Justin B. Lemberg
I am interested in the biomechanics of feeding in stem-group and early tetrapods. Tiktaalik roseae is a stem-group tetrapod from the Frasnian stage of the Late Devonian (approximately 375 mya) that predates the fin-to-limb and water-to-land transitions. Due to its exceptional preservation and close affinity to limbed tetrapods, studying Tiktaalik can elucidate much about the evolutionary history of our own lineage.
My research will involve using models (both physical and digital) and comparisons with extant analogs to reconstruct the feeding mechanics of this important transitional form. Physical models that take cervical mobility into account will be used to measure the fluid dynamic forces (drag, lift, and pressure differences) during feeding. I am in the process of digitally preparing CT scans of specimens that take sutural morphology into account, which will form the basis of a finite element model of the skull that will measure static internal forces (stress and strain). Finally, the assumptions necessary for inferring any sort of behavior in an extinct animal will be tempered by observing and making comparisons with living, modern-day analogs of Tiktaalik (Neoceratodus forsteri, Cryptobranchus alleganiensis, Alligator mississippiensis).
Reed, D. A., L. B. Porro, J. Iriarte-Diaz, J. B. Lemberg, C. M. Holliday, F. Anapol, and C. F. Ross. 2011. The impact of bone and suture material properties on mandibular function in Alligator mississippiensis: testing theoretical phenotypes with finite element analysis. Journal of Anatomy 218: 59-74.
Lemberg, J. B., L. B. Porro, D. A. Reed, and C. F. Ross. 2009. 3D Visualization and morphometric analysis comparing mandibular sutures in a hatchling and sub-adult Alligator mississippiensis. Journal of Vertebrate Paleontology, SVP Program and Abstracts Book 2009: 134A.
Porro, L. B., J. B. Lemberg, D. A. Reed, C. F. Ross, and K. A. Metzger. 2009. Finite element modeling of Alligator mississippiensis: multidimensional analysis, validation, and implications for fossil taxa. Journal of Vertebrate Paleontology, SVP Program and Abstracts Book 2009: 166A.
Porro, L. B., D. A. Reed, J. B. Lemberg, U. Zapata, and C. F. Ross. 2010. Mandibular mechanics of Alligator mississippiensis: from beam models to finite element analysis. Journal of Vertebrate Paleontology, SVP Program and Abstracts Book 2010: 147A.
Reed, D. A., L. B. Porro, C. M. Holliday, J. B. Lemberg, K. A. Metzger, and C. F. Ross. 2010. Multidimensional analysis of mandibular function in Alligator mississippiensis using geometric morphometrics and finite element modeling. Integrative and Comparative Biology 50: E144-E144.