Ophiocoma (Breviturma) doederleini de Loriol, 1899

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, European Journal of Taxonomy 68, pp. 1-26 : 7-10

Ophiocoma (Breviturma) doederleini de Loriol, 1899

Figs 2 A-C, 3

Ophiocoma doederleini de Loriol, 1899: 30 , pl. 3 fig. 2.

Diagnosis

Species of Ophiocoma (Breviturma) subgen. nov. characterized by strongly dark and light banded (annulated) arm spines; slender arm spines, the longest up to three segments long; up to five arm spines on few segments from segment 6; variable in dorsal disc colour pattern (reticulating or spotted); density of dorsal disc granules reaches more than 200 mm-2. Maximum size at least 26 mm according to the studied material.

Material examined

UF 5318

COLLECTING DATA. Polynesia, Moorea, 17°28’55” S, 149°50’32” W, fore reef between Cook’s and Opunohu Bays, outer reef slope, under rocks, partly in sand, 10-15 m, by hand, collectors C. McKeon, C. Meyer, G. Paulay, 19 Jul. 2006, 1 spm.

MORPHOLOGICAL DATA. 13 mm dd. Granule density on light image 180-200 mm-2. Arm spine sequence 3, 3, 3, 3, 4, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3. Dorsal disc dark brown with irregular white patches, with a net-like reticulating darker brown pattern ( Fig. 2A, B ). Dorsal arms dark brown with widely spaced white bands with brown spots. Ventral disc white with brown spots. Oral frame white, oral shields with brown spots. Ventral arms with long white and brown bands, brown spots on the white bands. Arm spines strongly annulated with white and brown rings, long and slender, dorsalmost spine barely two segments long, middle spines longer than two segments.

Dorsal disc granule diameter 47-51 µm, granule density 224 mm-2 ( Fig. 3A, C ). Third spine on proximal segments 2.3 mm long; proximal DAPs 1.74-1.8 mm wide ( Fig. 3B ). Oral shields slightly wider than long; 5-6 tooth papillae, 5 lateral oral papillae at each jaw edge, outer papilla widest ( Fig. 3D ). Dental plate short, externally with two large tooth foramina in dorsal half, dorsalmost foramen oval, wider than long, other foramen square ( Fig. 3H ); internally each foramen divided by a wide septum, dorsalmost one into two small holes, other foramen into two parallel slits (lower septum broken in Fig. 3H 2 ). 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. Radial plate shaped as a wide triangle, proximal edge concave, distal point with condyle, depressed at lateral edge ( Fig. 3F ), but not as ball-like as in O. brevipes and O. krohi sp. nov. Adradial genital plate long, flat, thin, thickened at distal end, with condyle and pit ( Fig. 3I 1 ); abradial genital plate thin, blade-like, curved distally ( Fig. 3I 2 ). Oral plates, adradial distal part with strong folds, abradial face with large muscle flange with horizontal striations, 2.5 mm wide, 2.0 mm high ( Fig. 3G ). Proximal vertebrae are 2.4 mm wide and 1.8 mm high ( Fig. 3J ).

UF 6512

COLLECTING DATA. La Réunion Island, Saint Gilles, Point des Aigrettes, 21°02’11” S, 55°13’01” E, fore reef, under rocks, 6-22 m dive, collectors H. Bruggemann, N. Hubert, F. Michonneau, G. Paulay, 12 Aug. 2007, 1 spm.

MORPHOLOGICAL DATA. 17 mm dd. Granule density 88-96 mm-2. Arm spine sequence 3, 3, 3, 4, 4, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, continued until the distal arm where the spines decrease to three. Brown dorsal disc with reticulating net pattern. Dorsal arms dark brown with widely spaced short white bands with dark markings. Ventral disc dark and light brown mottled. Oral frame white with few dark spots. Ventral arms dark brown with few short white bands. Spines white, strongly annulated with brown rings, long and slender, dorsalmost spine barely two segments long, middle spines longer than two segments.

