Chaetopleura pustulata ( Krauss, 1848 )

Schwabe, Enrico, 2006, Taxonomic notes on chitons. On some species of Chaetopleura from South Africa (Mollusca: Polyplacophora: Ischnochitonidae), African Invertebrates 47, pp. 23-30 : 25-27

Chaetopleura pustulata ( Krauss, 1848)

Fig. 2

This beautiful species ( Figs 2A–D ), ‘Eine sehr niedliche und ausgezeichnete Art.’ to quote the original description, was described and illustrated in convincing detail by Krauss (1848: 42, pl. 3, fig. 7). The species’ type locality is Natal, South Africa, where it was collected by J.A. Wahlberg, who sent the material to Krauss .

Ashby (1931: 24) proposed ‘to recognise Reeve’s C. [ Chiton – E. Schwabe] pertusus in Chiton pustulatus Krauss , for Reeve’s description, figure, and locality can well be applied to that species..’ and thus he synonymised the two taxa. Unfortunately, this decision was accepted (or just repeated) by subsequent authors (e.g. Barnard 1963; Kaas & Van Belle 1987, 1998; Slieker 2000) and Chiton pustulatus has fallen into oblivion.

While revising the world-wide species of Chaetopleura, Kaas and Van Belle (1990) correctely recognised that there are differences between characteristic specimens of Chaetopleura pertusa and specimens from KwaZulu-Natal, leading them to describe a new species Chaetopleura natalensis , from 13.5 km south of Tongaat, KwaZulu-Natal. As usual their description is very detailed and leaves no doubt that the separation of the two species is justified. What they overlooked is that there was already an identical species with ‘Natal’ as its type locality.

The present author examined the primary types of both taxa. Chaetopleura pustulata is available from a single specimen, wet and preserved flat, partly disarticulated with three valves still in situ ( Fig. 2A ) in the SMNH (# 4983). The specimen measures 13.3 x 9 mm (‘6.5 x 4 lin.’ in the original description = 13.7 x 8.5 mm). With the sample are four isolated valves, two intermediate and one tail valve ( Figs 2B–D ). The fourth valve is attributed by the present author to Ischnochiton bergoti (Vélain, 1877) , meaning that the head valve and one intermediate valve are missing. From Krauss’ description it remains unclear how many specimens he had available, therefore I regard the single available specimen as a syntype. It is also indicated as such on the label.

The holotype of Chaetopleura natalensis Kaas & Van Belle, 1990 , deposited in NM (D4842), is completely disarticulated. Soft parts are missing except for the dried perinotum.All valves except for the tail valve ( Fig. 2E ) are broken longitudinally. Despite the bad condition of the specimen it is obvious from the shell sculpture that this species does not differ in any way from the syntype of Chiton pustulatus , and thus I consider them to be conspecific, Chaetopleura natalensis being a junior synonym of Chiton pustulatus .

Figures

Fig. 2. Chaetopleura pustulata (Krauss, 1848): (A–D) partly disarticulated syntype of Chiton pustulatus Krauss, 1848 (SMNH # 4983): (A) dorsal view of the syntype, showing valves ii, iii and vii in situ, anterior at right, (B) dorsal view of valve iv, anterior at top, (C) dorsal view of the tail valve, anterior at top, (D) ventral view of the tail valve, anterior at top; (E–F) isolated valves of the holotype of Chaetopleura natalensis Kaas & Van Belle, 1990 (NM D4842): (E) dorsal view of the tail valve, anterior at top, (F) dorsal view of the right half of valve iv, anterior at top. Scale bars A = 2 mm, B–F = 1 mm.