Key to World species of Pardaliscoides

1A- Uropod 3 rami narrow, more than 2 x longer than peduncle (Philippine Trench; Kamchatka Trench, 6180–10000 m in depth)............................................................................. P. longicaudatus Dahl, 1959

1B- Uropod 3 rami as long as or shorter than peduncle........................................................... 2

2A- Telson cleft 40 % or more of its total length................................................................ 3

2B- Telson cleft 30 % or less of its total length................................................................. 4

3A- Telson cleft 40 %; the uropod 3 peduncle length is shorter than rami (Corsica, Mediterranean Sea, 530 m in depth)...................................................................................... P. stebbingi Ledoyer, 1970

3B- Telson cleft 60 %; the uropod 3 peduncle length is longer than rami (West Indies, Caribbean Sea, 3228 m in depth)....................................................................................... P. tenellus Stebbing, 1888

4A- Telson cleft with V-shaped notch (Perdido Fold Belt, offshore Tamaulipas, Western Gulf of Mexico, 1998 m in depth)................................................................................ P. ecosur Paz-Ríos & Pech 2022

4B- Telson cleft with rectangular-shaped notch................................................................. 5

5A- Accessory flagellum with 10 articles; basal article as long as articles 2–3 combined; basis of pereopod 7 widely expanded, peduncle uropod 1, twice as long as rami; telson with one dorsal intermediate single seta; no seta distally (Campeche Bay, Gulf of Mexico; 2125 m in depth)............................................................. P. whiteae sp. nov .

5B- Accessory flagellum with 8 articles; basal article more than twice length of articles 2–3 combined; basis of pereopod 7 not expanded, peduncle uropod 1 as long as rami; telson with three setae on lateral margins; one distal long seta (Submarine canyons, Southern California, 218 m in depth)........................................ P. fictotelson Barnard, 1966