Odontohenricia violacea, Clark, Roger N. & Jewett, Stephen C., 2010

Clark, Roger N. & Jewett, Stephen C., 2010, A new genus and thirteen new species of sea stars (Asteroidea: Echinasteridae) from the Aleutian Island Archipelago, Zootaxa 2571, pp. 1-36 : 30-32

Odontohenricia violacea sp. nov.

Figures 83–88

Type locality: Alaska, Aleutian Islands, Andreanof Islands, S of Amatignak Island (51º 11.935 N, 179º 05.87 E), 95 m.

Type material: Holotype, LACM 2004-279.001 (leg. R.N. Clark, 4 July, 2004; trawled R/V Sea Storm, 95 m) ( NMFS 143-0401-110).

Diagnosis: Large, slender stars; disc small, rays very long, slender; abactinal surface covered with a thick, cuticle-like epidermal layer; aboral plates small, close-set, bearing 6–12 pointed spinelets; Color violet abactinally, pale yellow-cream actinally.

Description: Large, long, slender rays, R to 21.3 cm, r 2 cm, R:r 10.65:1 ( Figs. 83 & 84 ); disc small, rays very long, slender, gradually tapering. Abactinal surface ( Fig. 85 ) covered with a thick, purple, almost cuticlelike epidermal layer which completely obscures the abactinal plates. Abactinal plates small, round or oblong, crowned with five to ten short (0.5 mm), bluntly pointed spinelets; abactinal plates close set, forming a very fine reticulation with small papular areas, each with a single papula; madreporite small, about 3 mm in diameter, with irregular radiating ridges. Superomarginals about twice as long as wide, bearing three or four rows of 8–10, stout, sharp, thorn-like spines 0.4 mm in length; inferomarginals three times as long as wide, bearing three or four rows of 11–13 spines, similar to those of the superomarginals; intermarginals small, about the same size as abactinal plates, in a single series extending 20% of R; two series of actinal intermediate plates, the first about half as large as inferomarginals, bearing three or four rows of six to eight sharp, thorn-like spines, about 0.4 mm long, and extending about 1/2 of R, where they become very irregular and mostly absent, to about 3/4 of R; second row much smaller, bearing five to ten similar spines and extending irregularly to about 20% of R. Adambulacrals ( Fig. 86 ) with a single short, deep furrow spinelet, one or two large flesh covered spines at the furrow edge, with two similar, slightly smaller spines behind, followed by mostly three series of seven to ten, smaller, sharper, distally grading spines; adambulacral, actinal intermediate and marginal plates forming regular, transverse ridges, the furrows between bearing four or five large, well spaced papulae. Oral plates ( Fig. 87 ) with a large, slender, sharply pointed apical spine, beside which on each plate is a similar, spine about 3/4 as large as the apical spine, five or six sharply pointed marginal spines, a group of eight to ten sharp, suboral spines, and four or five short, very stout, blunt teeth deep in the furrow. Color in life ( Fig. 88), uniformly violet aborally, pale yellowish-cream orally. Color remains even after years in ethanol;

Distribution: Alaska, Aleutian Islands, Rat and Andreanof Islands. Only known from two locations, the type locality, south of Amatignak Island (51º 11.935 N, 179º 05.87 E) and the north side of Rat Island (51º 49.594 N, 178º 16.676 E) (leg. Stephen Jewett, 1 July, 2007, scuba 14 m; AKALE07-A0031; photo only) at depths of 14– 95 m. A rare species, apparently endemic to the central Aleutian Islands. Further investigation is needed to precisely map out its distribution.

Habitat: Subtidal bedrock and boulder bottoms with abundant sponges, and bottom temperatures of 5– 5.4ºC.

Etymology: Named for the beautiful violet aboral coloration.

Remarks: This unusual star is unique among Odontohenricia because of its very slender rays, very tight meshed aboral plates and strange, dermal layer on the aboral surface.

The three presently described species of Odontohenricia are the first of this genus described from the Aleutian Islands, and are part of a complex of at least six species in the region (R.N. Clark, unpub.), some of which grow to considerable size, R to 23 cm.

One other species of Odontohenricia is known from Alaskan waters, Odontohenricia fisheri Rowe and Albertson, 1988 ( Fig. 89), previously known only from the type specimen from off Washington State (48º33' N, 124º53' W), at 108 m. R.N. Clark has collected this species from several localities in the Gulf of Alaska, at depths of 105–210 m on black (volcanic) sand and pebbles, rich with sponges. The northwestern most site SW of the Shumagin Islands (54º 25.542 N, 161º 2.886 W) (leg. R.N. Clark, 27 May, 1999; trawled R/V Dominator, 105 m on black sand; NMFS 23-199901-48; LACM 1999-182.001), eastern end of the Aleutian chain. The range herein extended north and west approximately 2400 km.

Figures

FIGURES 83 – 87. Odontohenricia violacea, Holotype, LACM 2004 - 279.001. Fig. 83, Whole animal, abactinal view. Bar = 5.0 cm. Fig. 84, Whole animal, actinal view. Bar = 5.0 cm. Fig. 85, Close-up, abactinal surface showing thick cuticle-like dermal layer that obscures the abactinal plates. Bar = 1.0 cm. Fig. 86, Close-up, adambulacral region. Bar = 5.0 mm. Fig. 87, Close-up, oral region. Bar = 5.0 mm.