THE IDENTITY OF EURYPLAX BEVISI STEBBING, 1921 (, BRACHYURA)

BY

PETER K.L. NG1,3) and PAUL F. CLARK2,4) 1) Tropical Marine Science Institute and Department of Biological Sciences, National University of Singapore, Lower Kent Ridge Road, Singapore 119260, Republic of Singapore 2) Department of Zoology, The Natural History Museum, Cromwell Road, London SW7 5BD, England

ABSTRACT

The identity of the problematic euryplacid , Euryplax bevisi Stebbing, 1921, is resolved. The species is rediagnosed, figured and transferred to the portunid genus Thalamita. Thalamita bevisi, comb. nov., is now regarded as the senior synonym of the widely distributed T. dakini Montgomery, 1931. In addition, Lipkeplax Števciˇ c,´ 2005, a nomen nudum established for E. bevisi, is considered to be a junior synonym of Thalamita Latreille, 1829.

RÉSUMÉ

L’identité du crabe Euryplacidae problématique, Euryplax bevisi Stebbing, 1921, est résolue. L’espèce est redécrite, illustrée et transférée dans le genre Thalamita (Portunidae). Thalamita bevisi, comb. nov., est maintenant considérée comme un synonyme plus ancien de l’espèce à large distribution, T. dakini Montgomery, 1931. En outre, Lipkeplax Števciˇ c,´ 2005, un nomen nudum établi pour E. bevisi, est considéré comme un synonyme plus récent de Thalamita Latreille, 1829.

INTRODUCTION

Euryplax bevisi was briefly described by Stebbing (1921) from a South African specimen. He noted that it differed from the two known species (E. nitida Stimpson, 1859, and E. polita Smith, 1870) in having four rather

3) Corresponding author; email: [email protected] 4) e-mail: [email protected]

© Koninklijke Brill NV, Leiden, 2010 Studies on : 573-584 574 CRM 014 – Fransen et al. (eds.), LIPKE BIJDELEY HOLTHUIS MEMORIAL VOLUME than three anterolateral teeth, the dorsal carapace covered with setae and granules (versus smooth), and the chelae possessing numerous strong granules, spines and teeth (versus smooth). Several authors have commented that his description and figure did not agree with Euryplax, a genus currently placed in the Euryplacidae Stimpson, 1871 (, see Ng et al., 2008). Barnard (1950) was the first to comment that the species “reminds one very much of a Thalamita” and Guinot (1969), in her reappraisal of the Goneplacoidea, considered that this species was more likely to be a portunid. However, Števciˇ c´ (2005: 134) considered E. bevisi to be so unusual that it could not be accommodated in any known family, and in his section on incertae sedis taxa, established a new genus, Lipkeplax, to accommodate it. Ng et al. (2008: 78) noted that Lipkeplax is a nomen nudum, also doubted the establishment of a new genus for E. bevisi and, as a consequence, retained Stebbing’s (1921) species tentatively under Euryplax (see also Castro & Ng, 2010). The carapace figure of Stebbing (1921, pl. 2) is reproduced for the present study (fig. 1). Although the lateral spines are portunid-like, the carapace proportions are unusual and suggest that the carapace is squarer (Stebbing’s

Fig. 1. Plate II of Stebbing (1921), modified to show only the carapace of Euryplax bevisi Stebbing, 1921.