Genus key of Dirivultidae.

Dirivultid genera and number of described species within each genus (#). Genera can be distinguished by the number of setae (Arabic numbers) and spines (Latin numbers) on their leg 4 endopod. 1st indicates setation of the first segment of leg 4 endopod, 2nd indicates setation of the second segment of leg 4 endopod (see for example Figure 1H, showing leg 4 of Stygiopontius). The first step of genus identification is to analyze leg 4 endopod, afterwards the description of other characters should be followed. Other characters include number of segments and setation of other legs (terminology of different parts of legs see Figure 1A and 1G), number of setae on caudal rami and lobe presence/absence at anal somite (see for example Figure 1I showing Aphotopontius with 6 setae on caudal rami and anal somite without lobes), shape of antenna (A2) (Figure 1B shows a typical antenna of Dirivultidae; Figure 1C shows the antenna with a hook like claw as typical for the genera Ceuthoecetes, Dirivultus, and Nilva), and number of segments in antennule (A1).