Pleistocene glaciation of New England excluded both terrestrial and aquatic herpetofauna from the region until the retreat of the ice began approximately 22,500 years ago. Three general dispersal routes appear to dominate the post-Pleistocene re-colonization of New England by reptiles and amphibians. (1) As the ice sheet receded beyond the St. Lawrence River, immigration from refugia in the Mississippi Valley was facilitated by the newly formed Prairie Peninsula corridor which channeled organisms north and east into New York and the Champlain Basin. (2) The Coastal Lowlands Corridor, connecting the southern coastal regions and the southern Appalachian refugia with coastal New England. (3) Exposed regions of Coastal Plain off the coast of New England allowed regional re-colonization.
The mudpuppy ( Necturus maculosus ) a wholly aquatic, perennibranchiate salamander, is the largest salamander found in New England (20-33 cm TL). Annual samples of Necturus were collected from 1990-1998, during the draw-down of a canal adjacent to the Connecticut River. Snout vent lengths were taken and animals were allotted to year class based on length. Skeletochronology confirmed the age/length correlation. The location of a subset of animals was marked and the depth at which they were found was calculated. The age of the animals was correlated with bottom structure and depth.
The four-toed salamander ( Hemidactylium scutatum ), is the smallest and rarest of New England's salamanders. As adults, four-toed salamanders are terrestrial. Observations show that female four-toed salamanders migrate in early spring into wetland breeding sites where they nest colonially. Embryonic development is temperature dependent with hatching occurring in late spring. The pond-type larvae wriggle from the nest chamber into the water where, after six or seven weeks, they metamorphose into small terrestrial juveniles.
Massachusetts populations of the eastern spadefoot ( Scaphiopus holbrookii ) are at the extreme northern limits of the species' range. Breeding sites and upland habitat are frequently destroyed by development. A survey of historic sightings and major museum collections shows the historical distribution of spadefoots. New collections and records were made of existing populations in Massachusetts. The habitat and other ecological requirements to maintain a viable population are characterized.
