Odontohenricia aurantia, 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 : 26-28

Odontohenricia aurantia sp. nov.

Figures 71–76

Henricia sanguinolenta (Muller) , Fisher, 1910: 272, variety C (in part), non Asterias sanguinolenta O.F. Müller, 1776 .

Type locality: Alaska, Aleutian Islands, Rat Islands, Rat Island (51º 49.594 N, 178º 27.184 E), 13 m. ( AKALE 07-A0031).

Type material: Holotype, LACM 2008-030.002 (Leg. R.N. Clark, 8 June, 2008; scuba 13 m); Paratype 1, USNM 1125116; Paratype 2, CASIZ 180537 (leg. S. Jewett & Shawn Harper, 1 July, 2007; scuba 14 m).

Additional material: 1, USNM (not located), Semisopochnoi Island (Albatross St. # 4778) Fisher, 1911: 275, plate 65.2 (upper specimen); plate 66.5.

Diagnosis: Very large, slender-rayed, R to 17 cm; disc relatively small, rays very long, slender, tapering. Abactinal plates small, forming a rather close reticulation and crowned with numerous short (to 0.8 mm) spinelets; marginal plates forming two prominent series; oral plates with a very large apical spine, bordered on each side on each side by a similar smaller spine about 3/4 as large. Color in life bright orange.

Description: Very large, slender, R to 17 cm (Holotype 16.2 cm), r 2.7, R:r 6.2:1 ( Figs. 71 & 72 ); disc relatively small, rays long, slender, tapering. Abactinal plates ( Fig. 73 ) small, rather close set, forming a fine, relatively tight meshed skeleton, crowned with 10–20 pointed, thorn-tipped spinelets about 0.5 mm long; papular areas slightly larger than plates, with one to two papulae; madreporite small, equidistant between anus and disc margin, beset with radiating rows of spinelets. Superomarginals much larger than abactinals; intermarginal small, a single series extend just past the base of the rays, inferomarginals marginals somewhat larger than superomarginals, about twice as high as wide; actinal intermediates in three series, the first as large as superomarginals, and extending about 1/2 to 2/3 of R, second series smaller, and extending just past the base of the rays, and the third does not extend to the edge of the disc; adambulacrals ( Fig. 74 ) with one or two spines deep in the furrow, one large, slender, blunt spine on the edge of the furrow, with two to five only slightly smaller, similar spines behind, followed by a grading series of 25–30 smaller spines, which may be in a random group, or in two to four linear series; adambulacral, actinal intermediate and marginal plates forming regular, transverse ridges, the furrows between bearing five to eight large, well spaced papulae. Oral plates ( Fig. 75 ) with a single very large, curved spine at the apex of the paired plates, bounded on each side by a single slightly smaller spine, about 3/4 as large, and three to seven much smaller marginal spines, 13–24 suboral spines, and three to five short, pointed spines deep in the furrow, near the distal end of the edge of the plate. Color in life ( Fig. 76 ), bright orange aborally and orally.

Distribution: Known from the type locality at Rat Island, east to Chuginadak Island (52º 48.289 N, 169º 42.526 W), at depths of 7– 17 m. Endemic to the Aleutian Islands. Odontohenricia aurantia appears to be endemic to the central Aleutian region.

Habitat: Bedrock and boulders covered with the thick encrusting, coralline red algae Clathromorphum nereostratum , and large upright, red-orange sponges of an unknown identity, upon which it appears to feed, at temperatures of 4.4–4.6º C.

Etymology: From the Latin noun for orange, in reference to the bright orange coloration of living animals.

Remarks: Fisher (1911) apparently struggled with these animals, and finally took the view that the enormous henriciids from the Aleutians were varieties of Henricia sanguinolenta (O. F. Müller, 1776) and remarked that "The variations are legion and are bewildering" "A ventral view reminds one strongly of a very large (Henricia) leviuscula with compressed marginals, while an abactinal view suggests sometimes sanguinolenta , and sometimes leviuscula with unusually small plates". Fisher went on to discuss Gigantism and possible hybridization, finally remarking that " they act like hybrids", and "whatever the true explanation of these remarkable variations, it does not seem advisable at present to give them a name". It is obvious from Fisher's descriptions and illustrations that this is (at least in part) his " H. sanguinolenta variety C" ( Fisher, 1911, plate 66 figs. 2–5) from Semisopochnoi Island (Albatross St. # 4778) (Fisher's material was examined by R.N. Clark in February, 1998, and confirm these findings). Other similar (but as yet undescribed) species were also included in Fisher's "variety C". Apparently he did not notice the remarkable oral plate pairs united by an oversized apical tooth.

Figures

FIGURES 71 – 76. Odontohenricia aurantia, Holotype, LACM 2008 - 030.002. Fig. 71, Whole animal, abactinal view. Bar = 5.0 cm. Fig. 72, Whole animal, actinal view. Bar = 5.0 cm. Fig. 73, Close-up, abactinal surface. Bar = 5.0 mm. Fig. 74, Close-up, adambulacral region. Bar = 5.0 mm. Fig. 75, Close-up, oral region. Bar = 5.0 mm. Fig. 76, Live, in situ N side, Rat Island, 10 m, (AKALE 07 - A 0031) (image: R. Clark, 8 June, 2008). R = 16 cm.