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
  • spadefoot toads (Pelobatidae)
    • mostly live underground and come out at night
    • have a horny digger on their hind feet and help them dig
    • breed in temporary pools, and therefore their eggs and larval can develop as quickly as 12 days
    • scaphiopus_couchii_anra
  • narrow-toed toads (Leptodactylidae)
    • most species are tropical and lay eggs on land
    • found in the Southern US to South America
    • there are over 800 species, so characteristics vary widely
    • eleutherodactylus_guttilatus
  • true toads (Bufonidae)
    • over 350 species, 17 species in the US
    • skins very warty with parotid glands behind the eyes
    • shorter legs than frogs as they are designed for hopping, not leaping
    • usually burrow during the day, hunt insects at night
    • a toad light can be set up for their observation See this link by Michigan DNR
20170314_181037
Red-Spotted Toad (Bufo punctatus), captured by Lauren Schramm, Lajitas, Texas
  • true frogs (Ranidae)
    • long legs and slim waist
    • have a very distinct eardrum
    • webbed feet, usually have distinct ridges down the back
    • aquatic larvae, aquatic and terrestrial adults

 

green frog
Green frog (Rana clamitans)  Inlet, NY- captured by Lauren Schramm, photo credit- Peter Spawn

Going back to the salamanders, order Caudata, they are distinct by a long slender body, four limbs, and tail. There are 340 species worldwide. They almost call have smooth skin and glands that promote poison. Salamanders can be found in soil, leaf litter, or in water bodies. They have internal fertilization via spermatophores, which means that the male gives a packet of sperm to the female which she absorbs into her body to fertilize eggs. Breeding occurs in the early spring, often with the 1st warm rain. Salamanders start to migrate to the breeding location, in this process road present a huge barrier to them. Some states even have groups that go out during this time and act as crossing guards for the salamanders. If you are interested I found groups in New Hampshire and Vermont. Sexual dimorphism is common in salamanders meaning that the males and females have different physical characters. The 5 families I will talk about in this blog post are giant salamanders (Cryptobranchidae), mole salamanders (Ambystomatidae), Conger eels (Amphiumidae), lungless salamanders (Plethodontidae), and newts (Salamandridae).

  • giant salamanders (Cryptobranchidae)
    • largest living salamanders
    • fully aquatic
    • the largest species is the giant salamander (Cryptobranchus alleganiensis) which can be almost 6 feet long and lives in Japan
    • one species, the Hellbender (Cryptobranchus alleganiensis), lives in the US but is near threatened
    • 4739185259_6e3f628337_b
  • mole salamanders (Ambystomatidae)
    • characterized by their stout bodies
    • found in the US and Canada
    • there are 30 species of this burrowing salamander
    • named after the fact that they only emerge to breed

    eastern_tiger_salamander_28ambystoma_tigrinum29_282552238976229

  • Conger eels (Amphiumidae)
    • only 3 species
    • named the overall body shape
    • found in the southern US
    • named for the number of toes they have; One-toed amphiuma (Amphiuma pholeter), Two-toed amphiuma (Amphiuma means), Three-toed amphiuma (Amphiuma tridactylum)
  • 4625374379_f74148c602_b
  • lungless salamanders (Plethodontidae)
    • breathe through the skin and the mouth
    • there are over 250 species, making it the most diverse family of salamanders
    • most are found in the Americas but a few are found in Europe
    • 20180111_195853.jpg
      Red-backed salamander (Plethodon cinereus)- captured by Lauren Schramm, Norcross, GA
  • newts and salamanders (Salamandridae)
    • has the largest geographic distribution of any salamander family
    • has two subgroups that contain true salamanders (genera ChioglossaMertensiella, and Salamandra) and newts (other genera)
    • most adults are smaller and rarely longer than 20 cm
    • notophthalmus_viridescenspcca20040816-3983a

Finally, the last order, Apoda, contains caecilians, which are the lesser known group of amphibians and for good reasons. Caecilians is latin for blind onesThey are basically salamanders without legs, although some do have very tiny legs. They live underground and very little is known about them. There are 160 species. THeir eyes may be covered with bone or skin. They hunt prey underground using their head as a sensor. My old biology professor called them nightmare material. vivipary is common among them, meaning that the young develop inside the mother and then they are born. They are found in the tropics in of South and Central America, Africa, and southern Asia. Their skin contains calcite scales which led scientists to originally think they were related to Stegocephalia which is a salamander/ lizard-like creature that lived 350 million years ago.

siphonops_paulensis02

 

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