Parvulastra exigua ( Lamarck, 1816 )

Jangoux, Michel, 2021, The asteroid species of Lamarck (Echinodermata: Asteroidea), Zoosystema 43 (13), pp. 213-252 : 228-229

exigua Lamarck, 1816 , Asterias

( Fig. 15 )

Asterias exigua Lamarck, 1816: 554 .

Asterias calcar var. quinqueangula Lamarck, 1816: 557 .

Parvulastra exigua – O’Loughlin & Waters 2004: 225.

CURRENT STATUS. — Parvulastra exigua ( Lamarck, 1816) .

MATERIAL EXAMINED. — South AFrica • MNHN-IE-2014-526; Asterias exigua ; 6 syntypes; Cape of Good, Hope Baudin expedition (1800-1804); Péron and Lesueur leg.

Australia • MNHN-IE-2014-30; Asterias calcar var. quinqueangula ; 4 syntypes; Baudin expedition (1800-1804); King George Sound, Albany, Péron and Lesueur leg. • MHNH; Lesueur drawings collection, ref. 74004; Baudin expedition.

DISTRIBUTION. — From the southernmost part of Africa to the south of Australia and Tasmania.

REMARKS

According to Lamarck (1816) Asterias exigua came from American seas and was the smallest known species of asteroid. As far as size is concerned, he is almost correct. Yet A. exigua does not occur in the Atlantic but in the south of Africa and Australia as well as in Tasmania. Indeed the type specimens of A. exigua were collected in South Africa by Péron and Lesueur in 1804 ( Fig. 15B ). Individuals of a most likely similar species had been obtained early in 1803 by the same collectors in SE Australia (King George Sound, Albany). The latter were identified Asterina calcar var. quinqueangula by Lamarck, who added on a label that they should be considered juvenile individuals (“ specimen junius ”) ( Fig. 15 C-F). Comparing the type specimens of the two Lamarckian species (and to the drawings of Bruguière [1791] to which Lamarck refered, Figure 15A ), it is highly likely they are conspecific.

Due to incorrect information (types of Asterias exigua presumed loss), Dartnall (1971) designated a neotype for the species. The latter originated from False Bay ( South Africa) and is in the Tasmanian Museum, Hobart (ref. TM H508).

Figures

FIG. 15. — Asterias exigua Lamarck,1816: A, drawings of Bruguière (1791); B, type specimens of Asterias exigua. C, type specimens of Asterias calcar var.quinqueangula, D-F, Lesueur’s drawings of Asterias exigua: abactinal (D) and actinal (E) surfaces,and profile view (F) (B, MNHN-IE-2014-526; C, MNHN-IE-2014-30; D-F, MHNH, Lesueur collection 74004, details, courtesy of MHNH).