Thursday, September 22, 2011
Green Anole
First Reptile Genome Sequenced
The green anole lizard (Anolis carolinensis) – a native of the southeastern United States – is the first reptile to have its genetic blueprint, known as a genome, sequenced and assembled. Broad Institute researchers have studied more than 20 mammalian genomes – including those of some of our closest relatives – but the genetic landscape of reptiles has remained relatively unexplored.
Lizards are more closely related to birds than to any of the other groups whose genomes have been sequenced in full. "People have been sequencing animals from different parts of the vertebrate tree, but lizards had not been previously sampled," explained Kerstin Lindblad-Toh, scientific director of vertebrate genome biology at the Broad who has been closely involved in the research. "This was an important branch to look at."
Amazing DiversityFour hundred species of anole lizards have fanned out across North America, Central America, the islands of the Caribbean and South America, making them an appealing model for studying evolution. Although much is known about their biology and behavior, genomic information may be a critical missing piece for understanding how the lizards have become so diverse.
"Anoles are rich in ecology and morphology and have just the right amount of diversity to make them interesting yet tractable to study," said Jonathan Losos, an author of the paper, professor at Harvard University, and author of the book Lizards in an Evolutionary Tree: Ecology and Adaptive Radiation of Anoles.
"But a big stumbling block in studying them has been that they have not been great organisms for classical genetic study. This genome is going to revolutionize our ability to study that aspect of their evolutionary diversification."
In addition to insights into human and mammalian genomes, the anole lizard’s genome also offers up clues about how lizard species evolved to populate islands in the Greater Antilles. Much like Darwin’s finches, anoles adapted to fill all of the ecological niches the islands have to offer.
Some lizards have short legs and can walk along narrow twigs; others are green in color with big toe pads suited for living high up in trees; others are yellow and brown and live in the grass. But unlike the finches, lizards on different islands have independently evolved diverse communities of these twig, canopy, and grass dwelling species – almost identical lizard species have evolved in parallel on the islands of Hispaniola, Puerto Rico, Cuba, and Jamaica.
"These lizards have been compared to Darwin’s finches and in many respects they are similar," said Losos. "They show the workings of natural selection as species adapted to different habitats. But the difference is in the case of the lizards, this evolution has happened four times, once on each of the different islands."
By sampling the genomes of more than 90 species, the researchers were able to make a preliminary map of how these species evolved to colonize the islands. "This is setting the stage for the research community to be able to look for signatures of adaptation in a very informative and coherent way," said Lindblad-Toh.
Color VisionThe researchers were also able to create a "parts list" of proteins found in green anole eggs, which they compared with those found in eggs from chickens and they discovered that both bird and lizard egg genes are evolving rapidly. They also mapped many genes in the anoles’ genome associated with color vision, which these lizards use to identify mates.
"Anoles have extremely good color vision – some species can even see in the ultraviolet range," said Losos. Other studies have shown that anoles can distinguish between similar colors and patterns. "It’s pretty clear that one function of the dewlap is to distinguish one species from others and that they use the dewlap - the skin fold under the chin - to determine whether a particular individual belongs to their species or not."
Reference: Alfoldi J et al. "The genome of the green anole lizard and a comparative analysis with birds and mammals." Nature August 31, 2011 doi:10.1038/nature10390
Got From: http://www.reptilechannel.com/reptile-news/2011/09/07/reptile-genome-sequenced.aspx
Genetic map of the green anole produced for the first time
September 7, 2011
 Anoles are rich in ecology and morphology and have just the right amount of diversity to make them interesting yet tractable to study. Photo credit: David E. Scott, Savannah River Ecology Laboratory, Aiken, SC, USA. |
The green anole lizard (Anolis carolinensis) – a native of the southeastern United States – is the first reptile to have its genetic blueprint, known as a genome, sequenced and assembled. Broad Institute researchers have studied more than 20 mammalian genomes – including those of some of our closest relatives – but the genetic landscape of reptiles has remained relatively unexplored.
Lizards are more closely related to birds than to any of the other groups whose genomes have been sequenced in full. "People have been sequencing animals from different parts of the vertebrate tree, but lizards had not been previously sampled," explained Kerstin Lindblad-Toh, scientific director of vertebrate genome biology at the Broad who has been closely involved in the research. "This was an important branch to look at."
