Ophiomitra granifera Lütken & Mortensen, 1899

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 : 32

Ophiomitra granifera Lütken & Mortensen, 1899

Fig. 7G‒L

Ophiomitra granifera Lütken & Mortensen, 1899: 177‒178 , pl. 19, figs. 9‒12.

Material examined. 22 individuals at one station. TALUD XII, Sta. 27, 22 ind. (ICML-EMU-12998).

Comparative material. Syntypes, 10 ind.: MCZ OPH-2050 , MNHN-IE-2013-10260, USNM 19583 , USNM 19584 (Supplementary file 2) .

Description (ICML-EMU-12998). DD = 6.6 mm. Disc rounded, slightly indented interradially. Dorsal disc covered by imbricated scales and scattered thorny granules. Central primary plate evident. RS slightly longer than broad, triangular with rounded edges, separated by a row of scales and granules ( Fig. 7G ). Ventral interradii short, covered by imbricated scales ( Fig. 7H ). OSh broader than long, diamond-shape with rounded edges. Madreporite not evident. AdSh longer than broad, semilunar, almost meeting or meeting in front of OSh. Jaws bearing three papillae at each side; AdShSp lanceolate, larger than rest; LOPa and IPa elongated, pointed. vT longer than oral papillae ( Fig. 7I ). Arms slender, gradually narrowing distally. First two DAP reduced, covered by few granules similar to those on the disc; subsequent DAP longer than broad, triangular with rounded distal edge, slightly separated from each other ( Fig. 7J ). VAP slightly broader than long, heptagonal, separated from each other. LAP with 5‒6 ArSp, large (approximately 1.5 arm segment in length), serrated; dorsalmost the longest and ventralmost the shortest. One lanceolate TSc ( Fig. 7K ). Color pattern beige-whitish (ethanol preservation) ( Fig. 7G‒L ).

Habitat and distribution. Only recorded from the Mexican Pacific, off western Baja California, in the Gulf of California, off Nayarit, Colima, and Marias Islands; 267‒ 2,806 m depth, rocky and sandy bottoms (Lütken & Mortensen 1899; Luke 1982; Granja-Fernández et al. 2015, 2021; see Remarks). The material examined was collected off Colima; 1,040 ‒1,095 m depth.

Remarks. The collected material presented the following variations: 1) some individuals had radial shields in contact distally or entirely separated, and 2) the central primary plate is present (more common) or not. Ophiomitra granifera easily loses disc granules due to rough handling, which hampers identification since these granules are one of the diagnostic characters of the species; however, each detached granule leaves a fingerprint as a round articular depression in each scale which makes the presence of granules easily identifiable even if they are lost. The record of O. granifera off Colima (18º40′28″N; 104º35′51″W) is an extension of its southernmost distribution limit.

Figures

FIGURE 7. Stegophiura ponderosa (Lyman, 1878) (ICML-EMU-11694, DD = 25.3 mm). A, Dorsal disc; B, Ventral disc; C, Mouth; D, Dorsal arm; E, Ventral arm; F, Dorsal view. Ophiomitra granifera Lütken & Mortensen, 1899 (ICML-EMU-12998, DD = 6.6 mm). G, Dorsal disc; H, Ventral disc; I, Mouth; J, Dorsal arm; K, Ventral arm; L, Dorsal view.