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 Author Schwarzhans, Werner Natural History Museum of Denmark, Zoological Museum, Universitetsparken 15, 2100 Copenhagen, Denmark Author Klots, Oleksandr Author Ryabokon, Tamara Author Kovalchuk, Oleksandr text Swiss Journal of Palaeontology 2022 18 2022-11-17 141 1 1 35 http://dx.doi.org/10.1186/s13358-022-00261-3 journal article 10.1186/s13358-022-00261-3 1664-2384 11999827 Vanderhorstia prochazkai Schwarzhans et al., 2020a , 2020b Figure 6h–j 2020a Vanderhorstia prochazkai —Schwarzhans, Brzobohatý & Radwańska: pl. 7, figs. 12–18. Material 6 otoliths: 1 specimen , Kozatskyi Yar, NMNHU- P PI 2581; 2 specimens , Mlyntsi, NMB P1223; 3 specimens , Shydlivshchyna, NMNHU-P PI 2582. Discussion Tese are typical high-bodied and rather thick otoliths of V. prochazkai that are further characterized by a very large subcaudal iugum. Vanderhorstia prochazkai has been described from the late Badenian and early Sarmatian s.s. of the Central Paratethys by Schwarzhans et. al. (2020a). Today, species of the Asterropteryx Lineage live commensal with alpheid shrimps, and it has been suggested that this was also the case in the middle Miocene ( Radwańska, 2018 ; Schwarzhans et al., 2020a ). Vanderhorstia sp. Figure 6k Material 2 otoliths, Shydlivshchyna, NMNHU-P PI 2583 and NMB P1224. Discussion Two specimens differ from V. prochazkai in being distinctly thinner (OH:OT = 3.45 vs. mostly 3.0– 3.3, rarely 3.5) and in showing a narrow subcaudal iugum. It may represent a second species, but the available specimens are not sufficiently well-preserved for a definite assessment.