Bathyceramaster teres Mah, 2022

Bathyceramaster teres Mah, 2022 View in CoL .

Figures 8A–E

Mah 2022:36, Fig. 12A–G

Material Examined. WAM Z100655 About WAM . Ningaloo , Western Australia. 21º 50› 6» S, 112º 55› 35» E, 2535.3 m. Coll. Wilson N, Rouse, G., Kirkendale, L., Ritchie, J. aboard RV Falkor March 2020. 1 wet spec . R = 2.7 r = 1.7

WAM Z 110275. 203 km WNW Koks Island outside of Gascoyne Marine Park , Western Australia, 24º 0' 6.336" S, 111º 19' 45.8796" E, 2014.0 m. Coll. B. Alvarez, K. M. Naughton, K. Moore, C. Untiedt, 16 December 2022 GoogleMaps . CSIRO 10064864 View Materials . 1 wet spec . R = 3.3 r = 1.1.

WAM Z110010 About WAM . Gascoyne , Western Australia 21º 18› 25.8732› S, 112º 17› 25.7136» E, 2010 m. Coll. B. Alvarez, K. M. Naughton, K. Moore, C. Untiedt, 29 November 2022 , CSIRO 10051180 View Materials . 1 wet spec. R =1.5 r=0.6 .

WAM Z 110274. 203 km WNW Koks Island outside of Gascoyne Marine Park , Western Australia 24º0› 6.336» S, 111º19› 45.8796" E, 2014 m. Coll. B. Alvarez, K. M. Naughton, K. Moore, C. Untiedt, 16 December 2022 . CSIRO 10064863 View Materials 2 wet specs. R = 1.8 r = 0.6 R = 2.2 r = 1.0

WAM Z 110276. 203 km WNW Koks Island outside of Gascoyne Marine Park , Western Australia 24º 0' 6.336" S, 111º 19' 45.8796" E, 2014 m. Coll. B. Alvarez, K. M. Naughton, K. Moore, C. Untiedt, 16 December 2022. 3 wet specs GoogleMaps . R = 3.6 r = 1.5, R = 3.3 r = 1.3 R = 3.2 r = 1.2.

NMV F241946 About NMV . Off Fraser Island , Queensland, Australia, 25°19'31.1"S 154°04'04.8"E, 2342–2350 m. Coll. Tim O’Hara et al. IN 2017 GoogleMaps V 03 abyss Marine Invertebrates Team, 6 Nov. 2017. 1 wet spec . R = 3.7 r = 1.5

NMV F307965 About NMV . Cocos (Keeling) Islands, Indian Ocean Territory , Santa Ridge. 13º 33' 42" S to 13º 33' 10" S to 96º 22' 6" E to 96º 22' 56" E, 2418– 2156 m. Coll. O’Hara et al. 25 Oct 2022, 1 wet spec GoogleMaps . R = 3.5 r = 1.2

WAM Z 110102. 147 km WNW of Koks Island, outside Gascoyne Marine Park, 22º 16› 11.6832» S, 112º 57› 46.2672» E, 2073 m. Coll. Alvarez, B., Naughton, K.M., Moore, K., Unteidt, C. CSIRO Gascoyne 10052624, 25 November 2022, 1 wet spec. R = 2.7 r = 1.0.

Diagnosis. Body thick, weakly stellate (R/r = 1.77), interradial arcs straight to weakly curved. Lateral edge is thick and rounded. Abactinal plates tabulate, fasciolar grooves well-developed. Abactinals and marginal plates with coarse granules, abactinal plates each with four to fifty granules, most with 8 to 35 with convex surface. Superomarginal plates covered by continuous granular cover, but in Pacific specimens there are with variably quadrate to irregularly shaped bald spots. Actinal plates with dense covering of coarse granules similar to those on the abactinals. Pedicellariae tong-like, prominent on proximal adambulacral and actinal plates, with two or three valves. Furrow spines, 4 to 7 with 2 to 4 subambulacrals (mostly 3).

Living individuals orange, variably with lavender to purple coloured marginal plates.

Comments. The type specimens for this species were collected from Howland Island and Sibelius Seamount in the North Pacific. New specimens from the South Pacific and the Western Australian region in the Indian Ocean indicate remarkable new occurrence for what is apparently a wide-ranging species. This apparently suggests that this species is similar to goniasterids such as Sibogaster nieseni ( Mah 2016) and porcellanasterids such as Hyphalaster inermis ( Madsen, 1961) which show widespread distributions throughout deep-sea settings.

There are variations. Abactinal plates on the type series are more distinctly convex whereas those here are more weakly so. The superomarginal count in the type specimens ranges from 22 to 24 at R = 3.2 whereas those herein number approximately 30 at similar R. The granules covering proximal superomarginals but absent along distal superomarginals is present in some, e.g. WZ110102, but not all specimens. Furrow and subambulacral spination shows are consistent but with pedicellariae positioned slightly further away adjacent to the subambulacral spines the adjacent to the furrow spines in the type specimens.

