Mocallichirus, 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 : 113

Mocallichirus gen. nov.

http://zoobank.org/urn:lsid:zoobank.org:act:8E845452-37C7-

4271-B787-E28D6285AE8F

Type species. Callianassa mocambiquensis Sakai, 2004 , by present designation and monotypy.

Diagnosis. Anterior branchiostegal lobe sclerotised, well produced anteriorly beyond junction with oblique branchiostegal ridge with which it articulates by means of a virtual condyle. Rostrum obsolete or obtusely triangular, flat, not reaching cornea. Pleomere 1 tergite undivided or with weak transverse step. Maxilliped 3 ischium and merus narrow, more than twice as long as wide at their articulation; crista dentata a row of numerous denticles; propodus free distal margin clearly oblique. Male major cheliped merus with denticulate blade, more prominent over proximal half of lower margin. Male minor cheliped half or more as wide as major, carpus as long as or shorter than palm, fingers as long as or longer than palm. Pereopod 3 propodus subpentagonal, with strong broadly rounded proximal lobe on lower margin, lower margin straight-concave. Pereopod 4 propodus simple, distally rounded on lower margin. Male pleopod 1 consisting only of 1 article. Male pleopod 2 uniramous; appendix interna absent or reduced to obsolete distomesial lobe. Pleopods 3–5 appendices internae barely emerging from endopod margin. Uropodal endopod with convex anterior margin, acute-rounded apex, straight-slightly curved posterior margin, longer than wide. Telson parallel-sided over most of length, with broadly rounded apex, domed, posterior margin broadly semicircular.

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

Remarks. Robles et al.’s (in press) molecular analysis placed Callianassa mocambiquensis sister to Michaelcallianassa (two species) in Callichiridae . Sakai (2004) thought the species similar to Callianassa plantei Sakai, 2004 (also found in Mozambique), C. joculatrix and three others, all members of Callianassidae s.s. GCBP was able to examine numerous specimens from Madagascar from the collections of MNHN and FMNH. The broad female pleopod 2, the attenuated distal lobe on the epipod of maxilliped 1 and the apical notch on the male pleopod 1 confirm the species as a callichirid. The species is recognisable by the unusual shape of the telson; it is domed, longer than in most callichirids with a broadly semicircular posterior half parallel-sided over most of length, with broadly rounded apex. The antennal peduncle is longer than the antennular peduncle, the male pleopod 1 is of one article and the male pleopod 2 uniramous.

Mocallichirus mocambiquensis shares with members of the callianassid genus Coriollianassa a proximal neck on the carpus of the chelipeds, a case of remarkable convergence.