Asterina gracilispina H.L. Clark, 1923

O'Loughlin, P. Mark, 2009, New asterinid species from Africa and Australia (Echinodermata: Asteroidea: Asterinidae), Memoirs of Museum Victoria 66 (2), pp. 203-213 : 204-207

Asterina gracilispina H.L. Clark, 1923

Figure 2a–d

Asterina gracilispina H.L. Clark, 1923: 286–287 , pl. 16 figs. 3–4.—A.M. Clark, 1974: 437 (part).—A.M. Clark and Courtman-Stock, 1976: 77 (part).

Material examined. Holotype (dry): South Africa, East London , SW of Cove Rock, 40 m, S.A.M. A6421.

Description. Small, subpentagonal, R = 6 mm, r = 4 mm; rays 5, discrete, wide at base, short, rounded distally; low convex abactinally, flat actinally, sides not steep, margin acute; body integument not evident; single inconspicuous madreporite; not fissiparous; gonopores not seen; glassy convexities on plates; presence or absence of superambulacral and superactinal plates unknown (small type specimen not dissected); glassy convexities on plates.

Abactinal: disc not distinctly bordered; plates imbricate, projecting proximal edge frequently tabular, plates not notched, slight proximal indentation for papula sometimes present, papulae emerge from under projecting proximal raised edge of plates; doubly papulate carinal series of plates along most of upper ray, rare secondary plates; papulae large, single per papular space, rarely 2; 8 longitudinal series of papulae across mid ray; small subsacciform to conical, pointed glassy spinelets, up to about 0.15 mm long, spread over plates, up to 20 per plate.

Margin: superomarginal plates longitudinally elongate, in regular series, up to about 14 spinelets spread over each plate, subequal with abactinal and inferomarginal spinelets, projecting inferomarginal plates with up to about 20 spinelets.

Actinal: interradial plates in longitudinal series, not predominantly oblique; complete series of adradial actinal plates and spines. Actinal spines per plate: oral 5 (2 long proximal; gap to 3 short distally, increasing in length to distalmost longest of 3); suboral 2 (webbed, long); furrow 4–3; subambulacral 4–3; adradial actinal 3–5; actinal interradial up to 7 mid ray, webbed transverse series, frequently 5–6; spines subsacciform to conical.

Distribution. South Africa, East London, 40 m.

Remarks. For O’Loughlin and Waters (2004) I used a specimen from Cape Agulhas, registered to the Natural History Museum in London as Asterina gracilispina ( NHM 1975.10.29.47), as evidence for remarks on A. gracilispina . The subsequent availability of the holotype of A. gracilispina for examination in this work has made it possible for me to recognize that the Cape Agulhas specimen is not conspecific. The Cape Agulhas specimen is similar in form, but is distinguished ( R = 12 mm) by: disc distinctly bordered; conspicuous madreporite; short, blunt, digitiform to subgranular abactinal spinelets; 9 oral spines in series tapering evenly from long to very short, spines slightly swollen distally; up to 3 actinal spines mid ray. This specimen is described below as a new species.

Mortensen (1933) referred “with considerable doubt” a specimen ( R = 10 mm) in the South Africa Museum from False Bay (26 m) to A. gracilispina . His grounds for doubt were: dorsal spinelets blunt; distinct madreporite; 2–3 stout actinal interradial spines. These characters are consistent with those of the Cape Agulhas specimen, described below as a new species of Asterina .

A.M. Clark (1974) reported on six specimens from South Africa determined as A. gracilispina , but her notes indicate to me that there were two species. Most of the specimens were in poor condition, but details of spine number for the Mossel Bay specimen ( R = 6 mm) are compatible with the holotype of A. gracilispina . Notes that the Algoa Bay specimen ( R = 10 mm) had 3–5 actinal spines per plate and an inconspicuous madreporite indicate that it is also probably A. gracilispina . But notes of 9 oral spines and only 2–3 actinal spines for the Cape Agulhas specimen ( R = 12 mm; registered to the NHM) confirm the observations discussed above that it is not conspecific with A. gracilispina and it is the type for the new species referred to above and described below.

H.L. Clark (1923) was uncertain about generic assignment for this species, and chose Asterina . Currently there is inadequate data to confirm or reassign. However, the atypical arrangement and form of the oral spines is similar to that in Parvulastra O’Loughlin, 2004 . If superambulacral and superactinal plates are present, then the species would be more appropriately assigned to Parvulastra .

Figures

Figure 2. Asterina gracilispina H.L. Clark, 1923 (photos by C. Rowley). Holotype, S.A.M. A22559 (R = 6 mm). a, abactinal surface, insert showing spinelets. b, carinal series of doubly papulate plates and spinelets. c, actinal surface with actinal plates in longitudinal series. d, oral, suboral, furrow, subambualcral and proximal actinal spines.