Description: Adult Morphology: A fairly large, stout black salamander with wide silver or white bands. Marbled salamanders are sexually dimorphic and dichromatic, meaning that males and females are shaped and colored differently. Females are larger and have a duller coloration (i.e. diffuse gray bands), while males are smaller and more vibrantly patterned with a bright silver bands. Ventral coloration is black. Marbled salamanders are quite stout, even for an Ambystoma. Recently metamorphosed marbled salamanders are approximately 1.5 inches in length and have a weak pattern of lighter flecks that scarcely resembles that of adults. Adult patterns take some time to develop.
Size: Marbled salamanders reach total lengths of about 3-4 in (7-10 cm).
Larvae: Marbled salamanders have pond-type larvae with tall tail fins and bushy external gills. Hatchlings are dark and nondescript, but older larvae typically gain a distinctive series of light spots along their side. As they age, larvae sometimes develop a yellow or green coloration.
Eggs: Eggs are laid individually (i.e. not gathered in one mass) and unattached, but they are laid in nests often of around up to 100 eggs per female. They are commonly laid under leaf litter, logs, or other cover on dry ground around ponds. Occasionally, several females will nest together and form a communal nest. Females commonly guard their eggs until they hatch.
Similar Species: The broad white/silver bands of this species distinguish it from all other Indiana salamanders and make it unlikely to be confused for any other species.
Distribution: Marbled salamanders are widespread throughout the eastern and south-central United States, with populations as far south as Texas and Florida and as far north as Michigan and New Hampshire.
Marbled salamanders are most common in the lowlands of southwestern Indiana and the hills of south-central Indiana but are also present in the upland flatwoods of southeastern Indiana. They range up to Tippecanoe County in western Indiana, and an apparently isolated population is found in the dunes along Lake Michigan. Another isolated population exists in the swamp forests of northeastern Indiana.
Taxonomy: The marbled salamander (Ambystoma opacum) has no recognized subspecies. It belongs to the genus Ambystoma and is in the family Ambystomatidae, which is represented in Indiana by 8 different species (the most of any state!).
Ecology: Habitat: This is a salamander of hardwood forests, and it will inhabit upland or lowland areas. They utilize frequently flooded bottomlands in southwestern Indiana, dry forested ridgetops in south-central Indiana, seasonally wet flatwoods in central and southeastern Indiana, and wet, swampy forests in northeastern Indiana. They have even been found breeding in great numbers in grasslands when forested areas are nearby.
Diet: Larval marbled salamanders will eat aquatic invertebrates as well as larval forms of other amphibians; they will also occasionally turn cannibalistic and consume their own siblings. Adults feed upon a variety of small, terrestrial invertebrates.
Reproduction and Life History: Unlike other Indiana Ambystoma, marbled salamanders are autumnal (September-November) breeders. Courtship and breeding are conducted on land, and afterwards, females conceal themselves under cover along the edges of dried ponds. Here, they lay their eggs and typically remain with the nest until hatching. Females are commonly found during the breeding season curled around their eggs under logs, leaves, and other types of cover. Once the pond is inundated with water from late autumnal or winter rains, the eggs quickly hatch and larvae overwinter in the ponds. This gives them a good head-start on syntopic spring-breeding amphibians.
Conservation: Although adults can be more selective than other Ambystoma in their choice of breeding sites, this species is common throughout most of its range in Indiana and adapts relatively well to moderate levels of habitat disturbance and alteration. Currently, there are no major threats to the conservation of this species in Indiana.
Brodman, R. 2003. Amphibians and Reptiles from Twenty-three Counties of Indiana. Proceedings of the Indiana Academy of Science 112.1:43-54.
Conant, R. and J. T . Collins. 1998. Reptiles and Amphibians of Eastern and Central North America. Third Edition, Expanded. Houghton Mifflin, New York, New York
Kinney, V. C., N. J. Engbrecht, J. L. Heemeyer, and M. J. Lannoo. 2010. New County Records for Amphibians and Reptiles in Southwestern Indiana. Herpetological Review 41.3:387
Minton, S. A. Jr. 2001. Amphibians and Reptiles of Indiana. Indiana Academy of Science, Indianapolis, IN
Petranka, J. W. 1998. Salamanders of the United States and Canada. Smithsonian Institute Press, Washington D.C.