Nymphaster moebi ( Studer, 1884 )

Nymphaster moebi ( Studer, 1884) .

Figures 14A–D, 15A–D

Pentagonaster (Dorigona) Studer 1884: 30 , 35 Nymphaster moebi Sladen, 1889: 869 ; Döderlein, 1924: 55;

Macan, 1938: 375; H.L. Clark, 1946: 87; A.M. Clark, 1993: 266

(checklist); Rowe and Gates, 1995: 67; A.M. Clark, 1993: 266 Nymphaster protentus Alcock, 1893: 95 Nymphaster basilicus Alcock, 1893: 95 Dorigona ternalis Koehler, 1909: 54 , pl. viii, figs 5, 6 Dorigona ludwigi Koehler, 1909: 61 , pl. ix, figs 5, 6 Dorigona belli Koehler, 1909: 58 , pl. viii, figs. 2,3,4; James 1983:

89 (checklist) Nymphaster pentagonus Clark, H.L., 1916: 36 .

Material Examined. WAM Z105015 About WAM . Off Perth , Western Australia, 31º 54' 24" S, 115º 6' 56" E, 534.3 m. Coll. A.M. Hosie, A. Hara, 22 Feb 2020.1 wet spec GoogleMaps . R=8.2 r=2.2.

WAM Z110064 About WAM . Gascoyne Marine Reserve 21º 45' 43.7976" S, 113º 40' 18.1452" E, 1104.0 m. Coll. B. Alvarez, K.M. Naughton, K. Moore, C. Untied GoogleMaps , CSIRO 10051905 View Materials , 5 December 2022 . 2 wet specs. R = 7.6 r = 1.8 R = 9.2 r = 1.8.

WAM Z110082 About WAM . Gascoyne Marine Reserve 22º 22' 05.9988" S, 113º 32' 04.92" E, 1075.0 m. Coll. B. Alvarez, K.M. Naughton, K. Moore, C. Untied GoogleMaps , CSIRO, 24 November 2022 . 2 wet specs. R = 6.7 r = 1.6, R = 8.2 r = 2.3.

Diagnosis (Based on Macan, 1938 and Mah, 2018). Abactinal plates covered by coarse granules, fourteen to eighteen on carinal plates. Eight to ten superomarginals form edge around disk, approximately 12 or more Furrow spines seven, then eleven distally, compressed in palmate arrangement. Mouth plates with ten or eleven furrow spines.

Comments. This species was recently reviewed by Mah (2018) as part of a survey of west Indian Ocean Goniasteridae . Rowe and Gates (1995) previously recorded this species from Australia, including New South Wales, Victoria, South Australia, and Western Australia. Specimens reported herein are new occurrences for the region. This appears to be the only known species of Nymphaster from Australian waters.

As touched upon by Mah (2018) distinctions between this species and the Atlantic N. arenatus are poorly defined and given the propensity for deep-sea goniasterids to be distributed widely (e.g. S. nieseni ) there lies the possibility for at least one wide-ranging species.

Occurrence/Distribution. Australian. Off northwest coast of Australia, New South Wales, Victoria, South Australia, Western Australia, 534–1104 m .

Indian Ocean. Madagascar, Mozambique Channel, Mascarene Islands, Off coast of Tanzania ( Zanzibar Island region). 195 – 1655 m.

Description. Body stout, strongly stellate (R/r = 3.0–4.4), arms elongate, sharply triangular in shape, acutely tapering. Interradial arcs curved to straight ( Figs. 14A, B; 15A, B).

Abactinal plates weakly tabulate, surface outline polygonal to round, radial and adradial plates hexagonal or nearly so ( Figs 15A, B). Fasciolar grooves present around radial regions, absent interradially. Abactinal plate surface covered by coarse, round granules, 4 to 20 total, fundamentally homogeneous, but forming a single-series peripheral, widely spaced from one another, approximately, 5 to 25 with a variable number and arrangement of central granules, numbering 3 to 20. Pedicellariae not observed on abactinal surface. Papulae primarily centred around radial regions, but absent interradially. Madreporite polygonal to round, variably quadrate to hexagonal, weakly convex with well-developed sulci, flanked by four to six abactinal plates.

Superomarginal plates, abutted over midline for the nearly complete arm distance ( Fig 15A, B). Arm tips on nearly all specimens broken, but pointed when present. Superomarginals per interradius, (25/60) approximately 40% of superomarginals in contact. Superomarginals elongate, with variably angular to rounded lateral edges ( Fig. 14A, B, 15A, B). Superomarginal and inferomarginal plates form discrete border around abactinal surface with plates forming variably wide periphery. Superomarginal and inferomarginal surface, covered by 200– 500 polygonal, coarsely grained granules, evenly, and widely distributed over plate surface. Peripheral granules number about 12–15 along short edge, 20–30 along elongate edge. Actinolateral edge along inferomarginal series variably round to angular. No pedicellariae observed.

Actinal intermediate region large, approximately four full series in chevron formation with a small number of irregular plates present adjacent to inferomarginal contact. Individual plates variably quadrate to polygonal in shape. Surface covered by homogenous sized and shaped granules, 10–20, round, evenly spaced ( Fig. 14C, D; 15C, D)

Furrow spines 8 to 9 in distinct angular arrangement (R=8.2). A discrete space separates the furrow spines from the subambulacral series behind it ( Fig. 15C, D). Subambulacral spines in 2 to 3 irregular series, each number four to six, but mostly five, spines more granular approaching actinal granules in size, shape. Oral plate with approximately 10–12 furrow spines similar to identical with furrow spines on other plates. Single spine, triangular in cross-section present on each oral plate, two total for each interradius. Oral plate surface with approximately six to eight blunt spines present along the edge of each sulcus directed along the middle of the oral plate.