An annotated checklist and key to the Crinoidea of Guam and the Commonwealth of the Northern Marianas Islands

Abstract

Twenty-one species of crinoids in six families are now known from the Marianas Islands, 17 species from Guam and 10 from the Commonwealth of the Northern Marianas Islands (CNMI). This paper adds nine previously unreported crinoid species each to Guam and the CNMI. The nomenclature of all 21 species is reviewed and updated following Rowe et al. (1986), Hoggett and Rowe (1986) and Messing (1995, 1998a). One apparently juvenile comasterid does not fit comfortably in any known genus and may represent a new taxon. A simple key to the shallow-water species of Guam is included. Crinoid faunal diversity on Guam is compared with that known elsewhere in the Indo-West Pacific.

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Micronesica 35-36:523-546. 2003
An annotated checklist and key to the Crinoidea of Guam and the
Commonwealth of the Northern Marianas Islands
LISA KIRKENDALE
Florida Museum of Natural History
University of Florida
Gainesville, Florida, 32611-7800 U.S.A.
email: marinverts@hotmail.com
CHARLES G. MESSING
Nova Southeastern University Oceanographic Center
8000 North Ocean Drive
Dania Beach, Florida 33004 U.S.A.
email: messingc@nova.edu
Abstract—Twenty-one species of crinoids in six families are now
known from the Marianas Islands, 17 species from Guam and 10 from
the Commonwealth of the Northern Marianas Islands (CNMI). This
paper adds nine previously unreported crinoid species each to Guam and
the CNMI. The nomenclature of all 21 species is reviewed and updated
following Rowe et al. (1986), Hoggett and Rowe (1986) and Messing
(1995, 1998a). One apparently juvenile comasterid does not fit
comfortably in any known genus and may represent a new taxon. A
simple key to the shallow-water species of Guam is included. Crinoid
faunal diversity on Guam is compared with that known elsewhere in the
Indo-West Pacific.
Introduction
Although general reviews of the shallow-water Indo-Pacific echinoderm
fauna have encompassed both Guam and the Commonwealth of the Northern
Marianas Islands (CNMI) (e.g., A. M. Clark & Rowe 1971), only two papers
specifically documented the crinoid fauna of these islands. A. H. Clark (1954)
listed one species from Guam and one from Rota, CNMI, and Meyer & Macurda
(1980) recorded 7 additional species from Guam. Since then, the known fauna
has more than doubled, and several taxonomic revisions have warranted re-
identification of earlier records (Rowe et al. 1986, Hoggett & Rowe 1986,
Messing 1995, 1998a, Rankin 2000). These are discussed below.
Species richness is now 21 species in six families. One apparently juvenile
comasterid does not completely conform to any current generic diagnosis and
may represent a new taxon.

524 Micronesica 35-36, 2003
Annotated List of Guam Crinoids
We follow the ordinal classification of Rasmussen & Sieverts-Doreck (1978)
for simplicity, recognizing that phylogenetic hypotheses at familial and higher
levels are in need of revision (e.g., Simms 1988, Roux 1997). Abbreviations are
as follows: United States National Museum, Smithsonian Institution (USNM),
University of Guam Invertebrates Collection (UGI), and Florida Museum of
Natural History (UF). In the distribution sections, Indo-Malaya includes the
islands of Malaysia, Indonesia, Papua New Guinea and the Philippines. Unless
noted otherwise, L.K. collected all specimens, C.G.M. identified all photographs,
and Gustav Paulay provided numbered photo records in the material examined
sections (three-digit film roll followed by one- or two-digit photo number). If
more than one specimen is included under a given catalogue number, the number
is given in parentheses.
Order Comatulida A. H. Clark, 1908
Family Comasteridae A. H. Clark, 1908
Subfamily Phanogeniinae White & Messing (in White et al. 2001)
Phanogenia Lovén, 1866
Phanogenia gracilis (Hartlaub, 1890)
Material examined: GUAM: UGI 2918 (2), “Mounds” N. of Tanguisson
Pt., in coral pockets, 10 m, 28 Aug 1977, [with galatheid] D.L. Meyer coll.; UGI
6110 (5), Gun Beach, East Tumon, exposed on coral heads at night, 15 m, 4 Aug
1997 [with polynoid], G. Paulay coll.; UGI 6679, Luminao Reef, under rubble, 5
m, 19 Oct 1998, [with galatheid]; UF 1 Gun Beach, East Tumon, fore reef under
crevices at night, 10-20 m, 22 Jun 2000; UF 2, Gun Beach, East Tumon, fore reef
under crevices at night, 12 m, 8 Oct 1995, G. Paulay coll.; UF 3 (2), Cocos I.,
rubble on outer W side of lagoon, 18 m, 23 Apr 1999, G. Paulay coll., photo
GP582:27, 28; UF 4, Cocos I., W. Barrier reef, groove on fore reef under rubble,
12-14 m, 23 Feb 1999, C. Meyer coll.; UF 5, South of Ritidian, partly exposed
under coral overhang, 35 m, 7 May 1999, [with alpheid], photo GP587:17; UF 6,
Gun Beach, East Tumon, fore reef under crevices at night, 10 m, 12 Jul 2000;
UF 7, north of Haputo fore reef, under coral overhangs, ~15 m, night, 9 Jun
2000, G. Paulay coll., photo GP830:18 [with commensals], 37; UF 8, Glass
Breakwater, directly offshore of small grove of trees, Luminao fore reef, under
overhang, 20-30 m, 12 Oct 1999, G. Paulay coll.; [photo(s) only] NW Orote Pt.,
15-20 m, 27 April 2000, night, photo GP812:3,6; Orote Pt., 13° 25.13 N, 144°
38.51 E, 35-40 m, 20 Jan 2000, photo GP746:8. NORTHERN CNMI: UF 9,
Maug I., R. Randall coll.
Additional records: GUAM: USNM E32078, Gab-Gab Beach, Apra
Harbor, 3 km E of Orote Pt., 13˚ 26’30”N, 144˚ 38’30”E, 6.1 m, 10 Dec 1983, R.
F. Bolland coll. & D. L. Meyer det.

