Pleistocene Survivors: The Amphibians

Extant species of amphibians not only survived the Pleistocene, but ancestral species withstood environmental changes that occurred in the Pliocene, Miocene, Oligocene, Eocene, Paleocene, Cretaceous, Jurrassic, and Triassic.  They may be physiologically primitive, but they’re adaptable.  Part of their ability to endure gross environmental change may be their habit of becoming dormant during unfavorable conditions such as drought or cold weather.  Amphibians can burrow into mud or forest litter, under rocks, or at the bottom of a pond and are thus protected, even if the atmosphere cooks following an extraterrestrial impact.

Amphibian fossils of extant species occur in some Georgia fossil sites.  Cavers and scientists found and identified 17 species of amphibians in Kingston Saltpeter Cave, Bartow County.  Amphiuma fossil bones associated with mammoth and bison fossils were among the treasures of the Clark Quarry fossil site near Brunswick.  Numerous fossil localities in South Carolina’s coastal plain, some dating back to the Pliocene, also are home to amphiuma fossils.  Incidentally, genetic tests determined all 3 amphiuma species descend from an ancestral species that lived 4-10 million years ago.

While reviewing existing amphibian species in Georgia along with the Pleistocene fossil record, I didn’t gain any surprising ecological insights, as I frequently do with mammals and birds.  Not many, if any, amphibian species in Georgia became extinct at the end of the Pleistocene.  However, the fossil record is incomplete, and therefore deceiving.  Reference sources on this subject are limited to a difficult to obtain academic book written by the late Alan Holman, but I’m pretty sure amphibians didn’t take the big hit that the Pleistocene megafauna did.  In any case it’s obvious that western spadefoot toads were once a continuous population with the eastern spadefoot toad.  Speciation probably occurred some time during the early Pleistocene.  And northern leopard frogs must have had a more southerly range because their present day range was under glacial ice during the Wisconsinian Ice Age.

Here’s a review of every known amphibian species in Georgia.

The Giant Salamander Family

Hellbender–Cryptobranchus allegheniensis

—Also known as devil dog, it’s restricted to fast moving mountain streams here in Georgia.  A Japanese cousin of this species grows to 5 feet long.  Wow!

The Siren Family

Dwarf siren–Pseudobranchus striatus

Lesser siren–Siren intermedia

Greater siren–Siren lacertina

—During droughts, these eel-shaped creatures encase themselves in mud and become dormant.  They “yelp” when captured.  They’re restricted to the coastal plain in state.

The Newt Family

Striped newt–Notophthalmus perstriatus

Eastern newt–Notophthalmus veridescens

The eastern is interspersed throughout the state.

The Mudpuppy/Waterdog Family

Alabama waterdog–Necturus alabamensis

Mudpuppy–Necturus maculosus

Dwarf waterdog–Necturus punctatus

Mudpuppies live in mountain streams; Alabama waterdogs live in the western part of Georgia; dwarf waterdogs live in the southeastern part of the state.

The Amphiuma Family

Two-toed amphiuma–Amphiuma means

One-toed amphiuma–Amphiuma pholeter

Three-toed amphiuma–Amphiuma triactylum

The species that lives in Georgia can grow to almost 4 feet long.  These slippery, eel-shaped animals, bite when handled.

Photo from google images.  Note the vestigial limb.

The Mole Salamander Family

Flatwoods salamander–Ambystoma cingulatum

Jefferson salamander–Ambystoma jeffersonianon

Spotted salamander–Ambystoma maculatum

Marbled salamander–Ambystoma opacum

Mole salamander– Ambystoma talpoideum

Tiger salamander–Ambystoma tigrinum

—The flatwoods salamander lives in wet pine savannahs and is often found in crayfish burrows. 

–Jefferson’s salamander doesn’t currently live in Georgia but may have occurred here during the Ice Age because most of its current range was under glacial ice. 

–Spotted salamanders live underground on forested hillsides near pools of water. 

–Marbled salamanders lay eggs when their nests fill with rain water. 

— Tiger salamanders frequently are found in my yard.  They feed upon insects, worms, mice, and other amphibians.

