Ambystoma talpoideum (Mole Salamander). Oviposition Mode and Timing.

Abstract/Summary

The Mole Salamander displays geographic variation in egg deposition mode, as well as other reproductive traits. Such variation suggests the potential for genetic differentiation within this species, yet no subspecies are currently recognized. We provide additional information on the timing and mode of oviposition in A. talpoideum to aid in further understanding the geographic scope of variation in this species’ reproductive traits. In 2009, we sampled 15 ponds at St. Marks National Wildlife Refuge, Wakulla County, Florida, USA for larval and paedomorphic A. talpoideum. During a period of heavy rainfall, we observed an adult metamorphosed female A. talpoideum and a newly-deposited egg mass on 2 and 3 April 2009, respectively. To our knowledge, our observation of a new egg mass on 3 April is the latest reported date of new oviposition for this species on the Coastal Plain. In contrast to populations in the Atlantic Coastal Plain, where females deposit eggs singly, our observation also reveals that individuals of A. talpoideum in the panhandle region of Florida produce egg masses, similar to populations of this species in western parts of its range (Mississippi and Louisiana). This observation suggests that the faunal break between populations that lay eggs singly, versus those that produce egg masses, is much farther east than has been previously reported and closer to the likely geographic point of separation between populations of the two egg-laying modes. Additional information on egg-laying mode and other reproductive characteristics in Gulf and Atlantic Coastal Plain populations would be insightful for understanding the extent of geographic variation in reproduction and would help pinpoint the location of a faunal break between populations of the two egg laying modes in this species.

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