HerpIndiana

Spotted Salamander (Ambystoma maculatum)

Adult Male from Jefferson County

Description

Morphology: A large, robust black to dark brown salamander with distinctive yellow spots or blotches. Some individuals have orangish spots on the head. The head is noticeably wide, the snout is blunt, and the tail is somewhat keeled. Ventral and lateral coloration is generally grayish.

Size: This species grows to around 7-8in total length (Conant and Collins 1998, 439).

Larvae: Larvae can grow up to around 2in total length and are a brown to greenish color with a line of dorsal spots and some light pigmentation on the tail fin (Minton 2001, 50).

Eggs: Females lay their eggs in shallow water in globular masses that are jelly like and quite firm (Minton 2001, 51). The eggs are usually attached to twigs or sticks and often have a symbiotic algae growing with them.

Similar Species: This species would likely only be confused with the Tiger Salamander (Ambystoma tigrinum) in which the dorsal blotches are usually duller in coloration, shaped more irregularly and not organized in two rows. Tiger Salamanders also have ventral mottling which this species lacks (Minton 2001, 45).

Distribution

Spotted Salamanders are common throughout most of Indiana, but are absent from the northwestern sand prairies (Minton 2001, 50).

Activity

This salamander turns up sporadically under logs and other cover objects year round, but is generally scarce outside the breeding season. We found them to be active throughout the summer in a lowland swamp in posey county where they can be reliably found any time of year. It is likely that this species remains more active during the summer months in swamps and flatwoods such as this where moisture is always present.

Breeding Season: Spotted Salamanders are generally the last Ambystomatids to move to their respective ponds. Rarely does major movement take place before March, with most activity being confined to mid March. In jefferson county, I have observed asmall migrations in early January as a result of unusual warm spells, but these movements never seem to result in any actual breeding. Eggs are usually laid during March and they take around a month to hatch (Minton 2001, 52). Adults have usually left the ponds by late March or April. The larvae transform sometime during early summer or late spring.

Taxonomy

The Spotted Salamander (Ambystoma maculatum) has no subspecies. The Spotted Salamander belongs to the genus Ambystoma and is in the family Ambystomatidae which is represented in Indiana by 8 different species.

Natural History

Habitat: Spotted Salamanders typically inhabit upland wooded areas but may also be found in lowland swamps and floodplains. I have encountered this species in a variety of woodland situations from rocky canyons to low cypress swamps and even in old flooded farm fields. During the breeding season, they can be encountered in large numbers crossing roads on rainy nights or in and around their breeding ponds. During the spring and fall, this species can be commonly encountered under rotten logs or rocks, and other debris. I have also encountered them infrequently during the heat of the summer in similar situations.

Feeding: This species feeds on a variety of terrestrial invertebrates (Minton 2001, 52).

Breeding: They will utilize both ephemeral and permanent pools as I have observed them in a deep pond that is inhabited by Painted Turtles (Chrysemys picta) as well as in roadside ditches. Flooded woodlands and swamps are also frequently used as breeding sites. After being deposited, the eggs take around a month to hatch and the larvae transform sometime during June or July (Minton 2001, 51-52).

Conservation: This species is widespread in Indiana and there is still quite a bit of suitable habitat left throughout its range. Research is currently being conducted in south central Indiana to investigate vernal pool dynamics and surveys are conducted every spring in various parts of southern Indiana for this species.