Rudisullianassa, 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 : 98-99

Rudisullianassa gen. nov.

http://zoobank.org/urn:lsid:zoobank.org:act:C2EFC849-6C6B-

4466-8B47-9DF66EBF5D46

Type species. Rayllianassa rudisulcus Komai, Fujita and Maenosono, 2014 , by present designation.

Diagnosis. Hermaphrodite. Rostrum obsolete or obtusely triangular, flat, not reaching cornea. Pleomere 1 tergite undivided or with weak transverse step. Antennular peduncle exceeded by all or most of antennal peduncular article 5; articles 2 and 3 with single lateral row of 6–10 well-spaced long setae along lower margin. Maxilliped 3 merus wider at ischium-merus suture than long; dactylus ovate, with dense brush of long setae over most of upper-distal margin, few setae along lower margin. Male major cheliped merus without prominent hook or spine on lower margin; propodus distal margin with small lateral tooth. Minor cheliped about two-thirds width of major cheliped, both swollen; 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. Uropodal endopod ovoid, usually longer than wide, anterior margin straight or slightly convex, posterodistal margin evenly convex, with or without facial spiniform setae on rib. Uropodal exopod 1.0–1.8 times as long as wide, posterodistal margin with row of 6–8 long blade-like setae proximal to long setae on distal margin. Telson about as wide as long, tapering from anterolateral lobe; anterolateral lobe obsolete, undefined; posterior margin slightly concave, sometimes with medial spine.

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

Remarks. Komai et al. (2014a) described Rayllianassa rudisulcus based on one female; they did not note how the setation on the dactylus of maxilliped 3, which they correctly described as “stout”, differed from that of R. amboinensis . The form found in Rayllianassa , tapering with few long setae on the upper surface and a dense brush of short setae below, is typical of most callianassids. Rudisullianassa differs further from Rayllianassa in having the antennular peduncle shorter than the antennal peduncle, whereas the opposite is true in Rayllianassa , and the minor cheliped is relatively smaller. The atypical maxilliped 3 dactylus seen in R. rudisulcus is also seen in Biffarius , Fragillianassa and Caviallianassa but these are gonochoristic genera. Rudisullianassa rudisulcus and a second undescribed species were common in collections from Papua New Guinea (Robles et al. 2019). All individuals had both male and female gonopores. Both species were associated with submerged wood.

The unusual maxilliped 3 was initially mistaken by one of us (GCBP) for the form seen in eucalliacids, also with swollen similar chelipeds. In eucalliacids, the dactylus is also extremely setose but in this case the apex is decidedly truncate.