Kirkendale & Messing: Crinoids of Guam 525
Notes: This species was formerly called either Comaster multifidus or C.
gracilis. Although several papers have recognized the two as separate species
throughout the western Pacific (e.g., A. H. Clark 1931, Zmarzly 1985, Messing
1994, 1998b, Kogo 1998), no morphological feature has yet been found that
consistently distinguishes them (Messing 1998a). Messing (1998a) also
recognized that Comaster multifidus, the type of the genus Comaster, was
identical and senior to Comanthina variabilis (Bell), an Australian endemic. He
transferred all species of Comanthina to Comaster and removed the remaining
species previously placed in Comaster to the next most senior available genus,
Phanogenia (Lovén). As a result, specimens from Guam identified by Meyer &
Macurda (1980) as C. multifidus have been re-identified as Phanogenia gracilis.
Yet, because multiple authors have recognized two similar taxa, they are
enumerated as separate in the discussion and table below.
This is the only Guamanian comatulid in which the centrodorsal is small,
star-shaped and completely lacks cirri. Phanogenia gracilis is largely cryptic
during the day under rubble, coral heads or overhangs. At night, its disk remains
concealed, but it extends most of its arms in a multiradial orientation with
pinnules oriented in four directions, or tetrads (see Meyer & Macurda 1980).
Despite its relatively small local size (arm length <10 cm), P. gracilis houses the
most diverse assemblage of symbionts so far observed on any host crinoid on
Guam. A brittlestar, a polynoid scale worm, a pair of alpheid shrimp, a
pontoniine shrimp, myzostomid worms and a squat lobster, probably
Allogalathea, are commonly observed on specimens of P. gracilis at night in 10-
40 m at Gun Beach in Tumon Bay, and Haputo Point, further north along the
same coastline.
Distribution: From the Maldive Islands to Fiji, Kwajalein and Onotoa Is.
including tropical Australia, Indo-Malaya, Taiwan, Palau, Guam and Okinawa
(A. H. Clark 1931, 1954, Meyer & Macurda 1980, Zmarzly 1984, 1985, Chen et
al. 1988, Messing 1994, 1998b, Rowe & Gates 1995, Kogo 1998). Depth range:
chiefly 10 to 50 m, but also shallower in some locales (6.1 m at Gab-Gab, see
additional records section above) with a few questionable dredging records from
as deep as 216 m (A. H. Clark 1931, Messing unpublished).
Phanogenia cf. distincta (Carpenter, 1888)
Material examined: GUAM: UF 10, W coast of Guam, Agana/Tumon Bay
area, 17-125 m, 1 Aug 1997, dredge #3, G. Paulay & B. Smith coll.; UF 46,
Mangilao, 13°25.15’N, 144°48.03’E, 95-130 m, 31 Jul 1997, dredge, T. Leberer
& G. Paulay, colls. (4).
Notes: These specimens fit the published description of Phanogenia distincta
(formerly Comaster distinctus, see under P. gracilis, above): a cirrus-bearing
Phanogenia with 35 or fewer arms. The four specimens from UF 46 range from a
ray length of 35 mm with 18 arms to 57 mm with 28 arms. However, the
diagnostic features of several cirrus-bearing Phanogenia form an apparent

526 Micronesica 35-36, 2003
growth series [e.g., P. distincta: ≤35 arms up to 60 mm long; P. fruticosa: 37-63
arms to 90 mm long, and P. multibrachiata: 140-160 arms to 150 mm long (A.
H. Clark 1931)]. Although P. distincta and P. multibrachiata exhibit distinctly
different color patterns at New Caledonia (Meyer 1986), it remains unclear
whether they are separate taxa or growth stages of a single species.
Distribution: [Including a likely synonym, Comaster brevicirrus (Bell)]
Madagascar to New Caledonia including the Andaman Islands, W and NW
tropical Australia, Indo-Malaya, the South China Sea, Guam and Japan (A.H.
Clark 1931, Marshall & Rowe 1981, Meyer 1986, Messing 1998b, Rowe &
Gates 1995, Kogo 1998). P. multibrachiata has a similar range; it has not been
recorded from Madagascar, but has been recorded from the Great Barrier Reef
(Stevens 1989). This is only the second record of a cirrus-bearing Phanogenia
from Oceania (after that from New Caledonia). Depth range: rarely <30 to at
least 55 m; some older dredging records exceed 100 m (possibly 290 m), but the
latter are not precise so the maximum depth of this species is unknown. P.
multibrachiata has a similar depth range.
Alloeocomatella Messing, 1995
Alloeocomatella pectinifera (A. H. Clark, 1911)
Material examined: GUAM: UF 11, Gun Beach, East Tumon, underneath
overhang, 30 m, 21 Oct 1999, night [with eulimid gastropod parasites]; UF 12,
Cocos Island, W Barrier Reef, groove on fore reef under rubble, 12-14 m, 23 Feb
1999, G. Paulay coll.; UF 13 (3), Cocos Island, W side of outer fore reef, in
rubble, 18 m, 23 Apr 1999, photo GP582:21-22,29; UF 14, Orote Pt., rubble
field, 18 m, 22 May 1998; [photo(s) only] NW Orote Pt., 15-20 m, 24 April
2000, night, photo GP812:5,7,10.
Notes: A combination of bright red, orange or maroon coloration and only
ten arms, some of which are much longer than the others, make this abundant
crinoid one of the most conspicuous species on Guam. It is cryptic during the day
and extends several of its longer arms at night. The pinnules typically orient in a
single plane (like barbs on a feather), unlike the tetrad arrangement in
Phanogenia gracilis. Alloeocomatella pectinifera was the most abundant crinoid
in an intensive recent survey along the Orote Peninsula (Paulay et al. 2001). It
has been found island-wide, but appears reliably at night off Gun Beach, Tumon
Bay, together with P. gracilis. This species was previously referred to as
Comissia pectinifera.
Distribution: Maldive Islands to New Caledonia and Kwajalein, including
the Great Barrier Reef, Indo-Malaya, Palau, Guam and Chuuk (Zmarzly 1985,
Meyer 1986, Messing 1995, 1998b). Depth range: 3-23 m (Messing 1995). Two
specimens recorded by Kogo (1998) as Comissia magnifica from a depth of 6.1-
6.2 m off Okinawa most likely represent A. pectinifera.

Kirkendale & Messing: Crinoids of Guam 527
Alloeocomatella polycladia Messing, 1995
Material examined: GUAM: UGI 2919, SW of Achae Pt., hidden beneath
dead coral, 21 m, 28 Aug 1977, D. L. Meyer coll.; UF 15, Cocos Island, W side
of outer fore reef in rubble, 18 m, 23 Apr 1999; UF 16, Gun Beach, East Tumon,
night, partially concealed under rock overhang, 30 m, 16 Aug 1998; UF 41,
Luminao fore reef, in rubble, 10 m, 9 Sep 1997, G. Paulay coll. SOUTHERN
CNMI: UF 17, Saipan, off Agingan Pt., under large flat rock, ~20 m, 10 Aug
2001 [with ~20 myzostomes]; UF 18, Saipan, off Agingan Pt., under large
rubble/rock, 30 m, 11 Aug 2001.
Notes: This is the first record of this species from Guam. A few records of
Comatella maculata (Carpenter) actually refer to A. polycladia: Meyer &
Macurda (1980) from Palau and Meyer (1986) from New Caledonia (cited in
Messing 1995). Juvenile A. polycladia with only ten arms may be confused with
A. pectinifera although the former usually bears arms of similar length, while the
latter typically bears much longer anterior arms (Messing 1995). The small
specimen reported here from Cocos I. may thus possibly be A. pectinifera.
A. polycladia hides during the day under corals, overhangs, rubble or in
crevices and often occurs with A. pectinifera. At night, it may remain partly
concealed, or perch completely in the open. It is dark red or purplish red,
sometimes with pinnules beaded with pink or tipped with yellow, orange or pink
(Messing 1995). The color forms observed on Guam are dark red to orange and
correspond to the above description.
Distribution: Indonesia to Fiji and Chuuk, including the Great Barrier Reef,
Indo-Malaya, Palau, CNMI and Okinawa (Messing 1995, Pilcher & Messing
2001). Because Messing (1998b) recorded both A. polycladia and true Comatella
maculata (which he treated as a synonym of Comatella stelligera) from Chuuk
Atoll, it is not possible to determine if some other records of C. maculata from
this region, unaccompanied by descriptive information, are correctly identified or
not [e.g., Mortlock I. (Hartlaub 1891)]. However, solid dark purple specimens
from Kwajalein that were cryptic during the day, exposed at night and identified
as C. maculata (Zmarzly 1985), likely represent A. polycladia. Depth range: 3 to
30 m.
Comatella A. H. Clark, 1908
Comatella stelligera (Carpenter, 1888)
Material examined: SOUTHERN CNMI: USNM E7726, Rota I. 12 Nov
1945, D. G. Frey, coll., C. G. Messing, det.
Notes: Members of the genera Comatella and Alloeocomatella are often
confused because both share the same ray branching pattern (i.e., brachitaxes of
two ossicles each united by synarthrial articulations and first pair of brachial
ossicles on interior arms united by syzygy). However, Comatella has distinctive
pinnules with a rounded keel on each of the basal two segments and combs that,
unlike that of any other Pacific comasterid, arise from the side of the pinnule

