Area of Interest
My research program is firmly rooted in comparative anatomy as an experimental science that creates natural experiments to answer specific functional and evolutionary questions. At a basic level, it seeks to understand how complex systems can evolve further while remaining functional at all stages. My overarching working hypothesis posits that seemingly large changes during macroevolutionary processes are actually the result of relatively small changes that fundamentally affect the construction and, thus, the functioning of an organism. My research group is working on a variety of vertebrate model species from lampreys to sharks, and from alligators, birds, and mammals to human beings.
Our research program explores the functional morphology and evolution of complex systems by discovering and analyzing structures and constructional principles, and by developing theoretical concepts. Examples of our discoveries are the special construction of the avian hyoid suspension and its implication for the evolution of feeding adaptations in birds and mammals; the fundamental roles of a kinetic larynx, air sacs, and the skin in avian vocalization; the mechanical role of cutaneous fat for the movement of contour feathers; the function of the depressor feather muscles and its significance for the evolution of birds and avian flight; the impossibility of feathers evolving from the scaly integument of dinosaurs; a method of biomechanical analysis and modeling of complex skeleto-muscular systems based on 3D visualization and animation of CT data; the role of the human shoulder suspension apparatus in the successful global invasion by hominins; the evolution of the shoulder suspension apparatus of bipedal humans from a head suspension apparatus of quadrupedal mammals; and the postulate that systematics and comparative anatomy are based on fundamentally distinct research programs.
All our research projects are tied to our fundamental interest in the reconstruction of macroevolutionary changes as a result of individual variation and natural selection by synthesizing functional-morphological and behavioral-ecological data of extant organisms with paleoclimatological and geological data. An example is my long-term study of the feeding and drinking behavior, functional morphology, ecology, and evolutionary history of the Psittaciformes (i.e., cockatoos and parrots), which has also implications for the evolution of the Gondwanan avifauna in general.
Homberger, D.G. (2015). Understanding Other Species' Needs: The Monetization of Nature -- Self-Restraint and a Global Rationing System of Natural Resources as an Antidote. Chapter 5. Pp. 91-139 in Ecopsychology: Advances from the Intersection of Psychology and Environmental Protection. Volume I: Science and Theory (R.B. Hamilton & D.G. Nemeth, eds.). Praeger, Santa Barbara, CA. ISBN 978-1-4408-3172-0 or 978-1-4408-3173-7
Osborn, M. L. and Homberger, D. G. (2015). The Human Shoulder Suspension Apparatus: A Causal Explanation for Bilateral Asymmetry and a Fresh Look at the Evolution of Human Bipedality. Anat. Rec., 298 (9): 1572–1588. doi:10.1002/ar.23178. http://www.ncbi.nlm.nih.gov/pubmed/26054034. See also Anatomy Now (Newsletter of the American Association of Anatomists), September 2015. http://amasan.informz.net/admin31/content/template.asp?sid=40684&ptid=1234&brandid=3960&uid=825289017&mi=4645285&ps=40684
Redd, T.C, Dubansky, B.H., Osborn, M.L., Tully, T.N., & Homberger, D.G. (2012). A registration algorithm for the identiﬁcation of individual parrots based on the patterns of filing ridges on their upper bill tip. International Journal of Biology and Biometrics, 6 (3): 68-91. http://cscjournals.org/csc/journals/IJBB/browsemanuscript.php?EJCode=126.96.36.199.105&JCode=IJBB&Volume=47.105&Issue=46.103
Legreneur, P., Homberger, D.G. & Bels, V. (2012). Assessment of the mass, length, center of mass, and principal moment of inertia of body segments in adult males of the brown anole (Anolis sagrei) and green, or Carolina, anole (Anolis carolinensis). Journal of Morphology, 273 (7): 265-275. doi: 10.1002/jmor.20022
Homberger, D.G. Ham, K., Ogunbakin, T., Bonin, J.A., Hopkins, B.A., Osborn, M.L., Hossain, I., Barnett, H.A., Matthews II, K.L., Butler, L.G., & Bragulla, H.H. 2009. The structure of the claw sheath in the domestic cat (Felis catus): Implications for the claw shedding mechanism. Journal of Anatomy, 214: 620-643. doi: 10.1111/j.1469-7580.2009.01068.x
Bragulla, H.H. & Homberger, D.G. 2009. Structure and functions of keratin proteins in simple, stratified, keratinized and cornified epithelia - a review. Journal of Anatomy, 214: 516-559. doi: 10.1111/j.14697580.2009.01066.x
Homberger, D.G. & Walker, W.F. 2004. Vertebrate Dissection, 9th revised edition. Brooks/Cole, Florence, Kentucky (formerly Harcourt Publishing, currently under Thomson Learning). ISBN 0-03-022522-1
Homberger, D.G. 2003. The role of mechanical forces on the patterning of the avian feather-bearing skin: Evidence from the integumentary musculature. J. exp. Zool. (Mol. Dev. Evol.), 298B: 123-139.
Homberger, D.G. 2003. The comparative biomechanics of a prey-predator relationship: The adaptive morphologies of the feeding apparatus of Australian Black-Cockatoos and their foods as a basis for the reconstruction of the evolutionary history of the Psittaciformes. Pp. 203-228 in Vertebrate Biomechanics and Evolution (V.L. Bels, J.-P. Gasc, & A. Casinos, eds.). BIOS Scientific Publishers, Oxford.
Gudo, M. & Homberger, D.G. 2002. The functional morphology of the pectoral fin girdle of the Spiny Dogfish (Squalus acanthias): Implications for the evolutionary history of the pectoral girdle of vertebrates. Senckenbergiana lethaea, 82 (1): 241-252.
Homberger, D.G. & de Silva, K.N. 2000. Functional microanatomy of the feather-bearing avian integument: Implications for the evolution of birds and avian flight. Amer. Zool. 40 (4): 553-574.
Homberger, D.G. 1999. The avian tongue and larynx: Multiple functions in nutrition and vocalization. Pp. 94-113 in Proceedings of the 22nd International Ornithological Congress (N. Adams & R. Slotow, eds.). University of Natal, Durban, South Africa.