Anthophiura ingolfi Fasmer 1930

Anthophiura ingolfi Fasmer, 1930

Fig. 4A–B

Anthophiura ingolfi Fasmer, 1930: 4–7, fig. 3–5.— Mortensen 1933b: 99–100, fig.52.— Vadon & Guille 1984: 593–595, fig. 1(a–b), pl. 4(4–6).— Paterson 1985: 140, fig. 53.— Vadon 1991: 348.

Material examined. MD 50 DC55, MNHN IE.2009.1608 (2). MD 50 DC64, MNHN IE.2009.1609 (1).

Distribution. Arctic (2448– 2448 m), NW Atlantic (3136–3796 m), NE Atlantic (2430–4020 m), E Atlantic (2976–3190 m), W Indian (1100–1600 m), E Indo-W Pacific (470–2040 m), E Pacific (4017–4078 m), S Africa (1000–1200 m), S Australia (1076–1147 m), New Zealand (1216–1222 m). SPA (1000–1125 m).

Remarks. The MD50 material, to 3.4 mm dd, has been identified as A. ingolfi on the basis of the disc scales, which are few in number and thickened around the distal edges, broadly contiguous radial shields, rudimentary genital papillae, no arm comb, second oral tentacle pores slit like and positioned well back out of the jaw, pentagonal oral shields, ventral disc dominated by a large pentagonal scale adjacent to the oral shield and two separated tuberculated marginal scales, no DAPs, very reduced VAPs, two arm spines and tentacle pores present down the arm with one spine like tentacle scale (Fig. 4A–B). Previous authors have emphasised the elevated star-shaped centrodorsal plate, but this plate is not always shaped like this, and can sometimes be pentagonal (Fasmer 1930). Fasmer emphasised the split nature of the genital plates on the type but this hasn’t been reported by others (e.g., Paterson 1985). He also described three arm spines (for animals 6 mm dd) while Paterson (1985) re-examining the types noted only two. The SPA material and that of Vadon and Guille (1984) from off Reunion Island differ from those reported from the North Atlantic in having tuberculated marginal disc scales.

There are several other species in this little known genus. The type species A. axiologa H.L. Clark, 1911 from the North Pacific (2226 m, 6 mm dd) is distinguished by having disc scales that are neither tuberculated nor thickened, a wide marginal disc scale ventrally and arm spines that become hooked only from the 10th segment. Anthophiura granulata (H.L. Clark, 1939) from the North Indian Ocean (3840 m, 4 mm dd) has disc scales that are sculptured and pitted, a wide marginal disc scale, and prominent genital papillae. Anthophiura challengeri Fasmer, 1930 from the central South Pacific (4417 m, 6 mm dd) has small disc scales that surround the primary plates and the large ventral scale, and separate the radial shields proximally. It also has a few prominent genital papillae. Anthophiura dilatata Tommasi, 1976 from the Peru Trench (1863–1965 m, 2.5 mm dd) has only one ventral disc scale that is flanked by the genital plates (Vadon & Guille 1984). Vadon (1991) transferred the species Ophiophycis nixastrum Litvinova, 1981 from the central North Pacific (1630–2000 m, 1.8–2.1 mm dd) to Anthophiura. However, the attenuated arm, large enlarged basal LAPs, prominent arm spines, and disc plating are more similar to Ophiophycis and in many ways the figures of the type are reminiscent of Ophiophycis johni McKnight, 2003, including the prominent star-shaped centrodorsal.

No genetic sequences are known from Anthophiura and its family level placement is uncertain. However, it is likely to be a member of the Ophiopyrgidae, given the position, shape and scales of the second oral tentacle pore, and the presence of pores all along the arm. However, the tube feet of the arm emerging though a hole in the lateral arm plate, the reduced DAPs and VAPs and the arm spines are also characteristic of the Ophiomusaidae. The presence in the SPA material of two tuberculated scales along the interradial disc margin is similar to Ophiomusa scalare from which it differs by having open tentacle pores along the arm.