Pseudasterina Aziz and Jangoux, 1985

O’Loughlin, P. Mark & Waters, Jonathan M., 2004, A molecular and morphological revision of genera of Asterinidae (Echinodermata: Asteroidea), Memoirs of Museum Victoria 61 (1), pp. 1-40 : 31

Pseudasterina Aziz and Jangoux

Pseudasterina Aziz and Jangoux, 1985: 283-284 .—A.M. Clark, 1993: 227.

Diagnosis. Small thin body; rays 5, discrete, broad base, rounded or pointed distally, medium-rayed stellate; abactinal upper ray plates variably regular in form and arrangement; interradial plates small, long imbricating oblique series; papulae along upper rays only, sparse, single; short columnar granuliform abactinal spinelets; superomarginal series of large plates with granuliform spinelets; inferomarginal plates project narrowly, with glassy subsacciform spinelets; actinal plates in oblique series; actinal interradial plates with numerous glassy subsacciform spines principally on proximal edge, few distally; lacking superambulacral and superactinal plates; very thin interradii, with abactinal and actinal imbricate plates angled and meeting internally throughout the interradii.

Type species. Pseudasterina delicata Aziz and Jangoux, 1985 (original designation).

Other species. P. granulosa Aziz and Jangoux, 1985 .

Material examined. P. delicata . Tonga, 149–157 m, MNHN EcAs11704 (2) ; Wallis and Futuna Is , 250 m, MNHN EcAs11706 (1) .

Description with species variations. Rays 5, discrete, broad base, distally rounded ( delicata ) or pointed ( granulosa ), medium-rayed stellate; body flat, thin; size small ( granulosa up to R = 18 mm); lacking pedicellariae; neither fissiparous.

Abactinal appearance dominated by imbricating small interradial plates in oblique series from upper rays to margin; papulate areas confined to narrow upper rays; papular spaces small, papulae single, rare secondary plates; abactinal plates on narrow upper rays variably regular in form and arrangement, some notched, some indented for papulae, proximal doubly or singly papulate carinal series sometimes present; disc distinctly bordered; abactinal plates with short columnar stout granuliform spinelets, weakly attached, spaced not clustered, up to 10 on proximal edge or covering plate, closer and slightly larger over some papulae; glassy reticulations on plates, not convexities; superomarginal plates larger than adjacent abactinals, regular series, longitudinally subrectangular, covered with granuliform spinelets; margin formed by narrowly projecting inferomarginal plates, each with numerous conical to subsacciform to splay-pointed sacciform spinelets.

Actinal interradial plates in distinct imbricating oblique series.

Actinal spines per plate: oral up to about 10, webbed; suboral up to about 15, short, glassy conical; furrow up to about 10 on furrow edge, webbed, up to about 10 on surface of plate; subambulacral, adradial actinal, and actinal interradial about 10, predominantly on proximal edge of plates; actinal spines glassy, short, pointed, sacciform.

Lacking superambulacral and superactinal plates; thin interradii with abactinal and actinal plates imbricating and angled interiorly to meet throughout the interradii; no tongue-like inner projections from abactinal or actinal plates.

Distribution. Philippines, Wallis, Futuna and Tonga Is, 130– 250 m.

Remarks. No molecular data are available and this review is based on morphology. Until recently the two species were known only from the type material from the Philippine Is ( Pseudasterina delicata holotype, MNHN EcAs10065; paratype, MNHN EcAs10066. P. granulosa holotype, MNHN EcAs10067). None of the type material could be located. Recently A.J. Dartnall determined material in the MNHN collections as P. delicata . These specimens have been examined in this study. The distinctive characters of Pseudasterina are: abactinal long imbricating oblique series of small plates from narrow upper radii to margin, and similar series from furrow to margin actinally; very thin interradii, with abactinal and actinal imbricate plates angled and meeting internally throughout the interradii; short columnar, granuliform, readily-detached spinelets on abactinal and superomarginal plates, but glassy, subsacciform, sometimes splay-pointed, spinelets on the inferomarginal plates. The spination characters given by Aziz and Jangoux (1985) for distinguishing P. delicata and P. granulosa appeared to be all variably present on the P. delicata specimens observed here, suggesting that P. granulosa may be a junior synonym. Aziz and Jangoux (1985) distinguished Pseudasterina from all other asterinid genera by the distinctive series of large superomarginal plates. This diagnostic character is a feature of Cryptasterina also, from which Pseudasterina differs in abactinal and actinal plate arrangement and spination, and in the absence of superambulacral and superactinal plates.