User:Vportugal/Phrynocephalus vlangalii

Article Draft

Lead

The Qinghai Toad-headed Agama (Phrynocephalus vlangalii), also commonly known as the Ching hai toad-headed agama, the Pylzow’s toad-headed agama, and the gecko toad-headed agama, is a species of viviparous agamid lizard endemic to the Tibetan Plateau in China. This lizard lives dwells in burrows at high elevations of 2,000 to 4,600 meters. The Qinghai toad-headed lizard is known for its aggression and curling its tail and showing a patch on its underbelly as defense displays against conspecifics.

Description

It has been shown that there is a positive correlation between a lizard’s body size and temperature, air pressure, and active season length, shown by differences in the body size of Qinghai toad-headed lizards 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. [9].

Habitat and Distribution

The lizard creates burrows about 70 cm into sand, which will become a refuge against predators in the summer and protect against harsh winter conditions [5]. Because they are found on a plateau, they are adapted to an arid and semi-arid environment with sparse vegetation located 2000-4600 meters high [10]. 1.    The Qinghai toad-headed agama is found in the Qinghai-Tibetan Plateau in China. Their range can also stretch north to the southern Arjin mountains and the Gansu province in China. Their southern range reaches the northern Tanggula mountains and the southern part of the Yellow River [2].

Population structure, speciation, and phylogeny

The eastern range of viviparous lizards is home to phrynocephalus guinanensis, phrynocephalus putjatia, andphrynocephalus vlangalii. These species are closely related but are subject to controversies regarding how they should be classified. In a study by Hu et al., researchers determined that 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. Additional evidence of possible historical hybridization events between these three species was also found, such as shared haplotypes and high gene flow levels [16].

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 [2]. Most recently, there are 2 subspecies considered under phrynocephalus vlangalii: phrynocephalus vlangalii hongyuanensis and phrynocephalus vlangalii vlangalii [18- reptile database].

Territoriality

Male territories tend to overlap more with females than with other males. Females not only avoid each other, but they also show each other aggression. They are more likely to overlap with males than with other females. [5].

Since these lizards live in burrows, the entrance to their burrow acts as the center of their territory and is actively defended. Males and females each have their own burrow, so they equally defend their own territory by using their tails to signal to rivals to not invade their space. They do this by coiling and lifting their tail, showing the tail-tip badge that is black among males and orange among females, as well as pushing-up on their legs to lift their belly from the ground in order to also display the patch of color located there.

Males were observed to coil their tails faster than females and the display of lashing one’s tail was only found among males. This display was the quickest when a male faced another male. On the other hand, besides tail displays, females also chase away their rivals. Overall, tail coiling is most pronounced (tight and high) when an adult faces another adult, rather than when facing a juvenile. Juveniles tend to mainly use the display of waving their tail as a signal of defense rather than coiling or lashing [13]. A positive correlation between tail length and territory size has also been observed [6].

Males employ resident and floater tactics. Residents are usually found in the same small areas to defend their territory against rivals by displaying their tails and patches and chasing conspecifics. Floaters do not occupy areas, do not defend territory, and are thought to display in a different manner than residents to signal that they are of a different social status than residents. [11]

Home range of the organism

They live in high densities where they each have their own burrow, but their overall home ranges overlap with those of others.

Migration

Qinghai toad-headed lizards are non-migratory and endemic to China.

Reproduction and Life cycle

Courtship occurs in May and females give birth to their young from mid-July to late August [10]. Brood size ranges from 2-6 offspring [12]. However, number of offspring and the mean mass of the offspring is positively correlated with female SVL, or snout-vent-length. [8]. As the elevation in which the lizards live increases, fewer, yet larger offspring are born.

A common garden experiment conducted by Lu et al. demonstrated that difference in growth rate between low-elevation Qinghai toad-headed lizards and high elevation Qinghai toad-headed lizards may be due to developmental plasticity rather than genetics. The lizards that were born and grew up at the highest elevations on the Tibetan plateau tended to grow faster and reach larger sizes as adults compared to those in relatively lower elevations. When both types of lizards were brought into a lab, the young lizards had similar growth rates, suggesting the difference in growth rate and adult size in the field is due to the lizards adapting to survive in their different habitats. Higher abundance of prey at higher elevation is likely associated for these differences, since smaller lizards born at high altitudes have higher growth rates than lizards born larger at a lower elevation if there is abundant food supply. [10].

Mating

Female/female interactions

These lizards participate in female-female aggression when there is competition for mates since the males would be useful for reproduction (especially since there are more females than males among this species) and defending territory and resources (males have been observed to help females defend their territory and defend against other males hoping to forcefully mate with females, but females themselves will display to other females to protect their burrows). Forced mating by floater males can be dangerous for females, since females have died from mating multiple times. Resident females, or females that tend to stay in one location, are faster to display their coiled tail and belly patch to a rival when there is a neighbor male nearby. They signal faster with a male present as well, but only during mating season. However, female-female aggression is also present outside of mating season [4].

Female/male interactions

copulation

These lizards are viviparous, meaning females give birth to live young.

number of mates

Females tend to have one mate since multiple matings, especially forced matings, can be deadly. [4]

mate guarding

Since females are very aggressive towards other females and do not overlap their territories with those of other females, it is difficult for males to defend potential multiple mates and therefore do not mate guard [5].

Social behavior

Adult sociality

Burrows are important for the survival of Qinghai toad-headed lizards both during the summer (when they are most active and there are many predators) and winter (against the harsh cold). Adult lizards occupy separate burrows, and young juveniles around 1 year old mostly live in abandoned burrows and occasionally stay in the burrows of their parents, however these instances are not common or numerous enough to be significant. Male adults’ territories tend to overlap more with adult females than with other males, especially males that have a better, healthier body condition. Similarly, adult females’ territories overlap more with males than with other females.

Each lizard tends to stay in their one burrow rather than move around in search for new ones, although some will dwell in two or three. [5]

Microbiome

Gut microbiome

An experiment conducted by Zhang et al. found that among three populations of Qinghai toad-headed lizards that lived at different altitudes, the most abundant intestinal microbiota were Bacteroidetes, firmicutes, and proteobacteria. As elevation increased, verrucomicrobia, the fourth most abundant microbiota found, decreased and bacteroides increased. Each microbiota in the lizard’s gut is important for biological functions such as nutrient metabolism. The types and amount of each micro biota found are affected by the geography and climate the lizard lives in. The lizards used in this study live at altitudes of 2,900 m, 3,338 m, and 4,250 m.