Amazing DiversityFour hundred species of anole lizards have fanned out across North America, Central America, the islands of the Caribbean and South America, making them an appealing model for studying evolution. Although much is known about their biology and behavior, genomic information may be a critical missing piece for understanding how the lizards have become so diverse.
"Anoles are rich in ecology and morphology and have just the right amount of diversity to make them interesting yet tractable to study," said Jonathan Losos, an author of the paper, professor at Harvard University, and author of the book Lizards in an Evolutionary Tree: Ecology and Adaptive Radiation of Anoles.
"But a big stumbling block in studying them has been that they have not been great organisms for classical genetic study. This genome is going to revolutionize our ability to study that aspect of their evolutionary diversification."
In addition to insights into human and mammalian genomes, the anole lizard’s genome also offers up clues about how lizard species evolved to populate islands in the Greater Antilles. Much like Darwin’s finches, anoles adapted to fill all of the ecological niches the islands have to offer.
Some lizards have short legs and can walk along narrow twigs; others are green in color with big toe pads suited for living high up in trees; others are yellow and brown and live in the grass. But unlike the finches, lizards on different islands have independently evolved diverse communities of these twig, canopy, and grass dwelling species – almost identical lizard species have evolved in parallel on the islands of Hispaniola, Puerto Rico, Cuba, and Jamaica.
"These lizards have been compared to Darwin’s finches and in many respects they are similar," said Losos. "They show the workings of natural selection as species adapted to different habitats. But the difference is in the case of the lizards, this evolution has happened four times, once on each of the different islands."
By sampling the genomes of more than 90 species, the researchers were able to make a preliminary map of how these species evolved to colonize the islands. "This is setting the stage for the research community to be able to look for signatures of adaptation in a very informative and coherent way," said Lindblad-Toh.
Color VisionThe researchers were also able to create a "parts list" of proteins found in green anole eggs, which they compared with those found in eggs from chickens and they discovered that both bird and lizard egg genes are evolving rapidly. They also mapped many genes in the anoles’ genome associated with color vision, which these lizards use to identify mates.
"Anoles have extremely good color vision – some species can even see in the ultraviolet range," said Losos. Other studies have shown that anoles can distinguish between similar colors and patterns. "It’s pretty clear that one function of the dewlap is to distinguish one species from others and that they use the dewlap - the skin fold under the chin - to determine whether a particular individual belongs to their species or not."
Reference: Alfoldi J et al. "The genome of the green anole lizard and a comparative analysis with birds and mammals." Nature August 31, 2011 doi:10.1038/nature10390
Got From: http://www.reptilechannel.com/reptile-news/2011/09/07/reptile-genome-sequenced.aspx
Wednesday, September 21, 2011
Beardie Health
Bearded Dragon Basking Open Mouth
Why do bearded dragons bask with their mouth open?
By Margaret A. Wissman, DVM, DABVP
Q. I own three bearded dragons. One of my male bearded dragons sits under his basking lamp with his mouth wide open. None of my other bearded dragons do this and I am concerned. My friend told me that it is normal and it is how bearded dragons regulate their heat but I read somewhere that it can mean they have a respiratory illness. He has been doing it for a while but is still very active and seems normal. Any help would be appreciated. Thanks.
A. The good news is that this is a normal behavior for bearded dragons. It seems that many owners don’t realize how warm these lizards should really be maintained, so they don’t see this behavior. The key to keeping bearded dragons happy is to have a basking spotlight that allows them to raise their body temperature to 95 to 110 degrees Fahrenheit. When a bearded dragon reaches its thermal maximum, it will often sit with its mouth open. This behavior, called gaping, shows that the lizard is at its optimal temperature for basking. This gaping will allow a bearded dragon to dissipate extra body heat. Since lizards don’t sweat, this is an effective way for them to regulate their body temperature. It is important that your bearded dragon habitat have a thermal gradient, so that your lizards can move to a cooler location, if they so desire, once they have reached their optimum body temperatures.
Open-mouth breathing is usually a sign of respiratory disease in other types of herps, and is an especially dangerous sign in snakes, however it can be normal in some lizards, including bearded dragons.
The good news is that you are keeping your bearded dragons at the correct temperature gradient, apparently, and you have nothing to worry about.
