Ophiacantha moniliformis 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 : 37

Ophiacantha moniliformis Lütken & Mortensen, 1899

Fig. 9G‒L

Ophiacantha moniliformis Lütken & Mortensen, 1899: 171‒172 , pl. 16, figs. 5‒8.

Material examined. 446 individuals at 10 stations. TALUD VIII, Sta. 11, 16 ind. (ICML-EMU-11187). TALUD X, Sta. 3, 4 ind. (ICML-EMU-11188-A); Sta. 4, 7 ind. (ICML-EMU-11188-B) and 59 ind. (ICML-EMU-11188-C); Sta. 5, 78 ind. (ICML-EMU-9017-A) and 2 ind. (ICML-EMU-9017-B). TALUD XI, Sta. 1, 1 ind. (ICML-EMU-11189- A). TALUD XIV, Sta. 15, 1 ind. (ICML-EMU-11189-B). TALUD XV, Sta. 5D, 217 ind. (ICML-EMU-11190) and 3 ind. (ICML-EMU-11701); Sta. 20, 22 ind. (ICML-EMU-11185); Sta. 23, 33 ind. (ICML-EMU-11186). TALUD XVIB, Sta. 5, 3 ind. (ICML-EMU-11191).

Comparative material. Syntypes, 10 ind.: MCZ OPH-1968 , MCZ OPH-1969 , USNM 19570 , USNM 19572 (Supplementary file 2) .

Description (ICML-EMU-11190). DD = 4 mm. Disc indented, swollen but depressed centrally. Dorsal disc covered by imbricated scales and minute multifid spines. Primary plates not evident. RS much longer than broad, bar-like, slender, covered by multifid spines, distally very conspicuous and in contact with each other ( Fig. 9G ). Ventral interradii covered by scales and multifid spines similar to those on the dorsal side ( Fig. 9H ). OSh broader than long, diamond-shaped with rounded edges. Madreporite larger than OSh. AdSh longer than broad, meeting in front of OSh. Jaws bear three papillae at each side; AdShSp lanceolate, slightly larger than rest; LOPa and IPa lanceolate, elongated. vT larger than oral papillae ( Fig. 9I ). Arms slender, with noded appearance. DAP slightly longer than broad, triangular with rounded edges, swollen, widely separated from each other ( Fig. 9J ). VAP broader than long, quadrangular with rounded edges, separated from each other. LAP much longer than wide with 4‒5 ArSp, large (approximately two arm segments in length), smooth, dorsalmost largest, ventralmost shortest. One lanceolate TSc ( Fig. 9K ). Color pattern beige-whitish (ethanol preservation) ( Fig. 9G‒L ).

Habitat and distribution. Mexican Pacific ( Granja-Fernández et al. 2015); 377 ‒ 1,244 m depth, sandy, muddy substrates, and black coral (Lütken & Mortensen 1899; see Remarks). The material examined was collected off western Baja California and Baja California Sur, in the Gulf of California, and off Guerrero; 377‒871 m depth.

Remarks. The swollen but depressed centrally dorsal disc observed in the material examined must be an artifact of preservation. The collection from off western Baja California (28ºN) corresponds to a new distribution record as well as the northernmost area of distribution for Ophiacantha moniliformis . The 377 m depth record represents the shallowest bathymetric record currently reported for this species; previously, the shallowest record was 519 m (H.L. Clark 1913).

Figures

FIGURE 9. Ophiacantha eurypoma H.L. Clark, 1911 (ICML-EMU-11184, DD = 8.3 mm). A, Dorsal disc; B, Ventral disc; C, Mouth; D, Dorsal arm; E, Ventral arm; F, Dorsal view. Ophiacantha moniliformis Lütken & Mortensen, 1899 (ICML-EMU- 11190, DD = 4 mm). G, Dorsal disc; H, Ventral disc; I, Mouth; J, Dorsal arm; K, Ventral arm; L, Dorsal view.