Ambystomatidae

Description: Mole salamanders: This is a family of chunky, largely terrestrial salamanders. Males have longer tails and longer and stouter hind limbs than females. All mole salamanders have more or less prominent vertical costal grooves along the sides corresponding to the number of muscle segments and ribs. Many species are secretive throughout most of the year, living in leaf litter, under stones and logs or in burrows of other animals, hence the name mole salamanders. They are most often seen at the surface during and after heavy rains, particularly after dark. This is strictly a North American family composed of 1 genus and 32 species. Most ambystomatids breed in early spring. The reproductive season is brief, adults migrate to ponds to court and deposit eggs. Eggs are usually laid in ponds or slow-moving streams. The eggs are small and the pond-adapted larvae have long gills and well-developed tail fins that extend far forward on the back. Adults return to land quickly, within a few days. These are relatively primitive salamanders, all species have a larval stages and there is a tendency toward paedogenesis. Metamorphosis is either facultative or obligate. Adults of transforming species are terrestrial. Transformation generally occurs in July or August. After transformation the young salamanders quickly disperse from the pond.

Larva Description: Larva in this family have a broad head, three pairs of bushy gills with well-developed rachises and broad caudal fins that extend well onto the back. The prevomerine teeth occur in a transverse row that crosses the palate near the posterior margin of the internal nares.

Dicamptodontidae

Description: Pacific Giant salamander: This family has only 1 genus and 4 species. Metamorphosis is facultative in individuals or populations. These salamanders inhabit damp coniferous forests with cold streams or cold mountain lakes. The eggs are large and white. They are laid in hidden nest sites in cold streams and females brood their clutches. The larval period may last 2-5 years. Metamorphosed adults are terrestrial.

Larva Description: The larvae have a dorsal tail fin marked with smoky light and dark marbling except in old larvae that become uniform in dorsal colouration. The dorsal surfaces of the body are brownish with numerous specks of white that may unite to form blotches. There is a whitish stripe behind the eye. The gills and toes are short, there are no balancers and 5-7 gill rakers.

Plethodontidae

Description: Lungless salamanders: Within this family there are 28 genera and 266 species worldwide. Plethodontids are the most diverse and species-rich group of salamanders. They are generally small and relatively slender with prominent costal grooves and upward protruding eyes. All species lungless and they also have a small distinct groove which runs from the nostril to the upper lip on each side. This nasolabial groove aids in chemoreception. They are the only salamander that have extensively radiated in the tropics. Plethodontids occupy subterranean, aquatic, terrestrial and arboreal habitats. They inhabit moist environments, streams, spring and river margins and damp woodlands. The origin of lunglessness is attributed to adaptation for a mountain stream habitat. Because they are lungless, they depend on moist skin and the roof of their mouth for respiration. A moist surface is essential for this exchange so plethodontids are highly intolerant of dryness and excess heat. They die quickly if exposed to a drying environment.

Larva Description: Life history traits have evolved from an ancestral life cycle involving aquatic larvae toward increased terrestriality and direct development. Species in the genera Eurycea, Gryinolphilus and Hemidactylium, have aquatic larval stages whereas those in Aneides, Plethodon and Ensatina have direct development. However with desmognathine salamanders the reverse trend, from terrestriality toward longer larval periods and increasing use of aquatic habitats has occurred. Fertilization is internal via spermatophores. Plethodontids deposit large white eggs in hidden nests and females guard the clutch. Nest sites are terrestrial and development is direct without a larval stage in Plethodon species. Nest sites are aquatic or semi-aquatic in primitive species having larvae. During dry periods, particularly in midsummer, both stream and woodland species may retreat beneath the surface of the ground. In spring and fall and in periods of soaking rain they will reemerge near the surface.

Proteidae

Description: Mudpuppy: In this family there are 2 genera and 6 species. This family is comprised of aquatic, paedomorphic salamanders. They have large gills and caudal fins. They lack maxillary bones, have two pairs of larval gill slits and have a diploid chromosome count of 38. Necturus species inhabit lakes or streams.

Larva Description: Young mudpuppies are black with longitudinal yellow stripes.

Salamandridae

Description: Newts: The newts of Eastern North America are relatively small and often partly or wholly aquatic as adults, between the larval stage and maturity they usually have a terrestrial eft stage. Western newts are larger, more robust in build and often largely terrestrial outside the breeding season. The vertical costal grooves, which are prominent on the sides of Canadian salamanders, are indistinct in newts and they have no nasolabial grooves. Worldwide there are 15 genera and 55 species. Life histories are highly varied. Newts spend prolonged periods annually or their entire adult lives in water. Aquatic species have well-developed tail fins. Adults of many North American and Eurasian salamandrids are terrestrial and migrate to ponds for breeding. Most species have a two-stage life cycle with aquatic larvae and terrestrial adults. Some species have populations with paedogenetic larvae but there are no obligatory paedogenetic species. There is a tendency for terrestrial adults to remain in breeding ponds and lakes for prolonged periods and develop secondary aquatic adaptations such as thin skin, high tail fins and fleshy lip folds. This aquatic phase may last several months until they return to land and regain terrestrial morphology with darker thicker skin. Courtship behaviours are often elaborate and usually involve prolonged interaction between partners. Visual recognition, smell and touch may all be used by a male in enticing a female to pick up the spermatophore he eventually deposits. Fertilization is then internal via the spermatophore. Many species have conspicuous skin glands that produce highly toxic secretions. They have the most potent skin toxins of all salamanders. Many also have aposematic colouration and elaborate defense displays. Bright red, orange, or yellow warning colouration is often on the belly and displayed when disturbed.

Larva Description: Newt larvae have high fins along the back and tail and usually some faint pattern of spots or stripes along the sides.