A new species of freshwater crab of the genus Allacanthos Smalley, 1964 (Crustacea, Decapoda, Pseudothelphusidae) from southern Costa Rica, Central America Author Magalhães, Célio Author Lara, Luis Rólier Author Wehrtmann, Ingo S. text Zootaxa 2010 2604 52 60 journal article 10.5281/zenodo.197643 23f5722f-6012-4147-bf57-7bf32cc2d900 1175-5326 197643 Allacanthos Smalley, 1964a Diagnosis (modified from Smalley 1964b ). Gonopod straight, apex folded, spermatic channel emerging on cephalic side, with proximal trianguliform lobe on lateral side. Marginal suture on mesial side, straight along most of stem. Subdistal portion of lateral and cephalic sides with field of minute spines. Distal part with large cephalic lobe and narrow lateral lobe. Field of apical spines weakly developed on internal surface of lateral lobe. Type species. Allacanthus pittieri Rathbun, 1898 (by original designation).