528 Micronesica 35-36, 2003
closest to the arm that bears it (Messing 2001). The Rota I. specimen was
originally identified by A. H. Clark (1954) as Comatella maculata (Carpenter,
1888). However, Messing (2001) recognized this species as a younger stage of C.
stelligera. The specimen has 22 arms and its rays orient in a single plane, unlike
the rays of Comatella nigra, which are distinctly twisted (and which has not yet
been recorded from the Marianas Chain).
C. stelligera typically occurs under ledges, coral rubble or among branching
corals with at least some of its arms extended. Colors include black, maroon,
brown or greenish-brown; the latter three usually mottled, flecked or spotted with
yellow or pale green; pinnules are often yellow-tipped. Small specimens formerly
identified as C. maculata are often dark red-brown with numerous yellow spots.
It is not yet clear if red-purple specimens with blue stripes or mottling are C.
stelligera or C. nigra.
Distribution: Indo-Malaya to Chuuk, CNMI and southern Japan (Messing
1998b, Pilcher & Messing 2001); probably also the Great Barrier Reef and
Nicobar Islands (Messing unpublished).
Subfamily Comasterinae A. H. Clark, 1909
Comaster Agassiz, 1836
Comaster schlegelii (Carpenter, 1881)
Material examined: GUAM: UGI 2909 (2), 2910, 2913 [with alpheids],
2914 [with Harrovia sp.], north of Tanguisson Point, on "exposed mounds", 10
m, 28 Aug 1977, D. L. Meyer & C. Birkeland coll., D. L. Meyer & D. B.
Macurda det.; UGI 2103, Orote Pt., on pavement, 10 m, 17 Jul 1968, R. Tsuda
coll.; UGI 2104, NW coast, outside of Pugua patch reef, 42 m, 19 Jul 1968, [with
alpheids, pontoniines, and a galatheid] R. Randall coll.; UF 19, W coast, Hospital
Point, under overhangs, 30-35 m, 7 Jun 1999; UF 20, Cocos Island, W side of
lagoon, under rubble, ~18 m, 23 Apr 1999; UF 21, Orote Pt. on coral rock, 34-35
m, 1969, R. Chesher coll., C. G. Messing det., RHCG62; UF 22, NW coast,
Pugua patch reef, exposed, ~13˚ 35.98’N, 144˚ 49.83’E, 15-25 m, 3 Aug 2000
[with alpheids and pontoniines]; [photos only] Orote Peninsula, 0.5 km NW of
Blue Hole, 30 m, 25 May 1988, R. Myers photo 216b; Orote Pt., 13º 26.96’ N,
144º 37.15’ E, 10-20 m, 16 Feb 2000, photo GP649:32; NORTHERN CNMI: UF
24, Maug I., R. Randall, coll. SOUTHERN CNMI: Saipan, inside Grotto, 8 m, 21
Feb 1988, R. Myers photo 214S; UF 25 (1 spec.), UF 26 (2), Saipan, off Agingan
Pt., exposed on boulder, 15-20 m, 11 Aug 2001 [with Allogalathea sp., alpheids,
pontoniines & myzostomes].
Additional records: GUAM: USNM E35079, Orote Pt., on top of rock, 30.5
m, 5 Feb 1976, D. L. Meyer coll. & det.
Notes: This is the most common large, bushy crinoid of the Guamanian fore
reef [although the Cocos I. specimen is the smallest Comaster schlegelii ever
observed by one of us (C.G.M.)]. It occurs widely along the west side of Guam
(where the majority of the diving occurs) and often hosts crustacean symbionts.

Kirkendale & Messing: Crinoids of Guam 529
Rarely encountered smaller animals are often partially hidden; larger animals are
fully exposed during the day (see Meyer & Macurda 1980, as Comanthina
schlegelii, for feeding behavior and field characters). Messing (1998b) has
suggested that C. schlegelii from Micronesia may be a distinct taxon: it develops
more arms, retains more cirri at a larger size and perches in the open to a greater
degree than C. schlegelii from Australia and Papua New Guinea. Specimens from
Guam are similar to those from Micronesia.
Local specimens are completely yellow; dark green to dark brown/black;
yellow with black banding on arms and pinnules; black with black and white
pinnules tipped with yellow; banded orange, brown and white; brown arms with
yellow pinnules and cirri, or black with a yellowish disk. Two photographed
specimens (R. Myers 216b, G. Paulay 649-32) with different color patterns are
tentatively included here. Both have brownish-yellow arms (also partly white in
the Myers photo) and either mostly black or mostly white pinnules with yellow
tips. These patterns resemble that of one Comaster schlegelii from Enewetak:
division series and arms orange to orange-brown with random white variegations;
pinnules “black with yellow tips except for variegations where pinnules are white
with yellow tips” (Zmarzly 1984:111). Other color patterns from other areas
include green, often mixed with black, orange and white (Rowe et al. 1986), and
orange or orange brown arms variegated with white, and with brown, orange-
brown or white pinnules tipped with yellow or white (Zmarzly 1984).
Distribution: Indo-Malaya to Fiji and Kwajalein, including tropical
Australia (Western Australia to Port Molle, Queensland), Taiwan, Palau, Guam,
Saipan and southern Japan (Meyer & Macurda 1980, Zmarzly 1984, 1985, Rowe
et al. 1986, Chen et al. 1988, Rowe & Gates 1995, Messing 1998b, Kogo 1998).
Records from the Maldive Is., Sri Lanka and the Andaman Is. that pre-date the
generic revision of Rowe et al. (1986) may refer to C. schlegelii or C. nobilis.
Depth range: 10-42 m locally; it has been collected in as little as 1.5 m at
Madang, Papua New Guinea (Messing unpublished). The specimens listed above
from Maug I. and Saipan are the first records of C. schlegelii from the CNMI.
Clarkcomanthus Rowe et al., 1986
Clarkcomanthus littoralis (Carpenter, 1888)
Material examined: SOUTHERN CNMI: UF 27 (2), Saipan, off Agingan
Pt., partly hidden under overhang, 10-13 m, 10 Aug 2001 [with Harrovia sp.];
UF 40, Saipan, off Agingan Pt., under overhang, ~15-20 m, 11 Aug 2001 [with
Harrovia sp.].
Notes: This is the first record of this species from the Marianas Chain.
Members of the genus Clarkcomanthus differ from Comanthus in having pinnule
combs only as far as the second pinnule on the undivided arm (P2) and in lacking
an initial transversely oriented comb tooth. C. littoralis differs from C.
luteofuscum (below) in having a small centrodorsal that does not obscure the
radial ossicles (and usually fewer than 12 cirri). The Saipan specimens are

