Lacertidae

The Lacertidae, commonly called wall lizards, true lizards, or simply lacertas, are a family native to Afro-Eurasia. With roughly 360 species spread across 39 genera, they are the most common reptiles in Europe. Their habitats vary by region. In Europe and the Mediterranean, lacertids are mostly found in forests and scrublands.

Habitat

In Asia, species from the genera Eremias and Ophisops take over in grasslands and deserts. African species typically inhabit rocky, arid areas. Only a few lacertids, such as the two species of Holaspis (Holaspis guentheri and Holaspis laevis), are arboreal; these are gliders, though not very skilled ones, using their broad tails and flattened bodies as an aerofoil. Most lacertids are small to medium-sized, with the majority under 9 centimeters long (not counting the tail).

Description

The largest living species, Gallotia stehlini, reaches 46 centimeters, and some extinct forms were even larger. They are mainly insectivorous, but Meroles anchietae is an exception: some individuals eat mostly arthropods and plants, while others in the Namib Desert specialize in seeds. Lacertids share a similar body shape—slender bodies and long tails—but their patterns and colors vary greatly, even within a single species. Their scales are large on the head (which often has osteoderms), small and granular on the back, and rectangular on the underside.

Evolutionary history

Most species show sexual dimorphism, with males and females having different patterns. At least eight species from the Caucasus are parthenogenetic, and three species give birth to live young, including the viviparous lizard, Zootoca vivipara. The earliest fossils suggest lacertids originated in Europe, alongside their extinct sister group, the Eolacertidae. Possible lacertid fossils are known from the Paleocene of France and Belgium, but the oldest definite specimen comes from the early Eocene (Ypresian) of Mutigny, France, in the Paris Basin.

Classification

They spread into Asia by the early Oligocene. The timing of their colonization of Africa is uncertain, ranging from the Eocene to the Miocene. The classification below, into subfamilies and tribes, follows Arnold et al. (2007), based on their phylogenetic analysis. The most recent extensive phylogenetic tree for lacertids was published by Baeckens et al. in 2015.