Current Projects: _________________________________________ *Biogeography and Phylogeography of Corallus hortulanus: The spatial and temporal events that give rise to the diverse number of species in the tropics is of great interest to researchers. I am using tissue samples from Corallus hortulanus collected throughout the species' range to test several biogeographic hypotheses.I am sequencing individuals from over 40 localities for 2 mitochondrial genes (cyt-b, ND2) and 1 nuclear gene (rag-1). I will use this molecular phylogeny to test the timing and diversification patterns of this group. As this species is wide-ranging, from central Venezuela south to Peru, and across Amazonia east through the Cerrado to Brazilian Atlantic Rainforest; I can infer general patterns and form testable hypotheses about South American reptile diversification. I will also sequence several individuals from each species of Corallus for cyt-b, ND2 and rag-1 in order to construct a well resolved molecular phylogeny for the genus. * Thesis project Colston, TJ. Costa, GC.Vitt, LJ. Evolutionary Shifts in Dietary History of Snakes Impacts Present Day Community Structure (in prep for Proc-B). Poster presentations at Evolution Meetings 2008 and IV Annual Brazilian Herpetology Congress 2009. Abstract: How animal communities are structured has long been of interest to ecologists. Two very different hypotheses have been proposed to explain origins of ecological differences among species within present-day communities. The Competition Hypothesis states that, species interactions drive the evolution of divergence in resource use and niche characteristics. This hypothesis predicts that ecological traits of coexisting species are independent of phylogeny and/or major shifts in niche preference will be observed in closely related recent groups. The Deep History Hypothesis suggests that divergences deep in the evolutionary history of organisms resulted in niche preferences that are maintained for the most part, in species represented in present-day assemblages. The Deep History Hypothesis predicts that ecological traits of coexisting species can be predicted based on phylogeny regardless of the community in which individual species presently reside. In this study, we test the Deep History Hypothesis along one niche axis, diet, using snakes as our model clade of organisms. We found that nearly 70% of the variation in diets among snake clades is associated with seven major divergences in snake evolutionary history. The most ancient divergence explains 25% of the dietary divergence. We discuss these results in light of relevant morphological, behavioral, and ecological correlates of dietary shifts in snakes. We also discuss the implications of our results to the Deep History Hypothesis. |
Tim Colston's Research
My general areas of interest are ecology, evolution and conservation of
amphibians and reptiles. While there are always many things that interest
me, this page will give you an overview of some current and past projects
I have been involved in.
My general areas of interest are ecology, evolution and conservation of
amphibians and reptiles. While there are always many things that interest
me, this page will give you an overview of some current and past projects
I have been involved in.
Tim Colston tim@maddreptiles.com
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Past Projects:
________________________________________________
Survey and Inventory of the Amphians and
Reptiles in Wildlife Management Areas of
Oklahoma:
From 2006-2009 I assisted Dr. Laurie Vitt,
Dr. Janalee Caldwell and the other graduate students
in the herpetology lab at the Sam Noble Oklahoma Museum of Natural History
with intense herpetological surveys of the Wildlife Management Areas in
Oklahoma. Since Oklahoma lies in the dividing zone between East/West species in
the United States we have a diverse array flora and fauna. The data generated
from these surveys will provide detailed species lists, relative abundance and
ecological data that will be used in future conservation efforts.
Check out the project website here.
Survey and Inventory of the Small Mammals in
the State of Colima, Mexico:
From December 28, 2007-January 15, 2008
I assisted Dr. Gary Schnell of the Sam Noble Noble
Oklahoma Museum of Natural History, Dr. Mike
Kennedy of the University of Memphis, and Dr. Troy Best of Auburn University with
their ongoing survey of small mammals in Colima, Mexico. On this expedition our
basecamp was located at the foot of the Fire Volcano at the Jalisco/Colima
border. We took species abundance and activity data as well as species
distribution data.
________________________________________________
Survey and Inventory of the Amphians and
Reptiles in Wildlife Management Areas of
Oklahoma:
From 2006-2009 I assisted Dr. Laurie Vitt,
Dr. Janalee Caldwell and the other graduate students
in the herpetology lab at the Sam Noble Oklahoma Museum of Natural History
with intense herpetological surveys of the Wildlife Management Areas in
Oklahoma. Since Oklahoma lies in the dividing zone between East/West species in
the United States we have a diverse array flora and fauna. The data generated
from these surveys will provide detailed species lists, relative abundance and
ecological data that will be used in future conservation efforts.
Check out the project website here.
Survey and Inventory of the Small Mammals in
the State of Colima, Mexico:
From December 28, 2007-January 15, 2008
I assisted Dr. Gary Schnell of the Sam Noble Noble
Oklahoma Museum of Natural History, Dr. Mike
Kennedy of the University of Memphis, and Dr. Troy Best of Auburn University with
their ongoing survey of small mammals in Colima, Mexico. On this expedition our
basecamp was located at the foot of the Fire Volcano at the Jalisco/Colima
border. We took species abundance and activity data as well as species
distribution data.
