The researcher at the National Museum of Natural Sciences (MNCN-CSIC) Jan van der Made has described a more recent descendant of Megaloceros savini, which is a dwarf form of the giant deer group.
The new species, named Megaloceros matritensis, is closely related to others of the genus of giant deer Megaloceros. "It was surely a fairly common animal around 350,000 years ago, at which time it was a contemporary of its more famous relative, M. giganteus," says Van der Made.
The fossils on which the definition of the species is based are deposited in the MNCN collections where, since last February 7, you can visit a sample which describes what this deer was like and the geological characteristics of the river terraces. The period to which they belong is well documented in Europe and it is striking that the species has not been detected before.
“Until now it was thought that the fossils of the Manzanares terraces belonged to their predecessor M. savini, which led to contradictions in the dating of the river terraces. With this discovery, the confusion about the age of the terraces has been solved: they were formed between 400,000 and 300,000 years ago ”, the researcher clarifies.
A smaller giant deer
In addition to differences in the shape of the antlers and the size of their teeth and bones, the species had masticatory adaptations, such as particularly large premolars, teeth with especially thick enamel and a lower position of the condyle (the joint that joins the jaw with the skull).
“Although we do not know the diet of this deer, the data provided by its fossils allow us to infer that it was a browsing herbivore that selected a lot of food. The thickness of the enamel of its dentition, makes us think that it possibly fed on harder plants than those that usually form the diet of giant deer. Likewise, the geological characteristics of the areas where their fossils have been found favor the growth of plants adapted to soils rich in gypsum that were possibly part of their diet ”, explains the paleontologist.
The species has been described thanks to fossil material collected on the terraces that for thousands of years was forming the Manzanares river south of Madrid.
"We are talking about a geological stage that is highly documented," explains Van der Made. "Much material that we now know that belonged to M. matritensis has been found in archaeological sites, along with Acheulean and Mousterian lithic industry, because our protagonist was part of the diet of the inhabitants of the Manzanares basin at that time," continues the expert.
“One of the curiosities of this research is that it contradicts Cope's rule, according to which species tend to evolve by increasing their size, a rule that cervids did seem to comply with. However, M. matritensis, the last member of a giant deer lineage, was decreasing in size during the Middle Pleistocene”Says Van der Made.
Jan van der Made. «The dwarfed “giant deer” Megaloceros matritensis n.sp. from the Middle Pleistocene of Madrid - A descendant of M. savini and contemporary to M. giganteus«. (2018) Quaternary International. DOI: https://doi.org/10.1016/j.quaint.2018.06.006.