''Anniella pulchra'', the California legless lizard, is a limbless, burrowing lizard often mistaken for a snake.

Description

''Anniella pulchra'' measures around from snout to vent (excluding the tail). The slightly pointed head and eyes are both rather small—adaptations for a primarily

fossorial A fossorial animal () is one that is adapted to digging and which lives primarily (but not solely) underground. Examples of fossorial vertebrates are Mole (animal), moles, badgers, naked mole-rats, meerkats, armadillos, wombats, and mole salamand ...

(burrowing) lifestyle. Colors are usually a silver-bronze dorsal (back) side and a yellow underside, separated by black side-stripes or markings extending from the lizard's head down the length of its body. Black (

melanistic Melanism is the congenital excess of melanin in an organism resulting in dark pigment. Pseudomelanism, also called abundism, is another variant of pigmentation, identifiable by dark spots or enlarged stripes, which cover a large part of the bod ...

) and darker brown forms, which were thought to be a separate subspecies at one point,CaliforniaHerps.com on Anniella pulchra
/ref> have been observed in

Monterey County Monterey County ( ), officially the County of Monterey, is a county located on the Pacific coast in the U.S. state of California. As of the 2020 United States census, its population was 439,035. The county's largest city and county seat is ...

, California.

Taxonomy

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

morph. 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''.

Distribution and habitat

''A. pulchra'' live in loose, sandy soils or leaf litter, or among

sand dunes A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat ...

along the

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

coast. They are found from

Contra Costa County Contra Costa County (; ''Contra Costa'', Spanish language, Spanish for 'Opposite Coast') is a U.S. county, county located in the U.S. state of California, in the East Bay of the San Francisco Bay Area. As of the 2020 United States census, the ...

Northern California Northern California (commonly shortened to NorCal) is a geocultural region that comprises the northern portion of the U.S. state of California, spanning the northernmost 48 of the state's List of counties in California, 58 counties. Northern Ca ...

, south to

Baja California Baja California, officially the Free and Sovereign State of Baja California, is a state in Mexico. It is the northwesternmost of the 32 federal entities of Mexico. Before becoming a state in 1952, the area was known as the North Territory of B ...

, although its population distribution is often scattered. They require some source of moisture to aid in the regular shedding of their skin; without shedding properly, the lizard's ability to eat and see can be affected, potentially starving the animal. These lizards can be found in diverse vegetation zones, ranging from seaside dunes to inland open pine woodlands. In the

Sierra Nevada The Sierra Nevada ( ) is a mountain range in the Western United States, between the Central Valley of California and the Great Basin. The vast majority of the range lies in the state of California, although the Carson Range spur lies primari ...

, the species been spotted at elevations of up to 2050 meters (6,725’), and 1360 meters (4,461’) in

Sierra de Juárez The Sierra de Juárez, also known as the Sierra Juarez, is a mountain range located in Tecate Municipality and northern Ensenada Municipality, within the northern Baja California state of northwestern Mexico. It is a major mountain range in ...

and

Sierra de San Pedro Mártir Sierra de San Pedro Mártir ( Kiliwa: ʔxaal haq, ) is a mountain range located within southern Ensenada Municipality and southern Baja California state, of northwestern Mexico. It is a major mountain range in the long Peninsular Ranges System, ...

Diet

Their diet consists of mainly beetles, larval insects, termites, ants, and spiders. To obtain food, they

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...

themselves under leaves and ambush their prey.

Reproduction

Males are slightly smaller than females, otherwise there is no discernible difference between the two sexes. Females are

ovoviviparous Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a "bridging" form of reproduction between egg-laying oviparity, oviparous and live-bearing viviparity, viviparous reproduction. Ovoviviparous animals possess embryos that develo ...

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.

Defense

These lizards when provoked can use their tails as a dummy to distract a predator. When threatened, its tail detaches and acts like the lizard, giving it a chance to escape from its predator.

