Bathyceramaster wami, Mah, 2025

Bathyceramaster wami View in CoL n. sp.

Figures 9A–E

Material Examined. Holotype. WAM Z110181 About WAM . Gascoyne Marine Reserve 23º 9' 21.2688" S, 112º 48' 21.654" E, 992.0 m. Coll. B. Alvarez, K.M. Naughton, K. Moore, C. Untiedt, 9 December 2022, CSIRO 10056099 View Materials , 1 View Materials wet spec. R = 6.2 r = 2.3 GoogleMaps

Etymology. This species is named for the Western Australian Museum.

Diagnosis. Abactinal, marginal granules large, coarse, 3 counted along a 1.0 mm line. Marginal plates 16 per arm side, 32 total from arm tip to arm tip. Granular cover continuous over abactinal, marginal, actinal surfaces. Abactinal granules along the plate surface of tabulae, tightly articulated, with granules in some areas forming an almost solid surface. Furrow spines 3–5, blunt, subambulacral spines 2 to 3, in two series, each twice the thickness of the furrow spines.

Comments. A species distinguished by the large, course granules forming a relatively abundant and continuous covering on the abactinal, marginal and actinal surfaces, as well as the distinct marginal plates forming a rolled edge. The dense abactinal covering is similar to that of the North Pacific Bathyceramaster elegans , which differs from Bathyceramaster wami n. sp. in having many more furrow spines, 9 to 15, much finer and smaller granules, and a much more stellate shape (R/ r=3.7 to 4.9).

Occurrence/Distribution. Gascoyne Marine Reserve , Western Australia, Indian Ocean. 992.0 m .

Description. Body stout, stellate in shape (R/r = 2.69), arms triangular in outline, thick, broadly trapezoidal in cross-section ( Fig. 9A, D). Arm tips upturned.

Abactinal surface arched. Surface composed of closely articulated, short tabulate plates. Tabular surfaces quadrate, hexagonal to irregularly polygonal. Surface covered by coarse, polygonal-shaped granules, 4 to 12, approximately 3 present along a 1.0 mm count, ranging from a flush flat surface to a convex plate surface, each displaying a very homogeneous appearance ( Fig. 9A–B). Granules along the plate surface of these tabulae, tightly articulated, with granules in some areas forming an almost solid surface. These are more prevalent centrally on the disk with more weakly articulated tabulae distally, especially interradially adjacent to the contact with the superomarginal plates. Papulae not observed. Madreporite strongly convex with polygonal granules forming a ring around the base of the plate. Pedicellariae, small, near granule-size, paddle-shaped, embedded among plates near contact with superomarginal series.

Marginal plates 16 per arm side, 32 total per interradius (arm tip to arm tip) ( Fig. 9A, C). Individual plates quadrate, especially interradially becoming slightly wider distally. Overall marginal plate series round in appearance, “rolled” with lateral edges from abactinal and actinal plate series rounded where they form angular contact with the marginal plates. Superomarginal and inferomarginal plates articulated more 1:1 interradially becoming more offset and forming zigzag contact which is more prominent distally along arm. Superomarginal and inferomarginal plate surfaces covered by coarse granules, approximately 40–150, each polygonal in shape, closely but evenly spaced, forming a continuous layer with granules from the abactinal surface. Granules coarse, approximately 3 along a 1.0 mm line, covering all plate surfaces along the arm. A discrete series, slightly larger than those centrally, present around each plate surface periphery, approximately 10 to 40 per side. Inferomarginal plates wide, larger than superomarginal plates with 40–200 granules covering surface, identical in overall size, shape to those covering superomarginal plate surface. Terminal plate triangular with smooth surface, no spines. Pedicellariae absent from marginal plate surface.

Actinal surface large with three to four full series in chevron formation with a single actinal series extending onto the arm and an irregular number array of these distally adjacent to contact with inferomarginal plates ( Fig. 9D). Each plate quadrate in shape, covered by coarse, round granules, widely spaced. Surficial granules 25–50, granular cover identical to those on abactinal and marginal plates, obscuring plate boundaries.

Furrow spines, 3 to 5, mostly 3 or 4, blunt-tipped, quadrate in cross-section, palmate to straight in formation, widely spaced ( Fig. 9E). Two rows of subambulacral spines set off from furrow spines by distinct diastema, first row composed of mostly 2, exceptionally 3, spines, approximately twice the thickness of the furrow spines, forming a nearly straight line along the adambulacral series. The second subambulacral series composed of approximately 2 to 3 spines, shorter spines similar in size, height to granules on actinal plate surface, triangular to quadrate in cross-section. All widely spaced.

Oral plates with furrow spines, 8, quadrate in cross-section with a ninth spine directed into mouth ( Fig. 9D, E). Five blunt, thick spines, each triangular in cross-section present along either side of the diastema between oral plates. Additional oral plate spines, 5 to 9 on plate surface, similar in appearance to oral furrow spines. First adambulacral plate with distinct forceps like pedicellariae.