About 34 million years ago, in the Eocene period of the Paleogene (the period from 66 to 23 million years ago), and in a tropical-like environment with forests and swamps in what is today the Qatrani Desert in Egypt’s Fayoum Depression, a genus of rodents that was not known before, used to live.
In a new study published in PeerJ, researcher Shorouk Al-Ashqar, a member of the “Sallam Lab” team specialised in vertebrate fossils at Mansoura University, studied two skulls and a large group of mandibles of fossils belong to the “Qatranimys Safroutus”.
“But it wasn’t easy; the samples were very small and very thin and adhered to the solid rocky clay, which made preparing the samples for study very difficult. We had to make accurate CT scans to be able to study them in a three-dimensional image,” said Hesham Sallam, the lead author of the study.
The newly discovered genus of rodents was called “Qatranimys Safroutus” which refers to the location of the discovery in the first word, whilst “safroutus” means too small in the Egyptian Arabic dialect.
The length of the molar of Qatranimys Safroutus was one millimetre, and its skull was about 1.5 centimetres long, and its weight did not exceed 45 grams.
Jebel Qatrani Formation is famous for its rich rodent assemblages from the Eocene–Oligocene deposits, which contributes to enhancing our understanding of the origin and paleobiogeography of what scientists call the “Hystricognathi” which are an infraorder of rodents, distinguished from other rodents by the bone structure of their skulls.
Al-Ashqar said that the samples used in the study showed clear differences in the morphological characteristics of the upper and lower teeth. And by comparing these samples with the discovered rodents from Afro-Arabia, it was clear that it belongs to a new genus that has never been discovered before.
“We did not only record a new genus and species, but we were able to record the first bones of the skull of a large group to which the discovery belongs, called the “Phiocricetomys”, she added.
Researchers from Mansoura University, the American University in Cairo, the Egyptian Environmental Affairs Agency, Duke University and the University of Salford participated in the study.