Genus Guyanacaris K. Sakai, 2011

Guyanacaris K. Sakai, 2011: 119 . Type species: Calocaris (Calastacus) hirsutimana Boesch & Smalley, 1972, by original designation, gender feminine.

Neoaxius Sakai, 2017a: 504 . Type species: Neoaxius nicoyaensis Sakai, 2017, by original designation and monotypy, gender masculine.

Diagnosis: Carapace smooth or spinose. Rostrum spine-like, narrow, slightly shorter to slightly longer than eyestalks, slightly depressed, continuous with lateral carinae laterally denticulate; supraocular spines short; gastric carinae spinose, lateral gastric carina converging anteriorly on supraocular spines; postcervical carina present. Pleonal 1 pleuron acute (or obtuse), margin dentate; pleuron 2 broad, less rounded anteriorly and posteriorly, ventral margin truncate, margins dentate or smooth; posterior margins of pleura 3–5 angular to almost straight, dentate or smooth; pleonal 1–5 terga and pleura separated by weak longitudinal carinae. Eyestalk cylindrical, articulating; cornea pigmented. Antennal scaphocerite short, gently curved, with mesial spine at base; distal spine on antennal article 2 directed anteriorly (or anteromesially) and acute. Maxilliped 3 exopod not clearly bent at base of flagellum. Pleurobranchs absent; podobranchs and arthrobranchs well developed; epipods present on maxilliped 2 to P4. P1 unequal or subequal, asymmetrical, with propodus subcylindrical; carpus-dactylus upper margins prominently spinose (or unarmed). P3–5 propodi with (or without) transverse rows of robust setae; dactyli tapering, with or without longitudinal row of robust setae. Pleopods 3–5 appendix interna present. Male pleopod 1 present; pleopod 2 with appendix masculina. Uropodal exopod with transverse suture. Telson with lateral fixed spines, posterolateral robust setae absent (or present); apex truncate-rounded to nearly straight (Sakai 2011; Poore 2020).