Ophiocoma (Breviturma) dentata Muller & Troschel 1842
Creators: name: Stöhr, Sabine
name: Boissin, Emilie
name: Hoareau, Thierry B.
Publisher: name: Zenodo
Year: 2013
Subjects: Biodiversity
Taxonomy
Animalia
Echinodermata
Ophiuroidea
Ophiurida
Ophiocomidae
Ophiocoma
Ophiocoma dentata

description: Ophiocoma (Breviturma) dentata Müller & Troschel, 1842
Figs 2E, F, 4 F-J, 5B, E, H, K, N, Q
Ophiocoma dentata Müller & Troschel, 1842: 99, pl. 7, figs 3-3a.
Ophiocoma ternispina v. Martens, 1870: 252.
Ophiocoma insularia Lyman, 1862: 80.
Ophiocoma variegata Smith, 1876: 39.
non Ophiocoma marmorata – Devaney 1970: 17.
Diagnosis
Species of Ophiocoma (Breviturma) subgen. nov. characterized by rarely possessing more than four arm spines and if present only at few segments; arm spines never annulated; variable in colour pattern (uniformly or marbled brown, reticulated of spotted); dorsal disc granule density less than 150 mm-2. Maximum size at least 28 mm dd (Devaney 1970).
Type material examined
Holotype ZMB Ech 931
Holotype of Ophiocoma dentata.
COLLECTING DATA. Celebes (Sulawesi), 1° 50.875’ S 120° 31.675’ E (from atlas), collector Deppe.
MORPHOLOGICAL DATA. 18-19 mm dd (irregular disc), granules on dorsal disc mostly rubbed off, light and dark brown pattern on dorsal disc, dorsal arms medium brown, ventral interradii fully granulated, white, DAP W:L 2:1, arm spine sequence 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, oral shield longer than wide, ventralmost and 2 nd ventral spine longest, longer than an arm segment, dorsal spines thickened, ventral ones slender, not annulated.
Holotype ZMB Ech 1815
Holotype of Ophiocoma ternispina.
COLLECTING DATA. Indonesia, Flores-Sea, Larantuka, Flores, 8° 21.4’ N 122° 57.817’ E (from atlas), 1 spm.
MORPHOLOGICAL DATA. 16 mm dd, disc light brown, triangular brown spots and curved lines on DAPs, spines weakly annulated, DAP W:L 2:1, disc irregular round, ventral interradii completely granulated, arm spine sequence 3, 3, 3, (3)4, 4, 4, (4)3, 3, 3, 3, 3, 3, 3, 3, 3,3, 3 (numbers vary between arms), 2 nd ventral spine longest, slender spines, oral shield twice as long as wide.
Syntype SMNH-Type-5244
Syntype of Ophiocoma insularia.
COLLECTING DATA. Hawaii, 1860, 1 spm (originally donated to Stockholm by Museum of Comparative Zoology at Harvard).
MORPHOLOGICAL DATA. 17.6 mm dd, disc light brown marbled, arms light brown, dorsal and ventral side similar in colour, disc fully granulated dorsally and ventrally. No annulations on arm spines, spine sequence 3, 3, 3, 4, 4, 4, 5(4), 5(4), 5(4), 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3 (two arms with only 4 spines). Oral shield oval. Granule density 96-120 mm-2.
Syntypes MCZN 1668
Syntypes of Ophiocoma insularia.
COLLECTING DATA. Hawaii, Maui, 1860, 7 spms.
MORPHOLOGICAL DATA. 13.3-16.6 mm dd, all dark brown to black on dorsal disc and arms, including spines, ventral side slightly lighter brown. Both middle spines about equal, longer than dorsal and ventral spines. (Photos provided by Adam Baldinger, MCZN).
Syntypes MCZN 1666
Syntypes of Ophiocoma insularia.
COLLECTING DATA. Hawaii, 1860, 2 spms.
MORPHOLOGICAL DATA. 19.5 and 31.6 mm dd, dark brown disc and arms, with lighter abraded patches on dorsal disc, dark brown on ventral disc and arms; a note among the labels reads “4-5 spines, 3 upper about equal”. (Photos provided by Adam Baldinger, MCZN).
Other material examined
SMNH- 133232
COLLECTING DATA. La Réunion, Etang Salé, 21°16’17” S 55°19’56” E, collectors E. Boissin, T. Hoareau, 24 Feb. 2009, 1 spm.
