Key to the genera and species of Bathytanaidinae, new subfamily

1. Antenna article 2 with anterior directed ventral process (Fig 3 D)[ Bathytanais]... 2

Antenna article 2 without anterior directed ventral process (Fig 10H)........... [ Pseudobathytanais]................................................. 7

2. Antenna article 3 with both dorso­ and ventro­distal processes............... 3

Antenna article 3 without ventro­distal process............................ 5

3. Antenna article 2 not subquadrate, produced disto­ventrally into rounded lobe extending nearly to articulation of article 4; article 3 with both dorso­ and ventro­distal processes rounded (lobate)............................ B. bathybrotes

Antenna article 2 subquadrate, ventral margin produced distally into subacute process not reaching articulation of article 4; article 3 with both dorsal and ventral distal processes acute (not lobate)............................................ 4

4. Antenna article 2 ventral margin smooth (cleaver­shaped, fig. 1D). B. culterformis

Antenna article 2 ventral margin serrated (halberd­shaped).......... B. bipennifer

5. Antenna article 2 ventral projection membranous and transparent (Fig. 6 B).................................................................. B. fragilis

Antenna article 2 ventral projection solid and not transparent................. 6

6. Antenna article 2 longer than deep; disto­ventral quadrate process not extending to articulation of article 3 and 4; article 3 not inserted dorsally into article 2. Antennule article1notswollenandclearlylongerthanwide.Labiumwithanterolateralprojections............................................................ B. juergeni

Antennal 2 article 2 as deep as long; disto­ventral quadrate process extending just past articulation of article 3 and 4; article 3 inserted dorsally into article 2. Antennule article 1 swollen and almost as wide as long. Labium without anterolateral projections (Fig 3 D).......................................... B. arenamans

7. First pleonite with prominent dorsal anteriorly directed process (Fig 10D)................................................................ P. gibberosus

First pleonite without prominent dorsal anteriorly directed process.... P. shtokmani