On argentodromas bellanella gen. nov., sp. nov. (Crustacea, Ostracoda) from a stream in Northeastern Argentina (South America)

Abstract

Argentodromas bellanella gen. nov., sp. nov. is here described from streams in the province of Misiones, in northeastern Argentina. The new genus and species belong to the family Notodromadidae. Most species in the family have morphological adaptations to a hyponeustic mode of life: their carapaces have lip-like protrusions of the valve margins near the mouth and a flat plate-like expansion of the ventral part. The new genus can be distinguished from other genera in the subfamily Notodromadinae based on valve ornamentation (surface of valves covered with polygonal elevations and many pores with setae), the ventral plate-like expansion which is set with 3-4 rows of rounded elevations and bordered with an elevated outer list, eye tubercles softly pronounced, and soft parts features (male prehensile palps moderately asymmetrical and both with elongated first segments, posterior seta of caudal ramus longer than terminal claws and anterior seta present, hemipenis with rounded outer lobe and small rounded inner lobe). For comparative purposes, valves and carapaces of species in three other Notodromadinae genera (Newnhamia, Kennethia, Notodromas) are also illustrated and re-diagnosed.