Posts Tagged ‘salamanders’

The Plot “Thickens”

Tuesday, May 17th, 2011

If you have ever had the misfortune of turning over a log or rock in eastern Oklahoma and grabbing a black salamander with white spots, you know that washing off the thick, sticky liquid that they secrete from their skin in defense is no easy matter. Imagine being a small predator like a snake, biting the salamander, getting a mouthful of that sticky stuff, and then trying to rub it off in the leaf litter ending up with a mouthful of leaves stuck to your mouth! These salamanders, which look pretty much the same from mountain ridge to mountain ridge, and even resemble a lowland salamander, form a complex of species whose identities and relationships are just beginning to be understood. To the layman, these are known as the “slimy” salamanders.

The salamander Plethodon ouachitae, occurs along several ridges in the Ouachita Mountains and is commonly known as the Rich Mountain Salamander.

The Rich Mountain Salamander (P. ouachitae) occurs along several ridges in the Ouachita Mountains.

Dr. Don Shepard, a former graduate student from the University of Oklahoma, has combined field studies with DNA sequence data to unravel relationships among these species. Until recently, these salamanders have been considered as four species. One, Plethodon albagula, appears to be widespread in lowlands and the Ozark foothills of eastern Oklahoma, extending up into Missouri. Three other species, P. caddoensis, P. fourchensis, and P. ouachitae, each occur on their own mountain ridges in the Ouachita Mountains of southeastern Oklahoma and southwestern Arkansas. If only it were that simple!

By combining DNA sequence data with known rates of evolutionary change for specific genes, Don has discovered that not only have some of these “species” experienced divergence into genetically different populations, the causes of divergence differ among species. For P. ouachitae and P. fourchensis, genetically different populations are associated with mountain ridges, indicating that populations were isolated on mountain tops as the climate slowly changed over geologic time. Why would they become isolated? The answer is that these salamanders require a specific set of environmental conditions to survive. These include relatively cool temperatures and high humidity, usually associated with mountain tops. The salamanders appear unable to adapt to warmer and drier conditions so they simply live in the same kind of microhabitats that they lived in historically. This inability to adapt is referred to by scientists as “niche conservatism.”

For P. caddoensis, diversification is associated with stream drainages. Four distinct lineages within P. caddoensis have been identified from each of the following four streams; lower Caddo River, Upper Caddo River, Brushy Creek, and Cossatot and Little Missouri Rivers. Diversification in this “species” appears tied to more recent climatic change and specialized niche characteristics of the salamanders, primarily related to thermal and humidity variables associated with stream drainages.

The Western Slimy Salamander, Plethodon albagula, occurs from Missouri south to extreme southeastern Oklahoma and into Texas.

The Western Slimy Salamander (P. albagula) occurs from Missouri south to extreme southeastern Oklahoma and into Texas.

Dr. Shepard is now beginning to examine the lowland and widespread “species” P. albagula. No doubt this species has undergone some interesting divergences in the past, but what the pattern is and how it occurred remains a mystery to be unraveled. So, the next time you pick up one of these so-called “slimy salamanders,” reflect on their evolutionary history and what they tell us about past events underscoring the remarkable diversity that we see today in eastern Oklahoma. Oh, and if you have been slimed, try WD-40 followed by soap and water. WD-40 seems to be a universal solvent and will clean many things!

Slimy Salamanders and Bigfoot

Tuesday, June 15th, 2010

Southeastern Oklahoma harbors an interesting set of reptiles and amphibians, dominated by species typical of southeastern deciduous forests. However, a small group of related salamanders are endemic to the east to west chain of mountains collectively known as the Ouachita Mountains. Also known as the Interior Highlands, these are the only mountains between the Appalachian Mountains to the east and the Rocky Mountains to the West. Each mountain has a name (e.g., Kiamichi Mountains, Winding Stair, Boktuklos, Rich Mountain), and almost all have their own endemic salamander species. The salamanders have been collectively called “slimy salamanders” and are in a large group of salamanders known as lungless salamaders (Family Plethodontidae). They are “slimy” because they produce a viscous liquid from glands in the skin that is first slimy, but then sticky. They are “lungless” because they do not have lungs, but rather breath entirely through their skin!

The lungless salamander, Plethodon sequoia

The lungless salamander, Plethodon sequoyah

Slimy salamanders of the Ouachita Mountains have recently been studied in detail by Dr. Don Shepard, formerly a graduate student at the University of Oklahoma and here in the Sam Noble Museum. One of the salamanders is shown above and a future blog will detail what Don has discovered about these interesting salamanders.