MORPHOLOGICAL DATA. 11 mm dd, dorsal disc with a brown multipointed star-shape, white centre spot with brown dots, interradii white with brown marbled pattern (Fig. 2E); dorsal arm white with rectangular dark brown outlines, spines brown at base, fading into white towards their tip. Ventral interradii brown and white marbled, fully granulated to oral shields, oral frame white, oral shields with 2 parallel longitudinal brown lines. Ventral arm white with median brown dots and short lines. Arm spine sequence 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3. Granule density 216-224 mm-2.
Dorsal disc granule diameter 49-54 µm, granule density 120-144 mm-2, on SEM image (Fig. 4F, H); third spine on proximal segments 1 mm long, DAPs 1.4-1.6 mm wide Fig. 4G). Oral shields as wide as long; 5-6 tooth papillae, 5 lateral oral papillae at each jaw edge, outer papilla widest (Fig. 4I). Few granules on proximal ends of oral plates. Oral plates, adradial distal part with strong folds, abradial face with large muscle flange with horizontal striations (Fig. 5B), 1.6 mm wide, 2.0 mm high. Dental plate short, externally with two large tooth foramina in dorsal half, dorsalmost foramen oval, wider than long, other foramen square; internally each foramen divided by a wide septum, dorsalmost one into two wide vertical oval slits (septum broken), other foramen into two short parallel holes (Fig. 5E). External ventral half of dental plate with smooth horizontal ridges, forming two wide ovals, the ventralmost one half the size of the other; a cluster of tiny depressions at ventral end of plate (Fig. 5E 1). Radial shield triangular with concave proximal edge, internally with distal round condyle (Fig. 5H), not as ball-like pronounced as in O. brevipes and O. krohi sp. nov. Adradial genital plate (Fig. 5K 1) long, flat, thin, thickened at distal end, with condyle and pit; abradial genital plate (Fig. 5K 2) thin, blade-like, curved distally. Proximal vertebrae 1.6 mm wide and 1.2 mm high (Fig. 5N).
URUN 2009-11047
COLLECTING DATA. La Réunion, Etang Salé, 21°16’17” S 55°19’56” E, collectors E. Boissin, T. Hoareau, 24 Feb. 2009, 1 spm.
MORPHOLOGICAL DATA. 23.7 mm dd, dorsal disc uniformly reddish brown (Fig. 2F), dorsal arm dark brown, ventral disc and arms dark brown. Granule density 44-60 mm-2, granule diameter 70-90 µm. Arm spine sequence 3, 3, 3, 4, 4, 4, 4 (5), 4 (5), 4, 4, 4, 4, 4, 3, 3, 3, 3 (5 spines on one side of one arm, once at segment 7 and once at segment 8).
URUN 2007-00380
COLLECTING DATA. La Réunion, La Saline Trou d’eau, 21°06’09” S 55°14’24” E, collector G. Paulay, 2007, 1 spm.
MORPHOLOGICAL DATA. 24.2 mm dd, dorsal disc brown, dorsal arms dark brown with widely spaced light markings, spine slighter brown, ventral disc brown, oral frame lighter, ventral arms brown. Granule density 52-68 mm-2. Arm spine sequence 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3.
Remarks
The types of O. insularia are clearly all conspecific. Their colouration and large size suggest that they are also conspecific with O. dentata. Ophiocoma dentata occurs in several colour morphs, from uniformly dark brown to brown marbled discs with banded arms, and reticulated or spotted forms that resemble O. doederleini. It can always be distinguished from the latter species by the absence of annulations on the arm spines, and shorter arm spines. In addition, only the largest individuals sometimes have more than four spines on few arm segments. The conspecificity of the various colour morphs is also confirmed by molecular data (Boissin & Hoareau, unpublished). Another species currently believed to be conspecific with O. dentata is O. variegata with type locality Rodriguez Island. According to the original description (Smith 1876), the type measured 28 mm dd and had only four arm spines, which agrees with O. dentata.
Devaney (1970) synonymized O. marmorata with O. dentata, but as we discuss below, the holotype of O. marmorata is most likely not conspecific with O. dentata.
description: Published as part of Stöhr, Sabine, Boissin, Emilie & Hoareau, Thierry B., 2013, Taxonomic revision and phylogeny of the Ophiocoma brevipes group (Echinodermata, Ophiuroidea), with description of a new subgenus (Breviturma) and a new species, pp. 1-26 in European Journal of Taxonomy 68 on pages 13-17, DOI: 10.5852/ejt.2013.68, http://zenodo.org/record/3827674