Hanken Laboratory
Evolution: Morphology, Development, and Systematics
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Evolution: Morphology, Development and Systematics The Hanken Lab studies the evolution of morphology, developmental biology, and systematics. Most work focuses on amphibians but otherwise addresses a wide range of topics, taxa, and methodologies. The latter range from laboratory-based molecular analyses to extensive field surveys. Current subjects include the evolution of craniofacial patterning in vertebrates; the developmental basis of life-history evolution; systematics, taxonomy and evolution of African frogs and neotropical and Asian salamanders; and amphibian declines and conservation. Active field programs are maintained in Mexico, Argentina, China, Africa, and Sri Lanka, and my laboratory serves as a community research facility for NSF’s AmphibiaTree project. Here are a few examples of current research projects in the lab: |
 Philautus femoralis photo by: Madhava Meegaskumbura |
Amphibian Conservation |
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 photo by: Breda Zimkus |
 Phrynobatrachus natalensis photo by: L. Mahler & B. Zimkus |
 SS Phrynobatrachus pakenhami photo by: R. Kerney & B. Zimkus |
Systematics of puddle frogs Breda is currently completing her dissertation research on the evolution of puddle frogs (Anura: Phrynobatrachidae), a lineage that includes approximately seventy-five species distributed across sub-Saharan Africa. Using molecular and morphological data collected from museum specimens and specimens collected during her fieldwork in Malawi, Ethiopia, and Tanzania, Breda is constructing a phylogeny of this notoriously difficult family. This will allow her to resolve the taxonomy of the group, as well as investigate evolution of karyotype diversity, body size, and reproductive mode within the lineage. |
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 Pachytriton labiatus photo by: Yunke Wu |
Systematics of Chinese salamanders Based on multiple independent evidences, Yunke's doctoral study aims at understanding the phylogeny of Pachytriton, Paramesotriton and Cynops, evaluating taxonomical relationships and validity of controversial taxa, and answering questions like how genetic differentiation has been driven by geological or historical factors. This long-term research would focus on the biodiversity of Asian newts, the evolution of morphological characters associated with adaptation and the biogeography of East Asian amphibians. Pachytriton, Paramesotriton and Cynops are part of the Salamandridae, a speciose urodele family, which mostly occur at the Holarctic region with its diversity center in temperate Europe and Asia. They are collectively called the modern Asian newts, and are monophyletic supported by mitochondrial DNA. Nevertheless, complicated morphological homoplasies and possible long branch attraction of molecular sequences obscure phylogenetic relationships among and within these three genera. Descriptions of newly discovered species and reports of unusual phenotypes further increase complexity of this clade. Meanwhile, the three genera are widely distributed in East Asia, especially in southeastern China, providing excellent materials to understand historical factors that have influenced animal population structures in this area, a vast region yet with little knowledge on biogeographic patterns. |
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