Another interesting point about southeastern Oklahoma is a growing interest in Bigfoot, the large, hairy, man-like beast that purportedly runs wild in the forests near the tiny town of Honobia. A fall festival (the Bigfoot Festival) occurs each year in which various groups attempting to gather evidence of Bigfoot’s existence meet and discuss their findings. Honobia is remote and located equidistant from Oklahoma City, Dallas, and Shreveport. Limited lodging is available at Dancing Rain Ranch and the Honobia Creek Country Store, with additional lodging in Talihina. Each year, Bigfoot researchers claim to have gathered additional evidence, but firm verifiable physical evidence that Bigfoot exists has still not been presented to the public. Perhaps in the next few years, Bigfoot will step on a slimy salamander and lose some hair so that DNA can be collected and analyzed—but please, don’t hold your breath, unless you are a slimy salamander!

The First Spring Rains Bring Out Frogs and Salamanders

Wednesday, April 21st, 2010

Rains that occurred several weeks ago in southeastern Oklahoma brought out all of the early spring frogs, including Spring peepers (Pseudacris crucifer), Cajun chorus frogs (Pseudacris fouquettei), Pickerel frogs (Lithobates palustris), and Southern crawfish frogs (Lithobates areolata). Even Southern leopard frogs (Lithobates sphenocephala) and American toads (Anaxyrus americanus) were active. In addition to running our traps at our primary research site in Le Flore County, we spent time driving roads at night in both Le Flore and McCurtain Counties. Nearly every roadside pond contained some mix of the above frog species. The only two that did not occur together were Pickerel and Crawfish frogs.

An adult Cajon chorus frog

An adult Cajun chorus frog

A number of amphibian species in Oklahoma breed during late winter and early spring, and their nearly deafening choruses can be easily experienced by driving around in rural areas at night. Males congregate in ponds when rains first begin, and their calls attract females that have spent the fall and winter converting energy that they stored from spring, summer, and fall activity into eggs. Examination of ponds during the daytime usually reveals many egg masses attached to vegetation or floating on the pond surfaces.

In addition to frogs that reveal their presence by calling, salamanders are moving into ponds to breed. We found large numbers of Spotted salamanders (Ambystoma maculatum) moving across roads heading for ponds during rains, and we captured some in our traps. Unlike frogs, salamanders do not vocalize. Whereas female frogs are attracted to individual males by the quality of the call, female salamanders are attracted to individual males by the quality of their courtship behavior.

An adult Spotted salamander

An adult Spotted salamander

So, for those of you are interested in amphibians, drive around in rural areas when it begins to rain and listen for frog choruses.  With the windows cracked, you can hear choruses in breeding ponds along the roads.  If you find a chorus on public property, put on your boots, turn on your good flashlight or headlight (preferred), and see if you can locate individual frogs that are calling. Chorus frogs are tiny and usually call inside grass clumps at the surface of the water. A Chorus frog calling right at your feet can be difficult to locate and requires persistence. If you are lucky enough to hear the low snoring calls of Pickerel or Crawfish frogs, you will need to move slowly without sloshing the water.  Even slight movement of the water caused these wary frogs to stop calling and dive below the surface. If you stand quietly for ten minutes or so, males will reappear and begin calling.

Amphibians and Reptiles at the SNOMNH

Thursday, September 3rd, 2009
Male Broad-headed Skink showing breeding coloration
Male Broad-headed Skink showing breeding coloration

Hello, interested readers. Herpetologists at the Sam Noble Oklahoma Museum of Natural History in Norman have been monitoring amphibians and reptiles in southeastern Le Flore County for the past year and have run across some interesting aspects of the biology of these often abundant and visible animals. We are so excited about our findings, and herpetology in general, that we decided to create this blog to keep others around the state, the nation, and the world informed.

As some of you already know, Dr. Laurie Vitt and Dr. Janalee Caldwell (us!) have spent many years studying amphibians and reptiles in the United States, Central America, South America, and a few other exotic places. We are professional researchers, but like most people who are fortunate enough to be paid for what they love to do, we started out by observing amphibians, reptiles, and other animals in their natural habitats when we were just children. So, in a sense, we never grew up! What we have learned directly from these animals is remarkable, and as you will see in the forthcoming blogs, the natural world is even stranger and more interesting than anything that we could make up.

We hope that you will join us by keeping up with our blog, and we will do our best to provide you with interesting information on these fascinating animals. For those of you who are particularly interested in amphibians and reptiles of Oklahoma, we invite you to visit our web personal pages, and more specifically, to examine the web pages that we have prepared for some of the Wildlife Management Areas (WMAs) around the state, in collaboration with the Oklahoma Department of Wildlife Conservation. We now have three WMA web pages, Packsaddle, Atoka, and Cookson, and all can be accessed from our WMA web page (http://www.snomnh.ou.edu/personnel/herpetology/vitt/WMA/index.shtml). We are working on more. We also have web pages for some of our South American research sites. So, for now, welcome to our blog, keep checking, and feast your imagination on this beautiful male Broad-Headed Skink from the Cookson Hills in NE Oklahoma.