Ophiocoma (Breviturma) krohi Stöhr & Boissin & Hoareau & Ecomar & Usr 2013, sp. nov.
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 krohi

description: Ophiocoma (Breviturma) krohi sp. nov.
urn:lsid:zoobank.org:act: D662D2A3-330D-4693-8757-E6112C4BABC1
Figs 2 G-L, 4K-O, 5C, F, I, L, O, R, 6
Ophiocoma brevipes – Stöhr et al. 2008: 553.
Ophiocoma sp. nov. – Hoareau et al. 2013: 2.
Diagnosis
Species of Ophiocoma (Breviturma) subgen. nov. with variegated to uniform dark brown colour pattern; arm spines may be weakly annulated, but not as clearly light and dark banded as in O. doederleini; up to four arm spines (in large specimens beyond segment 15), sometimes five at segments 6-9 (rarely 5-8); relatively coarse disc granulation. Maximum size about 16 mm dd.
Etymology
The species is named in honour of Dr. Andreas Kroh, Vienna, for his important contributions to echinoderm systematics.
Type material
Holotype
La Réunion Island, St. Pierre, 21°20’27 S 55°27’31 E, collectors E. Boissin, T. Hoareau, 25 Mar. 2009, in ethanol (MNHN-IE-4300).
Paratypes
From same locality as holotype 8 spms: 1 spm, dissected, fragments on SEM stubs and arms in ethanol (SMNH-Type- 8535); 1 spm gold coated and uncoated arms dry (SMNH-Type- 8534); 2 spms in ethanol (SMNH-Type- 8531, 8536); 1 spm in ethanol (UF 13938); 1 spm in ethanol (URUN 2009-11108); 2 spms in ethanol (MNHN-IE- 4301, 4302). La Réunion, Cap Homard, 21°02’07” S 55°13’06” E, collectors E. Boissin, T. Hoareau, 23 Feb. 2009: 2 spms in ethanol (SMNH-Type- 8532, 8533); 1 spm in ethanol (MNHN-IE- 4303).
Description
Holotype
12.7 mm dd, radial shields completely obscured by granules, granule density 104 mm-2. Arm spine sequence 3(2), 3(2), 3, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3. Dorsal disc with dark and lighter brown lines radiating from a dark central patch, some white spots at disc edge (Fig. 6A). Dorsal arms medium brown with dark and white transverse bands (Fig. 6B). Ventral disc dark brown mottled, ventral arms and oral frame lighter brown, oral shields dark. Ventral interradii completely, but sparsely granulated (Fig. 6D, E). Dorsal spines brown, ventral spines weakly annulated brown on white. DAPs oval, W:L 1.8:1, contiguous. Dorsalmost spine a little longer than a segment, middle spines about 2 segments long, ventralmost spine slightly shorter. Arm spines flattened, slightly tapered with truncated tips, dorsalmost spine wider than other spines. Oral shields trapezoid, distally almost as wide as long, proximally just over half as wide as long, lateral edges straight (except madreporite), proximal and distal edges convex (Fig. 6D). Madreporite larger than other oral shields, more rounded, all edges convex. At tip of jaw a cluster of 8-10 small, round tooth papillae. Along each jaw edge 4 rectangular, wider than high, oral papillae, and distally a smaller papilla at an angle to the others (Fig. 6E).Adoral shields uneven triangular, framing the lateral edges of the oral shield, not meeting proximally. Bursal slits extend from oral shield to disc edge. First ventral arm plate outside mouth-slit, small, winglike pentagonal, middle of distal edge notched. Following plates pentagonal, about as long as greatest width, with obtuse proximal angle, lateral edges notched, distal edge convex, contiguous (Fig. 6C). 2 oval scales at a slightly open angle at the lateral arm plate of each tentacle pore proximally; the inner scale decreases gradually and is absent on the distalmost segments. Tube feet expanded, smooth, with distal constrictions and terminal bulb.
The paratypes are similar to the holotype in most characters, except as follows:
SMNH-Type-8534
1 spm, 11 mm dd, dark brown radiating stripes on dorsal disc, interradii mottled light and dark brown, overall small white dots; dorsal arms dark brown with some lighter markings, spines white with diffuse brown pattern, some with annulations (not figured). Ventral interradii dark brown mottled with white, fully granulated; adoral shields and oral plates unevenly brown, oral shields dark brown with white edges, oral papillae white. Ventral arm plates and tentacle scales brown with white edges. Arm spine sequence 3, 3, 3, 4, 4, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4. Granule density 132-136 mm-2 on light image.
Dorsal disc granule diameter 57-73 µm, granule density 132-136 mm-2, on SEM image (Fig. 4K, M); third arm spine 1.3 mm long, DAP 1.2 mm wide (Fig. 4L). Oral shields as wide as long (Fig. 4N). 5 tooth papillae, 5 lateral oral papillae at each jaw edge, outer papilla widest. Few granules on proximal ends of oral plates (Fig. 4N).
SMNH-Type-8535
1 spm, 13 mm dd, dorsal disc dark brown, white spots on radial shields; dorsal arms banded dark and light brown; spines dark brown, on distal arm annulated (not figured). Granule diameter 57-74 µm, density 104 mm-2. Ventral interradii dark brown; adoral shields light brown with dark spots; oral shields dark brown with white edges; oral papillae white. Ventral arm plates brown with white edges and lighter areas. Arm spine sequence 3, 3, 3, 4, 4, 5, 5, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4. Up to 5 tooth papillae, 5 lateral oral papillae at each jaw edge, outer papilla widest. Few granules on distal ends of oral plates.
