Keeled Earless Lizard (Holbrookia propinqua)
Description: These are small lizards that have no external ear opening, and have a tail that is longer than their head and body. They range from 4 1/2 to 5 9/16 inches in length. Maximum head and body length is 2 3/8 inch, so the tail can be about as long as 3 inches. However, these lizards often lose part of their tails to predators, and can grow a new one, so tail length is not a good characteristic for identification. Unlike the other species of earless lizards (all genus Holbrookia), they have tiny keels on their dorsal scales. Their scales are granular, meaning they do not over lap and very small. The males and females have different and unique markings that are useful in telling them apart. The males have large black bands on either side of their stomach. The females are lighter in color and lack the black bands. Most of the males and females have irregular patterns of brown and grey stripes and blotches that cover their back and head
Habitat: Keeled earless lizards are endemic to barrier beaches and sand dumes. Some prefer to live closer to the coast than others, but all of them prefer to live in dry sandy places. There are unique adaptions that Keeled earless lizards have, that allows them to live on sandy habitats. For a small lizard, they have long legs and feet for getting around at relatively fast speeds on the sand. Their blotched coloring gives them the advantage of camouflage. Burrowing into sand to hide and regulate their temperature is made easier by the shape of their head. The sand dunes on Padre Island on the Texas coast is one place where there are many keeled earless lizards.
Range: This species ranges from southern Texas south along northeastern coastal Mexico; inland in southern Texas, this lizard occurs northward to the southern edge of the Edwards Plateau. In Mexico, the species reaches as far south as the Tropic of Cancer (Tamaulipas), but does not range as far south as the State of Veracruz.
Found in these States:
TX
Diet: Keeled earless lizards are insectivorous, which means that they hunt down and eat insects. It is unknown which insects these lizards prefer. They seem to eat whatever they can get ahold of. They are diurnal, so they are only active and forage for food during the day and not at night. It may get too cold for them at night, as they are cold blooded animals.
Reproduction: Keeled earless lizards have femoral pores on each hind leg. There are on average 14 to 15, but they can have as many as 20. The femoral glands open into the dermal follicles. It is not known what they do exactly, but it is agreed that they are used for reproduction. Since they are diurnal, they have fairly good vision. They rely on their vision for courtship. They have very noticable sexual dimorphism. The male and female coloring is very important. The female coloring is controlled by hormones. When they change colors, it is a signal to males that they are ready to mate. Like most lizards, Keeled earless lizards are oviparous. Females have unique coloring when they are carrying eggs. They tend to be orange or pink. The female digs a burrow in which to deposit her eggs. After hatching, their young on average are 1 1/2 inch long and have the same blotchy coloring as the adults.
Status: Listed as Least Concern in view of the apparently stable extent of occurrence, area of occupancy, number of subpopulations, and population size. Habitat loss to agriculture and coastal development are concerns for the long-term future.
Subspecies: There are three recognized subspecies of Holbrookia propinqua with just one found in the United States:
Northern Keeled Earless Lizard - (Holbrookia propinqua propinqua)
Southern Keeled Earless Lizard - (Holbrookia propinqua piperat)
Stone's Keeled Earless Lizard - (Holbrookia propinqua stonei)
»» Kingdom: Animalia - Animals
»» Phylum: Chordata - Chordates
»» Subphylum: Vertebrata - Vertebrates
»» Class: Reptilia - Reptiles
»» Order: Squamata - Lizards
»» Family: Phrynosomatidae - North American Spiny Lizards
»» Genus: Holbrookia
»» Species: Holbrookia propinqua - Keeled Earless Lizard
This article uses material from the Wikipedia article "Holbrookia propinqua", which is released under the Creative Commons Attribution-Share-Alike License 3.0. Content may have been omitted from the original, but no content has been changed or extended.
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