Relationships of the amphibian clades Gymnophiona Caudata Anura Gymnophiona Caudata Anura Gymnophiona Caudata Anura Morphology (e.g., Milner 1988)

Molecular evidence shakes up the amphibian tree Hay et al. 1995 1995 One mtDNA gene 850 bp 28 of 40 Families sampled Parsimony and distance analyses Feller and Hedges 1998 1998 Four mtDNA genes 2700 bp Parsimony, distance (neighbor joiningj), and Bayesian analyses

2005 Full mitochondrial genomes (~15000 bp) Parsimony, distance (nj), and Bayesian analyses 2005

522 species 2400 bp mtDNA 2300 bp nDNA 156 morph characters Parsimony analysis Gymnophiona Caudata Anura

3 genes mtDNA 9 genes nDNA likelihood

Caudata: node-based name for salamanders Urodela: stem-based name for salamanders 10 families, 695 species

Salamander characteristics Tailed, most with four limbs of approximately equal length, four digits on front limbs, five digits on hindlimbs Aquatic, terrestrial/fossorial, arboreal Breathe through lungs, gills, and/or skin Sprawling gait Large genome 15-90 pg (humans: 3pg) Diverse life cycles, reproductive modes Skull: absence of postorbital, supratemporal, jugal, supraoccipital, basioccipital, ectopterygoid Limb regeneration

Sprawling gait Long tail Hindlimbs = forelimbs Loss of limbs Tail reduced Cylindrical body Upright posture Loss of tail Hindlimbs > forelimbs Sprawling gait Long tail Hindlimbs = forelimbs

digimorph

Salamander reproduction Internal (spermatophore) or external fertilization Most oviparous Most breed, lay eggs in water Most have larval stage (tadpole) Few have parental care Complex courtship, pheromones spermatophore

Courtship in Ambystoma talpoideum

Mating behavior...

Salamander diversity

Variable characters within Caudata External/internal fertilization (w spermatophore) Costal grooves Ribs unicapitate/bicapitate Paedomorphic characters Gills Absence of eyelids Tailfin, webbed feet Chromosome number, amount of DNA

Sirenidae two genera, 4 species SE USA elongate, paedomorphic external gills, lack eyelids nonpedicellate teeth lack pelvic girdle, hindimbs aquatic external fertilization

Sirenidae two genera, 4 species SE USA elongate, paedomorphic external gills, lack eyelids nonpedicellate teeth lack pelvic girdle, hindimbs aquatic external fertilization

Cryptobranchidae Andrias (2 sp: China, Japan), Cryptobranchus alleganiensis (E USA) paedomorphic lidless eyes, (internal) gills, absence of tongue pad aquatic largest amphibians (1.8 m) external fertilization

Cryptobranchidae

Amphiumidae one genus, 3 species SE USA elongate, paedomorphic: lack eyelids, tongue; have (internal) gills retain both pairs of limbs (and girdles), but small limbs aquatic up to 1.1 m long internal fertilization female parental care Two-toed amphiuma Amphiuma means

Ambystomatidae One genus, 32 species North America some paedomorphic hybrids, unisexual forms most terrestrial as adults, some aquatic

Dicamptodontidae one genus, four species NW USA large, up to 17 cm SVL eats terrestrial vertebrates facultative metamorphosis

Proteidae two genera, six species Italy, Slovenia, Croatia, Eastern USA aquatic paedomorphic, external gills, tail fin

Plethodontidae 27 genera, 458 species Americas, Italy, S Korea nasolabial groove lack lungs diverse Fossorial, terrestrial, aquatic, arboreal Webbed feet, ballistic tongue, prehensile tail well-studied for speciation

Plethodontidae 27 genera, 433 species Americas, Italy, S Korea Nasolabial groove lack lungs diverse Fossorial, terrestrial, aquatic, arboreal Webbed feet, ballistic tongue, prehensile tail well-studied for speciation

Plethodontidae

Salamandridae 21 genera, 115 spp N America, Europe, Asia, N Africa Newts poisonous skin, aposematic coloration some with terrestrial eft stage

Rhyacotritonidae Hynobiidae One genus, four species Pacific NW USA old growth coniferous forests internal fertilization Hynobiidae Nine genera, 43 species Asia external fertilization lungs reduced to absent

Caudata phylogeny Duellman & Trueb (1986) Larson and Dimmick (1993) Parsimony, 30 morph characters Larson and Dimmick (1993) 29 morph characters, 177 nDNA, parsimony Gao and Shubin (2001) 60 morph characters, 177 nDNA, parsimony; incl. fossil taxa Weisrock et al. (2005) mtDNA, nDNA (~1300 chars); parsimony, ML, Bayesian Wiens et al. (2005) Morph chars (~300), nDNA, mtDNA; parsimony, ML, Bayesian Frost et al. (2006), Pyron and Wiens (2011)

Pyron and Wiens 2011

Anura (Salientia): Frogs

Anura (Salientia): Frogs 6728 species

Synapomorphies of Anura urostyle lack tail fused tibia and fibula fused ulna and radius hindlimbs > forelimbs Nine (or fewer) presacral vertebrae