530 Micronesica 35-36, 2003
yellow-green aborally with a black disk and ambulacra; in one, the arms become
yellow distally. Other color patterns recorded elsewhere include green or brown
proximal rays becoming pale green distally; pale gray or white with articulations
and soft parts ginger brown, or green with yellow spots; pinnules may have
yellow tips (Rowe et al. 1986, Messing unpublished).
Distribution: Northern Australia (from Lancelin, W.A., to Lady Elliot I.,
Queensland), Indo-Malaya, southern Japan, Fiji, New Caledonia, Tonga, Saipan
and Chuuk Atoll. Depth range: 1-144 m (Rowe et al. 1986).
Clarkcomanthus luteofuscum (H. L. Clark, 1915)
Material examined: SOUTHERN CNMI: UF 44, Saipan, off Agingan Pt.,
in coral thicket, 10-13 m, 10 Aug 2001 [with pontoniines].
Notes: This is the first record of this species from the Marianas Chain. It
differs from C. littoralis in having a large centrodorsal that covers the radial
ossicles and rarely bears fewer than 15 cirri. The single specimen has a “starry
night” color pattern: uniformly black with numerous tiny yellow spots.
Elsewhere, the species is recorded as being dull brown or green; rays greenish-
brown proximally with brown articulations and small yellow spots, becoming
yellowish or light green distally, and with pinnules green or brown and spotted or
beaded with yellow or green; and rays very dark brown with small green spots on
articulations, centrodorsal, cirri and pinnules (Rowe et al. 1986, Messing
unpublished). Meyer & Macurda (1980) recorded this species from Palau as
Comanthus samoana.
Distribution: Northern Australia (from NW Cape, W.A., to Swain Reefs,
Queensland), southern Japan, Indo-Malaya, Solomon Is., New Caledonia, Tonga,
Palau, Saipan, Chuuk Atoll (Rowe et al. 1986, Messing 1998b [the record from
Chuuk incorrectly omitted from his Table 1], Kogo 1998). Depth range: 0-18 m.
Comanthus A. H. Clark, 1908
Comanthus alternans (Carpenter, 1881)
Material examined: GUAM: UF 42, Orote Pt., on coral/rock, 13 m, 2 Aug
1969, RHCG54; UF 43, Pati Pt., exposed, 24 m, 25 July 2001, V. Bonito, coll.
Notes: This large, bushy comatulid may have even more arms than Comaster
schlegelii (i.e., up to about 125), but it differs in having a small stellate
centrodorsal without cirri (at least in specimens with more than 40 arms), and
well-separated rays without any pavement of small plates between them.
Individuals use some of their arms to cling to prominent perches in exposed
positions, with the centrodorsal raised above the substrate. Both specimens are
dried and uniformly dark brown (almost black). Other color patterns recorded
elsewhere include black or deep mahogany with green or white pinnule tips, and
sometimes with a white aboral arm stripe; dark brown with a dusting of tiny
white or yellow spots; rays greenish yellow with groups of pinnules alternating

Kirkendale & Messing: Crinoids of Guam 531
between black with white tips and white with a middle black band; and pale gray
or white with few to many pinnules black or brown with white tips (Meyer &
Macurda 1980, Zmarzly 1985, Rowe et al. 1986, Messing unpublished observa-
tions). Meyer & Macurda (1980) reported this species from Palau as
Comantheria briareus and Comantheria sp. cf. C. briareus. Zmarzly (1985)
reported it from Kwajalein as Comantheria briareus.
Distribution: Northern Australia (Carnarvon, W.A., to One Tree Reef,
Queensland), Indo-Malaya, southern Japan, Palau, Guam, Chuuk and Kwajalein
Atolls and New Caledonia. Depth range: 0-90 m (Rowe et al. 1986).
Comanthus parvicirrus (Müller, 1841)
Material examined: GUAM: UGI 2920, SW of Achae Pt., 21 m, 28 Aug
1977 [with two alpheids], D.L. Meyer coll. & det. SOUTHERN CNMI: Saipan,
USNM E18210, lagoon, in clump of Montipora verrucosa, 3.4 m, 4 Oct 1949, P.
E. Cloud coll.; UF 39, Saipan, off Agingan Pt., under rubble & overhangs, ~15-
20 m, 11 Aug 2001 [with two alpheids].
Notes: Unlike Comaster schlegelii and Oxycomanthus bennetti, this species
usually has 20-40 arms and is more slender with fewer, smaller cirri, characters
that it shares with Clarkcomanthus littoralis and Comanthus walhbergii. It differs
from C. wahlbergii in having the radial ossicles visible beyond the small
centrodorsal, and from C. littoralis in having pinnule combs at intervals along the
entire arm length and a transversely oriented first comb tooth. Older records of C.
parvicirrus (before Rowe et al. 1986) may be referable to Comanthus briareus,
C. gisleni, C. suavia or Clarkcomanthus littoralis. For example, the specimen
identified as C. parvicirrus in figure 6g of Meyer & Macurda (1980) from Palau
is almost identical to C. suavia from Papua New Guinea (Messing unpublished);
both have greenish rays with distinctly darker articulations, a paler centrodorsal
with at most one cirrus, and reddish pinnules.
Distribution: Thailand to Fiji and Tonga, including Indo-Malaya, northern
Australia (Cockburn Sound, Western Australia to Julian Rocks, New South
Wales), the Coral Sea, Taiwan, Palau, Chuuk, Guam, CNMI and Okinawa (Rowe
et al. 1986, Chen et al. 1988, Kogo 1998, Messing 1998b). Records from
Madagascar (Marshall & Rowe 1981), Enewetak and Kwajalein (Zmarzly 1984,
1985) may or may not represent this species. Depth range: shoreline to 28 m
(Rowe et al. 1986). A specimen in the Smithsonian Institution extends the range
of this species to Saipan.
Comanthus wahlbergii (Müller, 1843)
Material examined: GUAM: UF 29, Orote Pt., cryptic under rock, 27-34 m,
4 Nov 1998, H.T. Conley coll.; UF 30, Ritidian fore reef, 7-9 m, 4 May 2000,
night, G. Paulay coll., photos GP815:18, 818:2.

532 Micronesica 35-36, 2003
Notes: This is a new record for Guam. The white and reddish (photo 815:18)
and white, pale brown and darker brown (photo 818:2) concentrically banded
color patterns are similar to the pale and dark brown concentric banding
previously recorded for this species elsewhere, although other colors have also
been recorded (Rowe et al. 1986). This species differs from both Comanthus
parvicirrus and Clarkcomanthus littoralis in having usually at least 20 cirri on a
larger centrodorsal that covers the radial ossicles.
Distribution: False Bay, South Africa, to Samoa, including Indo-Malaya,
northern Australia (Garden Island near Perth to Mooloolaba, Queensland), Lord
Howe Island, New Zealand, Admiralty Islands, New Caledonia, Guam and
southern Japan (Rowe et al. 1986, Messing 1998b, Kogo 1998). Messing (1998b)
tentatively identified this species from the Sulu Sea. Marshall & Rowe (1981)
recorded this species as Comanthus sp. aff. C. samoanus from Madagascar and
Meyer & Macurda (1980) recorded it as C. samoanus from Palau. Depth range:
1-103 m (Rowe et al. 1986).
Oxycomanthus Rowe et al., 1986
Oxycomanthus bennetti (Müller, 1841)
Material examined: GUAM: UGI 2911, Southwest side of Achae Pt.,
exposed, 21 m, 28 Aug 1977, D. L. Meyer, C. Birkeland & J. Eads coll., D. L.
Meyer det.; UF 31, Uruno Point, exposed on coral head, 20 m, 7 Nov 1999;
[photo only] Anae Island, 18-24 m, 25 Aug 1999, photo GP762:16. SOUTHERN
CNMI: Saipan, inside the Grotto, 27 July 1985, 18 m, R. Myers photo S-10; UF
32, Saipan, off Agingan Pt., exposed on coral head, ~15-20 m, 11 Aug 2001
[with Allogalathea sp.].
Notes: As with Comaster schlegelii, this is a large (usually >50 arms), bushy,
diurnally-active and rheophilic species. However, the cirri of O. bennetti are
usually 3.0-4.5 cm long and elevate the animal above its perch, whereas in C.
schlegelii, the cirri are rarely as much as 2.0 cm long, weaker and more strongly
curled. These anatomical differences result in postural differences that are
observable in the field, and are useful in distinguishing these otherwise similar
species on Guam (see Meyer & Macurda 1980, as Comanthus bennetti, for
further field characters). The UF 32 specimen from Saipan was black with
yellow-tipped distal pinnules and with a greenish-yellow tinge around the cirri
and mouth.
Distribution: Andaman Islands to Fiji and Arno Atoll, including Indo-
Malaya, tropical Australia (Ashmore Reef to Elliot Island), Lord Howe I.,
Taiwan, Palau, Guam, Saipan and Okinawa (Meyer & Macurda 1980, Zmarzly
1984, Rowe et al. 1986, Chen et al. 1988, Rowe & Gates 1995, Messing 1998b,
Kogo 1998). Although Rowe et al. (1986) give the depth range as 8-25 m, O.
bennetti is common in <10 m and may be found in as little as 1 m. A less
common, differently colored, deeper water form, which may have fewer longer
arms, occurs in 15-46 m (Meyer & Macurda 1980, Messing unpublished). The

