My research interests lie in understanding Biodiversity, asking how the great diversity in animal forms came about under the influence of various evolutionary processes. As a research scholar, I have contributed to our basic understanding of biodiversity, by describing new species, revising taxonomy, and assessing distributions diversity (see Publications).
My main research focus is in Macroevolution - to identify the patterns and infer processes underlying morphological diversity, by choosing biologically diverse systems and formulating research hypotheses that can be tested quantitatively. In general, I apply a suite of statistical tools to measure variation in form, specifically size and shape of morphological structures, within a comparative framework. Predominantly, I use X-Ray Micro Computed Tomography and surface scanning technology to gather three-dimensional representations of an organism's anatomy, and traditional and geometric morphometrics to quantify and study variation in morphological traits.
To date I have studied a variety of organisms including rabbits (Lagomorpha), scallops (Pectinidae), Anolis lizards, caecilian amphibians (Gymnophiona), and laboratory mice.
My main research focus is in Macroevolution - to identify the patterns and infer processes underlying morphological diversity, by choosing biologically diverse systems and formulating research hypotheses that can be tested quantitatively. In general, I apply a suite of statistical tools to measure variation in form, specifically size and shape of morphological structures, within a comparative framework. Predominantly, I use X-Ray Micro Computed Tomography and surface scanning technology to gather three-dimensional representations of an organism's anatomy, and traditional and geometric morphometrics to quantify and study variation in morphological traits.
To date I have studied a variety of organisms including rabbits (Lagomorpha), scallops (Pectinidae), Anolis lizards, caecilian amphibians (Gymnophiona), and laboratory mice.
Current Research
Understanding the mechanisms of biological diversity using Australian elapid snakes
Australia is home to many such radiations of reptiles, including highly-venomous snakes, Elapidae. Comprising ~160 species, they have radiated into a wide range of ecosystems (both terrestrial and marine) and a variety of dietary specialists. Australia’s elapids are a unique model system to answer fundamental questions in evolutionary biology:
- Understand the genetic basis of morphological evolution
- Investigate the tempo and mode of morphological evolution
- Investigate whether evolution is predictable
Investigating Macroevolutionary and Ecomorphological diversity in Australia's larval Frogs
Tadpoles are the free-living aquatic larval stage of frogs and toads. Australia is home to 244 species of frogs, and around 200 of those have a free-living larval stage that is aquatic, or has some terrestrial development in moist burrows. I am using the comprehensive work "Tadpoles and frogs of Australia" by Marion Anstis to study macroevolutionary patterns of tadpoles and their adult frogs, and understand the ecomorpholgical diversity of Australia's tadpoles.
This research is ongoing with J. Scott Keogh at Australian National University and Marion Anstis of University of Newcastle, Australia.
This research is ongoing with J. Scott Keogh at Australian National University and Marion Anstis of University of Newcastle, Australia.
Examining tempo and mode of Evolution in Scallops
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The tempo (rate) and mode (process) or Evolution has long been a source of question and debate in biology. My research in this area focusses on the tempo and mode of Evolution at a broad (macro-) evolutionary scale, i.e across many species, in bivalved scallops (Pectinidae).
We have identified that scallop shell shape is influenced by life habit. This research is ongoing with Dean C. Adams and Jeanne Serb at Iowa State University. You can read the first article about directional evolution in recessing scallop species in Evolution. And the second article about convergent evolution of gliding scallop species in Journal of Evolutionary Biology. |
Past Research Topics
Investigating Anolis lizard history using amber fossils
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Anoles are a model system for evolutionary research. To date, a great deal has been learnt about the convergent evolution and multiple radiations of this group (see the Losos Lab page for more details). Phylogenetic trees from molecular data have given us a peek into the evolutionary history of the group.
The purpose of my research is to add a fossil component to the Caribbean Anolis diversification story, using amber preserved fossils from the Dominican Republic. To date, three specimens have been published upon: Rieppel 1980, De Queiroz et al. 1998, and Polcyn et al. 2002. Using these and a number of unpublished specimens, I have added to our knowledge of the evolutionary history of anoles by building a picture of the anole community composition at 20MYA, a point halfway through the predicted age of the radiation. You can read more about this project here and here. Articles on this research in PNAS and ZOJ. |
Evolution of the Caecilian Skull
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A rare and uncommon group of vertebrates are caecilians, limbless amphibians distantly related to frogs and salamanders. I study caecilians because they have fascinating skulls, quite unlike their superficial vertebrate cousins -snakes- and far more similar to extinct early tetrapods. They are cryptic and most are burrowing specialists. Though despite efforts by keen herpetologists, they remain relatively understudied. Extensive fieldwork done by Dr Mark Wilkinson, Dr David Gower and their colleagues has provided the Natural History Museum London UK with the largest collection of caecilians in the world. I have spent over 160 scanning hours to collect micro CT scans of 615 caecilian specimens, around 150 species. From these scans I examined cranial evolution of caecilians, following the geometric morphometric methods developed and published on by Dr Christian P. Klingenberg. We are also using the micro CT scans to help with taxonomic character identification.
Article on this research in Evolutionary Biology and Zootaxa |
Collaborations
Various projects with my role as the CT scan or Morphometrics go-to with the following researchers:
Evolution of the Anolis skull with Thomas J. Sanger, Postdoctoral Researcher at University of Florida Convergent evolution of sexual dimorphism in skull shape using distinct developmental strategies. Sanger, T.J, Sherratt, E., McGlothlin, J.W., Brodie III, E.D., Losos, J.B., Abzhanov, A. (2013). Evolution, 67: 2180–2193. doi: 10.1111/evo.12100. here |
Evolution of the rabbit (Leporidae) skull with Brian P. Kraatz Western University of Health Sciences Department of Anatomy, CA. Evolutionary morphology of the rabbit skull. Kraatz, B. & Sherratt, E. PeerJ. 4:e2453. doi: 10.7717/peerj.2453 here Ecological correlates to cranial morphology in Leporids (Mammalia, Lagomorpha). Kraatz, B.P., Sherratt, E., Bumacod, N., Wedel, M.J. PeerJ 3 :e844. here |
Marsupial evolution with Vera Weisbecker, Lecturer at University of Queensland. New collaboration, involving the marsupial brain And limb evo-devo with student Kathleen Garland. |