The Hedrick Lab seeks to better understand the interconnected relationship between morphology, phylogeny, and ecology in order to answer the question:
How do morphological innovations lead to the radiation of taxa?
By studying a wide variety of taxa ranging from sharks, to bats, to rodents, to dinosaurs, we assess the impact of morphological evolution on the great diversity of life, past, present, and future.
December 20, 2020: New Paper Out on Archosaur Lung Evolution
Lungs are the organ of respiration, allowing the majority of tetrapods to live their lives out of the water. In spite of their crucial role in breathing, and their near ubiquitous presence in tetrapods (except for things like lungless salamanders! weird!), they are poorly understood from a morphological standpoint in the vast majority of taxa. This is because they are represented by negative space and require high-powered imaging to visualize in small animals.
My colleague, Emma Schachner, and I have published a paper assessing the morphological structure of ostrich and alligator lungs for the first time using micro-computed tomography in the Journal of Anatomy. In this work, we visualize and quantify interspecific lung differences in these two representatives of the Archosauria, and also assess intraspecific variation and ontogenetic changes.
August 10, 2020: Salamander Field Work
We got started setting up some coverboard sites in Hammond, LA and in Tickfaw State Park. Oliver Ljustina (at Southeastern Louisiana University), my wife Sam Cordero, and I braved the summer Louisiana heat to get 200 coverboards set up to monitor Plethodon mississippi (Mississippi Slimy Salamander).
In October once the boards are integrated, we'll start a spatial capture recapture study. The goal will be to understand differences in population density, land use, and demographics in urban and rural populations. More to come!
April 15, 2020: Special Anatomical Record Volume Out!
Peter Dodson and I have been working on a special issue for the Anatomical Record on dinosaurs since early 2018 and it just came out! We really appreciate the hard work and patience of all of our contributing authors.
The volume has 25 original research articles on a wide variety of topics ranging from a description of the largest specimen of T. rex to convergence in tail weaponry in glyptodonts and ankylosaurs to the reconstruction of blood vessels in dinosaur heads. My contribution to the issue concerned paleohistology of horned dinosaurs.
Thanks so much to Jeff Laitman and Kurt Albertine for inviting us to edit the volume. It was a lot of fun!
Feb 15, 2020: The Future of Museum Collections
We recently published a manuscript concerning the global effort to digitize specimens in museum collections. We outline two processes that are currently being undertaken in natural history museums, Digitization 1.0 (the conversion of collections into digitized forms within museums) and Digitization 2.0 (the recent push to accelerate the digitization process using the products digitized during Digitization 1.0). Check it out!
Jan 20, 2020: The Evolution of Rodent Limbs
Our paper on the evolution of proximal rodent limb bones was just published in Scientific Reports. This study aimed to examine internal and external limb geometry of 76 rodent species (including terrestrial, arboreal, semi-aquatic, semi-fossorial, fossorial, and jumping rodents) using microCT. We found that only digging rodents have statistically different limb shapes from other ecological modes. We propose that rodents have been so successful at spreading into new niches and colonizing new areas due to high locomotor plasticity, allowing them to modify their locomotor mode without requiring major body plan modifications.
Now we're working on expanding our dataset to incorporate other groups including moles, shrews, and of course, bats.