Asteronyx loveni Müller & Troschel, 1842

Fig. 1G‒M

Asteronyx loveni Müller & Troschel, 1842: 119‒120, pl. 10, figs. 3‒5.—H.L. Clark 1913: 219.— Döderlein 1927: 59‒63, pl. 7, figs. 7‒8.— Kyte 1969a: 1737.— Lambert & Austin 2007: 71‒72, fig. 27.— Okanishi et al. 2011: 370‒371, fig. 2; 2017: 6‒12, figs. 1‒6.

Asteronyx locardi Koehler, 1895: 88 .

Asteronyx dispar Lütken & Mortensen, 1899: 185, pl. 21, figs. 1‒2.—H.L. Clark 1913: 218.

Asteronyx cooperi Bell, 1909: 22 .

Ophiuropsis lymani Studer, 1884: 85, pl. 5, figs. 12a‒d.

Ophiuraster patersoni Litvinova, 1998: 441‒443, fig. 3.

See Paterson (1985) for other synonymous records.

Material examined.11 individuals at six stations. TALUD VI, Sta. 34, 1 ind. (ICML-EMU-11115). TALUD VIII, Sta. 11, 2 ind. (ICML-EMU-11110). TALUD IX, Sta. 21B, 1 ind. (ICML-EMU-9012). TALUD X, Sta. 22, 2 ind. (ICML-EMU-11112). TALUD XII, Sta. 29, 3 ind. (ICML-EMU-11111) and 1 ind. (ICML-EMU-11698). TALUD XIII, Sta. B, 1 ind. (ICML-EMU-11113).

Comparative material. Asteronyx dispar Lütken & Mortensen, 1899, syntypes, 15 ind.: MCZ OPH-2816, MCZ OPH-2875, MCZ OPH-2876, USNM 19592, USNM 19593, USNM 19595, USNM 19596, USNM 19597 (Supplementary file 2).

Description (ICML-EMU-11111). DD = 23 mm. Disc subpentagonal, indented interradially. Dorsal disc covered with thickened skin and sparse epidermal circular ossicles, lacking scales. RS clearly multilayered, elongated, thin, prominent distally, almost reaching the center of the disc (Fig. 1G). Ventral interradii entirely covered by integument with circular-shaped epidermal ossicles. Genital slits round, restricted to proximal part of the interradius, short, covering approximately 1/6 of interradius. OSh not evident (Fig. 1H). One small circular madreporite.AdSh broader than long, rectangular with rounded edges, meeting in front of OSh. Jaws bearing seven papillae at each side; OPa four, granule-like; TPa three at jaw tips, spiniform, larger than OPa, separated. Teeth several, similar to TPa (Fig. 1I). Arms entirely covered by integument, coiled, gradually narrowing distally (Fig. 1J); two arms wider and slightly shorter than the remaining three. LAP located on the ventral lateral side of vertebrae, rounded, prominent (Fig. 1K). First tentacle pore lacking ArSp; second with one ArSp; subsequent pores gradually reaching up to 6‒7 ArSp in the middle of the arm, hook-shaped, serrated (Fig. 1K). Middle part of the arm with ventralmost ArSp very elongated (approximately two VAP in length), bulbous (Fig. 1L). TSc lacking. Color pattern yellowish-brown (ethanol preservation) (Fig. 1G‒M).

Habitat and distribution. Widely distributed in deep waters worldwide, except polar regions (Paterson 1985). In the eastern tropical Pacific, A. loveni has been reported from Mexico, Panama, and the Galapagos Islands (Lütken & Mortensen 1899; Maluf 1991; Granja-Fernández et al. 2015); 100‒ 4,721 m, but more common at 200‒ 2,000 m depth (Paterson 1985; Okanishi et al. 2018). Associated with gorgonians and Pennatulacea (Fujita & Ohta 1988). The material of the TALUD cruises is from the southern Gulf of California and off Jalisco; 920‒ 1,643 m depth, associated with unidentified gorgonians.

Remarks. Asteronyx loveni has been recorded in Mexico in the Gulf of California and off western Baja California and Baja California Sur (Granja-Fernández et al. 2015). During the TALUD cruises it was collected further south, off Jalisco (19º19′37″N; 105º26′20″W), which represents a significant extension of its distribution in western Mexico. Some of the TALUD specimens were associated with unidentified gorgonians. The arms of A. loveni have a specific function since the two wider arms firmly attach to the substrate (the gorgonians in this case), and the remainder, long and slender arms, extend into the water column to collect particles used for feeding (Paterson 1985; Fujita & Ohta 1988). Genetic data show considerable diversity suggesting that A. loveni might be a complex of several closely related species (Christodoulou et al. 2019).