Kirkendale & Messing: Crinoids of Guam 533
photo-identified animal from Saipan listed above has attributes consistent with
the deep-water form.
Oxycomanthus exilis Rowe et al., 1986
Material examined: none.
Additional records: GUAM: USNM E33982, Gab-Gab Beach, Apra Harb-
or, 3 km E of Orote Pt., 13˚ 26’30”N, 144˚ 38’30”E, 3.1 m, 20 Nov 1983, R. F.
Bolland coll. & F. W. E. Rowe det.
Notes: This record, the only one for this species from Guam, is based on a
specimen not seen by us, but identified by one of the describers of the species.
Distribution: Indo-Malaya to New Caledonia and Fiji, including tropical
Australia (Ashmore Reef to Moreton Bay, Queensland), Solomon Is., Guam,
Chuuk and possibly southern Japan (Rowe et al. 1986, Rowe & Gates 1995,
Messing 1998b, Kogo 1998). Depth range: 3-25 m.
Oxycomanthus cf. mirus Rowe et al., 1986
Material examined: GUAM: UF 717, Luminao fore reef, in rubble, 10 m, 9
Sep 1997, G. Paulay coll.
Notes: This specimen most closely approaches Oxycomanthus mirus al-
though it exhibits several features in common with closely similar O. coman-
thipinna (Gislén). As in O. mirus, the oral pinnule combs bear straight, blade-like
primary teeth set in from the edge of the segments that bear them, the distal teeth
are fused to each other and taper to form a sharp pinnule tip, and most tooth-
bearing segments also bear a secondary peg-like tooth. Unlike O. mirus, all
second brachitaxes consist of two segments rather than all or mostly four, and
seven functional cirri are present. Described specimens of O. mirus have at most
one rudimentary cirrus and three cirrus scars (Rowe et al. 1986). O. coman-
thipinna bears 8-15 functional cirri, no secondary comb teeth, and its second
brachitaxes may consist either of two or four segments. The larger number of
cirri in the Guam specimen (relative to described O. mirus) may be accounted for
by its small size: 20 arms, ray length 70 mm and centrodorsal diameter 2.1 mm.
The holotype of O. mirus has 38 arms, ray length 140 mm and a centrodorsal 2.5
mm across. A larger specimen collected off Palawan I., Philippines, has 41 arms,
ray length 170 mm and four rudimentary cirrus scars on a centrodorsal 3.1 mm
across (Messing unpublished). Several other comasterids lose cirri as they
increase in size (e.g., Comaster nobilis) and others vary in the proportions of
brachitaxes of two versus four segments (Comanthus gisleni, Clarkcomanthus
albinotus).
Distribution: Great Barrier Reef, Australia; Palawan, Philippines; New
Caledonia and Guam. Depth range: 3-18 m (Rowe et al. 1986, Messing
unpublished).

534 Micronesica 35-36, 2003
Subfamily incertae sedis
Genus incertae sedis
Comasterid sp. A
Material examined: SOUTHERN CNMI: UF 33, SW Aguijan I., Tow 27,
140-420 m, 9 Apr 1983, Eldredge et al. colls. (1984).
Notes: This specimen shares with Rowemissia scitulus similar small size
(centrodorsal diameter 2.6 mm; estimated ray length ~50 mm), ten arms, a
roughly central mouth, and distinctive pinnule combs tapering to a sharp tip with
the initial and distal 1-2 teeth single and nonconfluent, and middle teeth paired
separated and peglike (Messing 2001). However, unlike R. scitulus, it bears no
gonads, lacks P3 and Pc on at least two rays and thus appears to be a juvenile. It
also differs in having more cirri composed of more segments that are much
shorter than in R. scitulus (20 cirri of +17 segments with a maximum
length/width ratio of 1.3 versus 11 cirri of 10-11 segments with a maximum ratio
of 3.4); U-shaped aboral ridges on the distal cirrus segments instead of weak
spines; proportionally larger comb teeth, and a distal syzygial interval of 4-10
instead of 2-4. Finally, numerous calcareous nodules cover the aboral interradial
areas and are scattered on the oral surface of the Aguijan specimen whereas both
surfaces in R. scitulus bear thin calcareous scales.
The distinctive comb form distinguishes the Aguijan specimen from
Comissia spp. but approaches that of both Comaster spp. and Oxycomanthus
mirus. However, similarly sized specimens of, e.g., Comaster schlegelii (ray
length 60 mm) already have as many as 38 arms and well developed diagnostic
aboral interradial plating. In O. mirus, the larger of the paired comb teeth is
bladelike rather than peglike, and in both Oxycomanthus and Comaster the mouth
is excentric rather than central or subcentral. We treat the specimen as
unidentified because it is apparently juvenile and has not developed all features
diagnostic of its genus, whichever that may be. We include it in the species list
because it clearly differs from all other crinoids known from this area.
Family Mariametridae A. H. Clark, 1909
Stephanometra A. H. Clark, 1909
Stephanometra indica (Smith, 1876)
Material examined: none.
Additional records: GUAM: USNM E7727, tide pools, 25 Nov 1945, D. G.
Frey coll. & A.H. Clark det.
Notes: Rowe & Gates (1995) formally synonymized S. spicata under S.
indica. Rankin (2000) added S. spinipinna and S. oxyacantha as junior synonyms
of S. indica. Of the 103 specimens she examined, which ranged from the Red Sea
to Fiji and the South China Sea, over 20% were intermediates that could not be
satisfactorily assigned to species.
Both Stephanometra and Lamprometra (below) are usually cryptic under
rubble and within the reef framework during the day. At dusk, they crawl to

