Re-evaluation of squaloid shark records from the Albian and Cenomanian of Lithuania

In 1935, Dalinkevičius described and illustrated several teeth of squaloid sharks from Lithuania, originating from deposits considered by him to be of Cenomanian and Turonian age. To date, these strata are known to be of late Albian and late Cenomanian age, respectively. A re-examination of the original collection, together with an analysis of newly collected material, allows these squaloid teeth to be identified as Protosqualus glickmani Averianov, 1997, Squalus sp., Squaliodalatias sp. and Protocentrophorus balticus (Dalinkevičius, 1935) nov. gen., morphologically different from the extant genus Centrophorus. The present material also enables a detailed insight into the first evolutionary stages of deep-sea squaloid sharks, confirmation of the most recent phylogenetic hypotheses regarding extant taxa (e.g., dalatiids being no more derived than other 'modern-type' squaloid families) and identification of a possible centre of origin of such sharks in Boreal Europe and the Central Asian seaway.