Callichimaeroidea Luque & Feldmann & Vernygora & Schweitzer & Cameron & Kerr & Vega & Duque & Strange & Palmer & Jaramillo 2019, superfam. nov.

Callichimaeroidea superfam. nov.

Included family. Callichimaeridae fam. nov. Tentatively Retrorsichelidae Feldmann et al. (20).

Diagnosis. Crabs with carapaces longer than wide, small and fusiform (Callichimaeridae), or large and ovate (Retrorsichelidae). Sternites 1 to 4 are fused and visible ventrally, forming an elongated sternal crown; sternite 4 is not mesially depressed; sternites 5 to 7 are unfused and axially sulcate by linea media; sternite 5 is very wide, almost as wide as the carapace; suture 5/6 is complete, but lacks a true sterno-pleonal cavity. Thepleon is symmetrical, sexually dimorphic, narrower in males than females, and in both sexes narrower than sternite 6 (Callichimaeridae). Pleonal somites are not fused, lacking articulating rings and bearing dorsal median tubercle or crest; pleonites 1 to 3 are exposed subdorsally; uropods or uropodal plates areabsent. True orbits, orbital fissures, or any protective structures are absent. Eyes are large in Callichimaeridae but are likely small and reduced in Retrorsichelidae. Chelipeds (claws) are isochelous, and the manus is stout, with pollex or fixed finger slightly (Retrorsichelidae) or strongly (Callichimaeridae) deflected downward; chelipedsarefoldedventrallyandposteriorlybeneath carapace. Pereopods (legs) P2 and P3 are much larger than P4 and P5; P4 and P5 are situatedsubdorsallyand directed posteriorly, lacking spines, neither subchelate nor modified for carrying or grasping. In Callichimaeridae, P2 and P3 are large and wide and positioned laterally, withdistal podomeres flattened and paddle-like; P4 and P5 are shortand narrow, withthedorsallongitudinalkeelneitherflattenednor paddle-like; P5 isthe smallest, well developed butreduced, and carried subdorsally. In Retrorsichelidae, P2 and P3 areapparentlylarge andpositioned ventrally; atleastone pereopod bearsflattened distal articles.