A new species of the extinct land snail genus Ferussina has been identified from a complete specimen found in Hațeg Basin, Romania.

The newly-described species belongs to Ferussina, a small extinct genus of land snails known from the Paleogene period of Europe.

The genus is currently classified in its own family, Ferussinidae, in the superfamily Cyclophoroidea.

Named Ferussina petofiana, the new species lived during the Maastrichtian age of the Late Cretaceous epoch, some 72 million yeas ago.

“Ferussina was until now recorded only from Paleogene (Middle Eocene to Upper Oligocene and maybe to Upper Miocene) deposits of Western Europe (France, Germany, Switzerland, northern Italy),” said Dr. Barna Páll-Gergely from the HUN-REN Centre for Agricultural Research and colleagues.

“The new species is the oldest, as well as the easternmost representative of its genus.”

The shell of Ferussina petofiana was 10.8 mm in diameter and 4.4 mm in height.

“The shell is depressed with flat base, domed dorsal surface, and rounded or slightly shouldered body whorl,” the paleontologists said.

“Last ca. quarter whorl turns upright, elevating higher than apex.”

Holotype and only specimen of Ferussina petofiana. Image credit: Páll-Gergely et al., doi: 10.17109/azh.69.4.337.2023.

The only specimen of Ferussina petofiana was found in the Densuș-Ciula Formation in Romania.

“Ferussina petofiana was discovered in uppermost Cretaceous deposits cropping out in the neighborhood of Vălioara village, in the northwestern corner of Hațeg Basin, in western Romania,” the researchers said.

“These deposits are primarily known for their fossil vertebrate fauna which includes dwarf dinosaurs first described more than a century ago, although rare invertebrates and plants have also been reported from them.”

The discovery of Ferussina petofiana represents an important range extension for the genus Ferussina, and adds it to the brief list of European groups that appear to have survived the end-Cretaceous mass extinction event.

“The occurrence of Ferussina in layers of Maastrichtian age, represents a minimum chronostratigraphic range extension of about 23 million years for this genus,” the authors said.

“Furthermore, its presence in western Romania during the latest Cretaceous also implies an important geographic range extension eastward compared to its Paleogene area of distribution that covers parts of Western Europe.”

“Based on currently available data, it appears that the geographic distribution of the genus shifted westward over time, which is in agreement with the fact that Cyclophoridae are of Asian origin, although such a picture may represent at least in part the result of its somewhat patchy fossil record.”

“The most important implication of the discovery of Ferussina petofiana in the uppermost Cretaceous of Hațeg Basin is that the resulting extended chronostratigraphic range of the genus (and that of its parent subfamily, Ferussininae) crosses the Cretaceous-Paleogene boundary which coincides with one of the most devastating mass extinctions of the Phanerozoic.”

A paper about the discovery was published in the journal Acta Zoologica Academiae Scientiarum Hungaricae.

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B. Páll-Gergely et al. 2023. Ferussina petofiana sp. n. (Gastropoda, Caenogastropoda, Cyclophoridae), the oldest representative of its subfamily from the Late Cretaceous of Romania. Acta Zoologica Academiae Scientiarum Hungaricae 69 (4): 337-352; doi: 10.17109/azh.69.4.337.202