Ecology
Associations
Known predators
Pseuderemias
Red racer
Pituophis
Crotalus
Buteo jamaicensis
Geococcyx velox
Based on studies in:
USA: Arizona, Sonora Desert (Desert or dune)
This list may not be complete but is based on published studies.
© SPIRE project
Source:
SPIRE
Trusted
Known prey organisms
Coleoptera
ground invertebrates
Hymenoptera
leaves
Pogonomyrmex
Atta
Based on studies in:
USA: Arizona (Forest, Montane)
USA: Arizona, Sonora Desert (Desert or dune)
This list may not be complete but is based on published studies.
© SPIRE project
Source:
SPIRE
Trusted
Evolution and Systematics
Functional Adaptations
Functional adaptation
Blood-filled sinuses within the eye sockets of horned toads squirt blood at predators after a rapid increase in pressure breaks the sinuses' thin walls.
"Among the most famous, and spectacular, performers of autohemorrhaging are three species of North American desert-dwelling lizard, Phrynosoma cornutum, P. coronatum, and P. solare, which are commonly known (albeit inaccurately) as horned toads…If the predator is still not intimidated, however, and persists in its attack, the lizard has one final, and quite grotesque, defense mechanism. It uses a series of thin-walled, blood-filled spaces called sinuses found within its eye sockets. When the lizard rapidly increases the blood pressure within these sinuses, it causes the sinus walls to break suddenly. The blood is then forced out in jet-like squirts of crimson droplets. Sometimes, the force with which the lizard squirts this eye-ejected blood is so powerful that it can send sprays shooting up to distances of 4 feet (1.2 m). This bizarre squirting can be repeated several times if necessary, which is usually sufficient to frighten off any predator. Also, the squirted blood may contain a distasteful chemical, which would act as an additional deterrant to potential predators." (Shuker 2001:128)
Watch video
Learn more about this functional adaptation.
- Shuker, KPN. 2001. The Hidden Powers of Animals: Uncovering the Secrets of Nature. London: Marshall Editions Ltd. 240 p.
© The Biomimicry Institute
Source:
AskNature
Trusted
Molecular Biology and Genetics
Barcode
Statistics of barcoding coverage
| Specimen Records: | 1 |
| Specimens with Sequences: | 1 |
| Specimens with Barcodes: | 1 |
| Public Records: | 0 |
| Species: | 1 |
| Species With Barcodes: | 1 |
© Barcode of Life Data Systems
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Barcode data
© Barcode of Life Data Systems
Trusted
Molecular Biology
Statistics of barcoding coverage: Phrynosoma douglassi
Public Records: 0
Species: 1
Species With Barcodes: 1
© Barcode of Life Data Systems
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Wikipedia
Horned lizard
 | This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (July 2007) |
Horned lizards (Phrynosoma) are a genus of lizards which are the type genus of the family Phrynosomatidae. The horned lizard is popularly called a "horned toad", "horny toad", or "horned frog", but it is neither a toad nor a frog. The popular names come from the lizard's rounded body and blunt snout, which make it resemble a toad or frog. (Phrynosoma literally means "toad-bodied".) The spines on its back and sides are made from modified scales, whereas the horns on the heads are true horns (i.e. they have a bony core). There are 15 species of horned lizards in North America, eight of which are native to the United States. The largest-bodied and most widely distributed of the U.S. species is the Texas horned lizard (P. cornutum).
Contents |
Description
Horned lizards are morphologically similar to the Australian thorny devil (Moloch horridus), but are only distantly related. They also have other similarities, such as being sit-and-wait predators and preying upon ants, so the two species are considered a great example of convergent evolution.