Kirkendale & Messing: Crinoids of Guam 535
exposed perches and spread their arms in a biplanar posture. For further
behavioral and postural details, see Meyer & Macurda (1980) and Messing
(1994).
Distribution: (S. indica plus synonyms) Red Sea, Tanzania and Madagascar
to Guam and the Tonga Islands, including Indo-Malaya, tropical Australia as far
south as the Capricorn Channel, Queensland, Palau and Okinawa. Previously
published records extending the distribution as far east as Jaluit and Arno
(Zmarzly 1984) may be based on incorrect identifications (Rankin 2000). Depth
range: 1 to at least 15 m; a few older dredging records from substantially deeper
than about 30 m (50-73 m) may not be accurate (A.H. Clark 1941, Rankin 2000,
Messing unpublished).
Lamprometra A. H. Clark, 1913
Lamprometra palmata (Müller, 1841)
Material examined: GUAM: UF 34, Facpi Point, on rock substrate with
algal and sand covering, 23-27 m, 20 Mar 1993, F. Thomas coll., donated by
H.T. Conley; NORTHERN CNMI: Alamagan, UF 35, reef slope, on rock, 20 m,
19 May 1992, P. Schupp coll.
Notes: This single specimen is a new record for Guam. See Stephanometra,
above, for posture and behavior. Rankin (2000) considered L. klunzingeri from
the Red Sea and northwestern Indian Ocean as a synonym of L. palmata and
noted that some previously published records of L. palmata may represent
Stephanometra indica, Liparometra spp. or Dichrometra spp.
Distribution: Red Sea and Mauritius (possibly Zanzibar and Tanzania) to
Tonga, Marshall Islands and possibly Hawai’i, including tropical Australia and
Indo-Malaya north to southern Japan (Utinomi & Kogo 1965, Kogo 1998,
Rankin 2000). The only record from Hawai’i (Hartlaub 1912) refers to a single
broken specimen supposedly from Oahu in the Museum of Comparative
Zoology, Harvard; no catalogue number has been published. Depth range:
shoreline to 35 m (plus a few questionable deeper old dredging records)(A. H.
Clark 1941, Rankin 2000).
Family Colobometridae A. H. Clark, 1909
Cenometra A. H. Clark, 1909
Cenometra bella (Hartlaub, 1890)
Material examined: GUAM: UGI 2921, SW of Achae Point, on wire coral,
45 m, 28 Aug 1977, D. L. Meyer coll. & det.; UGI 2915, "Blue Hole", Orote Pt.,
attached to antipatharian, 48 m, 30 Aug 1977, J. Eads coll. & D. L. Meyer det.;
UF 36, Orote Pt., near Blue Hole, on cliff, 67 m, 29 Dec 1971, N. Vag coll.; UF
28, Haputo, reef flat under rock, 4 Aug 2000, V. Bonito coll.
Notes: This species typically clings to gorgonian and antipatharian sea
whips, usually arranging its arms in an irregular radial fan. Specimens usually

536 Micronesica 35-36, 2003
bear 25-30 (sometimes up to 40) arms and exhibit a wide range of colors, often
with cirri of a sharply contrasting color. In addition to the material examined
above, G. Paulay (personal communications) has observed this species off
Hospital Point (on Cirrhipathes sp.) and ~2 km north of the University of Guam
Marine Lab/Pago Bay (on a gorgonian) in 30-40 m.
Distribution: Burma to New Caledonia, Kwajalein and Jaluit, including
Indo-Malaya, tropical Australia (Ashmore Reef to the Great Barrier Reef),
Taiwan, Palau, Guam, Chuuk and Japan (A.H. Clark 1947, A. M. Clark & Rowe
1971, Meyer & Macurda 1980, Zmarzly 1985, Chen et al. 1988, Rowe & Gates
1995, Messing 1998b). Inclusion of Cenometra herdmani A.H. Clark and C.
cornuta A.H. Clark within C. bella following A. M. Clark & Rowe (1971)
extends the range eastward at least to Sri Lanka [although Rowe & Gates (1995)
maintain C. cornuta as distinct]. Depth range: chiefly 10-55 m, with a few
records from shallower water (A. H. Clark 1947, Meyer & Macurda 1980,
Messing unpublished).
Family Charitometridae A. H. Clark, 1909
Monachometra A. H. Clark, 1916
Monachometra cf. patula (Carpenter, 1888)
Material examined: GUAM: UF 37, Eleven Mile Bank, 73-110 m, 1997, F.
Cushing coll.
Notes. According to the most recent treatment of the Charitometridae, this
specimen most closely approaches Monachometra in that “the genital pinnules
taper evenly from the usually more or less broadened earlier segments to a
delicate and slender tip, the portion beyond the gonads being much longer than
the gonads themselves; the outer portion of the arms is rounded dorsally
[=aborally], sometimes with a slightly raised broad median line;…the IIBr series
are 2;…and the cirri have 17-31 segments with the opposing spine often
bifurcate” (A. H. Clark 1950:208). The specimen also bears distinct synarthrial
tubercles although they are not as prominent as those described for
Monachometra. It differs from the generic diagnosis in having oral pinnules
somewhat longer than genital pinnules (rather than shorter or about the same
length), 28 arms (rather than 10-21), and cirrus sockets irregularly crowded
rather than arranged in 10-15 columns.
Within the genus, the specimen most closely approaches M. patula
(Carpenter) in having proximal brachials with prominently raised distal margins
and exteriorly developed IIIBr series. Although it differs significantly in having
cirrus sockets crowded irregularly around the centrodorsal rather than in 10-12
columns separated midradially, the difference may be due to size. The Guam
specimen bears 28 arms and 39 cirri composed of up to 24 segments while
previously recorded specimens have at most 21 arms and 30 cirri with 22
segments. The brachitaxis ossicles of the Guam specimen also bear irregularly
crenulate margins, a feature not previously recorded in M. patula.

Kirkendale & Messing: Crinoids of Guam 537
Distribution: M. patula has previously been recorded from the Philippines,
eastern Indonesia (Kai Is.) and Sahul Shelf (Timor Sea) in 104-385 m (A. H.
Clark 1941). The current record, if conspecific, extends the range to Guam in 73-
110 m.
Family Antedonidae Norman, 1865
Dorometra A. H. Clark, 1917
Dorometra nana (Hartlaub, 1890)
Material examined: GUAM: UGI 6209, Pati Pt., outer reef slope, under
rock, 10 m, 27 May 1997, T. Leberer coll.; UF 38, Orote Pt., under rock, 20 m,
May 2000, V. Bonito coll.
Notes: These are the first records of Dorometra nana from Guam. Both
specimens are small, delicate and mottled. The Orote Pt. specimen is brown,
beige and white; the Pati Pt. specimen is maroon and mauve.
Distribution: Andaman and Nicobar Islands to Tonga, Jaluit and Ebon
atolls, including Australia (W coast to New South Wales), Indo-Malaya, Palau,
Guam and Chuuk (A. H. Clark & A. M. Clark 1967, Meyer & Macurda 1980,
Zmarzly 1984, Messing 1998b). Utinomi & Kogo (1968) list it as a member of
the Japanese crinoid fauna, but Kogo (1998) does not.
Order Isocrinida Sieverts-Doreck, 1952
Family Isocrinidae Gislén, 1924
Subfamily Metacrininae Roux, 1981
Saracrinus A. H. Clark, 1923
Saracrinus nobilis (Carpenter, 1884)
Material examined: GUAM: UGI 6812, Thompson-Cromwell Cruise 84-
02/04 Sta.08, off Hospital Pt., on outside of shrimp trap, haul #15, ~366 m, 10
May 1984, R. Strong coll.
Additional records: NORTHERN CNMI: UGI 6680, SW Aguijan, Tow 27,
4 Sep 1983, D. Meyer det.
Notes: Roux (1981) transferred this species from Metacrinus to Saracrinus.
This is the only stalked crinoid reported from the Marianas chain so far. The
Aguijan specimen retains 38 cm of stalk and was reported to be tan to brown in
life (Meyer & Macurda 1980).
Distribution: Western Sumatra to New Caledonia, the Kermadec Islands and
New Zealand, and as far north as southern Japan and the Bonin Islands
(Carpenter 1884, A.H. Clark 1923, Meyer & Macurda 1980, Roux 1981,
Bourseau et al. 1991).

