I am an evolutionary biologist interested in phylogenetic analysis methods, historical biogeography, and studies of geographic variation in morphology and ecology in a phylogenetic context. I have a strong related interest in the development of nuclear loci for phylogenetic analyses. My work centers mainly on reptiles and amphibians. Some past and current projects include the systematics and biogeography of chameleons at various hierarchical levels, higher-level frog relationships, and (here at SDSU) participation in the NSF-funded Assembling the Tree of Life (AToL) project for squamate reptiles (snakes and lizards) as a postdoc in Tod Reeder’s lab. For this project, I have worked with Scott Kelley and his student Eric Alegre to develop and implement a bioinformatic approach to the discovery of novel nuclear protein-coding loci for phylogenetic analyses of squamates. We have successfully developed over nearly 50 genes that appear to be useful at several hierarchical levels within squamates.
Aside from developing loci, my main focus on the AToL project has been phylogenetic relationships within the large and diverse squamate clade Iguania. Iguanian lizards are divided into two clades whose names refer to their contrasting dentition. All extant acrodont iguanians (chameleons and agamids) are Old World lizards, and extant pleurodont iguanians (iguanas and their relatives) are restricted to New World, with a couple of biogeographically interesting exceptions. Iguanians play an important role in many comparative studies of adaptive radiation, diversification rates and patterns, reproductive mode, ecomorph evolution, and mitochondrial genome evolution, etc. An accurate phylogeny of the group is therefore of great interest to many researchers, and although recent progress has been made, it is somewhat surprising that so little is known about many aspects of the evolutionary history of iguanians. This is especially true of the pleurodonts, which appear to represent an ancient rapid radiation of 12 major lineages that diverged in the Late Cretaceous/Early Tertiary. Although respective monophyly of these lineages is well supported, their interrelationships are almost completely unknown. The group is traditionally assumed to have originated in South America and spread northward, but the oldest fossils are all Northern Hemisphere, and lack of a robust phylogeny has left even this basic biogeographic issue unsettled. A primary goal of our work is therefore to provide a robust phylogenetic framework for testing evolutionary hypotheses within this group.
I am also currently working with Tod Reeder and Bradford Hollingsworth (San Diego Natural History Museum) on a bioinventory/ multispecies biogeographical analysis of the herpetofauna of southern California, including the Baja Peninsula. One outcome of this project will be a Museum-sponsored online herpetological atlas of the study area.
As an adjunct lecturer here at SDSU, I have taught Genetics and Evolution (Biology 352) and Organismal Biology (Bio 201B).
Wiens, J. J., C. A. Kuczynski, T. M. Townsend, T. W. Reeder, D. G. Mulcahy, and J. W. Sites, Jr. 2009. Combining phylogenomics and fossils in higher-level squamate phylogeny: Molecular data change the placement of fossil taxa. Systematic Biology 59(6):674-688.
Townsend, T. M., M. Vences, D. Vieites, and F. Glaw. 2009. Testing species-level diversification hypotheses in Madagascar: The case of microendemic Brookesia leaf chameleons. Systematic Biology 58:641-656.
Townsend, T. M., E. R. Alegre, S. T. Kelley, J. J. Wiens, Tod W. Reeder. 2008. Rapid development of multiple nuclear loci for phylogenetic analysis using genomic resources: An example from squamate reptiles. Molecular Phylogenetics and Evolution 47:129-142. MPE Top Cited Paper 2008-2010.
Wiens, J. J., C. A. Kuczynski, S. A. Smith, D. Mulcahy, J. W. Sites, Jr., T. M. Townsend,and T. W. Reeder. 2008. Branch length, clade support, and gene-treecongruence: Testing the phylogenomic approach with 20 nuclear loci in snakes. Systematic Biology 57:420-431.
Ricklefs, R. E., J. B. Losos, and T. M. Townsend. 2007. Patterns of diversification and species richness among squamate clades Journal of Evolutionary Biology 20(5): 1751-1762.
Bickford, D., J. Supriatna, Y. Nanda, D. Iskandar, B. Evans, R. Brown, T. Townsend, Umilaela, D. Azhari, and J. McGuire. 2007. Indonesia’s protected areas need more protection suggestions from island examples. In Sodhi, N.S., G. Acciaioli, M. Erb & A. K.-J. Tan (Editors). Biodiversity and human livelihoods in protected areas: case studies from the Malay Archipelago. Cambridge University Press, Cambridge, UK.
Hedtke, S. M., T. M. Townsend, and D. M. Hillis. 2006. Resolution of phylogenetic conflict in large data sets by increased taxon sampling. Systematic Biology 55(3):522-529.
Townsend, T. M., A. Larson, E. Louis, and J. R. Macey. 2004. Molecular phylogenetics of Squamata: The position of snakes, amphisbaenians, and dibamids, and the root of the squamate tree. Systematic Biology 53(5):735-757.
Matthee, C., C. Tilbury, and T. M. Townsend. 2004. A phylogenetic review of the African leaf chameleons genus Rhampholeon (Chamaeleonidae): The role of vicariance and climate change in speciation. Proceedings of the Royal Society: Biological Sciences 271:1967-1975.
Townsend, T. M. and A. Larson. 2002. Molecular phylogenetics and mitochondrial genomic evolution in the Chamaeleonidae (Reptilia, Squamata) Molecular Phylogenetics and Evolution 23:22-36.
Glor, R. E., T. M. Townsend, M. F. Benard, and A. S. Flecker. 2000. Sampling reptile diversity in the West Indies with mouse glue traps. Herpetological Review 31:88-90.
Townsend, T. M., D. T. Kochevar, G. Manthriratna, and R. Straw. 1992. Restriction Fragment length polymorphism analysis of the retinoblastoma gene in canine osteosarcoma. Veterinary Cancer Society Newsletter, 16(34) winter issue