NOTES AND NEWS ON A TERATOLOGICAL SPECIMEN OF ATHANAS NITESCENS (DECAPODA, CARIDEA, ALPHEIDAE) BY CHRISTOPHER W. ASHELBY 1,3 ) and NICOLAS LAVESQUE 2 ) 1 ) Thomson Unicomarine Ltd., 7a Diamond Centre, Works Road, Letchworth, Hertfordshire, SG6 1LW, United Kingdom 2 ) UMR 5805 EPOC, CNRS, Université Bordeaux 1, Station Marine d’Arcachon, 2 rue du Professeur Jolyet, F-33120 Arcachon, France Alpheid shrimps typically have small rostra compared to many other carideans and, when present, it is usually unarmed dorsally. Within the family, it is most developed in almost all Athanas and Arete, most Salmoneus, and some Pota- malpheops and Synalpheus (cf. Anker et al., 2006). Whilst the rostrum shape and length are usually stable within a species, Nomura & Anker (2001) noted consider- able intraspecific variation of this feature in Parabetaeus culliereti Coutière, 1896 and Anker & Ahyong (2007) commented on the variability of the length and shape of the rostrum in the genus Athanas noted in the literature. During routine sampling of seagrass (Zostera (Zostera) marina L.) beds in Arcachon Bay, Atlantic coast of France (44 ◦ 39 ′ 24 ′′ N 01 ◦ 14 ′ 12 ′′ W), on 7 July 2010, two small specimens of Athanas nitescens (Leach, 1813) were captured amongst a total catch of around 50 carideans. One of these specimens was unusual in that it possessed a bifurcated rostrum (fig. 1). The usual situation in A. nitescens is that the rostrum is straight, perpendicular to the carapace, and reaches a little beyond the distal margin of the basal segment of the antennular peduncle. In the present specimen, the longer of the two blades is of approximately normal length but trends to the right at an angle of about 110 ◦ . The second blade is shorter, being only about two-thirds the length of the longer one and reaching about mid-length of the basal segment of the antennal peduncle. This shorter blade trends to the left at an angle of about 65 ◦ . The two blades are in approximately the same horizontal plane and the bifurcation is at an angle of approximately 55 ◦ . The base of the rostrum appears wider than in typical specimens. The specimen is preserved in the collection of the Oxford University Museum of Natural History under the registration number OUMNH.ZC 2010-002-0014. 3 ) e-mail: chrisashelby@unicomarine.com © Koninklijke Brill NV, Leiden, 2011 Crustaceana 84 (12-13): 1649-1652 Also available online: www.brill.nl/cr DOI:10.1163/156854011X605710