Phrynocephalus vlangalii, also known as the Qinghai toad-headed agama, the Ching Hai toadhead agama, the Pylzow's toadhead agama, or gecko toadhead agama, is a species of viviparous agamid lizard endemic to the Tibetan Plateau in China. This lizard lives in burrows at high elevations of 2,000 to 4,600 meters. It is also known for its aggression, especially between females during mating season since females usually only have one mate. P. vlangalii curls its tail and shows a patch on its underbelly as defense displays against conspecifics. This lizard also has a variety of gut microbiota that help perform metabolic and biological functions depending on the altitude at which the lizard lives.
Description
As a small lizard, P. vlangalii can grow up to 80 mm from snout to vent. Sexual dimorphism is present in this species and most evident among adults. Adult males tend to have larger heads and tail lengths while adult females have larger bodies and abdomen lengths. Males and females are also distinguishable by their tail-tip badges: males have black tail-tips and females have orange tail-tips. Both males and females display their tail-tip badges and underbelly patches as a method of defending their territory against rival lizards. There is a positive correlation between a lizard's body size and temperature, air pressure, and active season length, demonstrated by differences in the body size of P. vlangalii among different elevations in the Tibetan plateau. This is because as the elevation increases, air temperature and pressure decrease. To avoid hypoxia, or lack of oxygen to the body, these lizards have smaller bodies to help maintain a constant body temperature.
Habitat and Distribution
P. vlangalii creates burrows about 70 cm into sand to act as refuge against predators. Burrows greater than 74 cm are deep enough to protect against low temperatures. Because P. vlangalii is found on a plateau, it is adapted to an arid and semi-arid environment with sparse vegetation located 2000-4600 meters high. P. vlangalii's preference for desert habitats makes it a good indicator species for desertification of grassland areas. This lizard is endemic to the Qinghai-Tibetan Plateau in China. The Tibetan plateau is known for its high altitude, cold temperatures, and dry atmosphere, which explains the lizard's burrow digging behavior. P. vlangalii's range can also stretch north to the southern Arjin mountains and the Gansu province in China. Its southern range reaches the northern Tanggula mountains and the southern part of the Yellow River.
Habitat Loss
P. vlangalii is one of the most common lizard species in its native range but its habitat is experiencing some loss for a variety of reasons. In central and southwestern Mongolia, as well as other parts of Asia, P. vlangalii is losing parts of its habitat to both human interference and climate change. These losses in habitats, particularly around the periphery of a range, can lead to changes in the behavior or other phenotypic characteristics of the species.
Home range of the organism
P. vlangalii lives in high densities where each lizard has its own burrow, but its overall home ranges overlap with those of others. These lizards guard these home ranges as they are used as a refuge from predators. These lizards do not migrate.
Population structure, speciation, and phylogeny
The eastern range of viviparous lizards is home to Phrynocephalus guinanensis, Phrynocephalus putjatia, and Phrynocephalus vlangalii. These species are closely related but are subject to controversies regarding how they should be classified. According to Hu et al., there is more morphological differentiation between these three species than there is genetic differentiation, likely due to adaptation to each species’ habitat. Habitat differentiation and contact between the species likely occurred due to the uplift or rising of the Qinghai-Tibetan plateau millions of years ago, when many areas became arid and dry. There is also additional evidence of possible historical hybridization events between these three species, such as shared haplotypes and high gene flow levels.
In 1909, Bedriaga et al. listed Phrynocephalus vlangalii parva, Phrynocephalus vlangalii nanschanica, and Phrynocephalus vlangalii pylzowi as subspecies of Phrynocephalus vlangii, or the Qinghai toad-headed agama. More recently, Phrynocephalus hongyuanensis was debated surrounding it being considered a potential subspecies but was ultimately placed in the main clade. There are two subspecies considered under Phrynocephalus vlangalii: Phrynocephalus vlangalii hongyuanensis and Phrynocephalus vlangalii vlangalii.