Margaret A. Wissman, DVM, DABVP has been an avian/exotic/herp animal veterinarian since 1981. She is a regular contributor to REPTILES magazine. Looking for a local herp vet? Click here>>
Got From: http://www.reptilechannel.com/lizards/lizard-care/bearded-dragon-basking.aspx
Tuesday, September 20, 2011
The Sandfish Lizard
How the Sandfish Lizard has Helped to Build a Machine
Machines able to navigate through the rubble of buildings in the aftermath of disasters such as earthquakes would be of great benefit to rescuers, saving vital time in the search for those trapped alive in the debris, but building effective machines is extremely challenging. Researchers at the Georgia Institute of Technology recently built a robot that can penetrate and 'swim' through granular material. They have now shown that varying the shape or adjusting the inclination of the robot's head affects the robot's movement in complex environments.
"We discovered that by changing the shape of the sand-swimming robot's head or by tilting its head up and down slightly, we could control the robot's vertical motion as it swam forward within a granular medium," explained Daniel Goldman, an assistant professor in the Georgia Tech School of Physics.
Desert reptile mechanics"The biological inspiration for our sand-swimming robot is the sandfish lizard, which inhabits the Sahara desert in Africa and rapidly buries into and swims within sand," explained Goldman. "We were intrigued by the sandfish lizard's wedge-shaped head that forms an angle of 140 degrees with the horizontal plane, and we thought its head might be responsible for or be contributing to the animal's ability to maneuver in complex environments."
For their experiments, the researchers attached a wedge-shaped block of wood to the head of their robot, which was built with seven connected segments, powered by servo motors, packed in a latex sock and wrapped in a spandex swimsuit. The doorstop-shaped head - resembling that of the sandfish - had a fixed lower length of approximately 4 inches, height of 2 inches and a tapered snout. The researchers examined whether the robot's vertical motion could be controlled simply by varying the inclination of the robot's head. Before each experimental run in a test chamber filled with plastic spheres which had a 0.25 inch diameter, the researchers submerged the robot a couple of inches into the granular medium and leveled the surface. Then they tracked the robot's position until it reached the end of the container or swam to the surface.
Effect of adjustments The researchers investigated the vertical movement of the robot when its head was placed at five different degrees of inclination. They found that when the sandfish-inspired head with a leading edge that formed an angle of 155 degrees with the horizontal plane was set flat, negative lift force was generated and the robot moved downward into the media. As the tip of the head was raised from zero to 7 degrees relative to the horizontal, the lift force increased until it became zero. At inclines above 7 degrees, the robot rose out of the medium. "The ability to control the vertical position of the robot by modulating its head inclination opens up avenues for further research into developing robots more capable of maneuvering in complex environments, like debris-filled areas produced by an earthquake or landslide," said Goldman. The robotics results matched the research team's findings from physics experiments and computational models designed to explore how head shape affects lift in granular media.
"While the lift forces of objects in air, such as airplanes, are well understood, our investigations into the lift forces of objects in granular media are some of the first ever," he added. Being able to precisely control the tilt of the head will allow the researchers to implement different strategies of head movement during burial and determine the best way to wiggle deep into sand. The researchers also plan to test the robot's ability to maneuver through material similar to the debris found after natural disasters and plan to examine whether the sandfish lizard adjusts its head inclination to ensure a straight motion as it dives into the sand.
Reptile inspires rescuers
September 12, 2011
Click image to enlarge Photo caption The inspiration sandfish (Scincus scincus), showing its distinctive head shape. Credit: Wilfried Berns/Tiermotive.de. |
"We discovered that by changing the shape of the sand-swimming robot's head or by tilting its head up and down slightly, we could control the robot's vertical motion as it swam forward within a granular medium," explained Daniel Goldman, an assistant professor in the Georgia Tech School of Physics.
Desert reptile mechanics"The biological inspiration for our sand-swimming robot is the sandfish lizard, which inhabits the Sahara desert in Africa and rapidly buries into and swims within sand," explained Goldman. "We were intrigued by the sandfish lizard's wedge-shaped head that forms an angle of 140 degrees with the horizontal plane, and we thought its head might be responsible for or be contributing to the animal's ability to maneuver in complex environments."
