A rare window into a back-reef fish community from the middle Miocene (late Badenian) Medobory Hills barrier reef in western Ukraine, reconstructed mostly by means of otoliths

Abstract

The Medobory Hills barrier reef in western Ukraine represents a unique environment during the late Badenian that existed for a relatively brief time. Here, we describe 170 specimens of otoliths and scarce skeletal elements that were collected in the back-reef environment of the central part of the barrier reef in the city of Horodok. They represent a rare window into a reef-associated bony fish fauna. The otolith assemblage is very diverse and differs in several aspects from time-equivalent otolith associations described from other regions and environments within the former Paratethys. The Medobory back-reef otolith assemblage is dominated by a highly diverse gobioid community, several of which are believed to reflect specific reef adaptations that have not been identified elsewhere. A total of 26 species have been identified, of which eight are described as new, including two new genera. In the order in which they are described, the new taxa are as follows: Gobiidae: Gobius bratishkoi n. sp., Gobius ukrainicus n. sp., Parenypnias n. gen. inauditus n. sp., Parenypnias n. gen. kiselevi n. sp., Medoborichthys n. gen. podolicus n. sp., and Medoborichthys n. gen. renesulcis n. sp.; Blenniidae: Blennius vernyhorovae n. sp.; and Labridae: Coris medoboryensis n. sp. The environmental implications of the otolith-based fish fauna are discussed, and a supraregional correlation of late Badenian otolith associations throughout the Paratethys is presented.