Frog Taxonomy (with a focus on Georgia frogs)

Georgia currently has 30 native frog species and two introduced frog species that fall into six different families.

The most distinct of these families is Bufonidae or the true toads. All toads will be found in this family. All toads are frogs but not all frogs are toads. Toads are a specialized group of frogs who typically have warty dry skin, are short and stubby, and large glands on the sides of their heads that kind of look like shoulder pads and are called parotoid glands.  Toads can actually aim these glands at predators. The glands release a toxin, called bufo. That’s why it’s common to see toads hopping around during the day. The eggs are typically laid in long strands. Toads also have no teeth. Worldwide there are 604 species in this family.  In Georgia we have 4 species; American Toad (Anaxyrus americanus), Fowler’s Toad (Anasyrus fowleri), the Oak Toad (Anaxyrus quercicus), and the Southern Toad (Anaxyrus terrestris). In the Metro Atlanta area, it’s common to hear both American and Fowler’s toads calling. The Ameican toad sounds like a long musically thrill that lasts between 6 and 30 seconds. The Fowler’s Toad sounds like a harsh thrill, kind of like a nasally WAAAHHHH.

 

20170314_181037 (1).jpg
Red-spotted toad (Anaxyrus punctatus, formerly Bufo punctatus), captured by Lauren Schramm

 

The largest family of frogs in Georgia is Hylidae or the tree frogs, chorus frogs, and cricket frogs. Worldwide the family has 710 species. They all shared a claw-shaped finger which is found at the end of their toe pad. The toe pads function not like suction cups, but via wet adhesion, similar to 2 pieces of wet glass sticking together. In Georgia we have the Northern Cricket Frog (Acris crepitans), Southern Cricket Frog (Acris gryllus), Bird-voiced Treefrog (Hyla avivoca), Cope’s Gray Treefrog (Hyla chrysoscelis), Green Treefrog (Hyla cinerea), Pine Woods Treefrog (Hyla femoralis), Barking Treefrog (Hyla gratiosa), Squirrel Treefrog (Hyla squirella), Cuban Treefrog (Osteopilis septentrionalis), Mountian Chorus Frog (Pseudacris brachyphona), BRimley’s Chorus Frog (Pseudacris brimleyi), Spring Pepper (Pseudacris cruicifer), Upland Chorus Frog (Pseudacris feriarum), Southern Chorus Frog (Pseudacris nigrita), Little Grass Frog (Pseudacris ocularis), and finally the Ornate Chorus Frog (Pseudacris ornata). The Cuban Treefrog is actually an invasive species that is twice as large as our native treefrogs and it consumes them! It’s really hard to find because it’s a treefrog and so there is not much we can do about it’s invasion. The upland chorus frog (sounds like running your finger along a comb), spring pepper (sounds like bird-like peeps), Cope’s gray treefrog (harsh, high pitched trill), green treefrog (nasally and duck-like), bird-voiced treefrog (like a bird call whit-whit-whit), squirrel treefrog (harsh repetitive, squirrel-like call), and northern cricket frog (sounds like two marbles being tapped together) can all be found in the Metro Atlanta area.

 

20180927_212400.jpg
Cope’s Grey Treefrog, captured by Lauren Schramm

 

The family Ranidae contains true frogs who have smooth and wet skin. Worldwide they have a large range. Generally, they are aquatic or live close to water. This family is probably what comes to mind when most people think of frogs. In Georgia you can find Gopher Frogs (Lithobates capito), Bullfrogs (Lithobates catesbeinanus), Green Frogs (Lithobates clamitans), Pig Frogs (Lithobates grylio), River Frogs (Lithobates heckscheri), Pickeral Frogs (Lithobates palustris), SOuthern Leopard Frogs (Lithobates sphenocephalus), Wood Frogs (Lithobates sylvaticus), and Carpenter Frogs (Lithobates virgatipes). Bullfrogs, green frogs, pickerel frogs, and Southern leopard frogs all have calls that can be heard in the metro Atlanta area. Respectively the calls sound like a repeated jug-o-ruummmm, like a banjo pluckling, a snoring person, and the sound of squeezing a balloon.

 

20190726_123736.jpg
Pickeral Frog, captured by Lauren Schramm

 

Continue reading

How will climate change impact amphibians? (focus on fungal disease)

Chytridiomycosis is a disease that is killing amphibians worldwide at alarming rates. To read more about amphibians see this blog post. The disease is caused by Batrachochytrium dendrobatidis or Bd for short. Bd is a fungus that is specific to amphibians. Currently, the disease is responsible for the greatest disease-caused loss of biodiversity in recorded history. Species have had massive drops in populations and seem to have disappeared overnight.Bd occurs inside the cells of the outer skin layer. It causes microscopic changes in the skin and enlarges this layer. This is deadly because amphibians absorb water and salts through the skin. In the family of lungless salamanders, and one lungless species of caecilian Bd causes them to suffocate. Bd travels into the mouthparts of tadpoles or other larval amphibians. When tadpoles change into adults the infection spreads to the skin. Spores, which are the reproductive part of the fungus, cause the skin to become enlarged. This reduces osmotic regulation and electrolyte blood levels drop which leads to cardiac arrest. Chytridiomycosis has almost a 100 percent mortality rate.

 

chytridiomycosis2
Cells infected with Batrachochytrium dendrobatidis 

 

Continue reading

Types of amphibians galore! Class Amphibia

The class Amphibia contains amphibians which are some of my favorite animals. There are three major types which are frogs & toads (order Anura), salamanders (order Caudata), and caecilians (order Apoda). All these orders share certain characteristic including being endothermic, meaning they are unable to regulate their own body temperature. They have both lungs and gills, typically they have gills in the larvae stage but then develop lungs in the adult stage. Their eggs are anamniotic, meaning they are covered by a gelatinous mass that protects the eggs and prevents them from drying out. The warmer and moister an area the more likely it is that they will have more species of Amphibia.

The order Anura contains both frogs and toads, and over 3,400 species! They have longer hind legs than front legs which gives them the ability to hop. The tail is lost in the adult stage and adult males are typically the only ones that vocalize, and they do so to attract mates. Within the order, there are a few distinct families which include the tailed-frog (Ascaphidae),  spadefoot toads (Pelobatidae), narrow-toed toads (Leptodactylidae), true toads (Bufonidae), and true frogs (Ranidae). These are only 5 families. I will post later but this is a good start. If you learned the basic characteristic of each family it will greatly improve the speed and accuracy with which you can identify species.

  • tailed-frog (Ascaphidae)
    • this family only has one species (Ascaphus truei) that lives in the Pacific Northwest
    • ascaphus_truei_web

Continue reading