For their experiments, the researchers attached a wedge-shaped block of wood to the head of their robot, which was built with seven connected segments, powered by servo motors, packed in a latex sock and wrapped in a spandex swimsuit. The doorstop-shaped head - resembling that of the sandfish - had a fixed lower length of approximately 4 inches, height of 2 inches and a tapered snout. The researchers examined whether the robot's vertical motion could be controlled simply by varying the inclination of the robot's head. Before each experimental run in a test chamber filled with plastic spheres which had a 0.25 inch diameter, the researchers submerged the robot a couple of inches into the granular medium and leveled the surface. Then they tracked the robot's position until it reached the end of the container or swam to the surface.
Effect of adjustments The researchers investigated the vertical movement of the robot when its head was placed at five different degrees of inclination. They found that when the sandfish-inspired head with a leading edge that formed an angle of 155 degrees with the horizontal plane was set flat, negative lift force was generated and the robot moved downward into the media. As the tip of the head was raised from zero to 7 degrees relative to the horizontal, the lift force increased until it became zero. At inclines above 7 degrees, the robot rose out of the medium. "The ability to control the vertical position of the robot by modulating its head inclination opens up avenues for further research into developing robots more capable of maneuvering in complex environments, like debris-filled areas produced by an earthquake or landslide," said Goldman. The robotics results matched the research team's findings from physics experiments and computational models designed to explore how head shape affects lift in granular media.
"While the lift forces of objects in air, such as airplanes, are well understood, our investigations into the lift forces of objects in granular media are some of the first ever," he added. Being able to precisely control the tilt of the head will allow the researchers to implement different strategies of head movement during burial and determine the best way to wiggle deep into sand. The researchers also plan to test the robot's ability to maneuver through material similar to the debris found after natural disasters and plan to examine whether the sandfish lizard adjusts its head inclination to ensure a straight motion as it dives into the sand.
Monday, September 19, 2011
Reptile Vocabulary
http://www.enchantedlearning.com/subjects/reptiles/printouts.shtml
Ar·cho·sau·ria
noun pl \ˌär-kə-ˈsȯr-ē-ə\ : a large subclass of Reptilia comprising the dinosaurs, pterosaurs, and crocodilians all distinguished by possessing temporal openings separated from each other by a postorbitosquamosal arch
— ar·cho·sau·ri·an \¦ar-kə-¦sȯr-ē-ən\archos02 adjective or noun
Origin of ARCHOSAURIA
NL, fr. archo- (fr. Gk archōn) + -sauria
Browse
Next Word in the Dictionary: arch–poet
Previous Word in the Dictionary: archosaur
All Words Near: Archosauria
GOT FROM: http://www.merriam-webster.com/dictionary/archosauria
Previous Word in the Dictionary: archosaur
All Words Near: Archosauria
GOT FROM: http://www.merriam-webster.com/dictionary/archosauria
Oklahoma Reptiles
Oklahoma is rich in reptiles and amphibians, ranking third of all fifty states in number of species. Eighty species are represented, including one alligator, seventeen turtle, eighteen lizard, and forty-six snake species; and fifty-one species of amphibians are also present, including twenty-three salamander and twenty-eight frog and toad species. The state reptile is the collared lizard (Crotaphytus collaris, also called mountain boomer, although it is mute).This large lizard, which can run on its hind legs, reaches a total length of fourteen inches and is found on sunny, rocky outcrops statewide. The American alligator (Alligator mississippiensis) is rare in Oklahoma, found only in the extreme southeastern corner of the state. It is the only Oklahoma reptile with current state and federal conservation protection.
Of the turtles, one of the most interesting is the alligator snapping turtle (Macrochelys temminckii). This is the largest freshwater turtle in North America, with males reaching 250 pounds or more. Found in the eastern part of Oklahoma, it is rarely seen because it spends its entire life at the bottom of slow-moving rivers and creeks, except for females, who briefly leave the water to lay eggs. This turtle has a pink, fleshy protuberance in its mouth, which it wriggles while its mouth is held open. Curious fish approach this "worm" mimic and are captured by the turtle's jaws, strong enough to break a man's arm. The common snapping turtle (Chelydra serpentina), is also quite large, commonly reaching thirty-five pounds. Oklahoma's other turtles are much smaller and mostly aquatic, except for two species of terrestrial box turtles (Terrapene carolina and Terrapene ornata).
