PROCHYDORIDAE SMIRNOV, 1992

Kotov, Alexey A., 2009, A revision of the extinct Mesozoic family Prochydoridae Smirnov, 1992 (Crustacea: Cladocera) with a discussion of its phylogenetic position, Zoological Journal of the Linnean Society 155 (2), pp. 253-265 : 254

FAMILY PROCHYDORIDAE SMIRNOV, 1992

Prochydoridae Smirnov, 1992a: 111–112 ; Fryer, 1995: 67 (subfamily Prochydorinae ); Negrea, Botnariuc & Dumont, 1999: 207.

Type genus: Prochydorus Smirnov, 1992 .

Emended diagnosis: Body high, head capsule well developed, durable, covered with a head shield. Post-cephalic body covered with valves. Antenna II relatively long (length of basal segment + exopod = about half body length), both branches three-segmented, antennal formula (4–7)– (1)–(3)/(1)–(1)–(3). Gut not convoluted.

Differential diagnosis: Unique antenna II (with lateral setae only on proximal segment of endopod) differentiates the family Prochydoridae from any other family in the known orders of the Cladocera .

KEY FOR DETERMINATION OF GENERA OF THE FAMILY PROCHYDORIDAE

1. Rostrum truncated in lateral view, ventral margin of valve armed with setae and denticles............................. ...................................................................................................................... 3. Palaeorak gen. nov.

2. Rostrum pointed, ventral margin of valves without setae and/or denticles

3. Body very high, mandible attached to the valve at a distance from point of joint of head and valve, antenna II short ........................................................................................................ 1. Prochydorus Smirnov, 1992

4. Body less high, mandible attached to the point of joint of head and valve, antenna II long................................. .................................................................................................................. 2. Archeoxus Smirnov, 1992