Xenosaurus grandis кесірткесінің сипаттамасы мен жағдайы

Species of lizard
Speciesbox
| image = Xenosaurus grandis. jpg
| status = VU
| status system = IUCN3.1
| status ref =
| genus = Xenosaurus
| species = grandis
| authority = (Gray, 1856)
| range map = Xenosaurus grandis distribution. png
| synonyms = *Cubina grandis
Xenosaurus fasciatus
Xenosaurus grandis
| synonyms ref =

There are five recognized subspecies, which are spread throughout the species’ range, and the species complex is being reevaluated. Some of the subspecies are currently in the process of being elevated to species status. The species as a whole is listed as vulnerable by the IUCN Red List and its population is currently decreasing. Its flattened physiology is most likely an adaptation to allow it to squeeze into narrow crevices. Its color ranges from dark grey to dark brown, with lighter bands or blotches. It has a forked tongue, and small, sharp, fang like teeth.

On average, the snout vent length (SVL) of Xenosaurus grandis is 6.8 12.9 cm. While some species of Xenosaurus do not exhibit sexual dimorphism, Xenosaurus grandis, among other species, is one that does. In Xenosaurus grandis, males and females do not differ significantly in body size, but males have proportionately larger heads (in length and width) than females. Males and females of X. grandis do not exhibit a significant difference in femur length or head shape. Air and substrate temperatures may be particularly relevant in Xenosaurus grandis since they are almost exclusively ground and crevice dwellers. Temperatures seem to differ across Xenosaurus species, possibly because of environment and habitat. Xenosaurus grandis appears to inhabit more dense tropical forests, where sunlight may not reach the ground as much. While body temperature is influenced by the lizard's amount of cover and its body position in its crevice, it does not seem to be influenced by sex, month, vegetation type, or any crevice characteristics. Their diet consists primarily of insects, but occasional lizard prey are taken. It is also plausible to say that X. grandis do not produce young every year.

There are five major population areas for the Xenosaurus grandis in Southern Mexico and Guatemala: central Veracruz, southern Oaxaca, north central Oaxaca, the highlands of central Chiapas, and central Guatemala.

All the subspecies of Xenosaurus grandis live exclusively in rock crevices, which allows them to live in many habitats, including: xerophytic vegetation, tropical rainforests, cloud forests, oak forests, and tropical deciduous rainforests. The lizards have strong attachments to where they live, only living in 1 2 rock crevices for 95% of their entire lives.

Currently Xenosaurus grandis is categorized as a vulnerable species according to the IUCN. The species was given this status because of fragmented populations, decreasing population size, and decreasing habitat quality and area, covering only 20,000 square km. The greatest threats to the survival of the species in the wild are habitat destruction and trapping for international pet trade. Eagles are the greatest natural predator of X. grandis, but they are not considered a threat to the survival of the species as a whole. Also, warmer temperatures in their habitat have been shown to cause greater mortality rates among the lizards, posing another potential threat to the species.

Higher temperatures have been associated with higher mortality rates for X. grandis. In the 2003 2004 wet season of Southern Mexico and Guatemala (the habitat regions of the species), the average temperature was 24.3 C. That temperature was in the top 12% of highest recorded temperatures in the past 34 years of record keeping. The mortality rate for yearlings (the youngest age group) increased from 0.1923 to 0.6551 and for adult II (the oldest age group) increased from 0.3956 to 0.5676 for the 2002 2003 and 2003 2004 wet seasons respectively. If temperatures continue to increase, the survival of the species will be further threatened and currently 50% of wet seasons are warm enough to be considered to be unfavorable for the species.

As of 2004, X. grandis had a survival rate of 70.5% and a growth rate of 0.851. Even though the rates may appear to be low, in comparison to other lizard genera and families X. grandis is doing well. Currently the species is decreasing in population, which is thought to be primarily caused by human development destroying their habitat. If habitat destruction stops, the population should at least be stable, if not prosperous.