Recent genetic research has brought up interesting questions about the evolutionary history of California legless lizards. Pearse and Pogson (2000) discovered the subspecies were split into separate northern and southern clades. They believe that the two populations are actually an example of parallel evolution, the darker variation of Anniella pulchra arising independently at least two times (2000). Another study done by Parham and Papenfuss (2008) determined the presence of at least five deep genetic lineages of Anniella pulcrha throughout California. They suggest that some clades are "genetically isolated to the point of being considered species under some concepts" (Parham and Papenfuss 2008, p. 5). These deep genetic variations require more study as they may have important conservation implications.
California legless lizards avoid most predation by spending most of their time underground. However, when threatened by a predator they are able to lose their tail in order to escape. The tail will regenerate over the course of about one year, but will be much shorter, darker, and more blunt than the original. More than half of all individuals have regrown tails (Miller 1944).
Predators include ringneck snakes (Diadophis punctatus), common kingsnakes (Lampropeltis getula), deer mice (Peromyscus maniculatus), long-tailed weasels (Mustela frenata), domestic cats (Felis sylvestris), California thrashers (Toxostoma redivivum), American robins (Turdus migratorius), and loggerhead shrikes (Lanius ludovicianus) (Jennings and Hayes 1994; Miller 1944).
Known Predators:
California legless lizards are often mistaken for snakes because of their complete lack of limbs and elongated bodies. However, California legless lizards lack external ear openings and have unreduced eyes with moveable lids (Cogger and Zweifel, 1998). California legless lizards can also use tail autotomy to avoid predation, unlike snakes. Snout to vent length is 90 to 170 mm and total length is around 200 mm. Generally females are slightly larger, males are smaller by up to 10% of female size. Sexes are nearly impossible to distinguish without dissection.
Color varies with subspecies. In the more common Anniella pulchra pulchra, newborn lizards start out as a silvery drab color on their dorsal side and various shades of yellow on the ventral side. Anniella pulchra nigra begin life as silvery on their dorsal side and yellowy on their underside, but change with age. Adults vary in color from brown, to dark brown, to completely black.
Markings include one generally well defined line along the top of the backside and several other lateral sides. Depending of the overall darkness of the specimen, the markings vary in prominence and definition. In the blackest examples, the lines are not noticeable (Miller 1943).
Range mass: 0.9 to 4.7 g.
Range length: 111 to 228 mm.
Range basal metabolic rate: .028 to .116 cm3.O2/g/hr.
Other Physical Features: heterothermic
Sexual Dimorphism: sexes alike; female larger
There exists almost no data on the longevity of California legless lizards in the wild, though one adult specimen is known to have lived for six years in a lab (Jennings and Hayes 1994).
Range lifespan
Status: captivity: 6 (high) years.
Unlike most lizards, California legless lizards prefer lower temperatures. In one study it was found that the average temperature of these lizards was between 21 and 28 degrees Celsius. They suggest that being adapted to this lower and wider range of temperatures allows them to remain active in the cooler temperatures of their subterranean environments. They can also remain active in cooler temperatures above ground. have “increased activity in its subterranean environment,” which is in line with observations that they are active on cooler days.
California legless lizards require loose sand for burrowing (sand, loam, or humus), moisture, warmth, and plant cover (Stebbins 2003). As a result, they are most commonly found within 100 km of the coast in dunes which harbor bush lupine (Lupinus arboreus), mock heather (Eriogonum parvilfolium), mock aster (Ericameria ericoides), and other native coastal shrubs (Jennings and Hayes 1994). These shrubs are ideal because they provide plenty of leaf litter, which helps keep temperatures in the sand relatively low and moisture content relatively high on hot days, and have extensive root systems, which attract plenty of insects for prey.
Additionally, moisture is a key aspect of their environment. Without adequate moisture they cannot shed their skin, which inhibits vision and feeding, causing them to become inactive and even starve to death (Miller 1944).
Range elevation: 0 to 1800 m.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: desert or dune ; chaparral ; scrub forest
California legless lizards are found in California and Mexico. They are found from western central California (San Joaquin and the coastal regions), through northwestern Baja California, and as far south as Colonia Guerrero, Mexico (Miller 1944; Stebbins 2003).
Biogeographic Regions: nearctic (Native )
California legless lizards forage in leaf litter for prey. Their primary diet consists of insect larvae, termites, beetles, spiders, and other invertebrates (Dudek and Associates, Inc. 2000; Stebbins 2003). Often they will not eat prey on the surface, but will burrow underground before consuming the prey (Miller 1944).
Animal Foods: insects; terrestrial non-insect arthropods
Primary Diet: carnivore (Insectivore , Eats non-insect arthropods)
Other than their immediate effect on prey and predators, not much is known about the role of Anniella pulchra in the ecosystems they inhabit. It is reported that they are parasitized by a nematode and a cestode (Miller 1944).
