Mud lobster Thalassina Latreille, 1806 (Decapoda: Gebiidea: Thalassinidae), its Cenozoic occurrences in Italy and palaeobiogeography

Two specimens of Thalassina sp. are reported from the lower Oligocene sediments cropping out at Salcedo, Italy. Although the material is not sufficiently preserved to be identified below the genus level, it represents an important addition to the known fossil record of the genus. Thalassina sp. from Salcedo is considered the oldest and the only fossil occurrence of the genus from Europe; indeed, the previous reports on Thalassina grandidactylus Robineau Desvoidy, 1849 from the Cretaceous of France and Thalassina sp. from the Pliocene of Italy are disputed herein. Thalassina is today known only from the Indo-West Pacific region; however, unequivocal evidence of Thalassina in the Oligocene strata of Europe suggests the origin of the genus in the west Tethyan (modern circum-Mediterranean area). Alternatively, the geographic distribution of the genus might be wider in the Oligocene than it is today. The Italian material presented herein comes from marine settings with strong fluvial influence, suggesting that the environmental preferences of Thalassina have not changed since the Oligocene.