Key to the species of Prodontorhabditis

1- Subventral denticles in cheilostom........................................................................ 2

- Subventral denticles in gymnostom....................................................................... 4

2- Stoma length less than 5 times diameter, cheilostom deeply arched with dorsal and subventral denticles at same level, spicules robust with a prominent dorsal hump......................................................... P. robustus sp. n.

- Stoma length more than 8 times diameter, spicules slender without dorsal hump.................................... 3

3- Male with 9 pairs of genital papillae (2 precloacal and 7 postcloacal pairs), bursal cleft at GP6, female length L=440–552 μm................................................................................... P. grandistoma sp. n.

- Male with 8 pairs of genital papillae: (1 preclocal and 7 postcloacal pairs) bursal cleft at GP5, female length L= 580–740 μm........................................................................................... P. pluvialis

4- Stoma length less than twice head diameters................................................................ 5

- Stoma length more than twice head diameters............................................................... 6

5- Stoma length 8–9.6 μm, spicules with swollen distal tip................................................. P. wirthi

- Stoma length 12–14 μm, spicules with pointed distal tip............................................... P. prodontis

6- Body length 649–782 μm, spicules short (14–15 μm long), c= 2.5–2.9 μm, V= 36.5–39 %, GP1 anterior to edge of bursa at half spicule length.................................................................................. P. parvus

- Body length 790–877 μm, spicules longer (17 μm), c= 3.2–3.6 μm, V= 42–44.5 %, GP1 anterior to capitulum..... P. gracilis