Comaster L. Agassiz, 1836
publication ID |
https://doi.org/10.11646/zootaxa.4268.2.1 |
publication LSID |
lsid:zoobank.org:pub:0742D287-B82C-4014-A6AC-C357F259D5D7 |
DOI |
https://doi.org/10.5281/zenodo.6009124 |
persistent identifier |
https://treatment.plazi.org/id/039EDF70-FFAA-A174-FF66-D9E71248F8B3 |
treatment provided by |
Plazi (2017-05-16 07:33:13, last updated 2024-11-29 15:24:32) |
scientific name |
Comaster L. Agassiz, 1836 |
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Table 1, Figs. 8–9 View FIGURE 8 View FIGURE 9
Type species. Alecto multifida Müller, 1841 .
Other included taxa (2). Actinometra schlegelii Carpenter, 1881 ; Comaster audax Rowe, Hoggett, Birtles & Vail, 1986 .
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; IBr2 united by synarthry; IIBr and beyond 2 or 4(3+4), usually with IIIBr of 2 ossicles exteriorly and 4(3+4) interiorly; first syzygy on undivided arms always 3+4; distal intersyzygial interval 4; distalmost pinnule comb at least P2 (usually P3–P8), sometimes at intervals to P14; combs arising gradually and tapering to a sharp point distally; pinnules on brachitaxes and sometimes P1 with comb of single, nonconfluent teeth; combs on brachial pinnules of paired, confluent, erect, more or less equal-sized and well separated teeth; pairs sometimes joined to form a transverse bar ( Fig. 8 View FIGURE 8 D, M). Paired comb teeth may be absent on juvenile specimens (10–13 arms).
Distribution. Tropical Indo-western Pacific from northern Australia (Perth, WA, to Solitary Is., NSW), west to the Maldives, east to Fiji, and north to Sagami Bay, Japan. Depth range: 2– 183 m. All but a very few records are from depths shallower than 50 m.
Molecular results. Specimens identified as Comaster nobilis and C. schlegelii are less than 1.6% divergent in uncorrected distances of COI. As a clade, specimens of nobilis / schlegelii were at least 4% divergent in uncorrected distances of COI from C. audax ( Fig. 9 View FIGURE 9 ). A more comprehensive molecular and morphological analysis of Comaster is in preparation (Owen et. al. in prep.)
Remarks. Species of Comaster are most easily distinguished from other comatulids by the irregular plates between the bases of adjacent rays, which give the aboral surface a solid, paved appearance. Because specimens identifiable as C. nobilis or C. schlegelii exhibit such minimal sequence divergence, we reinstate the former as a junior synonym of the latter, in agreement with AH Clark (1911b, 1911c, 1912b, 1931). Nevertheless, substantial morphological variation exists. Smaller C. schlegelii with numerous cirri are easily distinguished from larger cooccurring “ C. nobilis ” on the Great Barrier Reef. The distinction may be ontogenetic, although accompanied by distinct and consistent color pattern differences. Specimens attributed to “ C. nobilis ” lose cirri with growth. At Raja Ampat, Indonesia, C. schlegelii and “ C. nobilis ” with similar centrodorsal diameters have ~20 versus 1 (plus a few tiny buds) cirri, respectively, whereas a smaller “ C. nobilis ” with the same color pattern as the large specimen has ~20 cirri. Specimens attributed to C. schlegelii from Micronesia, where “ C. nobilis ” has not been collected, retain well-developed cirri, reach a larger size, and perch in the open instead of nestling in crevices as C. schlegelii typically does elsewhere ( Messing 1998b).
Agassiz, J. L. R. (1836) Prodrome d'une Monographie des Radiaires ou Echinodermes. Memoires de la Societe des Sciences Naturelles de Neuchatel, 1835, 168 - 199.
Carpenter, P. H. (1881) The Comatulae of the Leyden Museum. Notes from the Leyden Museum, 3, 173 - 217.
Clark, A. H. (1911 b) On a collection of unstalked crinoids made by the United States Fisheries Steamer Albatross in the vicinity of the Philippine Islands. Proceedings of the United States National Museum, 36, 529 - 563. https: // doi. org / 10.5479 / si. 00963801.39 - 1798.529
Clark, A. H. (1911 c) The recent crinoids of Australia. Australia Museum Memoir, 4, 705 - 804. https: // doi. org / 10.3853 / j. 0067 - 1967.4.1911.1511
Clark, A. H. (1912 b) The crinoids of the Indian Ocean. Echinoderma of the Indian Museum, Part VII. Trustees of the Indian Museum, Calcutta, 325 pp.
Clark, A. H. (1931) A monograph of the existing crinoids 1 (3). Bulletin of the United States National Museum, 82, 1 - 916.
Messing, C. G. (1998 b) An initial re-assessment of the distribution and diversity of the East Indian shallow-water crinoid fauna. Pp. 187 - 192. In: Mooi, R. & Telford, M. (eds.) Echinoderms: San Francisco. Balkema, Rotterdam.
Muller, J. (1841) Uber die Gattungen und Arten der Comatulen. Monatsberichte Koniglich Preussische Akademie der Wissenschaften zu Berlin, 1841, 179 - 189.
Rowe, F. W. E., Hoggett, A. K., Birtles, R. A. & Vail, L. L. (1986) Revision of some comasterid genera from Australia (Echinodermata: Crinoidea), with descriptions of two new genera and nine new species. Zoological Journal of the Linnean Society, 86, 197 - 277.
FIGURE 8. Comaster. (A – G) Comaster schlegelii— (A) live, exposed on sediment; (B) aboral surface, showing pentagonal centrodorsal lacking cirri; (C) live, exposed on reef; (D) paired comb teeth of equal shape, well separated and confluent with edge of pinnular, tapering to pinnule tip; (E) aboral surface, showing pentagonal centrodorsal with row of cirri; (F), live, tucked within coral structure; (G) aboral surface showing centrodorsal with ring of cirri. (H – M) Comaster audax— (H – I) live, exposed on reef, (J – L) aboral surface showing centrodorsal with few cirri, yellow distally; (M) paired comb teeth of equal shape, well separated and confluent with edge of pinnular, tapering to pinnule tip. Madang, Papua New Guinea: A – B. MNHN-IE- 2013 - 8147; C. MNHN-IE- 2013 - 8178; E. MNHN-IE- 2013 - 8071. I, L. not vouchered, SIO-BIC E 5998 (DNA subsample). Raja Ampat, Indonesia: D, F. SIO-BIC E 6260; G. SIO-BIC E 6261; H. not vouchered. K, M. SIO-BIC E 6258. Lizard Island, Australia: J. AM J 17567, holotype.
FIGURE 9. Maximum likelihood tree of Comaster inferred from COI. Symbols and labels as in Figure 2. Location abbreviations — Madang, Great Barrier Reef, Australia (GBR); Papua New Guinea (PNG); Raja Ampat, Indonesia (Raja); Goodwyn Island, Western Australia (WA). New COI sequences are Genbank KR 010330 - KR 010347.
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