Evoplosoma anguirus, Mah, 2024

Mah, Christopher L., 2024, New genera and species of deep-sea Goniasteridae (Asteroidea) from the North Pacific, Zootaxa 5543 (4), pp. 451-500 : 473-476

Evoplosoma anguirus n. sp.

FIGURE 7A–F , 18A–B

Etymology

This species name is derived from the Japanese kaiju Anguirus, from the 1995 movie Godzilla Raids Again alluding to the numerous spines present on this species. Noun is held in apposition.

Diagnosis

Body stellate, R/r=2.88, interracial arcs straight to weakly curved, arms elongate.Abactinal surface covered by thick granular covering composed of coarse, dense, round granules, polygonal to round in outline. Disk and arms with different sized granules and spines. Abrupt shift between blunt, short cone-like granules on disk to distinct, and prominent pointed spines on arms. Marginal plates approximately 40 per interradius, each with 1 to 3 large, prominent, cone-like spine, identical to those on the arm surface. Pedicellariae present, palmate. Actinal surface covered by coarse-grained granules with prominent paddle-shaped pedicellariae. Spines few. Furrow spines 8 or 9, 6 distally, compressed with blunt tips. Subambulacral spines 1 or 2 becoming enlarged distally.

Comments

This species is distinguished by the distinct change in abactinal surface texture of spination and granules at the transition of the disk and arms. The papulae abundant on the disk are absent from the arms.

This species and Evoplosoma claguei shares a very similar abactinal surface and body shape. The abrupt delineation between the elongate arms and the disk and the distinctly different spination between the disk and arms are very similar to E. claguei . Evoplosoma anguirus n. sp. differs significantly in that the arms show abruptly larger spines on the arms and smaller spines on the disk whereas those on E. claguei differ more in shape with conical arm spines versus more blunted and cylindrical disk spines. The single subambulacral spine on E. anguirus is distinctly conical and pointed versus that of E. claguei which is distinctly thick, broad and funnel shaped. Adambulacral pedicellariae are bivalve and clamp shaped in E. claguei versus the narrower valves present in E. anguirus n. sp..

This species also shares many characters with Evoplosoma voratus , including similar bullet-shaped abactinal spines and similar granules on the abactinal surface. This species differs from E. voratus based on the shape of the subambulacral spines which are thick with large, club like tips, which are polygonal in cross-section at the tip versus Evoplosoma anguirus n. sp. which have elongate, pointed subambulacral spines which are round in cross section at the tip. Furrow spines in Evoplosoma voratus number four to six versus those in Evoplosoma anguirus n. sp. which number eight or nine (six distally).

Occurrence

Juan de Fuca Ridge, North Pacific Ocean, 2269 m.

Description

Body stellate, R /r=2.88, interracial arcs straight to weakly curved. Arms elongate ( Fig. 7A ).

Abactinal surface covered by thick granular covering composed of coarse, dense, round granules, polygonal to round in outline ( Fig. 7B ). Disk with different sized granules, abruptly changing to spines with sharp, conical tips ( Fig. 7C ). Disk with granular cover interrupted by irregular but abundant strongly convex plates with bald surface bearing a large (up to 1.0 mm length x 1.0 mm width) bullet-shaped spine with a blunt tip. Abundantly small spines with 10 to 15 granules surrounding the plate periphery. Smaller plates with no plate surface around spine, larger plates showing bare surface between peripheral granules and central spine. Where larger plates are not present, coarse, round granules present in close contact (2 along a 2.0 mm line). Papulae large, one to three present between granules, each approaching 1.0 mm in length, broad based with pointed tip. Madreporite, large, approximately 0.5 cm in diameter, strongly convex, approximately 2.0 mm above body surface ( Fig. 7B ). Periphery around madreporite covered by approximately 25–28 coarse granules and two to four bullet-shaped spines. Surface texture on arms changes abruptly from that of the disk surface. Abactinal spines on arms more elongate (length=2.0 mm) than those on disk (length=1.0 mm), more pointed and conical rather than bullet shaped. Spines sit on round to polygonal plates with bare surfaces, each with coarse-grained, flattened, round to polygonal shaped, peripheral granules, 15–30 (mostly 20–25) around each plate. Interstitial spaces between plates on arm filled by these granules. Arm surface lacking bullet shaped spination. Papulae absent from arm surface. Only one or two small palmate pedicellariae with four teeth per valve observed on surface.

Marginal plates, wide, round directed laterally with no abactinal facing, approximately 40 per interradius, armtip to armtip. Superomarginal plate series in irregular, jumbled arrangement not in regular series, with no interradii showing complete plate series ( Fig. 7D ). Most show abactinal plates encroaching onto and in-between superomarginal plates (see Fig. 13D ) in some cases forming up to three parallel series along the arm lateral surface, forming a “third” faux marginal plate series. These plates all show peripheral areas with coarse, widely spaced, round to irregular granules Superomarginals, inferomarginals and all adjacent abactinal (“faux superomarginal”) plates with a large prominent, pointed cone-shaped spine, one to three, (each about 3.0 mm in length) identical to those on the abactinal arms surface. Pedicellariae, palmate with teeth on valves present on indented pits below spines on inferomarginals.

Actinal surface covered by densely arranged, coarse-grained granules. Prominent pedicellariae (approximately 1.0 mm in length) present in abundance on actinal surface, especially adjacent to oral plates, fewer distally adjacent to inferomarginal plates. Few conical spines similar to those on the abactinal surface present on actinal plate surface.

Furrow spines eight or nine proximally, (six distally) compressed, with blunt tips, round to quadrate in outline. Subambulacral spines one or two with distal spine approximately 4–5x the length of the furrow spines ( Fig. 7F ). Enlarged subambulacral spines round in cross-section with pointed tip (approximately 3.0 mm in length). Proximally on the adambulacral plate is a large pedicellariae, paddle to palm shaped with four interlacing teeth. Oral plates with 15–17 furrow spines, angular in cross-section, quadrate to rectangular tips. Oral spine projecting into mouth, enlarged, one per plate (two per interradius), triangular in cross-section.

Color in life, disk white with orange highlights, arms bright orange ( Fig. 18A–B ).

Material Examined

Holotype. CASIZ 229351 , Juan de Fuca Ridge , 45.04ºN 130.17º W, 2269 m. Coll. D. Clague, MBARI, sample, D80-A5. 2 Sept. 2009. 1 wet spec. R=10.4, r= 3.6 cm .

Figures

FIGURE 7. Evoplosoma anguirus n. sp. CASIZ 229351. Holotype. A. Abactinal. B. Abactinal spination and madreporite. C. Abactinal disk and arm spination. D. Lateral view showing spination on marginal plate surface. E. Actinal. F. Adambulacral closeup showing furrow and subambulacral spines. Scale bar=20.0 mm: A, E; Scale bar=5.0 mm: B, C; Scale bar=3.0 mm: D, F.

FIGURE 13. Bathyceramaster smithi (Fisher 1913) feeding on glass sponges. A–B. Feeding on Waltheria sp. Teutana Seamount, 1317.7 m. C–D. Feeding on Farrea sp. Winslow reef Area, 1374.8 m. No scale.

FIGURE 18. Evoplosoma anguirus n. sp. holotype. A. Holotype observed in situ on prey item (Isididae). B. Other side of specimen showing stomach extended. Distance between lasers = 10.0 cm.