Astrodia excavata (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 : 16

Astrodia excavata (Lütken & Mortensen, 1899)

Fig. 2A‒G

Asteronyx excavata Lütken & Mortensen, 1899: 185‒186 , pl. 22, figs. 2‒6.—H.L. Clark 1913: 219; 1923: 157.— Döderlein 1927: 59, 98.

Astrodia excavata . Okanishi & Fujita 2014: 192‒195, figs. 5‒7.

Material examined. 58 individuals at eight stations. TALUD IV, Sta. 19, 1 ind. (ICML-EMU-11094). TALUD VIII, Sta. 11, 1 ind. (ICML-EMU-11096). TALUD XII, Sta. 23, 1 ind. (ICML-EMU-11093); Sta. 27, 17 ind. (ICML-EMU-11114); Sta. 28, 1 ind. (ICML-EMU-11097). TALUD XV, Sta. 23, 6 ind. (ICML-EMU-11100); Sta. 24, 26 ind. (ICML-EMU-11099), 1 ind. (ICML-EMU-11101), and 3 ind. (ICML-EMU-11697). TALUD XVIB, Sta. 17, 1 ind. (ICML-EMU-11102).

Comparative material. Asteronyx excavata Lütken & Mortensen, 1899 , lectotype, 1 ind.: MCZ OPH-2817 . Paralectotype, 1 ind.: USNM 19598 . Syntype, 1 ind.: USNM 19599 (Supplementary file 2).

Description (ICML-EMU-11099). DD = 24.7 mm. Disc five-lobed, indented interradially. Dorsal disc covered with thickened skin, lacking scales. RS coarse, surrounded by epidermal ossicles, very prominent, almost reaching the center of the disc ( Fig. 2A ). Ventral interradii covered by integument and external ossicles. Genital slits oval, restricted to proximal-middle part, elongated, covering approximately 3/4 of the interradius ( Fig. 2B ). OSh broader than long, triangular. One madreporite, larger than OSh. AdSh broader than long, with rounded edges, meeting or almost meeting proximally. Jaws bearing six papillae at each side; OPa four, granule-like, distalmost papilla larger, rectangular-shaped; TPa two at jaw tips, spiniform, larger than OPa. Teeth several, similar to TPa ( Fig. 2C ). Arms entirely covered by integument, coiled, thick, gradually narrowing distally. LAP located on the ventral lateral side of vertebrae, bar-like, prominent ( Fig. 2D ). First to fourth tentacle pores lacking ArSp; fifth to ninth with one ArSp ( Fig. 2E ); subsequent pores with 3‒4 ArSp, 2‒3 serrated, one ventralmost elongated (approximately 1.5 VAP in length), bulbous, serrated at the tip, not hooked ( Fig. 2F ). TSc lacking. Color pattern brownish-beige (ethanol preservation) ( Fig. 2A‒G ).

Habitat and distribution. California, USA to Mexico ( Luke 1982; Granja-Fernández et al. 2015); doubtful record in Peru ( Granja-Fernández & Hooker 2020); 267‒ 1,273 m depth ( Okanishi & Fujita 2014), associated with rocks and gorgonians (Lütken & Mortensen 1899; H.L. Clark 1923). The material examined is from off western Baja California and Baja California Sur, the southern Gulf of California, and off Colima; 530‒ 1,245 m depth, associated with unidentified gorgonians.

Remarks. In Mexico, Astrodia excavata has been recorded in western Baja California and Baja California Sur, the Gulf of California, and Marias Islands ( Granja-Fernández et al. 2015). Present records in Colima represent a significant extension of its distribution to the south (to 18º33′43″N; 103º57′45″W) in western Mexico. GranjaFernández & Hooker (2020) suggested that the Peruvian record of A. excavata is doubtful and needs taxonomical confirmation. If further revision of the material from Peru indicates that this record is incorrect, then Colima (TALUD XII, Sta. 23) will be the southernmost distribution limit for this species.

Figures

FIGURE 2. Astrodia excavata (Lütken & Mortensen, 1899) (ICML-EMU-11099, DD = 24.7 mm). A, Dorsal disc; B, Ventral disc; C, Mouth; D, Dorsal arm; E, Proximalmost ventral arm; F, Middle ventral arm; G, Dorsal view. Ophiosphalma glabrum (Lütken & Mortensen, 1899) (ICML-EMU-11061, DD = 31 mm). H, Dorsal disc; I, Ventral disc; J, Mouth; K, Dorsal arm; L, Ventral arm; M, Dorsal view.