A newly discovered species of dolphin dating back 22 million years shows evidence of early echolocation, similar to the hearing abilities of modern dolphins. A research team led by SNSB paleontologist Gertrude Resner has discovered a new species of prehistoric dolphin. The dolphin lived in the coastal region of the Miocene Paratethys Sea in modern Upper Austria about 22 million years ago. Analysis of the inner ear confirmed that the animal had excellent hearing capacity in the high frequency range, similar to modern dolphins.

A unique fossil and scientific classification

A shallow inland sea that harbored the newly identified dolphin as well as many other organisms, including a variety of microorganisms, algae, snails, mussels, squid relatives, and fish, lay north of the nascent Alps. The only known fossil of this dolphin was found near Linz in Upper Austria. Researchers from the Bavarian State Collection of Paleontology and Geology (SNSB-BSPG) and the Ludwig-Maximilians-University in Munich, as well as the Senckenberg Research Center, assigned it to a new, previously unknown species and genus and gave it a scientific name. Romaleodelphis pollerspoecki. Frankfurt Institute and Natural History Museum.

“The only thing left is Romaleodelphis pollerspoecki, It is a “fragmented and incomplete skull with an elongated snout and 102 uniform teeth,” says first author Catalina Sánchez Posada, who studied the fossil as part of her master’s thesis.

Evolutionary significance Romaleodelphis pollerspoecki

The animal belongs to the toothed whales, but differs significantly from all previously known prehistoric representatives of this genus. Relationship comparisons with other fossil dolphins and extensive computer analysis showed that: romaleodelphisIt was probably related to the extinct, very archaic dolphins of the so-called class. chilcacetus.

“All previously known fossils of this dolphin genus come from the northeastern part of the Pacific Ocean and the coast of South America. Discovery Romaleodelphis pollerspoeckiPD Dr., curator of fossil mammals at the Bavarian State Collection. It may provide important new information about the origin and evolution of this lineage, its putative European relative, in the earliest Miocene,” says Gertrud Ressner, Department of Paleontology and Geology, senior author of the study.

Advanced hearing abilities revealed

The fossil skull is highly compressed and distorted, making it difficult to study the anatomy of the skull. Computed tomography images taken in the radiology department of the Ludwig Maximilian University Hospital in Munich allowed internal features to be explored and reconstructed. Anatomical reconstruction of the fossil’s inner ear using micro-computed tomography images also yielded impressive results.

“The shape of the well-preserved bony labyrinth within the skull indicates that: Romaleodelphis pollerspoecki it could hear high-frequency signals,” explains co-author Dr. Rachel Rakikot from the Senkenberg Research Institute and the Natural History Museum.

This makes this dolphin one of the oldest known toothed whales, having the same advanced hearing as modern porpoises, for example. These animals can communicate in frequency ranges beyond the hearing range of their predators. There is also a possible link to the development of the ability to navigate using echolocation, which is characteristic of dolphins.

The dolphin fossil was found in 1980 by Jürgen Pollerspek, a private collector, who later donated it to the Bavarian State Collection of Paleontology and Geology for restoration and proper preservation. The study was published on: Journal of Vertebrate Paleontology.