Astrostole platei ( Meissner, 1896 )

Mah, Christopher L., 2021, The East Pacific / South Pacific Boundary: New taxa and occurrences from Rapa Nui (Easter Island), New Caledonia and adjacent regions, Zootaxa 4980 (3), pp. 401-450 : 404-405

Astrostole platei ( Meissner, 1896)

Figure 1A–E

Meissner 1896: 103 [as Asterias (Coscinasterias) platei ].

Meissner 1896: 104 [as Asterias (Polyasterias) fernandensis ].

H.L. Clark 1920: 105 (as Stylasterias paschae ).

Fisher 1928: 130 (as Astrostole platei ).

Synonymy of Astrostole paschae (H.L. Clark, 1920) . Examination of specimens of the holotype of Astrostole paschae (USNM E703) as well as descriptions and specimens of Astrostole platei ( Meissner, 1896) from Rapa Nui and adjacent regions show no morphological differences. Furrow spine, marginal plate, and adambulacral spine numbers appear identical. Presence of straight and crossed pedicellariae as well as morphology were identical. Sizes of pedicellariae on the holotype of A. platei and other specimens differed ( Figs 1B vs. 1D) but these seemed attributable to the size difference between specimens. Arm number among examined specimens varied between seven and nine, ranging from nine in the holotype of Astrostole paschae , eight in the holotype of A. platei , and seven or eight arms among Astrostole platei specimens in the Juan Fernandez and other islands in the Chilean-South Pacific region. Inferomarginal spine number varied between two and three on some individuals to more distinctly three in larger specimens.

These two species of Astrostole , A. paschae and A. platei have never been directly compared. Meissner (1896) described Astrostole platei as Asterias (Coscinasterias) and H.L. Clark originally described Astrostole paschae in the genus Stylasterias . H.L. Clark made no comparisons of S. paschae in his description. The two species were not compared until Fisher (1923) established Astrostole and noted that the two were “not improbably” synonyms. Species within Astrostole display relatively few character differences but are widely occurring throughout the South Pacific, suggesting that an overview of the genus and/or further sampling of populations could present further synonyms.

Occurrence. Juan Fernandez Island, San Ambrosio and San Felix Islands, Rapa Nui (Easter Island), intertidal, 6– 11 m.

Material examined. Holotype: USNM E703 . Rapa Nui, 27ºS 109ºW. Coll. USFC Albatross, 21 Dec. 1904. 1 dry spec. R =8.5, r=0.5.

Juan Fernandez & South Pacific Islands: USNM E47598 . Juan Fernandez Islands , 33°28′48″S, 78°55′12″W, 10 – 13 m. Coll . R / V Anton Bruun , 15 Dec. 1965. 1 dry spec. 8 arms . R =12.0, r=1.0. USNM E47766 . Juan Fernandez Islands , Robinson Crusoe Island, 33º37′11.9994″S, 78º50′49.92″W, 10 m. Coll . R / V Anton Bruun , 12 Dec. 1965. 1 dry spec. 8 arms . R =11.2, r=1.0. USNM 1093844 . Juan Fernandez Islands , Robinson Crusoe Island, 33º38′20″S, 78º48′50″W, 6 – 11 m. Coll . R / V Anton Bruun , 11 Dec. 1965. 1 dry spec. 7 arms . R =2.0, r=0.2. USNM 1087198 . San Ambrosio and San Felix Islands, Mas Afuera Rock, 26º20′S, 80º00′W, intertidal. Coll . R / V Eltanin , 26 Nov. 1965. 1 dry spec . R =9.4, r=1.0. USNM E47767 . Juan Fernandez Islands , 33°34′18.12″S, 78°54′54″W. Coll . R / V Anton Bruun , 13 Dec. 1965. 2 dry specs . R =6.2, r=0.7; R =13.2, r=1.5.

Rapa Nui: USNM E33990 Rapa Nui. Coll. L. Salvo, Feb. 1984, 1 dry spec. 8 arms . R =4.2, r=0.7.

Figures

FIGURE 1. Astrostole platei. Holotype USNM E703 (Rapa Nui): A. Abactinal surface. Scale bar equals 1.5 cm. B. Straight and crossed pedicellariae on abactinal surface. Scale bar equals 2.0 mm. C. Actinal surface. Scale bar equals 1.5 cm. D. Pedicellariae of specimen USNM E47598. Scale bar equals 2.0 mm. E. Holotype furrow spination. Scale bar equals 2.0 mm.