2 genera, 4 sp
NA and China & Japan
Cryptobranchus in NA
Andrias in China and Japan
Paedomorphic - Lack eyelids and retain lateral line
Body and head dorsolateral flattened
Aquatic bottom walkers in cold mountain streams
Skin heavily folded for cutaneous respiration
M construct nests under rocks in streams or in river bank tunnels
External fertilization
Feed on aquatic inverts by unique asymmetrical suction mechanism
9 genera, 80+ sp
Asia, temperate subarctic and mountain species
External fertilization (one exception)
Most have free swimming larva that undergo complete metamorphosis
Mostly terrestrial, one sp is aquatic and lungless
Ecological equivalent of NA Ambystomids
2 genera, 5 sp
Many cryptic species may exist
SE US
Skeletal anatomy suggests basal to other salamanders
Entirely aquatic, paedomorphic
Tiny front limbs with 4 toes, no hindlimbs
Prominent external gills
Probably external fertilization
Eggs deposited in small clumps on submerged veg
Often filter feed but also capture individual prey
Horny beak instead of premaxillary teeth
Cocoon in layers of epidermal cells during drought, slowing metabolism
Occur in slow-moving waters
1 genus, 3 sp
SE US
Elongate, obligatory paedomorphic, aquatic burrowers
Tiny limbs, no external gills, no eyelids
Work bottom much and tangles of aquatic systems
Fertilization by cloaca-cloaca transfer of spermatophore
Eggs deposited on damp land; FM guards
Retain pedicellate teeth, have 4 limbs, lack external gills
Nocturnal, move overland during rain
Aquatic larvae with gills
Aestivate during drought