Jucaraseps grandipes is the name of the new genus and species of Cretaceous lizard that has recently been published in the journal Palaeontology. This is an extinct tiny lizard, of about 27 mm in length (excluding tail) and less than one gram of mass, which articulated fossil skeleton was found at the site of Las Hoyas, Cuenca. The work is signed by the Institut Català de Paleontologia Miquel Crusafont (ICP) researcher Arnau Bolet and the University College of London (UCL) researcher Susan E. Evans.
The Cretaceous paleontological site of Las Hoyas, which dates back some 120 million years ago, is internationally known for the discovery of numerous articulated vertebrate skeletons in an exceptional state of preservation. The work published in the online edition of the journal Palaeontology, signed by Arnau Bolet of the ICP and Susan E. Evans of the UCL, describes a new genus of lizard from the remains of a extremely small but well preserved connected skeleton.
The new species has been dubbed Jucaraseps grandipes. The genus gets its name from the Jucar river, which flows near the site, and from the Latin word seps meaning lizard or snake. grandipes derives from the Latin words grandis and pes, which mean big foot. In fact, the Jucaraseps configuration, in which the legs are quite small but the feet are proportionally very large, is unique among lizards, both fossil and extant. The holotype of this species is deposited in the Science Museum of Castilla-La Mancha in Cuenca.
When compared to other lizards and taking into account the habitat of Las Hoyas in the Early Cretaceous, Jucaraseps probably was a terrestrial lizard hunting small insects, which would have been the prey of other small vertebrates and, maybe, also of large invertebrates .
So far, such small lizards were unaware of the Cretaceous period, even if among extant amniotes the smallest species are always lizards. Having a small size implies a large number of advantages as a much faster maturation, more agility, smaller energy requirements and the fact that facilitates larger populations, with a larger genetic pool.
Jucaraseps is the smallest of the five types of lizards found in Las Hoyas. A few months ago, the same researchers published a paper on the second specimen of Scandensia ciervensis found in this site. In addition, different specimens of Meyasaurus have been found, six of which have already been described and others yet to be studied. A few years ago the lizard Hoyalacerta sanzi was also described , which is only known by the type specimen. Regarding the fifth lizard, only the osteoderms (dermal plates) are known, which are quite characteristic and enable us to connect it with Paramacellodids, a type of lizard widely distributed during the Mesozoic.
Las Hoyas is a site of exceptional richness, which has also given numerous fossil remains of fish, amphibians (frogs and salamanders) and reptiles such as crocodiles, turtles and birds, together with lizards.