Jassa calcaratus ( Rathke, 1843 )

Conlan, Kathleen E., Desiderato, Andrea & Beermann, Jan, 2021, Jassa (Crustacea: Amphipoda): a new morphological and molecular assessment of the genus, Zootaxa 4939 (1), pp. 1-191 : 160

Jassa calcaratus ( Rathke, 1843)

In documenting the fauna of Norway, Rathke (1843) described and figured a new species which he had collected from seaweed at Kristiansund, Norway. Named Podocerus calcaratus , his illustration of the male’s long-thumbed gnathopod 2 indicates that it is probably Jassa falcata . Rathke (1843) indicated that P. calcaratus was close to, but different from P. pulchellus (now Jassa falcata ) but did not state why. Bate (1862) disagreed and synonymized P. calcaratus under P. pulchellus (now Jassa falcata ). Sars (1894) listed P. calcaratus as a synonym of P. falcatus (now Jassa falcata ), saying that “The P. calcaratus of Rathke is undoubtedly the adult male of this species...” One large male specimen, collected at Tromsø, Norway, and identified as Podocerus calcaratus by Danielsen, (not type), was lent by the Zoological Museum, Bergen, Norway (ZMUB 2832) for this study. The vial held a secondary label, Jassa pulchella . This specimen was clearly a major form male J. falcata . Although the whereabouts of the type specimens are unknown, it is clear from Rathke’s (1843) description, illustrations and collection location that his P. calcaratus is indeed J. falcata ( Montagu, 1808) . Therefore, J. calcaratus is synonymized with J. falcata .