Cheramus Bate, 1888

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 : 93

Cheramus Bate, 1888

Cheramus Bate, 1888: 30 .— Manning and Felder, 1991: 91.— Poore, 1994: 101.— Davie, 2002: 459.— Sakai, 2011: 363–366 (partim).— Komai et al., 2014b: 504–505 (partim).

Callianassa (Cheramus) .— Borradaile, 1903: 545–546.—De Man, 1928: 26, 95.— Gurney, 1944: 8.

Type species. Cheramus occidentalis Bate, 1888 , preoccupied, replaced by Callianassa profunda Biffar, 1973 , by subsequent designation.

Diagnosis. Rostrum acute, anteriorly directed, as long as eyestalks. Pleomere 1 tergite fused, divided into 2 sections by transverse step. Pleomere 6 with sublateral ventral sharp ridge, flared posteriorly. Cornea with scattered reduced pigmentation. Antennular peduncle exceeded by all or most of antennal peduncular article 5. Maxilliped 3 merus almost rectangular, distally truncate with squarish angle between distal and lower margins, longer than wide at ischium-merus suture; crista dentata a prominent toothed ridge extending beyond proximal margin of merus. Male major cheliped merus with serrate blade over lower margin, upper margin concave. Minor and major chelipeds similar, both attenuated, with swollen palms; carpus upper margin as long as or shorter than propodus. Pereopod 3 propodus oval, lower margin slightly convex, leading to narrow sharply rounded proximal lobe. Male pleopod 2 present. Uropodal endopod ovoid, usually longer than wide, anterior margin straight or slightly convex, posterodistal margin evenly convex. Uropodal exopod about 1.5–1.8 times as long as wide, distal margin clearly differentiated from anterior margin, anterodistal corner right-angled. Telson anterolateral lobe obsolete, undefined.

Remarks. Cheramus is similar to Cheramoides but differs in having uniquely similar minor and major chelipeds, both attenuated and with swollen palms. Contrary to the views in recent accounts, only the type species agrees with this characterisation. Komai et al. (2014b) explained the complex taxonomic history of the type species but followed Manning and Felder (1991) in including other species, C. marginatus (type species of Cheramoides ), C. orientalis and C. oblonga . Several other species have been included since 1991 ( Komai et al., 2014b), but it has to be concluded from Robles et al.’s (in press) phylogeny, supported by morphology, that these and the 16 species included by Sakai (2011) are a diverse assemblage. Komai et al. (2014b) could list only “possibly diagnostic characters”, most of which, in our analyses, are features of more than one genus.