California legless lizard
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Anniellidae
Genus: Anniella
Species:
A. pulchra
Binomial name
Anniella pulchra
(Gray, 1852)
Range of Anniella pulchra (sensu lato) in purple

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

Description

Anniella pulchra, Los Osos, CA

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]

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 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]

Distribution and habitat

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]

These lizards can be found in diverse vegetation zones ranging from seaside dunes to open pine woodlands. In Sierra Nevada, it's been spotted at heights up to 2,050 meters and 1,360 meters in Sierra de Juárez and Sierra de San Pedro Márti. [8]

Diet

Their diet consists of mainly beetles, larval insects, termites, ants, and spiders. To obtain food, they camouflage themselves under leaves and ambush their prey. [3]

Reproduction

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. [3]

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. [3]

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 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. [9]

Genetic diversity

A study by Parham and Papenfuss in 2008 revealed a higher level of genetic diversity 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, with two being exclusive to the San Joaquin Valley and Carrizo Plain.

Their research has also revealed that due to urban development, only one of the three localities of the Anniella pulchra located in the Bakersfield region remains alive today.[10]

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 by absorbing water, only when their mouth is in direct contact with moist sand. 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 is why these lizards can thrive in environments where water is scarce and limited. [11]

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. [12]

Formerly Recognized Subspecies

According to 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. [3]

References

  1. ↑ Hammerson, G.A.; Hollingsworth, B. (2021). "Anniella pulchra". IUCN Red List of Threatened Species. 2021: e.T62227A167597877. doi:10.2305/IUCN.UK.2021-2.RLTS.T62227A167597877.en. Retrieved 20 November 2021.
  2. ↑ Kuhnz, Linda A.; Burton, Robert K.; Slattery, Peter N.; Oakden, James M. (2005-01-01). "Microhabitats and Population Densities of California Legless Lizards, with Comments on Effectiveness of Various Techniques for Estimating Numbers of Fossorial Reptiles". Journal of Herpetology. 39 (3): 395–402. doi:10.1670/126-04a.1. JSTOR 4092925. S2CID 86641172.
  3. 1 2 3 4 5 CaliforniaHerps.com on Anniella pulchra
  4. ↑ CaliforniaHerps.com on the former A. p. nigra "subspecies" Archived April 29, 2010, at the Wayback Machine
  5. ↑ Papenfuss, Theodore J.; Parham, James F. (2013). "Four New Species of California Legless Lizards (Anniella)". Breviora. 536: 1–17. doi:10.3099/MCZ10.1. S2CID 85350734.
  6. ↑ Anniella in the Reptile Database
  7. ↑ Animal Diversity Web: Anniella pulchra
  8. ↑ Hunt, L.E. “Anniella pulchra.” Catalogue of American Amphibians and Reptiles, 2006 https://repositories.lib.utexas.edu/bitstream/handle/2152/45523/0850_Anniella_pulchra.pdf
  9. ↑ Bury, R. Bruce; Balgooyen, Thomas G. (1976). "Temperature Selectivity in the Legless Lizard, Anniella pulchra". Copeia. 1976 (1): 152–155. doi:10.2307/1443785. ISSN 0045-8511. JSTOR 1443785.
  10. ↑ Parham, James F.; Papenfuss, Theodore J. (2009). "High genetic diversity among fossorial lizard populations (Anniella pulchra) in a rapidly developing landscape (Central California)". Conservation Genetics. 10 (1): 169–176. doi:10.1007/s10592-008-9544-y. ISSN 1566-0621. S2CID 33623597.
  11. ↑ Fusari, Margaret H. (1985). "Drinking of Soil Water by the California Legless Lizard, Anniella pulchra". Copeia. 1985 (4): 981–986. doi:10.2307/1445251. ISSN 0045-8511. JSTOR 1445251.
  12. ↑ Rieppel, Olivier (1980). The Phylogeny of Anguinomorph Lizards (1st ed. 1980. ed.). Boston : Birkhauser Verlag. pp. 31–33. ISBN 3-0348-9372-8.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.