Tiny teeth, no more than a handful’s worth, were all that researchers had to work with but it was enough. From the teeth they have identified a new rodent species and determined that it has been extinct for around 18 million years.
This new species – Sayimys negevensis – was discovered in Israel’s Negev desert (the species was named for the Negev area where it was discovered) and researchers hope it will shed new light on the dispersal routes of several species, including mammals, between Africa and Eurasia during the Early Miocene which occurred between 23 million and 16 million years ago.
The discovery has already highlighted Israel’s unique paleogeographic status as an important piece of the Levantine corridor which connected North Africa with Eurasia. Israel is the one place in the Eastern Mediterranean – from Sinai to Anatolia – where Early Miocene fossil sites have been discovered.
The research, published in the open access journal PLOS ONE, describes a distant ancestor of today’s gundi: a small rodent who sports bristles (which resemble a comb) on its hind feet’s two middle toes – not surprisingly the gundi is also referred to as a comb-rat.
“It is a pivotal species that bridges the gap between an array of primitive Ctenodactylines and the most derived, Early Miocene and later, gundis,” the authors wrote in the PLOS ONE article.
Gundis are the only remaining descendants of the Ctenodactylidae family whose ancestors appeared in Asia around 40 million years ago. The species’ widest distribution and greatest diversification occurred from the Far East to Africa, during the Miocene. Today, they live in groups in the deserts and semi-deserts of North and East Africa.
“The fossil sites of Israel are in a unique position to offer data on the early times of the large waves of faunal exchanges that took place around 19 million years ago between Eurasia and Africa,” Dr. Raquel Lopez-Antoñanzas, with the University of Bristol, said in a press release.
At the time of the Early Miocene, what’s known as Israel today was still attached to Africa. Almost all of the mammals found in modern Israel originated in Africa. Sayimys negevensis is one of only a few species found in Israel with connections to Eurasia.
“The new Israeli species is closer in morphology to nearly coeval species found in Pakistan, therefore demonstrating that mammals were already using the Levantine corridor to travel between Eurasia and Africa in the Early Miocene,” Dr. Rivka Rabinovich, a research co-author with the Institute of Earth Sciences and the National Natural History Collections at the Hebrew University of Jerusalem, said in the press release.
The new rodent discovery is part of international research being undertaken by scientists from the Israel Geological Survey, Midwestern University in Glendale, Arizona, the University of Manchester and the University of Connecticut; focusing on the paleogeographic implications involving the fauna of Israel during the Early Miocene.
For more information www.journals.plos.org
Image courtesy of Rivka Rabinovich