The giant 'shrews' of nearly 1 million years old fossils are found in Spain

Analysis of phylogenetic and dental measurements and fossilized functions of shrews found in Gran Dolina de Atapuerce sediment, Burgos concluded that this is a new species (scientific name is Dolinasorex glyphodon) has never been described before. This extinct animal has red teeth, larger in size than mammals of their relatives; and they are more closely related to Asian shrews than European shrews.

Researchers from the University of Zaragoza (UNIZAR) have discovered fossils in the TD4, TD5, and TD6 floors of Gran Dolina in Burgos dating from 78 to 90 thousand years ago, and show that fossils This is of a new shrew (Dolinasorex glyphodon), belonging to the Soricidae family (small mammal that feeds on insects).

Juan Rofes, the lead author of the paper, was recently published in the 'Zoological Journal of the Linnean Society' and a researcher of the Department of Paleontology, University of Zaragoza, said 'until now, all the samples Soricdae fossils found in sediments in the Atapuerca mountain range belong to the Beremendia fissidens family, a pleitoxen-period shrew that once dispersed throughout Europe. '

The research on phylogenetic development and the calculation of the size and weight of species has recently revealed a close relationship with East Asian shrews. That may be where the rat species grows and evolves before migrating to the Iberi Peninsula.

In addition, the analysis of jaw bone and teeth of Dolinasorex glyphodon collected between 1991 and 2007 in Atapuerca allows scientists to develop the hypothesis of ancient ecology and biogeography. According to this hypothesis, this animal used to live in a relatively stable warm, humid and climate. 'The origin and initial dispersion of this shrew is probably from and from Asia,' Rofes said.

The jaws and teeth of a shrew found in the sediment at Gran Dolina de Atapuerca, Burgos points out that this is a new animal. (Photo: J.Trueba)

Shrews with an unusual shape

Dolinasorex glyphodon is a red shrew of the Soricinae family. By contrast calculation method (finding the correlation between the size change of parts and the general size change of the whole body), the researchers describe it as a "giant". Compared to a modern, large-sized shrew, belonging to Soricidae relatives like water shrews (Neomys fodiens) weighing about 14 grams, the total weight of that extinct shrew reaches 60 grams.

Research on the remaining fossils of this mammal also shows that the shrew has the ability to transmit venom, similar to how snakes do, through a narrow and conspicuous poison conductor. the inside of the lower teeth 'The mechanism is very similar to modern solenodons and almiquis, close relatives of shrews, who now live in Cuba and the island of Haiti' explained Rofes.

Although the remains of shrews are often found in ancient sediments, their presence, above all, is due to the habit of feeding their predators. The birds eat small, vertebrate animals, and then they use the skin, feathers, and bones of the prey into small pellets to feed the chicks, the researcher adds.

Compared with animal populations from many other sediment areas in Europe, those who discovered Dolinasorex glyphodon could describe it as a local specialty, and this is the first time a species of Soricinae is known. arrived on the Iberi Peninsula. However, Rofes and his team also stressed that 'the results of this ancient phylogenetic study are only the first step and are not yet the end result. However, these results may be interesting to conduct more complete studies in the future. '

References:
Juan Rofes, Gloria Cuenca-Bescós.A new genus of red-toothed shrew (Mammalia, Soricidae) from the Early Pleistocene of Gran Dolina (Atapuerca, Burgos, Spain), and a phylogenetic approach to the Eurasiatic Soricinae.Zoological Journal of the Linnean Society, 2009;155 (4): 904 DOI: 10.1111 / j.1096-3642.2008.00470.x