Solaster spectabilis, Clark, Roger N. & Jewett, Stephen C., 2011

Clark, Roger N. & Jewett, Stephen C., 2011, Three new sea stars (Asteroidea: Solasteridae & Pterasteridae) from the Aleutian Islands, Zootaxa 3051, pp. 1-13 : 5-8

Solaster spectabilis sp. nov.

Figures 7–12

Solaster dawsoni non Verrill, Fisher, 1911: 313 (pars); D’yakonov, 1950: 59 (pars); Kessler, 1985: 197 (pars).

Type locality. Alaska, Aleutian Islands, SW of Tanaga Island (51° 44.50 N, 178° 07.68 W), 95 meters. Type material. Table 2 .

Type Deposition & No. of Collection Site Collection Collection Date Collector & Specimens Depth, m Method Paratypes LACM 2010- Petrel Bank 93 m 19 July, 2010 N. Roberson, 0 38.001 52° 13.09 N, 179° 58.12 E; trawled, R/ V 2 specimens, Eth. NMFS 143- 201001 -146 Sea Storm

Description. Large ten-rayed form (rarely 11), Holotype, R = 135 mm, r = 43 mm; R:r = 3.1. Disc broad, rays relatively long, tapering to slender tips. Dorsal side ( Fig. 8) moderately inflated, rather thin. Papular pores numerous, in groups of two or three; papulae relatively large. Abactinal plates small, Y or cruciform, closely imbricating. Pseudopaxillae ( Fig. 9) small, spaced and bearing 12–25 short spinelets. Madreporite relatively large, with irregular convolutions, surrounded by ten pseudopaxillae (some of which are with in the madreporite itself).

Superomarginals about twice as large as pseudopaxillae and bearing 30–45 spinelets. Inferomarginals fan-like, about four times as large as superomarginals, and located directly adjacent to them; about four times as wide as long, with 65–80 membrane-sheathed spinelets, grading distally. Oral interradial areas small, with about 50–55 oral intermediate plates; synactinal series extending just past interradial angle. Adambulacral plates ( Fig. 10) with bristling straight actinal series of six to eight moderately long, rather stout, blunt (sometimes spatulate), membranesheathed spines (distal one usually much smaller than the others), the proximal one of which is displaced distally, to between the distal and central furrow spines; furrow series of three long, stout, blunt spines webbed about half way; adoral spine often shorter than the other two. Paired oral plates ( Fig. 11) with 11–12 thick, blunt, often flattened, membrane-sheathed marginal spines, webbed half way or more, the first three much longer than the others; 12–17 suboral spines, in two rows or a group.

Living color variable, the “typical” color phase has a yellow or orange disc and purple rays ( Fig. 12 ). Other specimens may be solid orange, white or purple, others are cream or tan with pink stripe on the lower half of the rays or purple with red stripes radiating from the center of the disc to the tips of the rays.

Distribution & habitat. Solaster spectabilis sp. nov. appears to be restricted to the central Aleutian Islands (Fig. 7), from Chuginadak Island (169°30’W) to near Kiska Island (176°E), from 7–212 m on boulder, cobble sand, gravel and shell hash bottoms.

Etymology. The name spectabilis is Latin and means notable or showy, in regards to the many spectacular color morphs.

Remarks. Solaster spectabilis sp. nov. appears to be one of the Aleutian forms regarded by Fisher (1911:15) as Solaster dawsoni ( Fig. 13). The two species are superficially similar, but S. spectabilis sp. nov. differs in 1) having ten, rarely 11 rays, compared to 12–14 in S. dawsoni ; 2) in S. spectabilis sp. nov. aboral pseudopaxillae bear 12–18 marginal and 3–9 central spinelets, often bunched together, in S. dawsoni , they bare 10–26 marginal and 0–3 spaced central spinelets; 3) actinal series of adambulacrals of S. spectabilis sp. nov. has six to eight spines, as opposed to three to five in S. dawsoni ; and 4) coloration, S. spectabilis sp. nov. has a number of spectacular color morphs, whereas S. dawsoni occurs in only very basic, nearly uniform tones. The number of rays in Solaster spectabilis sp. nov. is remarkably consistent, of nearly fifty specimens observed (many observed in the field and released) all had ten rays except for two (LACM 1997-220.001 & CASIZ 184724) which have eleven. Data for Solaster dawsoni derived from Aleutian Islands specimens in the R. N. Clark collection, and from Lambert, 2000.

In addition to morphological differences, the geographic ranges also differ. Solaster dawsoni is found from California, north and west to the east side Samalga Pass (NW end of Umnak Island) ( Clark & Jewett, 2010). Solaster spectabilis sp. nov. is found from east side of Samalga Pass (the Islands of Four Mountains) west to near Kiska Island.

