Ptychophallus Smalley, 1964

Pseudothelphusa (Ptychophallus) Smalley, 1964b: 9 .

Ptychophallus (Semiptychophallus) Pretzmann, 1965: 5 [type species Pseudothelphusa xantusi Rathbun, 1893, by original designation].

Ptychophallus (Microptychophallus) Pretzmann, 1965: 5 [type species Ptychophallus (Microptychophallus) goldmanni Pretzmann, 1985, by original designation].

Type species. Pseudothelphusa tristani Rathbun, 1896 [by original designation].

Diagnosis. Third maxilliped with exopod about 0.5 to 0.7 length of ischium. G1 stout, with a prominent, oblong apex bent cephalically, joined to the main stem by narrow peduncle; marginal suture on mesial surface, usually straight, not twisted to other surfaces; lateral process large, usually bilobed (except P. goldmanni); caudal ridge extending longitudinally on distal half of caudal surface; mesial process usually subtriangular.

Distribution. The species of Ptychophallus are distributed from northern Costa Rica to southern Panama in hydrographic basins from both Caribbean and Pacific drainages.

Remarks. The relationships with other pseudothephusid genera, infered by G1 morphology, were discussed by Rodriguez (1982).