Commensal/Parasitic Species:
California legless lizards provide no known direct benefit to humans, although all species could play important roles in ecosystem stability.
There are no known adverse effects of Anniella pulchra on humans.
Aside from size and color, newly born Anniella pulchra are nearly identical to their adult forms. As they grow, their dorsal color usually darkens: slightly in Anniella pulchra pulchra, and more significantly in Anniella pulchra nigra.
The main threat facing California legless lizards is human habitat disturbance. Harmful activities include the destruction of natural habitat for agriculture, housing developments, sand mining, golf courses, and off-road vehicle activities (Stebbins 2003). Additionally, exotic plant species, such as ice plants (Carpobrotus edulis and Mesembryanthemum crystallinum), Marram grass (Ammophila arenaria), veldt grass (Ehrharta calycina) and eucalyptus trees (Eucalyptus spp.) support much smaller populations of insects and arthropods, which these lizards depend on for food (Jennings and Hayes 1994).
In 1998 to 1999, a moderate-high impact search was done at Moss Landing dune, California, over an area of 1.57 hectares. Previous studies based on lower impact searches would suggest a population of about 170, though researchers found nearly 3600. These results suggest that California legless lizards may be locally abundant (Kuhnz et al. 2005).
Though California legless lizards are listed as a species of special concern in California, they are not protected by federal or international regulations.
In 1998, a rule was proposed to the Department of the Interior Fish and Wildlife Service to list Anniella pulchra nigra as endangered, but it was withdrawn based on the amount of currently protected habitat and conservation efforts to restore native vegetation to dunes colonized by alien vegetation.
US Federal List: no special status
CITES: no special status
IUCN Red List of Threatened Species: least concern
Though it is unknown how California legless lizards communicate or interact,there is a fair bit known about how they perceive their environment. They have eyes and are believed to be relatively near-sighted. Though they have no external ear openings, they have a keen sense of mechanical disturbances and can sense vibrations well; individuals almost never feed aboveground, instead preferring to dig under ground and come up directly beneath the prey. Olfactory senses also seem likely as there are recorded instances of California legless lizards sticking their heads above ground while the body is still submerged and licking at the air, as if tasting it (Miller 1944).
Perception Channels: visual ; tactile ; vibrations ; chemical
Not much is known about mating in California legless lizards.
Little data is available on the reproductive behaviors of California legless lizards. The breeding season is thought to be between the spring months and July and young are commonly born between September and November, suggesting a gestation period of four months. California legless lizards typically mature at two to three years of age for males and females (respectively). Maturation seems to be linked to size: 90 mm snout to vent length in males and 121 mm snout to vent length in females are the sizes at which sexual maturity is reached. Females are ovoviviparous and give live birth to litters of one to four young, most often two (Jenning and Hayes 1994; Miller 1944; Dudek and Associates, Inc. 2000).
Breeding interval: California legless lizards have been observed to breed biennially, but it is not known if this is true of all populations.
Breeding season: The breeding season probably occurs between early spring and July.
Range number of offspring: 1 to 4.
Average number of offspring: 2.
Average gestation period: 4 months.
Average age at sexual or reproductive maturity (female): 2 years.
Average age at sexual or reproductive maturity (male): 3 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; sexual ; fertilization ; ovoviviparous
As with most species of lizards, there is little to no parental investment in California legless lizards. Young are born live and are immediately independent (Miller 1944).
Parental Investment: no parental involvement; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Female)
Anniella pulchra, the California legless lizard, is a limbless, burrowing lizard often mistaken for a snake.
These lizards are around 7 inches (18 cm) long from snout to vent (not including tail). They have small, smooth scales typically colored silvery above and yellow below, although black or dark brown forms exist in Monterey County, California[2] which were thought to be a separate subspecies at one point.[3]
There were formerly two subspecies of California legless lizard recognized based on individual color morphs: the silvery legless lizard, A. p. pulchra, and the black legless lizard, A. p. nigra. However, contemporary taxonomy considers them simply a melanistic morph.[4] More recently (in 2013), A. pulchra has been split up into five different species: A. pulchra (with a narrower definition), A. alexanderae, A. campi, A. grinnelli, and A. stebbinsi.[5][6]
They live in loose, sandy soils or leaf litter, typically in sand dunes along the coast. They are found from Contra Costa County in northern California, all the way south to Baja California, although occurrences are often scattered. They require moisture to aid in shedding their skin. Without it, their vision and feeding can be affected, potentially starving the animal.[7]
Their diet consists of mainly beetles, larval insects, termites, ants, and spiders.
Males are slightly smaller than females, otherwise there is no discernible difference between the two sexes. Females are ovoviviparous and probably breed between early spring and July, with 1 to 4 young born September–November. Young lizards resemble their parents except look like smaller versions of them.
Anniella pulchra, the California legless lizard, is a limbless, burrowing lizard often mistaken for a snake.
