Meyasaurus

Meyasaurus diazromerali was a small lizard from the Barremian of Las Hoyas in central Spain. The holotype LH 370 is a nearly complete skeleton preserved on a slab and its counterpart; five additional specimens described by Susan Evans and Luis Javier Barbadillo help show how the skull, limbs and teeth varied across the sample. Its fossils make it one of the better represented Mesozoic lizards from Iberia, yet they do not preserve a confirmed meal, original colour or a precise family-tree position accepted by every analysis. Meyasaurus belongs in the ancient lizard and snake catalogue with other early squamates such as Hoyalacerta.

Quick facts

A fossil series from Las Hoyas

Evans and Barbadillo described Meyasaurus diazromerali in 1997 from Las Hoyas, in Cuenca Province. The holotype LH 370 is held by the Museo de Cuenca and preserves the part and counterpart of a near-complete skeleton. The species name honours Armando Diaz-Romeral, who collected important Las Hoyas fossils. The limestone horizon is assigned to Unit III of the La Huérguina Formation and is Barremian in age.

The 1997 description also examined five referred specimens: LH 372, LH 33, LH 13510, LH 6026 and LH 14317. These fossils are not all equally complete. Some preserve a skull, neck and shoulder region; others are fragmentary or represent a very young individual. A sample of repeated elements lets researchers distinguish species-level traits from a break or a feature visible in only one slab.

The type specimen's preservation as two surfaces reflects how the limestone split. The counterpart is not a second individual and should not be counted as another skeleton. Flattening and displacement also affect measurements, so the anatomy is reconstructed from both sides and the additional specimens.

Skull and teeth

The skull is narrow, with large eye openings. A diagnostic feature in the adult skull is the frontal bones, which are broad near the frontoparietal contact but sharply constricted between the orbits. The holotype's jaws have about 30 tooth positions. Some teeth are bicuspid, while the shape and size vary along the tooth row.

Small, pointed teeth are compatible with taking insects and other small invertebrates. That is a functional interpretation, not a fossil meal: the described specimens do not preserve stomach contents or prey remains clearly linked to Meyasaurus. Tooth form can constrain how food was held, but it does not by itself provide a species-specific menu.

The original authors compared the palate, temporal region and lower jaw with other Early Cretaceous lizards. Later studies have described Meyasaurus as a lacertoid scincomorph or used broader groupings as classification changed. It is more accurate to report those analyses than to assign it without qualification to a modern family.

Body, limbs and growth

The holotype preserves a long tail and four well-developed limbs. The hind limb has a robust femur and shorter tibia and fibula; the foot includes a short, hooked fifth metatarsal. These proportions support a terrestrial lizard capable of moving on land. They do not show a specialised aquatic paddle or a gliding rib apparatus.

The referred series includes a very young individual as well as larger specimens. Differences in skull roof, limb bones and degree of fusion can reflect growth, and the authors noted features that change between young and adult stages. The sample is informative, but it is not a full histological series and cannot establish exact growth rate or lifespan.

Because the fossils are flattened, body depth, muscle volume and exact mass are not measurable from the slab. A restoration can follow the skeleton's proportions while still having to infer the soft outline. Skin colour and scale pattern are unknown.

Las Hoyas and what the fossils cannot show

Las Hoyas formed in a freshwater wetland and lake system. Fine-grained carbonate sediment helped preserve small vertebrates, plants and invertebrates. Fishes, amphibians, crocodyliforms, turtles, dinosaurs and birds all occur in the broader assemblage. The setting offers environmental context, but a skeleton in lake limestone does not prove the animal lived in the water.

Meyasaurus could have foraged on land near wetland margins, but the fossils do not preserve a trackway, nest or direct feeding trace. The site also contains other small lizards, including Kuroyuriella from Cretaceous Asia and Hoyalacerta from Las Hoyas; comparison helps define anatomy without implying that they had the same ecology.

The strongest reconstruction combines direct skeletal details from several specimens and labels the remaining uncertainty. The skull, limbs and tooth rows are known; exact prey, behaviour, colour and close phylogenetic relationships remain open to testing with additional fossils and revised analyses.