UF 6634

COLLECTING DATA. La Réunion Island, Saint-Leu Sec Jaune, 21°12’20” S, 55°16’58” E, under rocks, 12- 15 m dive, collectors H. Bruggemann, N. Hubert, F. Michonneau, G. Paulay, 17 Aug 2007, 1 spm.

MORPHOLOGICAL DATA. 26 mm dd. Granule density 60-64 mm-2. Arm spine sequence 3, 3, 3, 4, 4, 5, 5, 5, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4......3. Dorsal disc medium brown with dark mesh pattern (reticulated), dorsal arms dark brown with widely spaced lighter brown bands. Oral frame creamy white with brown spots and irregular markings, ventral disc light brown with dark reticulations, ventral arm medium brown with widely spaced cream markings. Spines white, strongly annulated with brown rings, long and slender, dorsalmost spine barely two segments long, longest middle spine almost as long as three segments.

UF 6518 (only image available)

COLLECTING DATA. La Réunion Island, Saint Gilles, Point des Aigrettes, 21°02’11” S, 55°13’01” E, fore reef, under rocks, 6-22 m dive, collectors H. Bruggemann, N. Hubert, F. Michonneau, G. Paulay, 12 Aug. 2007, 1 spm.

MORPHOLOGICAL DATA. 12.5 mm dd. Colour pattern on dorsal disc consists of thicker, brown, reticulating lines, instead of a thin net-like pattern as in the other specimens; otherwise similar to the others ( Fig. 2C ).

Remarks

Ophiocoma doederleini occurs in several colour morphs, with various reticulated patterns ( Fig. 2A, C ) or spotted disc ( Devaney 1970), which is confirmed by our molecular data (Boissin & Hoareau, unpublished). It can easily be distinguished from the other species of Breviturma subgen. nov. by its dark and light strongly annulated, more slender, and longer arm spines. It also has the widest dorsal arm plate of all species of Breviturma subgen. nov. The high granule density in the smallest specimen was surprising and may need further investigation. Maximum size at least 26 mm according to the studied material.

Figures

Fig. 2. Colour variations in species of Ophiocoma (Breviturma) subgen. nov. A-C. Ophiocoma doederleini Rowe & Pawson, 1977. A. Reticulated specimen (UF5318). B. Close-up of annulated arm spines. C. Densely reticulated specimen (UF6518). D. Ophiocoma brevipes Peters, 1851 (SMNH- 133230). E-F. Ophiocoma dentata Müller & Troschel, 1842. E. Variegated specimen (SMNH-133232). F. Uniformly reddish brown specimen (URUN2009-11047). G-L. Ophiocoma krohi sp. nov. paratypes. G. With large patches (SMNH-Type-8533). H. Small irregular spots (MNHN-IE-4302). I. Star-shaped radiating pattern (SMNH-Type-8531). J. Densely mottled (MNHN-IE-4301). K. Uniformly dark brown (SMNH-Type-8536). L. Light brown, sparsely mottled (UF13938). For institution codes see main text.

Fig. 3. Ophiocoma (Breviturma subgen. nov.) doederleini de Loriol, 1899 (UF5318). SEM images. A. Dorsal disc. B. Dorsal arm. C. Dorsal disc granules. D. Jaws. E. Ventral arm. F. Radial shield, internal aspect, distal edge downwards. G. Oral plates (half-jaws), abradial aspect left, adradial right, proximal edge left. H. Dental plates, external aspect on left, internal on right (lower septum broken), dorsal upwards. I. Genital plates abradial left, adradial right, distal upwards. J. Arm vertebrae, proximal aspect left, distal right, dorsal upwards. K. Lateral arm plates, external aspect left, internal right, distal to the right. UF, Florida Museum of Natural History.

Fig. 1. Phylogenetic reconstruction of Ophiocoma (Breviturma) subgen. nov. (two species of the scolopendrina group as outgroup), estimated by maximum likelihood and neighbour-joining analysis of concatenated sequences of the mitochondrial cytochrome c oxidase subunit I and rDNA 16S (in total 1125 bp). Values at branches indicate bootstrap values for maximum likelihood (above branches) and neighbour-joining (below branches). Specimen codes are resolved in the Supplementary file.