Zool 406 -Salamander Diversity

What order are salamanders contained in?

Caudata // Urodela

Where are salamanders found?

• Largely a Holoarctic group (N. Hemisphere); temperate and subtropical

• N. America, Eurasia and N. Africa

Only tropical invaders = Plethodontids

Holoarctic, mountains of Central America and Amazon basin

T/F Caudata is a monophyletic group? what characteristics are used to group them?

True!

• Ossification pattern

• Late appearance of maxilla

• Remodelling of palate during metamorphosis

• Absence of middle ear

• Form of jaw adductor muscles

What are some general characteritsics of salamanders?

• Well developed tails

• Cylindrical, often elongate bodies

• Distinct heads

• Relatively short limbs (can be reduced or lost)

• Heterochrony

What is paedomorphosis? & the two forms found in salamanders?

Paedomorphosis = retention of larval features in adult (gills, no eyelids)

2 forms

1. Neoteny

2. Progensis

What is neoteny?

Non-reproductive organs delayed in development compared to reproductive organs

What is progenesis?

Accelerated development of reproductive organs

What is the life history of most salamanders?

• “Normal” biphasic lifestyle found in only 20-25% of salamanders

• Most deposit eggs terrestrially in moist microhabitats; direct development of juveniles

• Very few have live births

How many families belong in caudata? what family is largest?

10 Families;

Plethodonidae is largest

What are the traits of Cryptobranchidae (asiatic giant salamanders + hellbender)?

= 2 genera, 3 species; Asia and USA

• Large bodies

• Folded, wrinkled skin, dorsoventrally flattened

• No costal grooves, no gills and small (almost non-functional lungs)

• No eye lids; single gill slit

What are the traits of Hynobiidae (Asiatic brook salamanders)?

• Found in Asia

• Heavy-bodied, thick tailed

• Coastal grooves present

• Complete metamorphosis

What are the traits of Sirenidae (Sirens and Dwarf Sirens)?

= 2 genera, 2 species

• Found in SE N. America

• Slender bodied, small forelimbs, lost pelvic girdle and limbs

• All paedomorphic (adults with external gills and no eyelids)

• External fertilization

What are the traits of Protieidae (Mudpuppies)?

• Moderately robust, well developed limbs, large laterally compressed tails

• All paedomorphic; but small lungs are present

• Coastal grooves on trunk

• Internal fertilization

• Aquatic adults

What are the traits of Salamandridae (newts and european salamanders)?

• Europe, NE. Africa, SE. China, Japan, E&W N. America

• Normally 20cm TL maximum

• No coastal grooves

• Courtship and internal fertilization

• Granular, rough skin with lots of poison glands

• Aposematic

What are the traits of Ambyostomatidae (Mole Salamanders)?

= 2 genera (Dicamptodon, Ambystoma) , 37 species

• N. America

• Heavy bodied, heavy tailed, well-developed limbs

• Courtship in water

What are the two Albertan species in Ambyostomatidae?

A. Macrodactylum

A. Tigrinum

What are the traits of Dicamptodontidae ‘Pacific Mole Salamanders’?

• Dicamptodon separated from Ambystoma, very similar traits

= 4 species

• Major predators on invertebrates

What are the traits of Rhycontritonidae ‘Torrent Salamanders”?

= 4 species

• PNW USA

• Heavy bodied, heavy tailed, robust, short limbs

• Up to 12 cm in length

• Adults have eyelids, lack gills, coastal grooves present

• Internal fertilization

• Semi-aquatic-well aerated streams

what are the traits of Amphiumidae?

• SE USA

• Eel-like with weakly developed limbs

• Partial metamorphosis, paedomorphic traits in adults (internal gills, lack eyelids and tongue)

• Lungs preset, costal grooves present

• Internal fertilization

What are the traits of plethodontidae?

= 24 genera with 378 species

• S. Canada to SW Brazil, central Mediterranean and Korea

• All have 4 limbs; but variable in shape

• Costal grooves present

• All with nasolabial grooves

• Courtship and internal fertilization