Potamalpheops Powell 1979

Key to species of Potamalpheops 1. Telson with 1 spiniform seta on each posterolateral angle.................................. 2 (P. haugi species group) – Telson with 2 spiniform setae on each posterolateral angle................................ 3 (P. monodi species group) 2. Cheliped merus unarmed; diaeresis of uropodal exopod with 9–13 teeth....................... P. haugi (Coutière, 1906) [West Africa; freshwater] – Cheliped merus armed with tooth on distoventral margin; diaeresis of uropodal exopod with 15–25 teeth.................................................................................................. P. pylorus Powell, 1979 [West Africa; peat swamps, transitional fresh-brackish water] 3. Pereopod 5 merus unarmed............................................................................. 4 – Pereopod 5 merus armed with at least 1 spiniform seta........................................................ 8 4. Carapace lateral surface with distinct longitudinal groove; eyestalk reduced, with unpigmented cornea................................................................................................. P. stygicola (Hobbs, 1973) [Mexico; freshwater caves] – Carapace lateral surface without groove; eyestalk normally developed, with darkly pigmented cornea.................. 5 5. Extra-corneal teeth located lateral to cornea.................................................................6 – Extra-corneal teeth located dorsolateral to cornea............................................................ 7 6. Rostrum armed with subapical spine on ventral margin; antennal carpocerite short, reaching 0.6 length of scaphocerite...................................................................................... P. johnsoni Anker, 2003 [SE Asia (Singapore); mangroves] – Rostrum unarmed on ventral margin; antennal carpocerite long, reaching 0.8–0.9 length of scaphocerite... P. yamakawai sp. nov. [East Asia (Japan); brackish water, penetrating into freshwater] 7. Rostrum distinctly overreaching distal corneal margins; eyestalk without anteromesial setae.................................................................................................. P. palawanensis Cai & Anker, 2004 [SE Asia (Philippines); caves, transitional fresh-brackish water] – Rostrum just reaching distal corneal margins; eyestalk with anteromesial setae................ P. amnicus Yeo & Ng, 1997 [SE Asia (Malaysia, Singapore, Indonesia); freshwater] 8. Carapace with interrupted longitudinal groove on lateral surface; [rostrum reaching distal corneal margins].................................................................................................. P. galle Anker, 2005 [South Asia (Sri Lanka); transitional fresh-brackish water] – Carapace without longitudinal groove on lateral surface....................................................... 9 9. Rostrum reaching or not reaching distal corneal margins..................................................... 10 – Rostrum clearly overreaching distal corneal margins........................................................ 14 10. Uropodal exopod with simple distolateral tooth............................................................ 11 – Uropodal exopod with bifid distolateral tooth.............................................................. 13 11. Rostrum very short, not reaching bases of antennular peduncles; eyes reduced, largely covered by frontal margin of carapace; extra-corneal tooth obsolescent; cheliped with robust chela............................. ... P. darwinensis Bruce, 1993 [Northern Australia; mangroves] – Rostrum at least reaching mid-point of corneas; eyes normally developed, corneas fully exposed; extra-corneal tooth acuminate; cheliped with moderately slender chela................................................................... 12 12. Carapace with row of setae on pterygostomial margin; cheliped carpus longer than palm......... P. monodi (Sollaud, 1932) [West Africa; freshwater] – Carapace without setae on pterygostomial margin; cheliped carpus as long as palm.............................................................................................. P. tyrymembe Soledade, Santos & Almeida, 2014 [Brazil, mangroves] 13. Carapace ventrolateral margin with row of sparse setae; penultimate article of antennular peduncle 2–3 times longer than broad; cheliped carpus 1.3–1.7 times as long as palm; pereopod 4 ischium armed with 1 spiniform setae... P. miyai Yeo & Ng, 1997 [SE Asia (Indonesia, Philippines); mangroves] – Carapace ventrolateral margin without setae; Penultimate article of antennular peduncle nearly as long as broad; cheliped carpus subequal in length to palm; pereopod 4 ischium unarmed.............................. P. hanleyi Bruce, 1991 [Northern Australia; mangrove swamps] 14. Rostrum not reaching distal margin of basal article of antennular peduncle; eyestalk with spiniform anteromesial tubercle; [rostral ventral margin usually with subapical spine].................... P. nazgul Christodoulou, Iliffe & De Grave, 2019 [Solomon Islands; anchialine caves] – Rostrum reaching or overreaching distal margin of basal article of antennular peduncle; eyestalk without anteromesial tubercle............................................................................................ 15 15. Antennular stylocerite reaching distal margin of basal peduncular article; pereopod 3 propodus with 10 spiniform setae on flexor margin............................................................. .. P. pininsulae Bruce & Ilife, 1992 [New Caledonia; anchialine caves] – Antennular stylocerite distinctly overreaching distal margin of basal peduncular article; pereopod 3 propodus with no more than 9 spiniform setae on flexor margin....................................................................... 16 16. Rostrum reaching 0.3–0.6 length of penultimate article of antennular peduncle; cheliped carpus as long as chela.......................................................................................... P. tigger Yeo & Ng, 1997 [SE Asia (Malaysia, Singapore); mangroves] – Rostrum reaching distal margin of basal article of antennular peduncle; cheliped carpus shorter than chela..................................................................................................... P. kisi Marin, 2021 [SE Asia (Vietnam), mangroves]