The Eudorella bathyalis group

Eudorella bathyalis Vassilenko & Tzareva, 2004, E. breviflagella sp. nov., E. fusafusa sp. nov., E. orientalis sp. nov., and E. setoensis Akiyama & Gamô, 2006, share the peculiar morphological character of a carapace furnished with a row of simple setae on each side. Other noteworthy characters are as follows. (1) The basis of maxilliped 2 has no setae on the inner margin or ventral surface, and (2) The propodus of pereopod 2 has a deep notch on the distal corner. Among them, although females of E. setoensis and E. breviflagella are closely similar to E. orientalis, the former two species are distinguished from the latter by the unusual male character of a short flagellum on antenna 2, which is against the diagnosis of the genus (Watling 1991). Because the other morphological characters of these species well agree with those of the other members of the genus, diagnosis of the genus Eudorella should be expanded to include “ flagellum of antenna 2 in adult male reaching pereonite 4 to pleonite 6”.

The adult male of E. breviflagella exhibits an additional unusual character: the absence of the outer ramus on the pleopods. The species can be placed in this E. bathyalis group, based on the close similarity of the females to the other members of E. bathyalis group. However this species may lie outside of the E. bathyalis group (or even outside of the genus), because modifications of the pleopods (and the short antenna 2 flagellum of males) are often used to define cumacean genera.