Amphiophiura superba (Lütken & Mortensen, 1899)

Fig. 6A‒F

Ophioglypha superba Lütken & Mortensen, 1899: 116‒117, pl. 1, figs. 4‒8, pl. 7, fig. 4.

Ophiura hadra H.L. Clark, 1911: 80‒82, fig. 24.

Ophiura superba . H.L. Clark 1913: 208‒209.

Amphiophiura superba . H.L. Clark 1915: 314.

Amphiophiura superba . Kyte 1969a: 1730, 1738.— Lambert & Boutillier 2011: 46, fig. 32.

Material examined. Eight individuals at four stations. TALUD XII, Sta. 24, 2 ind. (ICML-EMU-11135-A); Sta. 27, 3 ind. (ICML-EMU-11134-B) and 1 ind. (ICML-EMU-11135-B). TALUD XV, Sta. 3, 1 ind. (ICML-EMU-11663- B); Sta. 9, 1 ind. (ICML-EMU-11663-A).

Comparative material. Ophioglypha superba Lu ̈tken & Mortensen, 1899, syntypes, 4 ind.: MCZ OPH 726, MNHN-IE-2013-10248, USNM 19442. Ophiura hadra H.L. Clark, 1911, paratypes, 18 ind.: MCZ OPH- 3002, MCZ OPH- 3003, MCZ OPH- 3004, MCZ OPH- 3321, USNM 25542, USNM 25612, USNM 25751, USNM 26974, USNM 33366 (Supplementary file 2).

Description (ICML-EMU-11134-B). DD = 20 mm. Disc pentagonal, swollen. Dorsal disc covered by irregular, prominent, inflated right-angled plates. Primary plates not evident. RS longer than broad, triangular with rounded edges, a diamond-shaped plate inserted proximally. Ventral interradii covered by up to five large, rounded plates (Fig. 6A). Genital slits very conspicuous, with small quadrangular genital papillae, projecting dorsally and forming well-developed arm combs with pointed papillae, secondary arm comb present (Fig. 6B). OSh occupies 3/4 of the interradius, longer than broad, pentagonal proximally, rounded distally. Madreporite not evident. AdSh longer than broad, elongated, surrounding the oral shield, meeting in front of OSh. Jaws bearing 4‒5 papillae at each side; BSc rectangular, elongated; IPa rectangular, elongated; 2IPa quadrangular, slightly pointed; TPa 1‒2 pointed, the apicalmost the largest. vT pointed, larger than oral papillae. Preceding ossicles separated by a diastema; one AdShSp, three 2AdShSp, rectangular with rounded edges (Fig. 6C). Arms gradually narrowing distally. First DAP covered by the arm comb; subsequent DAP slightly broader than long, trapezoidal, meeting (Fig. 6D). VAP as broad as long, diamond-shaped, separating and decreasing in size distally. LAP with 3‒4 similar size ArSp, minute (approximately 1/6 LAP in length), blunt. First tentacle pore with 4‒5 rectangular with rounded edges TSc; subsequent tentacle pores decreasing the number of TSc until reaching one distally (Fig. 6E). Color pattern beige-whitish (ethanol preservation) (Fig. 6A‒F).

Habitat and distribution. British Columbia, Canada, California, USA, and Mexico; 51‒ 1,867 m depth, muddy and sandy bottoms (H.L. Clark 1913; Maluf 1988; Granja-Fernández et al. 2015). The material examined was collected off western Baja California Sur and off Colima; 1,040 ‒1,542 m depth.

Remarks. Amphiophiura superba presents two types of arm comb papillae: rounded-squared tips (Lütken & Mortensen 1899; H.L. Clark 1911; type material of Ophioglypha superba and Ophiura hadra) or pointed tips (Lambert & Boutillier 2011; type material of O. hadra; material examined). Differences in the shape of the arm comb papillae could be attributed to population differences. Nevertheless, further morphometric and molecular analysis is needed to confirm this. Larger specimens (DD = 24 mm) of A. superba present up to 4‒5 2AdShSp, and smaller ones (DD = 6.8 mm) up to three. Oral shields in this species can vary in shape; they can be complete or partially divided or amorphous. The presence of A. superba off Colima represents a new distribution record for this area and fills the distribution gap of this species in western Mexico.