark & Clark, 1967).
Remarks. A few small specimens collected during SSBW
have some characters of D. parvicirra, but appear to be
incompletely developed specimens of D. cf. nana.
Material previously collected at Singapore. USNM E1074,
Svend Gad, 27 November 1907 (2 specimens) (http://
collections.nmnh.si.edu/search/iz/). Clark & Clark (1967,
p. 65) list a single record from Singapore as USNM E3202
and ZMC (9 specimens) with no other data. However, the
National Museum of Natural History online catalog gives the
locality data for E3202 as Sta. 36, Mortensen Kai Expedition,
Bay at N end Noehoe Roa Island, Kepulauan Kai, Indonesia,
23 April 1922 (3 specimens).
ACKNOWLEDGEMENTS
The Singapore Strait marine biodiversity workshop was
held on St. John’s Island, Singapore from 20 May to 7 June
2013, and was organised by the National Parks Board and
National University of Singapore. The workshop, as part of
the Comprehensive Marine Biodiversity Survey (CMBS)
benefited greatly from generous contributions provided
by Asia Pacific Breweries Singapore, Care-for-Nature
Trust Fund, Keppel Care Foundation, Shell Companies in
Singapore and The Air Liquide Group. CGM rst gratefully
thanks Tan Koh Siang, Senior Research Fellow and Head
of the Marine Biology and Ecology Group at the Tropical
Marine Science Institute (TMSI) of the National University
of Singapore, for inviting him to participate in the Workshop,
and Daphne Fautin, University of Kansas, for informing
him about it and arranging for the invitation. Additional
thanks are due to the entire staff of TMSI, and the army of
volunteers and cadre of international researchers who made
the SSBW such a resounding success, and in particular
for their helpful discussions and crinoid collecting: Shane

656
Messing & Tay: Crinoidea (Echinodermata) of Singapore
Ahyong, Arthur Anker, Lim Swee Cheng, Bertrand Richer
de Forges, Toshihiko Fujita, Sammy de Grave, Tan Heok
Hui, David Lane, James Lowry, Peter Ng, Ria Tan, and
Daisuke Uyeno; CGM also thanks Greg W. Rouse and Mindi
Summers (Scripps Institute of Oceanography, University of
California San Diego) for their continuing collaborative work
on the phylogeny of crinoids. Both of us wish to thank the
reviewers for their thoughtful comments and suggestions.
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