Arenallianassa, Poore & Dworschak & Robles & Mantelatto & Felder, 2019

Poore, Gary C. B., Dworschak, Peter C., Robles, Rafael, Mantelatto, Fernando L. & Felder, Darryl L., 2019, A new classification of Callianassidae and related families (Crustacea: Decapoda: Axiidea) derived from a molecular phylogeny with morphological support, Memoirs of Museum Victoria (Mem. Mus. Vic.) 78, pp. 73-146 : 91

Arenallianassa gen. nov.

http://zoobank.org/urn:lsid:zoobank.org:act:7A9C78DE-06CA-

4407-BA4A-0A2BA6258BDE

Type species. Callianassa arenosa Poore, 1975 , by present designation.

Diagnosis. Rostrum obsolete or obtusely triangular, flat, not reaching cornea. Pleomere 1 tergite undivided or with weak transverse ridge. Maxilliped 3 merus wider at ischium-merus suture than long. Male major cheliped merus with prominent truncate hook armed with serrations along lower margin, excavate laterally at base; carpus and propodus flattened, upper and lower margins carinate, blade-like, submarginal mesial face especially of carpus deeply concave; propodus distal margin with deep notch at base of fixed finger. Pereopod 3 propodus rectangular, lower margin deeply convex, leading to broadly rounded free proximal lobe. Male pleopod 2 absent. Uropodal endopod ovoid, usually longer than wide, anterior margin straight or slightly convex, posterodistal margin evenly convex, with facial distal transverse row of short spiniform setae (reduced). Uropodal exopod distal margin clearly differentiated from anterior margin, anterodistal corner right-angled. Telson lateral margins convex.

Etymology. An alliteration of the name of the type species and Callianassa , type genus of the family.

Remarks. Only the type species is known, a common shallow subtidal species in south-eastern Australia. Arenallianassa arenosa resembles Paratrypaea but lacks the dense setation on the major cheliped of the latter genus and has a prominent truncate meral hook on the major cheliped, whereas Paratrypaea has a dentate blade, widest proximally instead. The chelipeds resemble those of species of Neotrypaea , a genus defined by a prominent distal lobe on the merus of maxilliped 3, but this is not especially more developed in some species than in A. arenosa . The telson is widest at its midpoint, whereas species of Paratrypaea and Neotrypaea have a tapering telson. Arenallianassa differs from Trypaea in lacking an extremely long and setose antennule, and differs from Filhollianassa in the anterior carapace being flat in profile and the uropodal endopod being ovoid rather than asymmetrical.