Paleontologists identify new genus of fossil fish

June 14 () –

A new fossil genus of goby, one of the most diverse groups of marine and freshwater fish in Europe, has been discovered in 18 million year old rocks in Türkiye.

With lengths of up to 34 millimeters, these fossil fish are characterized by a distinctive combination of morphological features, including uniquely shaped otoliths (hearing stones).

To determine the relationships of the so-called ‘Simpsonigobius’ within the gobioid phylogenetic tree, the researchers used a “total evidence” phylogenetic data set, which they enhanced to combine a total of 48 morphological and genetic data from five genes for 48 living and 10 fossil species.

Additionally, the team employed “tip dating” for the first time for fossil gobioid species. This is a phylogenetic method in which the age of the fossils (= tips) included in the phylogenetic tree is used to infer the chronology of the evolutionary history of the entire group.

The results, published in the Journal of Systematic Palaeontologyshow that the new genus is the oldest skeletal-based member of the family Oxudercidae, which is classified among the “modern” gobies (families Gobiidae and Oxudercidae), and the oldest freshwater goby within this modern group.

Cutting-edge dating analysis estimated the appearance of the Gobiidae 34.1 million years ago and that of the Oxudercidae 34.8 million years ago, which is consistent with previous dating studies that used other methods.

Additionally, stochastic habitat mapping, in which the researchers incorporated fossil gobies for the first time, revealed that gobies likely possessed broad salinity tolerance early in their evolutionary history, which challenges previous assumptions.

“The discovery of Simpsonigobius not only adds a new genus to the Gobioidei, but also provides Vital Clues to the Evolutionary Timeline and Habitat Adaptations of These Diverse Fish. Our research highlights the importance of analyzing fossil records using modern methods to achieve a more accurate picture of evolutionary processes,” says Bettina Reichenbacher, Professor of Earth and Environmental Sciences at the Ludwig Maximilian University of Munich, who led the research.