Ophiocten hastatum Lyman, 1878

Granja-Fernández, Rebeca, Hendrickx, Michel E., Rangel-Solís, Pedro Diego & López-Pérez, Andrés, 2023, Deep-sea Ophiuroidea (Echinodermata) collected during the TALUD cruises in western Mexico, Zootaxa 5259 (1), pp. 1-71 : 24-25

Ophiocten hastatum Lyman, 1878

Fig. 5A‒F

Ophiocten hastatum Lyman, 1878: 103 , pl. 5, figs. 133‒134.— Koehler 1922: 388‒389.— Paterson et al. 1982: 117‒119, fig. 5.— Martynov & Litvinova 2008: 83, fig. 3c.— Lambert & Boutillier 2011: 47, fig. 33.

Ophiocten pacificum Lütken & Mortensen, 1899: 131‒132 , pl. 3, figs. 5‒7.— H.L. Clark 1911: 96‒97; 1913: 211.— Kyte 1969a: 1738.

Ophiocten longispinum Koehler, 1896: 204‒205 .

Ophiocten latens Koehler, 1906: 7‒8 , pl. 1, figs. 9‒10.

Ophiocten australis Baker, 1979: 26‒28 , fig. 3a‒c.

See Paterson et al. (1982) for other synonymous records.

Material examined. 243 individuals at seven stations. TALUD XII, Sta. 27, 2 ind. (ICML-EMU-13002). TALUD XVIB, Sta. 1, 3 ind. (ICML-EMU-11117); Sta. 16, 2 ind. (ICML-EMU-11118-A); Sta. 19, 5 ind. (ICML-EMU-11118-B); Sta. 22, 22 ind. (ICML-EMU-11119) and 1 ind. (ICML-EMU-11680-B); Sta. 26, 90 ind. (ICML-EMU-11120); Sta. 27, 79 ind. (ICML-EMU-11121), 32 ind. (ICML-EMU-11122), and 7 ind. (ICML-EMU-11680-A).

Comparative material. Ophiocten hastatum Lyman, 1878 , syntypes, 4 ind.: MCZ OPH- 765, MNHN-IE-2013- 10285. Ophiocten pacificum Lu ̈tken & Mortensen, 1899, syntypes, 28 ind.: MCZ OPH- 767, MCZ OPH- 1019, USNM 19484, USNM 19485, USNM 19487, USNM 19488, NHMD 232, NHMD 396 (Supplementary file 2).

Description (ICML-EMU-11120). DD = 16 mm. Disc rounded. Dorsal disc covered by irregular and imbricated scales, largest surrounding the disc. Primary plates rounded, conspicuous, separated from each other. RS longer than broad, triangular, separated by numerous scales. Ventral interradii covered by imbricated scales, smaller than dorsal scales ( Fig. 5A ). Genital slits covering the whole interradius. Genital slits with minute, pointed genital papillae restricted distally, projecting dorsally and forming arm combs with small and slender papillae ( Fig. 5B ). OSh slightly broader than long, pentagonal. Madreporite not evident. AdSh longer than broad, elongated, slender, almost meeting or meeting in front of OSh. Jaws bearing four papillae at each side; BSc rectangular, very elongated; IPa rectangular, elongated; 2IPa oval; TPa pointed. vT pointed, larger than oral papillae. AdShSp oval, separated by a diastema ( Fig. 5C ). Arms slender. DAP broader than long, trapezoidal, meeting. First 4‒6 DAP with minute, pointed spines distally ( Fig. 5D ). VAP broader than long, almost hemispherical with a convex distal edge, obtuse angle proximally; widely separating and decreasing in size distally. LAP with three ArSp, pointed; dorsalmost the longest (one arm segment in length). First tentacle pore with 1‒2 oval TSc; subsequent tentacle pores with one lanceolate TSc ( Fig. 5E ). Color pattern beige-whitish ( Fig. 5A‒F ). Primary plates, some scales in dorsal disc, and DAP with light brown tint (ethanol preservation) (Fig. A, D).

Habitat and distribution. Atlantic and Pacific Oceans. In the eastern Pacific in California, USA, Mexico, Costa Rica, Panama, Colombia, Ecuador, and off the Galapagos Islands ( Paterson et al. 1982; Solís-Marín et al. 2013); 824‒ 4,700 m depth, muddy substrate (Lütken & Mortensen 1899; Maluf 1988). The material examined was collected off western Baja California and off Colima; 982‒ 2,054 m depth.

Remarks. The morphology of the TALUD specimens examined herein corresponded with that of the type material of Ophiocten pacificum , which showed differences with the examined type material of Ophiocten hastatum in the size and the shape of the radial shields and the oral papillae shape. Ophiocten hastatum has been recorded as a widespread species across all major oceans ( O’Hara & Thuy 2022); however, this taxon has been considered a species complex by Christodoulou et al. (2019). Due to the above, we propose conducting further analysis to determine whether O. hastatum and O. pacificum (as well as the other synonymous records of O. hastatum ) belong to the same species. In Mexico, O. hastatum has only been reported from off western Baja California and Baja California Sur ( Granja-Fernández et al. 2015). The finding of this species off Colima increases the distribution range of this species in western Mexico. In the eastern tropical Pacific, the genus Ophiocten is only recorded by this species.

Figures

FIGURE 5. Ophiocten hastatum Lyman, 1878 (ICML-EMU-11120, DD = 16 mm). A, Dorsal disc; B, Ventral disc; C, Mouth; D, Dorsal arm; E, Ventral arm; F, Dorsal view. Amphiophiura oligopora (H.L. Clark, 1913) (ICML-EMU-11139, DD = 9.4 mm). G, Dorsal disc; H, Ventral disc; I, Mouth; J, Dorsal arm; K, Ventral arm; L, Dorsal view.