Palaeontologists Vicente D. Crespo, Francisco Javier Ruiz Sánchez and Plini Montoya, from the department of Botanics and Geology of the Universitat de València, and Marc Furió, from the Institut Català de Paleontologia, have discovered a new fossilised species of insectivore belonging to the unusual and extinct Plesiodimylus family. The identification of this group, related to the fauna that lived in Central Europe during the Miocene (16 million years ago), is based on the study of isolated teeth found in l'Alcora (Castellón), in the district of Araya.

This new species of insectivore, found in the palaeontological site Mas d'Antolino B, has been unveiled in the Historical Biology journal and has the scientific denomination Plesiodimylus ilercavonicus, in reference to the Iberian Ilercavones people, who inhabited part of what are the provinces of Castellón and Tarrragona today.

This family is defined by having teeth that protrude from the jaw, with thicker dental enamel than other mammals, as well as the presence of four molars (two in each jawbones, or one in each jawbone and then one more in each maxilla). These characteristics give them an unusual look -- with overgrown teeth.

Furthermore, by studying the dentition of this species and specially with the type of wear suffered by the teeth's enamel, one can surmise they would have fed mainly on gastropods, the most common group of mollusks, according to Crespo, Ruiz Sánchez and Montoya -- also researchers for Valencia's Natural History Museum -, and Marc Furió.

Until now, the finding of material from this animal group in Araya is the only one of its kind in the Iberian Peninsula, joining findings of other species from Central Europe such as some types of hamsters and other rodents, bats and insectivores, which reveal a phase of faunistic exchange between Iberia and Central Europe in the Lower Miocene.

In order to obtain the fossilised remains of these small mammals, a strenuous process to clean and sieve through tones of sediment was undertaken, as well as the examination of the residue obtained through this process. The studying of the specimens was performed with various techniques, including some derived from the use of electronic microscopy devices. The results of the study were unveiled at the 15th Annual Meeting of the European Association of Vertebrate Palaeontologists, held in Munich (Germany) during the summer of 2017.

In the Mas d'Antolino B palaeontological site, available since 2008, fossils of other species of shrews, squirrels, hamsters, dormice, bats or crocodiles have been unearthed, among others. These faunas, in a context of an environment similar to the current day rainforests, date back to the Aragonian age of mammals, also within the Miocene period. In this era there was a rainforest where Araya is currently located, with meadows, which would have been located near a great lake which reached most of today's l'Alcora, Ribesalbes and Fanzara villages.