Noteworthy Oklahoma lizards (other than the state reptile mentioned above) include the Texas horned lizard (Phrynosoma cornutum), or horny toad, which is not a toad at all. This species has declined drastically in the last fifty to eighty years. It is a flattened, pancake sort of lizard, with sharp spines along its sides and stout horns projecting from the back of its head. It eats mostly ants and relies on its cryptic coloration to blend into its surroundings to escape predation. If severely disturbed by a dog or coyote, though, the horny toad is capable of spurting blood from the suborbital sinuses of its eyes, blood that apparently contains a substance that drives off the would-be predator. In southeastern Oklahoma lives the green anole (Anolis carolinensis), the popular "chameleon" sold in pet stores. This delicate lizard is arboreal and, like the true Old World chameleons (but not to the same extent), can change color from a drab brown to a bright emerald green.
Other lizards are long-tailed, actively foraging racerunners or whiptails (Teiidae), and smooth-scaled, shiny skinks (Scincidae). The slender glass lizard (Ophisaurus attenuatus) has no legs and is more tail than body. It is a lizard, though, as it has moveable eyelids and external ear openings. The Mediterranean house gecko (Hemidactylus turcicus) has been introduced from Texas (where it was introduced from the Mediterranean) to buildings on the campus of the University of Oklahoma and perhaps elsewhere in the southern part of the state. It is nocturnal, and the undersides of its toes have special microscopic, hairlike structures that allow it to climb on walls. It is the only species of lizard in Oklahoma that vocalizes. This, and some of the other lizards of Oklahoma (especially the skinks), can actively shed its tail (autotomy) if a predator grabs it, so as to be able to escape with its life. The tail can then regenerate.
Oklahoma sports more species of snakes than any other kind of reptile. There are blind snakes, hog-nosed snakes, wormsnakes, flat-headed snakes, groundsnakes, rough greensnakes, coachwhips, racers, ratsnakes, kingsnakes, milksnakes, bullsnakes, brownsnakes, earthsnakes, lined snakes, ribbonsnakes, gartersnakes, crayfish snakes, and watersnakes, among others. Probably the most common snake in Oklahoma is the small, gray ring-necked snake (Diadophis punctatus), usually found under rocks and logs. Although it is harmless to humans, this species can exude from its mouth a noxious fluid. When confronted by a potential predator, the snake will tightly coil its tail and flash its underside, which has a series of bright red and black bands, to warn or startle the molester.
Oklahoma has seven species of truly venomous snakes: the copperhead (Agkistrodon contortrix), cottonmouth or water moccasin (A. piscivorous), and five species of rattlesnakes, the Massasauga (Sistrurus catenatus), western pigmy (S. miliarius), timber (Crotalus horridus), western diamondback (C. atrox), and prairie rattler (C. viridis). All of these species are pit vipers, that is, between the eye and the nostril they have a heat-sensitive gland that is used to detect warm prey. The timber and diamondback rattlesnakes can grow especially large, over six feet long. Their rattles emit a loud, menacing warning sound, whereas the rattle of the much smaller Massasauga and western pygmy rattlesnake is nearly inaudible.
Turning to the amphibians, most of the salamanders require moist habitats and are found only in the eastern part of the state. They range in size from the diminutive, two-inch to three-inch Oklahoma salamander (Eurycea tynerensis), which reproduces in its gilled larval form, to the eighteen- to thirty-inch, three-toed amphiuma (Amphiuma tridactylium), which is aquatic and has extremely tiny limbs that cannot support its weight. One species, the central newt (Notophthalmus viridescens), has a complex life cycle in which it hatches from aquatic eggs into gilled larvae that live in small, fishless ponds. These larvae metamorphose into lunged efts, living on land for a few years, eventually returning to their natal ponds to take up an aquatic life again as gill-less newts. Here they reproduce. This species has highly toxic skin secretions and, especially the eft form, is bright red to warn potential predators. Most salamanders lay aquatic larvae that hatch into gilled larvae, but one genus (Plethodon) lays terrestrial eggs, in moist forest litter, moss, under logs, and so forth, that hatch into miniature, terrestrial adults. Interestingly, these adults lack both gills and lungs, "breathing" through their skin.
