Baja California legless lizard  (Anniella geronimensis)

The Baja California legless lizard is classified as Endangered (EN) on the IUCN Red List (1).

The Baja California legless lizard (Anniella geronimensis) is a secretive reptile that looks very much like a snake in appearance.  However, both snakes and legless lizards have evolved the legless trait independently from each other. The Baja California legless lizard can be distinguished from snake species by its moveable eyelids, and can even be seen blinking in good light. Unlike snakes, it is unable to flex its jaws to swallow something larger than its own head (2).

The Baja California legless lizard has smooth, glossy scales which vary in colour from silvery-grey to black, with multiple black stripes and a belly which is lighter in colour. The Baja California legless lizard has a shovel-shaped snout and a blunt tail, which are adapted to suit its burrowing lifestyle (2) (3).

The Baja California legless lizard is endemic to the Pacific peninsula of Mexico, occurring only on the western side of the state of Baja California. It occupies a narrow strip just 87 kilometres long, ranging from a few miles north of Colonia Guerrero, south to the vicinity of Punta Baja. It has also been found to inhabit the small Pacific island of Isla San Gerónimo (1) (3).

The Baja Californian legless lizard is restricted to the sand dunes of coastal regions, where it burrows into fine-grained sand to avoid detection by predators. It has adapted to a life underground, preferring warm and moist conditions (4). The Baja Californian legless lizard is commonly found at the base of plants present on the coastal dunes such as brittlebush (Encelia sp.), bursag (Ambrosia sp.) and locoweed (Astragulus sp.) (1).

The Baja California legless lizard gives birth to one to two live young, which develop as embryos inside the female’s body before being born. Breeding takes place during late spring and early summer, with the young born in September, October and even November (2) (3).

There is little information on the daily habits of the Baja California legless lizard. However, other species in the genus Aniella are known to be tolerant of relatively low temperatures allowing them to remain active in moist, cool, coastal habitats (4) (6).

Species of the genus Aniella primarily feed on insects, spiders and insect larvae (2).

Coastal tourist development, road building, intensification of agriculture (in particular the use of pesticides), use of off-road vehicles and general urbanisation all threaten the sand dune ecosystem which the Baja California legless lizard inhabits (1).

There are no specific conservation measures currently in place for the Baja California legless lizard. However, changes in the abundance and distribution of this species need to be recorded through the monitoring of its populations, and protected areas are urgently needed for its survival (1).

Like closely-related species, the Baja California legless lizard may potentially benefit from habitat restoration through the replacement of exotic plants with native communities (5).

View information on this species at the UNEP World Conservation Monitoring Centre.

Learn more about reptile conservation:

• International Reptile Conservation Foundation:
  http://www.ircf.org/