A new Silurian xiphosuran from Podolia, Ukraine, USSR

Abstract

A single incomplete specimen of a xiphosuran, Pasternakevia podolica gen. et sp. nov., from the Ludlow Series of Podolia, Ukraine, USSR, is described. It has a smooth, spatulate carapace and rounded genal cornua. The opisthosoma bears nine free tergites (second to tenth); the first tergite is reduced and hidden beneath the carapace. The tergites have a broad axial region and small pleurae; the second tergite is hypertrophic. Telson and appendages are not preserved. P. podolica resembles Pseudoniscus Nieszkowski, 1859 and Cyamocephalus Currie, 1927; it is thus placed in the infraorder Pseudoniscina Eldredge, 1974, but certain characters are shared with the synziphosurines. It comes from the lagoonal deposits of the upper part of the Ustye Suite (Bagovytsa Horizon) where it occurred together with Baltoeurypterus tetragonophthalmus (Fischer, 1839).