Ophiothrix galapagensis Lutken & Mortensen 1899

Ophiothrix galapagensis Lütken & Mortensen, 1899

Fig. 19G‒L

Ophiothrix galapagensis Lütken & Mortensen, 1899: 181‒183, pl. 20, figs.1‒4.— H.L. Clark 1917: 439; A.H. Clark 1939: 3‒4.— Ziesenhenne 1937: 224‒225.

Material examined. Three individuals at one station. TALUD XIV, Sta. 32, 1 ind. (ICML-EMU-11179) and 2 ind. (ICML-EMU-11691).

Comparative material. Syntypes, 2 ind.: MCZ OPH-2340, USNM 19588. Non-type, 12 ind.: ICML-UNAM 3.108.3, MCZ OPH-5434 (Supplementary file 2).

Description (ICML-EMU-11691). DD = 7 mm. Disc round. Dorsal disc covered by scales, few scattered elongated spines, and short multifid spines, spines at the margin larger than the others. Primary plates not evident. RS scalene triangular, without spines, almost as long as disc radius, separated by elongated scales except distally (Fig. 19G). Ventral interradii covered by integument proximally and few scales with multifid spines distally (Fig. 19H). OSh broader than long, pentagonal with rounded edges. Madreporite larger than OSh. AdSh trapezoidal with rounded edges, meeting in front of OSh. Jaws bear 24‒27 TPas, clustering, short (Fig. 19I). Arms slender. DAP longer than broad, diamond-shaped, contiguous (Fig. 19J). VAP broader than long, pentagonal, distal edge concave, slightly separated. LAP with up to 5‒6 ArSp, serrated, hyaline, elongated (approximately 2.5 arm segments in length), dorsalmost the longest, ventralmost the shortest, ventral and distalmost hook-shaped. Tentacle pores with one oval TSc (Fig. 19K). Color pattern dorsally and ventrally pink-whitish (ethanol preservation) (Fig. 19G‒L).

Habitat and distribution. Mexico and Galapagos Islands, Ecuador; 64‒549 m depth, sponges, rocky, muddy, and sandy substrates (Lütken & Mortensen 1899; Ziesenhenne 1937; Granja-Fernández et al. 2015). The material examined was collected in the Gulf of California; 123 m depth.

Remarks. The specimens of Ophiothrix galapagensis examined herein concurs morphologically with the type material. However, additional material in the holdings of other scientific collections (i.e., MCZ OPH-5434, ICMLUNAM 3.108.3) and examined during this study differs in having a dense number of spines on the dorsal disc and much larger radial shields. Based on these differences and considering the long distance between western Mexico, where our material was collected, and the Galapagos Islands, the species’ type locality, the specimens from Mexico might represent a geographical or size-related variation or even a different species. Molecular analysis of specimens collected along the geographical range of O. galapagensis is needed to solve this issue.