Freshwater gobies 30 million years ago: new insights into character evolution and phylogenetic relationships of †Pirskeniidae (Gobioidei, Teleostei)
Project
ID: 0000C1063
Public
The modern Gobioidei (Teleostei) comprise eight families, but the extinct †Pirskeniidae from the lower Oligocene of the Czech Republic indicate that family diversity was greater in the past. However, the validity of the †Pirskeniidae has been questioned and its single genus †Pirskenius has been assigned to the extant family Eleotridae in previous works. The objective of this study is to clarify the status of the †Pirskeniidae. Whether or not the †Pirskeniidae should be synonymised with the Eleotridae is also interesting from a biogeographical point of view as Eleotridae are not present in Europe or the Mediterranean Sea today. We present new specimens and re-examine the material on which the two known species of †Pirskenius are based (†P. diatomaceus Obrhelová, 1961, †P. radoni Přikryl, 2014). To provide a context for phylogenetically informative characters related to the palatine and the branchiostegal rays, two early-branching gobioids (Rhyacichthys, Protogobius), an odontobutid (Perccottus), an eleotrid (Eleotris) and a gobiid (Gobius) were subjected to micro-CT analysis. The new data justify revalidation of the family †Pirskeniidae, and a revised diagnosis is presented for both †Pirskenius and †Pirskeniidae. Phylogenetic analyses indicate a possible placement of †Pirskeniidae as sister to the Thalasseleotrididae + Gobiidae + Oxudercidae, or as sister to the Thalasseleotrididae. Considering the fossil record, the conquest of freshwater habitats by gobioids in the early Oligocene apparently had generated new lineages that finally were not successful and became extinct shortly after they had diverged. Moreover, the current data on fossil gobioids indicate that Eleotridae were not part of the European palaeo-ichthyofauna.