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Miocene fossils from Africa provide new evidence for the origins of American crocodile paleontology



A team of paleontologists from Italy and Spain compared the only preserved skull Crocodylus checchiai, an extinct species of crocodile that lived in present-day Libya about 7 million years ago (the Miocene epoch), for those of the four living species of crocodiles from America, and found that the ancient African reptile was closely related to American crocodiles. Findings suggest that crocodiles may have migrated from Africa to America during the Miocene.

Life appearance of Crocodylus checchiai from As Sahabi, Libya.  Image credit: DA Iurino.

Life look Crocodylus checchiai from As Sahabi, Libya. Image credit: DA Iurino.

Skull and associated lower jaw of adults Crocodylus checchiai were collected in 1938 at the palaeontological site of As Sahabi in northern Libya.

The sample was described by the Italian paleontologist Angiola Maria Maccagno in 1947 and then hosted in the collections of the Istituto di Paleontologia dell’Università di Roma.

In order to improve knowledge of Crocodylus checchiai and his possible relationships with American crocodiles, Dr. Massimo Delfino of the Università di Torino and the Universitat Autònoma de Barcelona and his colleagues tried to find the original Crocodylus checchiai skull.

Scientists have found this in the University of Earth Sciences collection at Sapienza University in Rome.

They then used computed tomography (CT) to re-examine well-preserved samples.

The seven million skull of Crocodylus checchiai from the As Sahabi mountains in Libya, in the dorsal (a1, a2), ventral (b1, b2), right lateral (cl, c2) and left lateral (dl, d2).  Anatomical abbreviations: bo - basioccipital, bs - basophenoid, ect - ectoterteroid, en - external naris, f - frontal, ak - incisive foramen, itf - infratemporal fenestra, j - jugal, l - tear, m - maxilla, n - nasal, o - orbit, pa - parietal, pal - palatine, pf - prefrontal, pm - premaxilla, po - postorbital, pt - pterygoid, q - quadrate, qj - quadratojugal, soc - supraoccipital, sof - suborbital fenestra, sq - squamosal, stf - supratemporal fenestra, t - tooth.  Scale - 10 cm.  Image credit: Delfino et al., Doi: 10,1038 / s41598-020-68482-5.

7-million-year-old skull Crocodylus checchiai from the point of view of Sahabi, Libya, in dorsal (a1, a2), ventral (b1, b2), right side (cl, c2) and left side (dl, d2) views. Anatomical abbreviations: bo – basioccipital, bs – basophenoid, ect – ectoterteroid, en – external naris, f – frontal, ak – incisive foramen, itf – infratemporal fenestra, j – jugal, l – tear, m – maxilla, n – nasal, o – orbit, pa – parietal, pal – palatine, pf – prefrontal, pm – premaxilla, po – postorbital, pt – pterygoid, q – quadrate, qj – quadratojugal, soc – supraoccipital, sof – suborbital fenestra, sq – squamosal, stf – supratemporal fenestra, t – tooth. Scale – 10 cm. Image credit: Delfino et al, doi: 10,1038 / s41598-020-68482-5.

They identified several new internal structures, including a protrusion in the center of the snout, which was not identified on any other African crocodile species.

This unique structure, called the mid-boss boss, also occurs in four living American crocodiles: Crocodylus intermedius. C. moreletii, C. acutus a C. diamondand suggests a close developmental relationship between Crocodylus checchiai and crocodiles from America.

“Analyzes of evolutionary relationships between species suggest that Crocodylus checchiai they can be part of the same line as the four American crocodiles, “the scientists said.

“remains Crocodylus checchiai were dated about 7 million years ago, while the oldest remnants of the American crocodile, extinct Crocodylus falconensis, were dated approximately 5 million years ago. “

“Based on these findings, we propose that crocodiles enter America by migrating west from Australasia through Africa.”

The findings were published in a journal Scientific reports.

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M. Delfino et al, 2020. Ancient African fossils provide new evidence of the origin of American crocodiles. Sci Rep 10, 11127; doi: 10,1038 / s41598-020-68482-5


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