Protection against predation
Horned lizards use a wide variety of means to avoid predation. Their coloration generally serves as camouflage. When threatened, their first defense is to remain still to avoid detection. If approached too closely, they generally run in short bursts and stop abruptly to confuse the predator's visual acuity. If this fails, they puff up their bodies to cause them to appear more horned and larger, so more difficult to swallow. At least four species are also able to squirt an aimed stream of blood (see Autohaemorrhaging) from the corners of the eyes for a distance of up to five feet.[1][2][3] They do this by restricting the blood flow leaving the head, thereby increasing blood pressure and rupturing tiny vessels around the eyelids. This not only confuses predators, but also the blood tastes foul to canine and feline predators. It appears to have no effect against predatory birds. To avoid being picked up by the head or neck, a horned lizard ducks or elevates its head and orients its cranial horns straight up, or back. If a predator tries to take it by the body, the lizard drives that side of its body down into the ground so the predator cannot easily get its lower jaw underneath the lizard.
Species and subspecies
- Giant Horned Lizard, Phrynosoma asio Cope, 1864
- Short-tailed Horned Lizard, Phrynosoma braconnieri Duméril, 1870
- Cedros Island Horned Lizard, Phrynosoma cerroense Stejneger, 1893
- Texas Horned Lizard, Phrynosoma cornutum (Harlan, 1825)
- Coast Horned Lizard, Phrynosoma coronatum
- Cape Horned Lizard, Phrynosoma coronatum coronatum (Blainville, 1835)
- San Diego Horned Lizard, Phrynosoma coronatum blainvillii Gray, 1839
- California Horned Lizard, Phrynosoma coronatum frontale Van Denburgh, 1894
- Central Peninsular Horned Lizard, Phrynosoma coronatum jamesi Schmidt, 1922
- Northern Peninsular Horned Lizard, Phrynosoma coronatum schmidti Barbour, 1921
- Ditmars' Horned Lizard or Rock Horned Lizard, Phrynosoma ditmarsi Stejneger, 1906
- Short-horned Lizard, Phrynosoma douglassii
- Mountain Short-horned Lizard, Phrynosoma hernandesi Girard, 1858
- Flat-tail Horned Lizard, Phrynosoma mcallii (Hallowell, 1852)
- Roundtail Horned Lizard, Phrynosoma modestum Girard, 1852
- Phrynosoma orbiculare boucardii (Duméril & Bocourt, 1870)
- Phrynosoma orbiculare bradti Horowitz, 1955
- Phrynosoma orbiculare orbiculare (Linnaeus, 1789)
- Phrynosoma orbiculare orinetale Horowitz, 1955
- Phrynosoma orbiculare cortezii (Duméril & Bocourt, 1870)
- Phrynosoma orbiculare dugesii (Duméril & Bocourt, 1870)
- Regal Horned Lizard, Phrynosoma solare Gray, 1845
- Mexican Horned Lizard, Phrynosoma taurus Dugès, 1873
- Gulf Coast Horned Lizard, Phrynosoma wigginsi Montanucci, 2004
Symbol
The genus of horned lizards is the official state reptile of Wyoming.[4]
The Texas horned lizard is the state reptile of Texas and the "horned frog" is the mascot of Texas Christian University in Fort Worth, Texas.
Notes
- ^ Middendorf III, G.A.; Sherbrooke, W.C. & Braun, E.J. (2001): Comparison of Blood Squirted from the Circumorbital Sinus and Systemic Blood in a Horned Lizard, Phrynosoma cornutum. The Southwestern Naturalist., 46(3): 384-387.
- ^ Sherbrooke, W.C. & Middendorf III, G.A. (2001): Blood-Squirting Variability in Horned Lizards (Phrynosoma). Copeia., 2001(4): 1114-1122.
- ^ Sherbrooke, W.C. & Middendorf III, G.A. (2004): Responses of Kit Foxes (Vulpes macrotis) to Antipredator Blood-Squirting and Blood of Texas Horned Lizards (Phrynosoma cornutum). Copeia., 2004(3): 652-658.
- ^ "State symbols". Wyoming Secretary of State's Office. 2011. http://soswy.state.wy.us/SecretaryDesk/StateInfo_Symbols.aspx. Retrieved January 22, 2011.
Source:
Wikipedia
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