Thailandcallichirus Sakai, 2011

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 : 114-115

Thailandcallichirus Sakai, 2011

Thailandcallichirus Sakai, 2011: 473–474 .— Komai et al., 2018:

23–24.

Type species. Callianassa ranongensis Sakai, 1983 , by original designation and monotypy.

Diagnosis. Anterior branchiostegal lobe sclerotised, well produced anteriorly beyond junction with oblique branchiostegal ridge, which it meets level with linea thalassinica. Rostrum spine-like. 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 absent (or few proximal spines only); propodus about as wide as long, free distal margin clearly oblique; dactylus curved, about twice as long as wide, concave below. Male major cheliped merus with proximal tubercle bearing spine(s) with or without more distal teeth along lower margin; dactylus massive, upper margin expanded, strongly convex, smooth. 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, lower margin with broad deep notch between distal lobe and heel. Pereopod 4 subchelate. Male pleopod 1 consisting of 2 articles, article 2 tapering, with small acute subdistal lobe and acute distal apex. Male pleopod 2 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 tapering from greatest width near base, posterior margin straight or convex between tapering posterolateral margins.

Remarks. Thailandcallichirus differs from Lepidophthalmus , its closest sibling, in having the antennular peduncle shorter than the antennal, rather than the other way around, a more compact maxilliped 3 dactylus, lacking a maxillipedal 3 exopod, a convex posterior margin on the telson and in having a massive dactylus on the major cheliped ( Komai et al., 2018). The minor cheliped is distally setose as in some Lepidophthalmus species. Sakai (2011) justified his new genus on differences between the type species and Neocallichirus , the genus in which he had previously placed it ( Sakai, 1999a, 2005b). Tudge et al. (2000) found it was a sister to other species of Lepidophthalmus and treated it as a species of this genus as did Robles and Felder (2015). Robles et al. (in press) found this alliance again but had no molecular data to support it.