Crocodiles that inhabited the shores of North Africa during the late Miocene embarked on crossing what is now the Mediterranean basin to reach Europe. This is confirmed by the analysis of the first fossils of the genusCrocodylus from the Iberian Peninsula, found in the Valencian site of Venta del Moro between 1995 and 2006, and which are now being described for the first time.
Millions of years ago in Europe inhabited various species ofcrocodiles of different genres and characteristics that sometimes coexisted. But among all these species, it was believed unlikely that crocodiles of the genusCrocodylus, fromAfrican origin, would have lived at some point in the Mediterranean basin. The remains found in the Italian regions of Gargano, Tuscany and Scontrone during the last decades confirm that they did.
Now a study published in theJournal of Paleontology corroborates it with the fossils oftwo crocodiles about three meters long discovered in the Valencian deposit ofSale of the Moro –Excavated by researchers from the University of Valencia between 1995 and 2006–, and which were assigned at the time to the speciesCrocodylus checchiai. The new work describes the remains for the first time more than 14 years after they were found.
“Our comparisons indicate that this material clearly does not belong to the genresDiplocynodon –An extinct genus of alligator, similar to current alligators– orTomistoma–Similar to the gharials–, the only other two crocodilians described so far for the European late Miocene ”, he explainsAngel Hernandez Luján, paleontologist at the Institut Català de Paleontologia Miquel Crusafont (ICP) and co-author of the work.
However, since they are too fragmented remains, analysis of cranial bones, isolated teeth and osteoderms (bone plate of the skin) suggests that they could belong to the speciesC. checchiai, as it was assigned at the time of its discovery, but its taxonomy is still not entirely clear and prevents a more precise specific identification. In any case, “the morphology of the Venta del Moro crocodile remains is congruent with gender.Crocodylus”, Assures the researcher.
From Africa to Europe I swim
The fossil remains of this Valencian site, which are the first ofCrocodylus of theIberian Peninsula, support "unequivocally" thenon-occasional dispersal of this genus from Africa to Europe during the late Miocene, according to paleontologists. The finding of two partial individuals, instead of just one, could indicate that an entire population was present in this area.
In its "colonization”, These reptiles spread more especially in the southern areas of Mediterranean Europe, as suggested by the Italian and Spanish areas where the fossils have been found. "All European localities with late Miocene crocodilians, including Venta del Moro, were at that time near the northern coast of the Mediterranean and, therefore, easily accessible by specimens that were dispersed by seawater", underline the authors in the study.
“The most certain is that it would have also inhabited the coasts ofMurcia YAndalusia, although we cannot rule out that it had also dispersed along theCatalonia andBalearic Islands”, Says Hernández Luján. But how could they get there from the African shores?
The researchers' hypothesis is that these crocodiles swam through the sea from one continent to another before a land connection was established between Africa and Europe. This idea would be supported by the behavior of modern crocodiles, which aregood swimmers and that they can even reach 32 km / h in the water.
An example of this is the currentsaltwater crocodile (Crocodylus porosus), which can make large inroads into the open sea to colonize other islands or other continents between Oceania and Southeast Asia. "You just have to see how easily it moves in the open sea, being seen in the waters of the Solomon Islands or even in French Polynesia," says the paleontologist.
But there are more examples that support this hypothesis. Due to the anatomical similarity with theamerican crocodiles, the extinct speciesCrocodylus checchiai, coming from Libya and Kenya, it could be his ancestor. This suggests that the crocodiles were able to cross theAtlantic Ocean during the Miocene, which would explain the appearance of the genus in America.
Therefore, in the case of the specimens found in Venta del Moro, swimming between the African and European continents “should not have involved a great effort until they reached the Peninsula”, concludes the researcher.
Massimo Delfino et al. "Late Miocene remains from Venta del Moro (Iberian Peninsula) provide further insights on the dispersal of crocodiles across the late Miocene Tethys"Journal of Paleontology August 2020
Rights: Creative Commons.