The diet of these two species differs also, S. dawsoni is well known as a sea star predator, feeding on a number of species, including other Solaster spp., the massive Pycnopodia helianthoides (Brandt, 1835) , and even members of its own species ( Lambert 2000). In contrast, S. spectabilis sp. nov. appears to feed predominantly on sea urchins ( Strongylocentrotus spp.). Five specimens were observed feeding on urchins when collected (including a Paratype, USNM 1153698). One specimen was feeding on a small Pteraster sp. nov. (R.N. Clark, unpub.).

Solaster spectabilis sp. nov. also superficially resembles Solaster arctica Verrill, 1914 , but may be easily distinguished by 1) spinelets of aboral pseudopaxillae longer, 0.8–1.0 mm and bearing 5–10 short, stout apical thorns, to 0.1 mm in length in S. spectabilis sp. nov., the pseudopaxillar spinelets of S. arctica are 0.5–0.6 mm in length, and bear 5–8 slender spicules to 0.2 mm in length; 2) more numerous spines in actinal series of adambulacrals, 7–8 compared to 5–6 in S. arctica ; 3) the furrow series of spines in S. spectabilis sp. nov. has 3 spines, two of sub-equal length and a third, shorter spine, 1/2 to 3/4 as long as the other two, the furrow series of S. arctica has two more or less equal length spines, and rarely a third, much shorter spinelet (1/2 or less the length of the others).

Discussion. Solaster arctica Verrill, 1914 (Type USNM 7624) was described as a subspecies of Solaster dawsoni Verrill. Fisher (1930) appeared to agree with Verrill, but suggested that it was probably an Arctic race of the latter. This assessment was followed by Mah (2010) as Solaster dawsoni arctica Verrill, 1914 , but incorrectly states that it was originally described as a variety of S. dawsoni . We herein raise this taxon to full species, based upon the original description, as well as specimens collected by the authors from SW of the type locality, in the Chukchi Sea, (Arctic Ocean) and in the central Aleutian Islands, at Tanaga Island.

Solaster arctica differs from Solaster dawsoni by 1) number of rays, 10, in all know specimens, where as S. dawsoni varies from 12–14; 2) in S. arctica spinelets cover the dorsal surface of the pseudopaxillae, in S. dawsoni most of the spinelets are restricted to the periphery of the pseudopaxillae, the central areas often are completely bare, or have only 1–3; 3) pseudopaxillar spinelets of S. arctica 0.5–0.6 mm in length, bearing 5–8 apical spicules to 0.2 mm in length, pseudopaxillae in S. dawsoni 0.2–0.4 mm in length with 3–5 short, often blunt apical thorns 0.05–0.08 mm in length; 4) maximum known radius for S. arctica is 9.3 cm, while S. dawsoni reaches 20 cm in radius.

The distribution of Solaster arctica appears to be restricted to the Arctic (NE Chukchi Sea), and colder regions of the Bering Sea, south to the central Aleutian Islands.

Figures

FIGURE 12. Solaster spectabilis sp. nov. live, in. situ. Kuluk Bay, Adak Island, 12 m. image: R. N. Clark, 22 June, 2007; R = approximately 15.0 cm.

Tables

TABLE 2. Type material: Solaster spectabilis sp. nov.

Holotype	LACM 1997- 154.014, dry	SW of Tanaga Island 51°44.50 95 m N, 178°07.68 W; NMFS 23-199701-137	15 July, 1997	R. N. Clark, trawled, R/V Dominator
Paratype	USNM 1153698 1 specimen, dry	W of Tanaga Island 103 m 51°46.69 N, 178°10.66 W; NMFS 23-199701-140	17 July, 1997	R. N. Clark, trawled, R/V Dominator
Paratype	LACM 1997- 220.001 1 specimen, dry	W of Tanaga Island 103 m 51°46.69 N, 178°10.66 W; NMFS 23-199701-140	17 July, 1997	R. N. Clark, trawled, R/V Dominator
Paratype	CASIZ 184724 1 specimen	W of Kiska Island 130 m 52°05.6 N, 177°42.6 E; NMFS 23-199701-197	31 July, 1997	R. N. Clark, trawled, R/V Dominator
Paratype	LACM 1997- 217.002 1 specimen, dry	W of Tanaga Island 108 m 51°46.55 N, 178°10.81 W; NMFS 23-199701-133	14 July, 1997	R. N. Clark, trawled, R/V Dominator
Paratype	LACM 1994- 173.001 1 specimen, dry	N of Atka Island 212 m 52°08.55 N, 175°16.99 W; NMFS 94-1994-156	12 July, 1994	R. N. Clark, trawled, R/V Veste raale n
Paratype	UAF 8137 1 specimen, dry	Kirilof Bay, Amchitka Is 7 m 51°25.85 N, 179°13.40 E; AKALE07- 0 0 16	2 July, 2007	R. Brewer, scuba
Paratype	LACM 2007- 119.001 1 specimen, dry	N. side of Tanaga Island 13 m 51°50.69 N, 177°51.21 W; AKALE07-0050	6 July, 2007	R. Brewer, scuba