BIO 370 — Vertebrate Zoology

Vertebrate Diversity
Class Amphibia — Amphibians

(Click on any image for larger version)

Tetrapod Characteristics

• 4 walking limbs with toes
• Specialized atlas, 2 occipital condyles
• Hyoid apparatus for tongue muscles
• Middle ear with tympanum, stapes
• Eyelids

Amphibia Characteristics

The following apply to Lissamphibia (extant amphibians):
• Glandular skin
• Cutaneous gas exchange
• Short ribs
• Hands with 4 digits
• Reduced or absent dermal armor
• Typically with aquatic larval stage

Order Caudata — Salamanders, newts

Marbled Salamander, Ambystoma opacum (Family Ambystomatidae), adult; SC; a mostly fossorial species	Spring Salamander, Gyrinophilus porphyriticus (Family Plethodontidae), adult; KY	Red-spotted Newt, Notophthalmus viridescens (Family Salamandridae); PA; terrestrial juvenile stage (larvae and breeding adults are aquatic)	Garden Slender Salamander, Batrachoseps major (Family Plethodontidae); CA; a fossorial, worm-like species: note reduced legs
Northwestern Salamander, Ambystoma gracile (Family Ambystomatidae), larva; WA	Spring Salamander, Gyrinophilus porphyriticus (Family Plethodontidae), larva; PA	Lesser Siren, Siren intermedia (Family Sirenidae), an aquatic salamander (note external gills) that lacks hind limbs	Chinese Giant Salamander, Andrias davidianus (Family Cryptobranchidae), the world's largest extant amphibian; aquatic

Order Anura — Frogs & Toads

Maya Mountain Frog, Rana juliani (Family Ranidae); Belize; a semiaquatic jumper	Peruvian Rain Frog, Pristimantis peruvianus (Family Craugastoridae); Ecuador; a semiarboreal? jumper	Sonoran Green Toad, Anaxyrus retiformis (Family Bufonidae); a terrestrial hopper	Western Spadefoot, Spea hammondii (Family Pelobatidae); CA; a burrower
Dyeing Dart-Poison Frog, Dendrobates tinctorius (Family Dendrobatidae); a terrestrial walker	Congo Spiny Reed Frog, Afrixalus osorioi (Family Hyperoliidae); Kenya; a climber	Veined Treefrog, Trachycephalus venulosa (Family Hylidae); Belize; a climber	Ornate Horned Frog, Ceratophrys ornata (Family Leptodactylidae); a sit-and-wait predator
African Clawed Frog, Xenopus sp.; (Family Pipidae) a fully aquatic swimmer	Tailed Frog, Ascaphus truei (Family Ascaphidae), tadpole (ventral side); CA	Bullfrog, Rana catesbeiana (Family Ranidae), tadpole; AZ	Pacific Treefrog, metamorphosing froglet, Pseudacris regilla (Family Hylidae); CA

Order Gymnophiona — Caecilians

Characteristics Greatly elongated, limbless bodies Usually have segmented rings (dermal folds) Eyes reduced or absent Most are burrowing; some aquatic

Gaboon Caecilian, Geotrypetes seraphini (Family Dermophiidae); a terrestrial, burrowing species from West Africa

Gaboon Caecilian, Geotrypetes seraphini (Family Dermophiidae); closeup of head (note lack of eyes)

Rubber Eel, Typhlonectes sp. (Family Typhlonectidae); preserved specimen of an aquatic species

Some Extinct Amphibians (Non-amniote Tetrapods)

See also examples of fossil tetrapods & amphibians

Early Basal Tetrapods: The most primitive basal tetrapods before the major radiations of Temnospondyls and Lepospondyls.	Temnospondyls: A large clade that was most diverse during the Permian Period; mostly went extinct by the end of the Triassic except for a few forms that survived into the Cretaceous. Many forms (especially during the Permian) were terrestrial; Triassic forms were mostly semiaquatic. Some reached enormous size.
Reptiliomorphs and Others: Reptiliomorphs are the sister-group to the Amniotes. The reptiles grouped here also include some (such as Eogyrinus, Chroniosuchus, Seymouria) that do not fit neatly into one of the other groups; their exact relationships are debated.	Lepospondyls: A group of mostly smaller-sized amphibians diverse during the Carboniferous and Permian Periods. This group may be paraphyletic (with Lissamphibians derived from within). Some were secondarily limbless.	Lissamphibia: The clade that includes all extant amphibians. The monophyly of this group has been debated, but supported by the most recent studies. Probably derived from within the Lepospondyls.