Henricia uluudax, 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 : 12-14

Henricia uluudax sp. nov.

Figures 21–26

Henricia spiculifera (Clark) Verrill, 1914: 232 (pars), non Cribrella spiculifera H.L. Clark, 1901 .

Henricia leviuscula multispina Fisher, 1911: 286 (pars), non Henricia leviuscula multispina Fisher, 1910: 571 .

Type locality: Alaska, Aleutian Islands, Fox Islands, Unalaska Island, NW entrance to Unalaska Bay, inside Eider Point (53º57. 33 N, 166º 35.5 W), 5 m.

Type material: Holotype, LACM 1999-178.001 (leg. R.N. Clark, 9 May, 1999); 1 Paratype, USNM 1125119 (leg. R.N. Clark, 9 may, 1999); 1, CASIZ 180536 (leg. R.N. Clark, 1999).

Material examined: 2, LACM 1997-219.001, Atka Island, Crescent Bay, point at W end, 10 m (leg. R.N. Clark & Robert Lauth, 8 July, 1997); 2, RNC, Unalaska Island, Eider Point, 0–5 m (leg. R.N. Clark, 2 October, 2001); 1, RNC, Seguam Island, 12 m (leg. Shawn Harper, 18 July, 2007); 2, LACM 2008-029.001, Avatanak Island, 6 m (leg. R.N. Clark, 12 June, 2008).

Diagnosis: Relatively small, fairly rigid, R to 5.3 cm (Holotype R = 4.5 cm), r to 10 cm, R:r 5–5.3; disc small, rays moderately long, slender, tapering. Abactinal plates small, close-set; some plates may form a single fine, faint medial line or ridge on the rays. Adambulacral plates with 19–24 fairly stout, compressed spines.

Description: Relatively small, R to 5.3 cm, r to 1.0 cm, R:r 5–5.3; disc small, rays moderately long, slender, tapering to fairly blunt tips ( Figs. 21 & 22 ). Abactinal plates very small, close-set ( Fig. 23 ); pseudopaxillae round on disc, becoming triangular on rays, forming a tight reticulation, some apical plates often very close-set, nearly coalescing, forming a single very fine line or ridge at apex of ray; plates crowned with 37–60 fine, divergent, thorn-tipped spinules, about 0.25 to 0.30 mm in length; usually 3 slender thorns per spinule; papular areas rather small, with 2 –3 papulae; madreporite small, circular, irregularly radially spinose, located about 1/3 of the distance between the anus and the edge of the disc. Superomarginals 2 or 3 times as large as abactinal plates; inferomarginals about 1/3 third larger than superomarginals, and bearing 60–70 thorny spinules; first intermarginal series about 1/2 as large as inferomarginals at base of rays, grading smaller aborally, extending about 40–50% of R, second series ends just pass the base of the rays; actinal interradial series extending 75–80% of R. Adambulacrals ( Fig. 24 ) with a single deep furrow spine, and 19–24 actinal spines, one (or two) large, thick, blunt spines at edge of furrow, backed by 2–3 similar spines, followed by a group of 16–20 smaller spines behind (usually arranged in 3 rows). Oral plates ( Fig. 25 ) with 3–4 thick, blunt marginal spines, and 6–9 similar, sub-oral spines; in addition there are two to four thick, blunt, triangular, teeth deep in the furrow near the distal edge of the plate. Color in life ( Fig. 26 ) uniformly bright red.

Distribution: Found from Fox Islands, Avatanak Island (54º 05.188 N, 165º 22.839 W) (leg. R.N. Clark, 12 June, 2008) to Andreanof Islands, Atka Island, Crescent Bay, point at W end (leg. R.N. Clark & Robert Lauth, 8 July, 1997) at depths of 0– 12 m. Henricia uluudax appears to be an endemic Aleutian species.

Habitat: Intertidal and shallow subtidal, on cobbles and boulders encrusted with coralline red algae. Frequently in kelp beds [ Eualaria (Alaria) fistulosa and Nereocystis luetkeana ].

Etymology: The name is the Aleut native word for red; (pronounced ō lō thux).

Remarks: Henricia uluudax is very similar superficially to H. lineata , but may be distinguished by 1) the lack light colored lines of coalescing plates; 2) more numerous abactinal spinules, 37–60, compared to 18–41; 3) more numerous inferomarginal spines, 60–70, opposed to 28–36; and 4) more numerous adambulacral spines, 19–24 compared to 15–17. The spinose nature of this form led Fisher (1911) to consider this an "extreme variant" of H. multispinosa , and Verrill thought it to be (at least in part) H.L. Clark's Cribrella spiculifera .

It differs from the similar appearing H. vermilion by 1) the slender body; 2) differently shaped abactinal plates; 3) much more slender, divergent pseudopaxillar spinules, which bear (usually) just 3 long thorns, those of H. vermilion are pointed and bear numerous thorns, 4) the much more numerous adambulacral spines, 19– 24 as opposed to 7–10 in H. vermilion ; and 5) presence of extensive intemarginal series.

From the southern H. leviuscula , it differs in having slender, divergent, 3-pronged abactinal spinules, and an intermarginal series extending to about 50% of R, H. leviuscula lacks an intermarginal series. True H. leviuscula is not known to occur north of extreme southeastern Alaska (Doug Eernisse, pers. comm., March, 2009). This species is part of a complex of several very similar appearing Henricia in the Aleutians.

Figures

FIGURES 21 – 26. Henricia uluudax, Holotype, LACM 1999 - 178.001. Fig. 21, Ray, abactinal view. Bar = 1.0 cm. Fig. 22, Ray, actinal view. Bar = 1.0 cm. Fig. 23, Abactinal surface. Bar = 2.0 mm. Fig. 24, Adambulacral region. Bar = 1.0 mm. Fig. 25, Oral region. Bar = 1.0 mm. Figure 26, Henricia uluudax, live animal, Type locality, 5 m. R = 5.0 cm (image: R. Clark, 15 June, 2008).