Key to the genera of the suborder Campydorina (see Table 2 for additional diagnostic characters)

1. Stoma with single well developed dorsal tooth …......................................................................…2

– Stoma with three denticles …….....................................................................................................…3

2. Stoma conoid with large tooth; cephalic sensilla and amphids posterior to labial region; caudal glands and spinneret present ………................………………. Campydoroides Holovachov gen. nov.

– Stoma cylindrical with small tooth; cephalic sensilla and amphids on cap-like labial region; caudal glands and spinneret absent ........................................................................ Campydora Cobb, 1920

3. Denticles located at different levels (dorsal and ventral in anterior and left lateral in posterior parts of stoma); female reproductive system monodelphic ……………..……. … Udonchus Cobb, 1913

– Denticles located at same level in anterior part of stoma; female reproductive system didelphic …..4

4. Ovaries outstretched …………........................................................................................…..…….…5

– Ovaries reflexed ….............................................................................................................................6

5. Cephalic sensilla setiform; caudal glands and spinneret present … Rogerus Hoeppli & Chu, 1934

– Cephalic sensilla papilliform; caudal glands and spinneret absent ….............................................. .................................................................. Mediolaimus Tahseen, Sultana, Khan & Hussain, 2012

6. Marine …...........................................................................................… Syringolaimus de Man, 1888

– Freshwater and terrestrial ………..................................................…… Rhabdolaimus de Man, 1880