ON SCHORNIKOVDONA GEN. NOV (OSTRACODA, CANDONIDAE) FROM RHEOCRENE SPRINGS IN TEXAS (USA)

A new candonid genus, Schornikovdona gen. nov., with its type species Schornikovdona bellensis sp. nov., is described from rheocrene springs of Bell County, Texas. It is designated to the tribe Candonini due to the smooth carapace surface, normal pore openings with sensory seta, the presence of a 5-segmented first antenna, two long sexual bristles on the second antenna in males, the narrowly fused terminal segment of the Md palp, a long penultimate segment of the Mxl palp, two long and one short setae on the terminal segment of T3, the absence of an e seta on T3, the presence of a posterior seta on the uropod, the presence of 5 + 2 rows of spines on Zenker's organ, and other characteristics found in the tribe. The main diagnostic characteristics separating the new genus from the other genera in the tribe are the shape of the carapace, the reduced numbers of segments in the first antenna, reduction or absence of exopodial setae in the second antenna, asymmetrical clasping organs, the uropod with one rod-shaped claw, the different shape of the hemipenis, and differences in parts of the chaetotaxy. Based on these differences, we propose Schornikovdona gen. nov. as a new genus, with the new species S. bellensis sp. nov., in the subfamily Candoninae in the family Candonidae.