Haie lived in Bavaria 150 million years ago

“Evolutionarily, cartilaginous fish like sharks and rays are a very old group of animals that lived on earth more than 400 million years ago, before the dinosaurs,” said the researcher in a broadcast from the University of Vienna. There are more than 500 species of sharks and over 600 species of rays. These fish have survived all five of Earth’s previous mass extinctions quite well. There are plenty of fossils of them found all over the world. However, mostly only their teeth remain, while the cartilaginous skeleton has decomposed like the rest of the body.

In a deposit in Bavaria, the “Solnhofer Archipelago”, the conditions are very special: not only skeletal remains but even imprints of the skin and muscles of the cartilaginous fish from the Jurassic period have been preserved. 150 million years ago in this place there was an archipelago in the Tethys Sea (primordial Mediterranean Sea) with coral islands where there were insects and the primordial bird Archeopteryx, as their remains testify.

Ancestor of the great white shark in Bavaria?

In turn, the lagoons were home to “Protospinax annectans” cartilaginous fish. This species was first described in 1918 as “five feet long, flattened cartilaginous fish with outstretched dorsal fins and two prominent spines in front of each dorsal fin,” the release says. So far it has been unclear where to classify them. Among other things, the following were discussed: as a “missing link” between sharks and rays, as a primal shark or as the ancestor of a subgroup that produced the great white shark that is alive today.

Jambura’s team first created a family tree of sharks and rays living today based on their genetic codes (mitochondrial DNA). Then the researchers compared 224 shape features (morphological features) in Protospinax annectans, extant sharks and rays, and other fossil sharks and rays. This enabled them to determine the relationships and position of Protospinax annectans in the evolutionary tree of sharks and rays.

Sawsharks are offspring

“Our analysis revealed that Protospinax’s closest relatives were those alive today English sharks and the Saw shark are,” reported Jambura. However, the differences to the two are so great that it probably belonged to its own, very well developed group. “That was unexpected, since with such an old species you actually have an original shark or an ancestor of a group would calculate,” said the paleontologist.

“Even though cartilaginous fish have survived as an animal group to this day, most species disappeared in the course of evolution,” the researchers write: This also happened to Protospinax annectans for unknown reasons at the boundary between the Jurassic and Cretaceous periods (about 145 million years ago). So before the demise of all dinosaurs, which marks the end of the Cretaceous period (66 million years ago).

(Those: APA)