538 Micronesica 35-36, 2003
Artificial key to the shallow-water (<50 m) crinoids of Guam and the
Commonwealth of the Northern Marianas Islands
This key to adult specimens includes only the most easily recognizable
features. Small ten-armed juveniles of species that normally develop more than
ten arms have not been included. For additional details, see the following sources
identified by superscript numbers accompanying each species: 1) Messing
(1998a), 2) A. H. Clark (1931), 3) Rowe et al. (1986), 4) A. M. Clark & Rowe
(1971), 5) Messing (1995).
1a. More than ten arms………………………………………………………….. 2
1b. Ten arms only……………………………………………………………… 17
2a. (1a) Cirri absent……………………………………………………………... 3
2b. (1a) Cirri present……………………………………………………………..5
3a. (2a) Exposed on prominent perches; anchors with curved lower arms that
raise the central body above the substrate…………...Comanthus alternans3
3b. (2a) Central body hidden within reef framework or under ledges; only arms
exposed…………………………………………………………………… 4
4a. (3b) Usually 40-125 fragile and extremely Velcro-like arms; rays well
separated basally, longest 11-20 cm (specimens with fewer than 40 arms
have ray lengths 5-9 cm); pinnule combs coiled into tiny fists or spirals;
usually gold, orange or brown with darker aboral arm stripe……………….
.………………………………………………………Phanogenia gracilis1,2
4b. (3b) Usually 30-48 robust arms, not extremely Velcro-like; rays crowded
basally (except in small specimens), longest usually 14-17 cm; pinnule
combs taper to a point; yellow or green with green or black articulations….
……………………………………………………….Oxycomanthus mirus3
5a. (2b) A few (usually <15) short cirri scattered around the margin of a small,
thin, discoidal or pentagonal centrodorsal………………………………...6
5b. (2b) Numerous (usually >20) cirri completely encircle centrodorsal, which
may be thin or thick………………………………………………………. 8
6a. (5a) Usually 10-20 arms with longest rays <7 cm; hidden during the day;
arms exposed at night, often banded white and red, lavender or brown;
combs taper to a point, present only on first pinnule..Oxycomanthus exilis3
6b. (5a) Usually 25-40 arms with longest rays usually >10 cm; arms extend from
crevices and branching corals during the day; sometimes more exposed at
night………………………………………………………………………. 7

Kirkendale & Messing: Crinoids of Guam 539
7a. (6b) Color variable, but most often brown or greenish with bluish pinnules
and cirri; combs coiled, present on several proximal pinnules and at
intervals along arm……………………………….. Comanthus parvicirrus3
7b. (6b) Color usually greenish or yellow-green, never with bluish pinnules or
cirri; combs not coiled, present only as far as second pinnule on undivided
arm………………………………………………Clarkcomanthus littoralis3
8a. (5b) Robust with more than 50 arms………………………………………... 9
8b. (5b) Slender with fewer than 40 arms………………………………………10
9a. (8a) Completely exposed; cirri 3-4 cm long, robust and elevating body above
substrate; bases of rays well separated; arms resemble feathers (i.e., with
pinnules arranged in single plane); colors variable: green, black, orange or
yellow, often with differently colored pinnule tips..Oxycomanthus bennetti3
9b. (8a) Completely exposed or with body partly hidden; cirri usually 2 cm long,
not elevating body above substrate; underside of body appears solid due to
pavement of small plates between bases of rays; successive pinnules offset
(not in single featherlike plane); usually black, brown, yellow or a
combination………………………………………….. Comaster schlegelii3
10a. (8b) Comb teeth present on at least proximal pinnules……………………11
10b. (8b) Proximal pinnules without comb teeth……………………………….15
11a. (10a) Pinnules lacking Velcro-like texture; color dark red or purplish;
pinnules combs usually of >20 tall narrow teeth; large specimens form fans
on exposed perches at night; small specimens extend arms from crevices…
………………………………………………...Alloeocomatella polycladia5
11b. (10a) Pinnules with Velcro-like texture; color never uniform dark red or
purplish; pinnule combs of <15 teeth; arms may be visible during the day;
sometimes completely exposed at night, but not forming fans on exposed
perches…………………………………………………………………... 12
12a. (11b) Arms slender and fragile; cirri fine and delicate; rays orange or orange
and white; rarely found shallower than 30 m…...Phanogenia cf. distincta1,2
12b. (11b) Arms and cirri stout; color variable; found as shallow as 1 m………13
13a. (12b) Color usually white with reddish or brown bands; pinnule combs
present at intervals to at least halfway out arm…….Comanthus wahlbergii3
13b. (12b) Color black, maroon, green or brown, sometimes yellow distally, and
often with green or yellow mottling, flecks or spots; pinnule combs present
only on proximal two or few pinnules on undivided arm………………..14
14a. (13b) Pinnule comb only as far as second pinnule on undivided arm; two or
four ossicles between ray branches…………Clarkcomanthus luteofuscum3

540 Micronesica 35-36, 2003
14b. (13b) Pinnule combs on first three to five pinnules; only two ossicles
between ray branches…………………………………Comatella stelligera2
15a. (10b) Usually clings to unbranched or sparsely branched antipatharians and
gorgonians; color variable, often with rays and cirri of contrasting color.…
…………………………………………………………... Cenometra bella4
15b. (10b) Hidden during the day; forming arc-shaped or radial fans on exposed
perches at night; usually concentrically banded with cream, brown and/or
orange (sometimes green) ………………………………………………. 16
16a. (15b) One to several pinnules near arm bases rigid and spike-like, its
component segments longer than wide……………. Stephanometra indica4
16b. (15b) Second pinnule larger than others but not rigid and spike-like, its
component segments squarish……………………...Lamprometra palmata4
17a. (1b) Rays reddish or orange, up to 50 cm long; 4-7 arms extend upward
from a crevice only at night; withdraws rapidly when illuminated; central
body almost never visible; centrodorsal discoidal with marginal ring of
cirri…………………………………………… Alloeocomatella pectinifera5
17b. (1b) Rays purplish, mauve, or pale tan and white, 3-4 cm long; cryptic under
rubble; capable of swimming via rapid arm flexing; up to 30 extremely
delicate cirri more or less cover a low hemispheric centrodorsal…………
…………………………………………………………... Dorometra nana4
Discussion
We report 21 species of crinoids from Guam and the CNMI distributed
among six families and thirteen genera; 20 are unstalked crinoids, or comatulids,
of which all but the unidentified juvenile comasterid sp. A and the charitometrid,
Monachometra cf. patula, are known from <50 m. This total adds twelve new
records to earlier reports (Clark 1954, Meyer & Macurda 1980), as follows:
Alloeocomatella pectinifera, Clarkcomanthus littoralis, Clarkcomanthus
luteofuscum, Comanthus alternans, Comanthus wahlbergii, Oxycomanthus exilis,
Oxycomanthus cf. mirus, Phanogenia cf. distincta, comasterid sp. A
(Comasteridae), Lamprometra palmata (Mariametridae), Monachometra cf.
patula (Charitometridae) and Dorometra nana (Antedonidae). Nine new records
are added for Guam and the total fauna there is now at least 17 species. Eight
new records are added for the CNMI (chiefly due to recent collecting by one of
us at Saipan [L.K.]) and the known fauna there is now at least 10 species. Most
of the 21 species reported here are well recognized and widely distributed across
the Indo-Malayan archipelago and islands of the western Pacific, a pattern that
also applies to the crinoid faunas of other Micronesian islands (A. M. Clark &
Rowe 1971, Meyer & Macurda 1980, Zmarzly 1984, 1985, Messing 1998b).
Species richness of these islands reflect well known declines among most groups

