Henricia echinata, 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 : 17-19

Henricia echinata spec. nov.

Figures 42–46

Type locality: Alaska, Aleutian Islands, Andreanof Islands, Adak Island, Bay of Isles (51º 49.023 N, 176º 50.385 W), 13 m. ( AKALE 07-0005).

Type material: Holotype, LACM 2007-098.001( leg. R.N. Clark, 1 July, 2007).

Diagnosis: Small, moderately inflated, R to 5.3 cm, R:r 4.8; abactinal skeleton irregular, open meshwork; abactinal plates with 5–11 blunt rather smooth spines; adambulacrals with 8–11 slender, blunt spines, 1 at furrow edge, followed by 2 slightly shorter spines, and 2 irregular rows of 3–4 shorter shorter spines; oral plates with 4–5 marginal and 1 or 2 sub-oral spines; Color in life, red.

Description: Small, moderately inflated, R 5.5 cm, r 1.1 cm, R:r 5.0 cm (Figs. 42 & 43); disc small, rays relatively short, tapering to slender, blunt tips. Abactinal plates forming an irregular, open reticulation (Fig. 44); pseudopaxillae bearing 5–11 short, thick, blunt, smooth spines in two irregular rows; spines to about 0.2 mm long; madreporite small, with irregular spinose ridges; papular area large, with 2–4 papulae per area. Superomarginals about 2–3 times larger than abactinals, and bearing 9–15 spines; intermaginals about half as large as superomarginals, and forming an irregular series extending 35–50% or R; inferomarginals about 1/3 larger than superomarginals, chevron-shaped and bearing 15–21 spines. Actinal iterradial plates less than 1/2 the size of inferomarginal, in a series extending about 75% of R, and bearing 7–12 spines. Adambulacrals (Fig. 45) with a single slender, deep furrow spine, 1 long slender spine at furrow edge backed by 2 similar but somewhat shorter spines, and then 2 rows of 3–4 shorter spines. Oral plates (Fig. 46) with 4–5 long, thick, blunt marginal spines, and 1–2 similar, slightly shorter sub-orals. Color in life uniformly reddish.

Distribution: Alaska, Aleutian Islands, Andreanof Islands, Adak Island, 16 m. Known so far only from the central Aleutians, the Holotype at Adak Island, and an image of a second specimen from Amchitka Island. Further investigation is needed to define the limits of distribution for Henricia echinata , but it may be endemic to the central Aleutians.

Habitat: Rocky substrate with encrusting coralline algae and sponges.

Etymology: From the Latin, for prickly.

Remarks: Henricia echinata is somewhat similar in general appearance to H. asthenactis ( Fig. 39 ), but differs in 1) having the abactinal spines in 2 rows, and lack the thick fleshy membrane; and 2) adambulacrals spines in 2 rows. It bears superficial resemblance to H. rhytisma , but is readily separated by the relatively long, smooth abactinal spines. Henricia echinata also resembles the Arctic-Atlantic Henricia perforata (Müller, 1776) , but differs in having much shorter ( 0.2 mm compared to 0.5–0.7 mm) spines, which are stout and blunt. The spines of H. perforata are slender and pointed ( Madsen, 1987).

Figures

FIGURE 39. Henricia asthenactis, live animal, S of Atka Island (51 º 51.467 N, 174 º 09.4 W) (NMFS 94 - 0201 - 151) trawled R / V Vesteraalen, 152 m (leg. R. Clark, 10 June, 2002). Bar = 5.0 cm.