Oral plates, adradial distal part with strong folds, abradial face with large muscle flange with horizontal striations that end in deep incisions in the distal edge; 1.9 mm wide, 2.3 mm high (Fig. 5C). Dental plate short, with two tooth foramina on external dorsal half, dorsalmost one oval, wider than long, other small, round; internally a wide septum divides each foramen into two pairs of vertical oval holes, upper ones larger than lower ones (Fig. 5F). Radial shield angular, with large round condyle at internal distal end (Fig. 5I). Adradial genital plate long, flat, thin, thickened at distal end, with deep pit; abradial genital plate thin, blade-like, curved distally (Fig 5L). Proximal vertebrae 2.0 mm wide and 1.5 mm high (Fig. 5Q).
SMNH-Type-8531
1 spm, 6.8 mm dd, granule density 152 mm-2. Arm spine sequence 3, 3, 3, 4, 4, 5, 5, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3. Dorsal disc with central dark brown patch, with white central spot, dark brown radiating lines, medium brown interradial lines on light brown background, white spots at disc edge (Fig. 2I). Dorsal arms with transverse dark and lighter brown bands. Ventral disc light brown with irregular cream patches, oral frame and ventral arms lighter brown, oral shields dark.
SMNH-Type-8532
1 spm, 9.6 mm dd, granule density 116-120 mm-2. Arm spine sequence 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3. Dorsal disc dark brown mottled, dorsal arms lighter brown with dark bands. Ventral disc light and dark brown mottled (not figured). Ventral arms and oral frame light brown, oral shields with dark patch.
MNHN-IE-4303
1 spm, 8.1 mm dd, granule density 124 mm-2. Arm spine sequence 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3. Dorsal disc light brown mottled, dorsal arms light brown with dark bands. Ventral disc light and dark brown mottled, arms and oral frame crème, oral shields with dark patches.
SMNH-Type-8533
1 spm, 10 mm dd, granule density 140-164 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, 3, 3, 3. Dorsal disc variegated white and brown, arms dark and lighter brown banded, spines annulated (Fig. 2G).
SMNH-Type-8536
1 spm, 15.5 mm dd, granule density 64-96 mm-2. Arm spine sequence 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3. Dorsal disc uniformly dark brown, except on radial shields white granules (Fig. 2K). DAPs dark brown, all spines weakly annulated with irregular dark stripes on white. Oral frame white with dark marks on oral shields. Ventral arm plates dark brown with white borders.
MNHN-IE-4302
1 spm, 13 mm dd, granule density 96-104 mm-2. Arm spine sequence 3, 3, 3, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3. Light brown disc with irregular dark spots or blotches. Dorsal arms medium brown with widely spaced dark brown transverse bands (Fig. 2H). Ventral disc medium and dark brown mottled, ventral arms and oral frame light brown to cream, oral shields with dark pattern.
MNHN-IE-4301
1 spm, 11.8 mm dd, granule density 72-96 mm-2. Arm spine sequence 3, 3, 3, 4, 5, 5, 5, 5(4), 4, 4(5), 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3. Dorsal disc dark brown mottled, dorsal arms dark brown with few white marks, spines dark brown (Fig. 2J). Oral frame cream white with light brown marks on oral shields, ventral arm plates brown.
URUN 2009-11108
1 spm, 11.3 mm dd, granule density 112-120 mm-2. Arm spine sequence 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 3, 3. Dorsal disc with dark brown star-shaped pattern, interradii brown with irregular white spots, irregular white spots in centre of disc, white granules on radial shields (not figured). Dorsal arms mostly dark brown, some lighter patches, spines dark brown. Oral frame white, brown patches on oral shields. Ventral arm plates brown with white margins.
UF13938
1 spm, 10.3 mm dd, granule density 112-116 mm-2. Arm spine sequence 3, 3, 3, 4, 4, 5, 5, 5, 5(4), 4, 4, 4, 4, 4, 3, 3, 3. Dorsal disc light brown with irregular dark patches and spots, dorsal arm light brown with widely spaced narrow dark brown bands (Fig. 2L). Spines light brown, weakly annulated. Oral frame white with light brown pattern on oral shields, ventral arm plates light brown with white margins.
Remarks
Ophiocoma krohi sp. nov. differs from O. brevipes and O. dentata in maximum size, granule size and density, and in colour pattern. Although quite variable in colour, it has never been observed with reticulated or spotted pattern as O. dentata and O. doederleini. We examined 12 specimens and half of them showed up to five arm spines on 2-4 segments, the other half had only four. Thus they all differ in spine number from O. brevipes, but some are similar to O. dentata in lacking a fifth spine, although they may have four spines farther out on the arm than O. dentata.
The specimens reported by Stöhr et al. (2008) are most likely conspecific with O. krohi sp. nov. based on colour pattern, the presence of five spines and their small size. The species has a wide geographic distribution on coral reefs across the Indian and Pacific Oceans at depths of 0-30 m (Hoareau et al. 2013).
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 17-20, DOI: 10.5852/ejt.2013.68, http://zenodo.org/record/3827674