HOLLIDAY LAB
The lab’s research focuses on the functional morphology and evolution of the vertebrate head. The lab’s primary goal is to understand the structural, biomechanical, and evolutionary patterns of the feeding apparatus in reptiles.
Data gathered from extant taxa are used to understand not only how living animals function but also how these animals evolved; therefore, incorporating fossil taxa into comparative and historical analyses is a common practice. Classical anatomical techniques used include dissection, vascular injection, and histology. These are coupled with CT scanning, MRI, and other imaging modalities that are analyzed with software packages that enable 3D visualization, reconstruction, and analysis of anatomical structures.
Currently there are two active projects underway:
Archosaur feeding evolution: Understanding feeding functional morphology is critical to gaining insight into how animals interact with their food and environment. We are currently reconstructing and analyzing jaw muscle morphology in living and fossil archosaurs (a group which includes birds, crocodilians, and dinosaurs) to not only understand feeding behavior and evolution in particular fossil groups (e.g., tyrannosaurs and early crocodyliforms), but to also understand how the highly-derived, modern avian and crocodylian conditions arose. Computer models of the head musculoskeletal system are developed and validated using living animals using dissection. These data are then incorporated into interactive surface models, finite element models (FEA), and eventually 3D-animated kinematic models used to explore feeding functional hypotheses in collaboration with researchers from several different institutions.
Reptilian connective tissues biology: Reptile heads are composed of a number of complicated bony and soft-tissue structures including sutures, fibrocartilaginous sesamoids, and synovial joints. For the most part however, little is known about the responses of reptile connective tissues to epigenetic (e.g., mechanical) and anthropogenic (e.g., pollutant) stimuli and the genetic and regulatory mechanisms responsible for reptilian cranial tissues is largely unexplored. Therefore the potential applicability of reptilian models to biomedical sciences remains untested, though insights into arthritis and osteoporosis appear possible. Particular joints and tissues are being harvested from alligators, birds, and lizards and analyzed using CT, material properties testing, and histology to understand the structure and function of sutures, synovial joints, cartilage, ligaments, and tendons of the head.
Opportunities for Students
— Learn anatomical techniques including
dissection, vascular injection, and histology
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Collect and analyze data from CT scanning for use in research and education
— Use cutting edge 3D visualization and animation software to reconstruct the
anatomy of living and fossil animals
— Learn
histology of skeletal tissues (e.g., bone, cartilage, muscle)
Ongoing
projects for students
Dinosaur and
crocodilian feeding evolution
reconstruct jaw muscles, nerves, and other tissues in 3D models of extinct
animals and track their changes over time.
Reptilian bone biology
generate and study histological and imaging data from reptiles for studies on suture
growth, bone density, and joint function
Human Gross Anatomy and Radiology
reconstruct and label human anatomy using CT and MRI data
| Publications | ||
| Casey M. Holliday, Ryan C. Ridgely, Amy M. Balanoff, and Lawrence M. Witmer. 2006. Cephalic vascular anatomy in flamingos (Phoenicopterus ruber) based on novel vascular injection and computed tomographic imaging analyses. Anatomical Record 288A(10):1031–1041. | ||
| Casey M. Holliday and Lawrence M. Witmer. 2007. Archosaur adductor chamber homology: integration of musculoskeletal and topological criteria in jaw muscle homology. Journal of Morphology.268:457-484. | ||
| Natalia Rybczynski, Alex Tirabasso, Paul Bloski, Robin Cuthbertson, and Casey M. Holliday. 2008. A three-dimensional animation models of Edmontosaurus (Hadrosauridae) for testing chewing hypotheses. Paleontologia Electronica 11(2):14p. | ||
| Lisa Cooper, Nils Sedano, Stig Johansson, Bryan May, Joey D. Brown, Casey M. Holliday, Brian W. Kot, and Frank E. Fish. 2008. Hydrodynamic performance of the minke whale (balaenoptera acutorostrata) flipper. Journal of Experimental Biology 211:1859-1867. | ||
| Casey M. Holliday and Lawrence M. Witmer. 2008. Cranial kinesis in dinosaurs: intracranial joints, protractor muscles, and their significance for cranial evolution and function in diapsids. Journal of Vertebrate Paleontology 28(4):1073-1088. | ||
| Casey M. Holliday.2009. New Perspectives on Dinosaur Jaw Muscle Anatomy. The Anatomical Record 292:1246-1265. | ||
| Casey M. Holliday and Lawrence M. Witmer. 2009. The epipterygoid of crocodyliforms and its significance in the evolution of the orbitotemporal region of eusuchians. Journal of Vertebrate Paleontology 29(3): 713-733 | Link to page |
Projects completed or underway
Published works are underlined and clicking the titles link to new pages that feature full-resolution figures, pdf access, and eventually other treasures. Other projects are in preparation or somewhere in the pipeline, as nebulous as that sounds, but I couldn't help but start getting the figures out there. Comments, queries, and collaborations welcome.
All images © Casey M Holliday 2008 unless otherwise noted
| Flamingo Head Vasculature | Archosaur Adductor Chamber Homology | ||
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| Hadrosaur Anatomy & Feeding Mechanics | |||
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| Lizard Mandibular Symphysis Morphology and 3D Database | |||
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| Crocodyliform Braincase and Epipterygoid Evolution | Limb Articular Cartilage in Extant and Fossil Archosaurs | ||
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Dinosaur Jaw Muscle
Anatomy
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Effects of PCBs on Turtle Bone Density (DK Holliday & CM Holliday) |
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