Of the frogs and toads, the most common and widespread species is the tiny cricket frog (Acris crepitans), which is often found along the shoreline of lakes and ponds. Unlike salamanders, frogs and toads vocalize; males sing to attract females for breeding. The call of the cricket frog sounds like two marbles repeatedly struck together. In contrast, the call of the also-abundant American toad (Bufo americanus) is a high-pitched trill lasting six to thirty seconds. This species, and its relatives, has a rough, warty skin containing irritating toxins that repel potential predators. On the back, just behind the head, are a pair of prominent parotid glands that deliver copious amounts of this chemical. Other frogs and toads of Oklahoma include treefrogs, with suction-cup toe tips to help them climb; narrowmouth toads, which often live together with tarantulas in their burrows; spadefoot toads, which live in more arid parts of the state and breed only after heavy summer rains; and true frogs, which include the largest frog of the state, the bullfrog (Rana catesbeiana). All of the state's species lay aquatic eggs that hatch into aquatic larvae (tadpoles) that later metamorphose into adults.
BIBLIOGRAPHY: Jeffrey H. Black and Gregory Sievert, A Field Guide to Amphibians of Oklahoma (Oklahoma City, Okla.: Oklahoma Department of Wildlife Conservation, 1989). Charles C. Carpenter and James J. Krupa, Oklahoma Herpetology: An Annotated Bibliography (Norman: University of Oklahoma Press, 1989). Roger Conant and Joseph T. Collins, Reptiles and Amphibians of Eastern/Central North America, Peterson Field Guide Series (3rd ed.; Boston: Houghton Mifflin, 1998). F. Harvey Pough, et al., Herpetology (2nd ed.; Upper Saddle River, N. J.: Prentice-Hall, 2001). George R. Zug, Laurie J. Vitt, and Janalee P. Caldwell, Herpetology: An Introductory Biology of Amphibians and Reptiles (2nd ed.; San Diego, Calif.: Academic Press, 2001).
Stanley F. Fox
GOT FROM: http://digital.library.okstate.edu/encyclopedia/entries/R/RE029.html
Of the turtles, one of the most interesting is the alligator snapping turtle (Macrochelys temminckii). This is the largest freshwater turtle in North America, with males reaching 250 pounds or more. Found in the eastern part of Oklahoma, it is rarely seen because it spends its entire life at the bottom of slow-moving rivers and creeks, except for females, who briefly leave the water to lay eggs. This turtle has a pink, fleshy protuberance in its mouth, which it wriggles while its mouth is held open. Curious fish approach this "worm" mimic and are captured by the turtle's jaws, strong enough to break a man's arm. The common snapping turtle (Chelydra serpentina), is also quite large, commonly reaching thirty-five pounds. Oklahoma's other turtles are much smaller and mostly aquatic, except for two species of terrestrial box turtles (Terrapene carolina and Terrapene ornata).
Noteworthy Oklahoma lizards (other than the state reptile mentioned above) include the Texas horned lizard (Phrynosoma cornutum), or horny toad, which is not a toad at all. This species has declined drastically in the last fifty to eighty years. It is a flattened, pancake sort of lizard, with sharp spines along its sides and stout horns projecting from the back of its head. It eats mostly ants and relies on its cryptic coloration to blend into its surroundings to escape predation. If severely disturbed by a dog or coyote, though, the horny toad is capable of spurting blood from the suborbital sinuses of its eyes, blood that apparently contains a substance that drives off the would-be predator. In southeastern Oklahoma lives the green anole (Anolis carolinensis), the popular "chameleon" sold in pet stores. This delicate lizard is arboreal and, like the true Old World chameleons (but not to the same extent), can change color from a drab brown to a bright emerald green.
Other lizards are long-tailed, actively foraging racerunners or whiptails (Teiidae), and smooth-scaled, shiny skinks (Scincidae). The slender glass lizard (Ophisaurus attenuatus) has no legs and is more tail than body. It is a lizard, though, as it has moveable eyelids and external ear openings. The Mediterranean house gecko (Hemidactylus turcicus) has been introduced from Texas (where it was introduced from the Mediterranean) to buildings on the campus of the University of Oklahoma and perhaps elsewhere in the southern part of the state. It is nocturnal, and the undersides of its toes have special microscopic, hairlike structures that allow it to climb on walls. It is the only species of lizard in Oklahoma that vocalizes. This, and some of the other lizards of Oklahoma (especially the skinks), can actively shed its tail (autotomy) if a predator grabs it, so as to be able to escape with its life. The tail can then regenerate.
