Amphipholis tuberosa, Stöhr, Sabine, 2011

Stöhr, Sabine, 2011, New records and new species of Ophiuroidea (Echinodermata) from Lifou, Loyalty Islands, New Caledonia, Zootaxa 3089, pp. 1-50 : 28-30

Amphipholis tuberosa sp. nov.

Figure 12

Type material. Holotype on SEM stub, sta. 1415, New Caledonia, Loyalty Islands, Lifou, Baie du Santal, off Chépénéhé, 20°47.1'S, 167°09.1'E, 3–7 m [ MNHN IE- 2009-9208]. Paratypes: Sta. 1413: 1 spm, in 95% ethanol [SMNH-Type-8078]; sta. 1450: 2 spms, in 80% ethanol [SMNH-Type-8079]; NC00-35: 2 spms, in 95% ethanol [SMNH-Type-8080].

Etymology. The specific name is derived from the Latin word for “full of lumps or protuberances” ( Brown 1956), alluding to the structure of the disk scales and other plates.

Holotype description. Dorsal disk covered with a central plate, a circle of five large radial, irregularly lobed plates, and columns of three overlapping plates of similar size interradially, all of which bear several small nonarticulated protuberances, 30–70 µm wide, 10–30 µm high, irregularly round to oval; 1.9 mm dd. Radial shields half-circle shaped, contiguous for their entire length, with several lower and some higher protuberances. Disk edge well-defined. Arms all broken, at least twice as long as dd. Dorsal arm plates bell shaped, separated by lateral plates, distal edges slightly convex, surface with low protuberances. Four spines on proximal joints, ventralmost spine smallest. All spines flat, hollow, shorter than an arm joint, with pointed finger-like extension in middle of distal end.

FIGURE 12. SEM images of Amphipholis tuberosa sp. nov. holotype MNHN IE- 2009-9208. A, dorsal aspect, note the protuberances; B, dorsal arm, note the peculiar shape of the spines; C, arm lateral; D, disk protuberances; E, ventral aspect; F, oral details; G, ventral arm. Scale bars in millimetre.

Ventral disk covered by thick, round overlapping scales of uneven appearance. Jaws bear paired pointed infradental papillae on the dental plate, followed by a low round lateral papilla on the proximal end of the oral plate, and an operculiform, much enlarged distal lateral papilla, partly on the oral plate and partly on the adoral shield. Oral shields spearhead-shaped, one of them with two hydropores to either side of the distal lobe. Adoral shields winglike, flaring, separating the oral shield from the arm. Adoral and oral shields as well as distal oral papilla microscopically tuberculous. First ventral arm plate between two jaws pentagonal, about as wide as long, rough. Following plates separated, pentagonal, twice as wide as long, distal edge slightly convex, lateral edges indented, surface microscopically tuberculous. A single small round tentacle scale on the first two joints, non on following joints.

Paratype variations. The paratypes measured 0.8, 1.2, 1.6, 1.75 and 1.9 mm dd. In the smallest paratypes the plates are light microscopically smooth, lacking tubercles, but the characteristic shape of the arm spines is present. The larger ones are similar to the holotype.

Remarks. The pattern of the oral papillae and the relatively short arms clearly place this species in the genus Amphipholis , which currently includes 30 species ( Stöhr & O’Hara 2007). Amphipholis tuberosa sp. nov. differs from all other species by its tuberculous plates and scales and the shape of the arm spines. Its closest affinities may be with A. sigillata Cherbonnier & Guille, 1978 , described from Madagascar, which shares the large primary rosette, some sculpturing of the disk scales and the lack of tentacle scales on all but the most proximal joints.

Distribution. Known only from the type locality. Found at depths of 3–31 m at Lifou on rocky and sandy bottoms.