Temperature selectivity

A study conducted by R. Bruce Bury and Thomas G. Balgooyen in 1976 revealed the "temperature selectivity" of ''Anniella pulchra.'' Based on the results of this study, the mean temperature these lizards preferred was 24-25 C. This temperature depended on the level of

moisture Moisture is the presence of a liquid, especially water, often in trace amounts. Moisture is defined as water in the adsorbed or absorbed phase. Small amounts of water may be found, for example, in the air (humidity), in foods, and in some comme ...

in the environment and is said to help them remain its increased activity in its environments where it is often cooler. The researchers compare the temperature preference of these lizards to be similar to the alligator lizard, the '' Gerrhonotus multi-carinatus'', as both lizards are noted to be active at lower temperatures more so than other diurnal species, while also avoiding temperatures over 30 C.

Genetic diversity

A study by Parham and Papenfuss in 2008 revealed a higher level of

genetic diversity Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species. It ranges widely, from the number of species to differences within species, and can be correlated to the span of survival for a species. It is d ...

than previously reported. Using mitochondrial and nuclear DNA sequences from museum-volunteered samples, their research identified five major genetic lineages of the ''Anniella pulchra''. Two of these lineages align with a north-south split observed in other widespread Californian reptiles. Notably, unlike many other Californian reptiles, ''Anniella pulchra'' has genetic lineages endemic to

Central California Central California is generally thought of as the middle third of the U.S. state of California, north of Southern California (which includes Los Angeles and San Diego) and south of Northern California (which includes San Francisco and San Jose, ...

, with two being exclusive to the

San Joaquin Valley The San Joaquin Valley ( ; Spanish language in California, Spanish: ''Valle de San Joaquín'') is the southern half of California's Central Valley (California), Central Valley. Famed as a major breadbasket, the San Joaquin Valley is an importa ...

and

Carrizo Plain The Carrizo Plain ( Obispeño: ''tšɨłkukunɨtš'', "Place of the rabbits") is a large enclosed grassland plain, approximately long and up to across, in southeastern San Luis Obispo County, California, United States, about northwest of Lo ...

. Their research has also revealed that due to urban development, only one of the three localities of the ''Anniella pulchra'' located in the

Bakersfield Bakersfield is a city in and the county seat of Kern County, California, United States. The city covers about near the southern end of the San Joaquin Valley, which is located in the Central Valley region. Bakersfield's population as of the ...

region remains alive today.

Water intake and adaption

The ''Anniella pulchra'' exhibits a unique method of water intake. According to a paper from Margaret Fusari, these lizards can increase their

mass Mass is an Intrinsic and extrinsic properties, intrinsic property of a physical body, body. It was traditionally believed to be related to the physical quantity, quantity of matter in a body, until the discovery of the atom and particle physi ...

by absorbing water, only when their mouth is in direct contact with moist

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is usually defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural ...

. The efficiency of their water absorption is directly related to the moisture content of the sand, suggesting that there are natural limits to their hydration based on the sand's properties. This

adaptation In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the p ...

is why these lizards can thrive in environments where water is scarce and limited.

Head musculature

The ''m. cervicomandibularis'' in ''Anniella'' is notably developed, and the ''depressor mandibulae'' has both a substantial extrinsic and a weaker intrinsic component. The structure of the ''m. pterygoideus'' in ''Anniella'' is typical of lizards, but with specific distinctions. The ''genioglossus'' muscle in ''Anniella'' consists of a prominent medialis portion and a smaller lateralis section.

Formerly Recognized Subspecies

According t
californiaherps.com
this lizard was previously split into two distinct species, the ''Anniella pulchra pulchra'', the Silver Legless Lizard, and the ''Anniella pulchra nigra'', the Black Legless Lizard. This distinction is no longer recognized due to a study that demonstrated that these populations have different ancestors, separating them into their own groups.

References

{{DEFAULTSORT:Anniella Pulchra Anniella Legless lizards Reptiles described in 1852 Reptiles of Mexico Reptiles of the United States Lizards of North America Taxa named by John Edward Gray