Biological Sciences

Tag N. Engstrom


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Courses Taught:

  • Biological University Experience (BIOL 109)
  • Principles of Ecological, Evolutionary, and Organismal Biology (BIOL 152)
  • Evolution - Capstone (BIOL 302Z)
  • Field Ecology (BIOL 484)
  • Research in Biological Sciences (BIOL 600)
  • Biological Seminar (BIOL 605)
  • Methods in Population Ecology (BIOL 613)
  • Topics in Ecology/Systematics (BIOL 614)


  • Ecology, Evolutionary, Organismal
  • Zoology


My general research interests are in the systematics, ecology and conservation of amphibians and reptiles, particularly turtles. I currently have active research projects or supervise masters students with active research in:

  • Conservation ecology of Western Pond Turtles
  • Conservation genetics of Giant Garter Snakes
  • Conservation genetics of marine turtles
  • Conservation and invasive species issues in Hawaii
  • Systematics of softshell turtles
  • Eco-morphology of garter snakes
  • Sexual selection and asymmetry in fence lizards

Past Masters Students:

  • Eric Hansen – Eric is a biological consultant working on distribution and conservation ecology of Giant Garter Snakes in the Sacramento Valley.
  • David Kelly – Dave studied demographics, reproductive biology, population genetics and morphology of western pond turtles in the Central Valley and Foothills and is now works for the USFWS in Sacramento.
  • Akiko Masuda – Akiko is using genetic markers to trace origins of loggerhead marine turtles when she is not playing mommy to her 95 percentile in height and weight daughter.
  • Julie Nelson – Julie studied the interactions of garter snakes, Yosemite toads and pacific chorus frogs in grazed and ungrazed meadows in the Sierra Nevada. She is now working on a sea turtle nesting beach in Costa Rica.
  • Eric Olson – Eric did a herp inventory of the new Sutter Buttes State Park and is now working as a biological consultant for Condor Country Consultants.
  • Jackson Shedd – Jackson is studying sexual selection and asymmetry in western fence lizards and is also the author/illustrator of a field guide to the Amphibians and Reptiles of Bidwell Park.
  • Heyo Tjarks – Heyo is working on ecomorphology and sexual dimorphism in garter snakes using geometric morphometrics. He also sometimes jumps out of airplanes.

Past Undergrad Students:

  • Rachel Bender – Rachel worked with Dave on the WPT project and on her own project looking at co-evolution of garter snakes and the toxic newts that some species prey upon.
  • Kyle Kappenman – Kyle was a key element of Team Pond Turtle and is interested in all things herpetological


Tibisay Escalona, Tag N. Engstrom, Hernandez OE, Brian C. Bock, Richard C. Vogt and Nicole Valenzuela. In press. Population genetics of the endangered South American freshwater turtle, Podocnemis unifilis, inferred from microsatellite DNA data. Conservation Genetics. In press.

Tag N. Engstrom, Taylor Edwards, Matt Ostentowski, Erin Meyers. 2007. A compendium of PCR primers for mtDNA, microsatellite and other nuclear markers for freshwater turtles and tortoises. Chelonian Research Monographs 4:124-141.pdf (PDF)

John J. Wiens, Tag. N. Engstrom, and Paul T. Chippindale. 2006. Rapid diversification, incomplete isolation, and the "speciation clock" in North American salamanders (Genus Plethodon): Testing the hybrid swarm hypothesis of rapid radiation. Evolution, 60(12): 2585–2603. A Compendium of PCR Primers for mtDNA, Microsatellite, and Other Nuclear Loci for Freshwater Turtles and Tortoises (PDF)

Tag N. Engstrom, H. Bradley Shaffer, & William P. McCord. 2004. Multiple datasets, high homoplasy and the phylogeny of softshell turtles. Systematic Biology 53(5):693-710. Multiple Data Sets, High Homoplasy, and the Phylogeny of Softshell Turtles (PDF)

Mathew K Fujita, Tag N. Engstrom, David E. Starkey, H. Bradley Shaffer. 2004. Turtle phylogeny: insights from a novel nuclear intron. Molecular Phylogenetics and Evolution 31:1031-1040. Turtle phylogeny: insights from a novel nuclear intron (PDF)

Kagima, B. W., N. Valenzuela, T. Engstrom, B. Bock. 2003. Preliminary population genetic study of the yellow spotted Amazon river turtle (Podocnemis unifilis) using microsatellite DNA data. Integrative and Comparative Biology 43: 1025-1025.

Tag N. Engstrom & William P. McCord. 2002. Molecular support for the taxonomic conclusions of McCord and Pritchard (2002) regarding Chitra. Hamadryad 27(1):57-61. Molecular Support For The Taxonomic Conclusions Of Mccord And Pritchard (2002), Regarding Chitra (PDF)

Tag N. Engstrom, Peter A. Meylan & Anne B. Meylan. 2002 Origin of Juvenile loggerhead turtles (Caretta caretta) in developmental habitat in Caribbean Panama. Animal Conservation. 5(2):125-133. Origin of juvenile loggerhead turtles (Caretta caretta) in a tropical developmental habitat in Caribbean Panamá (PDF)

Tag N. Engstrom, H. Bradley Shaffer, & William P. McCord. 2002. Phylogenetic diversity of endangered and critically endangered southeast Asian softshell turtles (Trionychidae: Chitra). Biological Conservation. 104:173–179. Phylogenetic diversity of endangered and critically endangered southeast Asian softshell turtles (Trionychidae: Chitra) (PDF)

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Portrait of Tag N. Engstrom