How crocodiles first reached the Americas has long been a matter of debate. Now Italian researchers are suggesting they came from Australasia, migrating west via Africa during the Late Miocene epoch (11–5 million years ago).
This follows a detailed analysis of a skull unearthed in Libya that has similarities to living species in America but not Africa.
What they describe as the only well-preserved skull of Crocodylus checchiai was discovered in As Sahabi back in 1939 and has been stored in the museum at Sapienza Università di Roma.
Recently, the team led by Sapienza’s Dawid Iurino and Massimo Delfino from Università di Torino used CT imaging to re-examine it and identified several new structures, including a protrusion in the middle of the snout that has not been identified on any other African crocodile species.
It is, however, present on the skulls of four American species – the Neotropical crocodiles C. intermedius, C. moreleti, C. acutus and C. rhombifer – suggesting, the researchers say, there is a close evolutionary relationship with C. checchiai.
“According to our phylogenetic analyses, C. checchiai is related to the Neotropical taxa and could be even located at the base of their radiation, therefore representing the missing link between the African and the American lineages,” the write in a paper in the journal Scientific Reports.
The remains of C. checchiai have been dated to around seven million years ago while the oldest known remains of an American crocodile, the extinct C. falconensis, are from around five million years ago.