Occurrence/Distribution. North Pacific. Howland Island and Sibelius Seamount, North Pacific Ocean. 2175–2439 m . South Pacific. Off Fraser Island , Queensland, Australia, Tasman Sea, 2342–2350 m .

Indian Ocean. Ningaloo, Gascoyne Marine Park, off the coast of Western Australia, Indian Ocean. 2073 m. Western Australia and Cocos (Keeling) Islands region. 2010–2418 m.

Description. Body stellate, R/r = 1.5 to 3.0, disk with surface weakly concave, arms elongate, weakly rectangular with broad tips. Arms, quadrate with rounded edges in cross-section. Disk with straight interradial arcs ( Fig. 8A, D)

Abactinal plates mostly polygonal, abutted, save for those on radial regions, composed of low tabulate plates, covered by abundant granular cover, densely packed over most of abactinal surface ( Fig. 8A, B). Plate surfaces round, shallow fasciolar grooves present. Granules, round to polygonal, forming dense surface, approximately 6 granules along a 1.0 mm line count, covering obscures boundary contact between proximal adjacent plates on disk centre. Granules form distinct, close-set cover interradially on disk and along lateral sides along arms. Most abactinal plates covered by polygonal granules, 10 to 25 variably crowded to widely spaced. Abactinal plates narrow along arms from approximately five series across arm base to 2 or 3 distally Papular and radial areas extend down arm, nearly to arm tip, tips of these plates round to polygonal. Plates on papular and radial areas with angular peripheral granules, trapezoid in shape, distinctly different from peripheral granules on other plates. Weakly hexagonal plate outlines observable on proximal arm regions, these with granules, 10–30, mostly 20 evenly distributed on plate surface. Interradial regions particularly dense. Plates more evident along arms in approximately 6 to 8 series. Madreporite triangular, flanked by three adjacent plates, sulci well-developed. Small forcep-like pedicellariae with wide valves present on a minority of plates, but variably sent on some specimens (e.g. WZ110102).

Marginal plates, variably approximately 11 to 16 per arm side, 22 to 32 per interradius with lateral facing, quadrate, elongate interradially with more square-shaped plates along arm ( Fig. 9A, C). Presence of granulation varies, WZ110102 with proximalmost granular cover, but subsequent marginal plates along disk and arms with a bare, irregular to quadrate region, bare, raised and surrounded by granules. These bare regions become largest distally, forming smooth, bald convex surface adjacent to terminal plate. Superomarginal and inferomarginal plate surfaces covered by granules, 20–60, widely but evenly spaced, with lateral facing ( Fig. 8C). Some marginal plates lacking bare spots. Granule covering is dense and continuous from abactinal and actinal surface and obscures plate boundaries. Abactinal-lateral and actinolateral edges, rounded. No pedicellariae on marginal plates. Terminal plate round to triangular in outline, surface bare.

Actinal surface small, approximately 2 to 4 full series in chevron arrangement with irregular plates present adjacent to inferomarginals, limited to disk, absent from arms ( Fig. 8D, E). Plates quadrate in shape, completely covered by granules, 8–16, mostly 12–14) per plate, variably with round to pointed surface. Granules more widely spaced proximally becoming more closely arranged forming a denser cluster closer to the actinolateral surface. Pedicellariae present, approximately 10 to 20 per interradius, paddle-shaped most with 2 valves, but exceptionally 3-valved pedicellariae present, widely spaced from one another.

Furrow spines 4 to 6, mostly 5 in palmate arrangement, each spine with blunt, round tips, round in cross-section ( Fig. 8E). Subambulacral spines, 3 to 4, mostly 3 set off from furrow spines by distinct space. Second subambulacral series, 2 to 3, mostly 3, these spines approximately half the height of the preceding series with a final series of pointed granules on plate surface adjacent to actinal plate contact. All subambulacral spines and granules widely spaced from one another. A single paddle pedicellariae present adjacent to the furrow but separated by a distinct field, blunt spines present adjacent to pedicellariae. Pedicellariae with elongate forceps like valves on 1 to 4 proximal adambulacral plates adjacent to the oral plates. Oral plate with 9 to 10 furrow spines, one blunt spine enlarged, quadrate in cross-section and directed into the mouth, thus a total of two enlarged spines per interradius directed into the mouth. Oral plate with five paired spine-like granules, terminating with sharp tips present along either side of diastema between oral plates. These spines largest proximally decreasing in size adjacent to the actinal surface. Approximately 3 to 7 other short, angular granules present on oral plate surface.