Alloceramaster pointsurae ( Mah 2016 )

Alloceramaster pointsurae ( Mah 2016) View in CoL nov. gen, nov. comb.

Figures 6A–E

Mah 2016: 114, Fig. 4A–D

Material Examined. Holotype. USNM 1407942 About USNM . President Jackson Seamount B, North Pacific , 42° 49' 59.304" N, 128° 9' 40.3914" W, 1975.7 m. Coll. D. Clague,1 wet spec. R = 1.8, r = 1.0. GoogleMaps

Paratypes. USNM 1407943 About USNM . President Jackson Seamount C, North Pacific , 42° 44' 24.0966" N 128° 5' 53.736" W, 1742.1 m. Coll. D. Clague GoogleMaps , MBARI, D82 – A3 . 1 wet spec . R = 1.0, r = 0.6; USNM 1407944 About USNM . President Jackson Seamount C, North Pacific , 42° 44' 23.9604" N, 128° 5' 49.776" W, 1730.1 m. Coll. D. Clague GoogleMaps , MBARI, D82 – A6 , 1 wet spec . R = 1.2, r = 0.6.

Diagnosis (Based on Mah, 2016). Body shape is stellate (R/r = 1.6–2.0 at R = 1.8). Interradial arcs curved. Abactinal plates Abactinal plates round to polygonal in outline, covered by 7–30 (mostly 10–25) granules. Six to 20 rectangular-oblong granules form discrete periphery surrounding one to eight round central granules on radial plates. Superomarginal and inferomarginal plates, 10–16 per interradius (arm tip to arm tip) with distinct, quadrate-shaped smooth, bald surfaces. Marginal plates wide, forming distinct periphery around body, approximately 22% of “r” (5.0 /23.0 mm), distalmost one or two pairs of superomarginal plates abutted at arm tip. Actinal plates covered by fine granules with angular tips, which obscure boundaries between plates. Furrow spines, 3–4, mostly 4 arranged in a straight to palmate pattern. Subambulacral spines in two rows, each with two thick but pointed subambulacral spines, approximately twice as thick as a single furrow spine, set off from furrow spines by discrete space. A second row of subambulacral spines sits adjacent to the first series, less than half the height but closely resembles angular granules on actinal surface.

Comments. This species displays the angular, elongate granules as well as well-developed fasciolar grooves around proximal papular pores which are shared by species within Alloceramaster . This species invites comparison with A. affinis , but differs in having much finer and more abundant actinal spines and much coarser and less angular peripheral granules around the proximal papular regions ( Fig. 6B, D). The superomarginal plates also form a much broader periphery (20% of “r”) than the one in A. affinis , which forms a much narrower marginal border (only 11% of “r”).

Occurrence/Distribution. President Jackson Seamount B and C. North Pacific. 1975– 1742 m.