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Intercontinental dispersal by a microendemic burrowing reptile (Dibamidae)
Ted M Townsend1, Dean H Leavitt, Tod W Reeder
1Department of Biology, San Diego State University, San Diego, CA 92182, USA. townsend@sciences.sdsu.edu
Proceedings. Biological Sciences
|January 29, 2011
Summary
Dibamid lizards, traditionally thought to be geographically isolated, show deep genetic divergence. DNA analysis suggests ancient intercontinental dispersal across the Bering Strait or via trans-Pacific rafting.
Area of Science:
- Evolutionary Biology
- Zoology
- Biogeography
Background:
- Intercontinental dispersal shapes biogeographic history.
- Dibamid lizards are fossorial, limbless reptiles with disjunct genera: Dibamus (Southeast Asia) and Anelytropsis (Mexico).
- A sister-taxon relationship between Dibamus and Anelytropsis has been inferred but not formally tested.
Purpose of the Study:
- To construct a molecular phylogeny for the Dibamidae family.
- To estimate divergence times within the Dibamidae.
- To investigate the biogeographic history and dispersal patterns of dibamid lizards.
Main Methods:
- DNA sequencing of one mitochondrial and six nuclear protein-coding genes.
- Phylogenetic analyses to reconstruct evolutionary relationships.
- Divergence time estimation using molecular data.
Main Results:
- Dibamus species form two deeply divergent clades.
- One Dibamus clade is the sister taxon to Anelytropsis papillosus.
- Phylogenetic analyses suggest dispersal from the Palearctic to the Nearctic via Beringia (Late Paleocene-Eocene) or trans-Pacific rafting (Late Cretaceous).
Conclusions:
- The study reveals significant genetic divergence within Dibamus, challenging previous assumptions.
- The findings support remarkable long-distance dispersal events in dibamid lizard evolution.
- Both Beringian land bridge dispersal and trans-Pacific rafting are plausible scenarios for the group's biogeography.
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