Oklahoma sports more species of snakes than any other kind of reptile. There are blind snakes, hog-nosed snakes, wormsnakes, flat-headed snakes, groundsnakes, rough greensnakes, coachwhips, racers, ratsnakes, kingsnakes, milksnakes, bullsnakes, brownsnakes, earthsnakes, lined snakes, ribbonsnakes, gartersnakes, crayfish snakes, and watersnakes, among others. Probably the most common snake in Oklahoma is the small, gray ring-necked snake (Diadophis punctatus), usually found under rocks and logs. Although it is harmless to humans, this species can exude from its mouth a noxious fluid. When confronted by a potential predator, the snake will tightly coil its tail and flash its underside, which has a series of bright red and black bands, to warn or startle the molester.
Oklahoma has seven species of truly venomous snakes: the copperhead (Agkistrodon contortrix), cottonmouth or water moccasin (A. piscivorous), and five species of rattlesnakes, the Massasauga (Sistrurus catenatus), western pigmy (S. miliarius), timber (Crotalus horridus), western diamondback (C. atrox), and prairie rattler (C. viridis). All of these species are pit vipers, that is, between the eye and the nostril they have a heat-sensitive gland that is used to detect warm prey. The timber and diamondback rattlesnakes can grow especially large, over six feet long. Their rattles emit a loud, menacing warning sound, whereas the rattle of the much smaller Massasauga and western pygmy rattlesnake is nearly inaudible.
Turning to the amphibians, most of the salamanders require moist habitats and are found only in the eastern part of the state. They range in size from the diminutive, two-inch to three-inch Oklahoma salamander (Eurycea tynerensis), which reproduces in its gilled larval form, to the eighteen- to thirty-inch, three-toed amphiuma (Amphiuma tridactylium), which is aquatic and has extremely tiny limbs that cannot support its weight. One species, the central newt (Notophthalmus viridescens), has a complex life cycle in which it hatches from aquatic eggs into gilled larvae that live in small, fishless ponds. These larvae metamorphose into lunged efts, living on land for a few years, eventually returning to their natal ponds to take up an aquatic life again as gill-less newts. Here they reproduce. This species has highly toxic skin secretions and, especially the eft form, is bright red to warn potential predators. Most salamanders lay aquatic larvae that hatch into gilled larvae, but one genus (Plethodon) lays terrestrial eggs, in moist forest litter, moss, under logs, and so forth, that hatch into miniature, terrestrial adults. Interestingly, these adults lack both gills and lungs, "breathing" through their skin.
Of the frogs and toads, the most common and widespread species is the tiny cricket frog (Acris crepitans), which is often found along the shoreline of lakes and ponds. Unlike salamanders, frogs and toads vocalize; males sing to attract females for breeding. The call of the cricket frog sounds like two marbles repeatedly struck together. In contrast, the call of the also-abundant American toad (Bufo americanus) is a high-pitched trill lasting six to thirty seconds. This species, and its relatives, has a rough, warty skin containing irritating toxins that repel potential predators. On the back, just behind the head, are a pair of prominent parotid glands that deliver copious amounts of this chemical. Other frogs and toads of Oklahoma include treefrogs, with suction-cup toe tips to help them climb; narrowmouth toads, which often live together with tarantulas in their burrows; spadefoot toads, which live in more arid parts of the state and breed only after heavy summer rains; and true frogs, which include the largest frog of the state, the bullfrog (Rana catesbeiana). All of the state's species lay aquatic eggs that hatch into aquatic larvae (tadpoles) that later metamorphose into adults.
BIBLIOGRAPHY: Jeffrey H. Black and Gregory Sievert, A Field Guide to Amphibians of Oklahoma (Oklahoma City, Okla.: Oklahoma Department of Wildlife Conservation, 1989). Charles C. Carpenter and James J. Krupa, Oklahoma Herpetology: An Annotated Bibliography (Norman: University of Oklahoma Press, 1989). Roger Conant and Joseph T. Collins, Reptiles and Amphibians of Eastern/Central North America, Peterson Field Guide Series (3rd ed.; Boston: Houghton Mifflin, 1998). F. Harvey Pough, et al., Herpetology (2nd ed.; Upper Saddle River, N. J.: Prentice-Hall, 2001). George R. Zug, Laurie J. Vitt, and Janalee P. Caldwell, Herpetology: An Introductory Biology of Amphibians and Reptiles (2nd ed.; San Diego, Calif.: Academic Press, 2001).
Stanley F. Fox
GOT FROM: http://digital.library.okstate.edu/encyclopedia/entries/R/RE029.html
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