The Lungless Salamanders

Green salamander–Aneidas aenus

Seepage salamander–Desmognathus aenus

Southern dusky salamander–Desmognathus auriculatus

Dusky salamander–Desmognathus fuscus

Imitator salamander–Desmognathus tutor

Seal salamander–Desmognathus monticola

Mountain dusky salamander–Desmognathus ochrophaeus

Black bellied salamander–Desmognathus quadramaculatus

Two-lined salamander–Euricea blisineata

Long-tailed salamander–Eurycea longicauda

Cave salamander–Euricea lucifoga

Dwarf salamander–Euricea quadridigitata

Tennessee cave salamander–Gyrinophilus palleucus

Spring salamander–Gyrinophilus porphyriticus

Georgia blind salamander–Haideotriton wallaces

4-toed salamander–Hemidactylium scutatum

Shovel-nosed salamander–Levrognathus marmoratus

Zig Zag salamander–Plethrodon dorsalis

Slimy salamander–Plethrodon glutinosus

Appalachian woodland salamander–Plethrodon jordani

Southern red-backed salamander–Plethrodon serratus

Mud salamander–Pseudotriton montanu

Red salamander–Pseudotriton ruber

Many lined salamander–Sterechilus marginatus

—Southern dusky salamander can change color like anole lizards.

–Black bellied salamanders originally were restricted to the mountain region, but their use as fish bait has expanded their range to include an irregular inhabitation of the piedmont.

–Cave salamanders have a prehensile tail and forage in cave crevices.

–Georgia blind salamanders live in ground water in southwest Georgia.

–Slimy salamanders secrete a glue-like substance difficult to remove.

Photo from google images of a Georgia blind salamander.  They live in well water.

Burrowing Toad Family

Eastern spadefoot toad–Scaphiobus holbrooki

–This animal can survive light brush fires.

The True Frog Family

Crawfish frog–Rana areolata

Bullfrog–Rana catesbeiana

Green frog–Rana clamitans

Pig frog–Rana grylia

River frog–Rana heckscher

Pickeral frog–Rana palustrus

Northern leopard frog–Rana pipiens

Southern leopard frog–Rana sphenocephala

Wood frog–Rana sylvatiea

Carpenter frog–Rana virgatipes

—Bullfrogs eat birds, mice, other frogs, crayfish, insects, and minnows.  Their croak sounds like a cow lowing.

Photo from google images of a bullfrog.

–Green frog croaking sounds like a banjo twang.

–Pig frog croaking sounds like pigs grunting.

–River frogs and pickeral frogs have a toxic skin secretion that repels snakes.

–Southern leopard frogs escape predation by leaping into the water, making a sharp right turn, and emerging in vegetation close to shore.

–Northern leopard frogs no longer occur in state but I suspect they did during the Ice Age.

–Wood frogs live as far north as Alaska where they survive being frozen in winter.  In Georgia they live in the northern part of the state.

–Carpenter frog croaking sounds like the hammering of carpenters.

The Narrow-mouthed Frog Family

Eastern narrow-mouthed frog–Gastrophryne carolinensis

–The narrow-mouthed frog’s croaking sounds like a sheep bleating.

The Toad Family

Oak toad–Bufo quericicus

Southern toad–Bufo terrestis

Fowler’s/Woodhouse Toad–Bufo woodhousei

–The southern toad likes sandy soil in oak scrub habitat.

The Tree Frog Family

Northern cricket frog–Acris crepitans

Southern cricket frog–Acris gryllus

Pine barrens tree frog–Hyla andersoni

Bird-voiced tree frog–Hyla avivoca

Cope’s gray tree frog–Hyla chrysoscalis

Common gray tree frog–Hyla versicola

Green tree frog–Hyla cinerea

Spring peeper–Hyla crucifera

Pine woods tree frog–Hyla femoralis

Barking tree frog–Hyla gratiosa

Squirrel tree frog–Hyla squirella

Little grass tree frog–Limnaoedus ocularis

Mountain chorus frog–Pseudacris brachyphone

Brimley’s chorus frog–Pseudacris brimleys

Southern chorus frog–Pseudacris nigrita

Ornate chorus frog–Pseudacris ornata

Chorus frog–Pseudacris triseriata

–Pine forest tree frog croaking sounds like a chorus of typists.  They live at the tops of trees in open pine savannahs.

Photo from google images of a pine forest tree frog.

–Barking tree frogs have scattered relic populations.  They probably had a continuous range during warm interglacials.

–Brimley’s tree frog changes color for camouflage.

Reference:

Behler, John; and F. Wayne King

The Audubon Society field guide to Reptiles and Amphibians

Knopf

 

 

Tags: Alan Holman, amphibians, amphiuma, frogs, mudpuppies, salamanders, toads, tree frogs, true frogs, water dogs