Kirkendale & Messing: Crinoids of Guam 541
of benthic macrofauna from the rich central Indo-Malayan archipelago to the
north, east and west (Table 1).
Although the marine fauna of Guam has been intensively surveyed during the
last several years and is now among the most thoroughly investigated in Oceania
(Amesbury et al. 2001, Paulay et al. 1997, Paulay et al. 2001, 2001, 2002), the
current faunal list is probably incomplete. Gislén (1922) listed an additional
seven shallow-water species (converted to current nomenclature) that occur in
both Indo-Malaya to the southwest and Ogasawara-Gunto (Bonin Is.) to the north
that have not yet been found in the Marianas Chain. Also, Comatella stelligera
found at Rota I, CNMI, and the two species of Clarkcomanthus reported from
Saipan herein have not yet been found at Guam. Although these absences may be
real, it is also plausible that these taxa inhabit areas that are visited infrequently,
or have never been sampled on Guam. Areas of strong currents not often visited
by divers (e.g., Pati Point at the northern tip of Guam) may support rheophilic
species such as Colobometra perspinosa, which has been reported anecdotally,
but has not yet been photographed or collected. Soft bottom habitats (e.g., Apra
Harbor) have not been explored as thoroughly as have reefs and hard-bottoms,
and little deep-water dredging has taken place.
Table 1. Number of shallow-water (<50 m) species recorded from areas in the
Indo-West Pacific region.
Island/Island Group No. species Source
Jolo Archipelago, Tubbataha Reefs
& central Palawan (Sulu Sea)
58 A.H. Clark 1941, 1947, A.H. & A.
M. Clark 1967, Messing 1998b
Lizard I., Great Barrier Reef 54 Hoggett & Vail, pers. commun. in
Messing 1998b
Papua New Guinea 44 Messing 1998b
Chuuk 21* Messing 1998b
Palau 19 Meyer & Macurda 1980
Madagascar ~20 Marshall & Rowe 1981
Taiwan 20 Chen et al. 1988
Guam 17 Meyer & Macurda 1980; this pape
r
CNMI 10 Meyer & Macurda 1980; this pape
r
Marshall Islands 14 Zmarzly 1984, 1985
Differing collecting methods, efforts, investigators and taxonomies among sites render the
following records imperfectly comparable although numbers have been modified to reflect
current taxonomy. *Messing’s (1998b) list of species from Chuuk totaled 22 species, but only
19 were actually checked off. He omitted Clarkcomanthus luteofuscum, Liparometra
articulata and Comanthus ?wahlbergii and treated Stephanometra indica and S. oxyacantha as
separate.
Shallow-water species richness supposedly declines with distance to the
north, west and east of the Indo-Malayan archipelago. However, Palau, which
sits much closer to Indo-Malaya, supports only about four more nominal species
than Guam (given taxonomic changes made since Meyer & Macurda 1980).

542 Micronesica 35-36, 2003
Although Chuuk atoll lies east of Guam, Messing (1998b) found 22 species there
during only 14 dives, a greater richness than Guam. Finally, the Marshall Islands
(Enewetak and Kwajalein), which lie twice as far from Indo-Malaya, support
about the same number of species as Guam (Zmarzly 1984, 1985)(Table 1).
Variable survey effort among sites notwithstanding, factors other than distance
from the Indo-Malayan archipelago must thus contribute to crinoid faunal
patterns among central western Pacific islands [although limited sampling in the
CNMI almost certainly underestimates that fauna].
First of all, recorded Palauan richness is probably artificially low. Though
reduced by taxonomic changes [e.g., synonymy of Stephanometra spicata and S.
oxyacantha under S. indica (Rowe & Gates 1995; Rankin 2000)], the fauna likely
includes several cryptic species distinguished since Meyer & Macurda (1980)
surveyed those islands (e.g., Comanthus suavia, C. gisleni and Clarkcomanthus
littoralis have all been confused with Comanthus parvicirrus), as well as others
recorded from Guam, Chuuk and Indo-Malaya (e.g., Alloeocomatella pectinifera,
Oxycomanthus exilis). Also, Meyer & Macurda dove at night at only one of more
than 20 survey sites. Secondly, Guam is a single pinnacle surrounded by a
narrow fringing reef. Chuuk, Enewetak and Kwajalein are atolls with broad
lagoons and Palau is an archipelago surrounded by extensive shallow banks. All
have substantially greater shallow-water area and habitat diversity than Guam.
Also, while Palau, Chuuk and the Marshall Islands lie along a chain of island and
bank stepping-stones that connect to the Indo-Malayan center of richness, about
450 km of open ocean separates Guam from its nearest potential shallow-water
source of larvae to the south.
Finally, Guam lies within the North Equatorial Current, so its most direct
source of larval recruitment might be Enewetak, almost 2000 km due east.
Although nothing is known about the longevity or dispersal capabilities of
tropical Pacific crinoid larvae, modern circulation patterns may not have
generated current faunas. For example, Benzie & Williams (1997) have shown
that the genetic structure of Tridacna spp. does not agree with modern current
patterns; they suggest that changes in circulation associated with Quaternary
climate changes and sea level fluctuations may have shaped faunal affinities
observed today. A more detailed understanding of crinoid faunal patterns must
await information about larval longevity, reproductive patterns and fecundity,
and evolutionary and biogeographic history, about which nothing is currently
known.
Little endemism exists among the shallow-water crinoids of Oceania and no
examples currently exist for Guam or CNMI. Eudiocrinus tenuissimus is known
only from Jaluit Atoll (Gislén 1940), Euantedon tahitiensis and Mastigometra
pacifica are known only from Tahiti (A. H. Clark & A. M. Clark 1967), and
several species are currently known only from Ogasawara-Gunto (A. H. Clark
1947, 1950), which, like the Marianas Chain (Guam + CNMI), is separated from
adjacent island groups by similarly broad deep-water gaps. However, given the
recent discovery of such morphologically cryptic taxa as the Comanthus gisleni-

Kirkendale & Messing: Crinoids of Guam 543
C. suavia-C. parvicirrus complex, endemism may be simply unrecognized in the
Marianas Chain. For example, the local C. schlegelii, which as outlined above
seems to be a heavier, robust morphotype exclusive to Micronesia, may at least
be restricted to this region. Given their demonstrated success with other difficult
groups of marine invertebrates, molecular techniques will likely prove extremely
useful in solving many of these systematic problems.
Acknowledgments
Lisa Kirkendale would like to thank Gustav Paulay for the encouragement to
delve into the crinoids of Guam, and the many other staff, students and faculty at
the University of Guam Marine Laboratory who contributed to this work. Charles
Messing would like to thank Cynthia Ahearn (Smithsonian Institution) for her
incredible promptness in providing specimen data. Contribution 484 of the
University of Guam Marine Laboratory.
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Received 1 June 2001