“It is those who know little, and not those who know much, who so positively assert that this or that problem will never be solved by science.” — Charles Darwin

Gabriel Rivera

Assistant Professor
Evolutionary Morphology

Ph.D. – Clemson University, 2009
M.S. – Old Dominion University, 2003
B.S. – Old Dominion University, 2000

Department of Biology
Creighton University
2500 California Plaza
Omaha, NE 68178-0103
Office: Hixson-Lied Science 426
Phone: 402-280-3822

Courses Offered

  • BIO 433 – Vertebrate Comparative Anatomy
  • BIO 445 – Environmental Physiology
  • BIO 559 – Special Topics in Physiology

Research Interests

My research focuses on understanding the factors that drive phenotypic evolution. I aim to understand patterns of phenotypic divergence, including the functional consequences of small- and large-scale morphological differences and the selective forces responsible for them. I am particularly interested in the selective pressures exerted by aquatic flow velocity and predator regime. My research integrates approaches from the fields of ecological and functional morphology, as well as biomechanics, and is comparative in nature. My research is also question driven and, while not obligately taxon-specific, focuses primarily on shell shape in turtles. I use geometric morphometrics and multivariate analyses to quantify variation in phenotypic characters. I also use a variety of physical and computational models, as well as the performance of live animals, to determine the functional consequences of phenotypic variation.

Scholarly Works


Mayerl, C. J., A. M. Sansone, L. M. Stevens, G. J. Hall, M. M. Porter, G. Rivera, and R. W. Blob. 2019. The impact of keels and tails on turtle swimming performance and their potential as models for biomimetic design. Bioinspiration and Biomimetics 14:016002. DOI:10.1088/1748-3190/aae906

Hedrick, B. P., E. R. Schachner, G. Rivera, P. Dodson, and S. E. Pierce. 2019. The effects of skeletal asymmetry on interpreting biologic variation and taphonomy in the fossil record. Paleobiology 45:154-166. DOI:10.1017/pab.2018.42

Didde, R. D., and G. Rivera. 2019. Patterns of fluctuating asymmetry in the limbs of anurans. Journal of Morphology 280:587-592. DOI:10.1002/jmor.20967

Blob, R. W., C. J. Mayerl, A. R. V. Rivera, G. Rivera, and V. K. H. Young. 2016. “On the fence” versus “all in”: Insights from turtles for the evolution of aquatic locomotor specializations and habitat transitions in tetrapod vertebrates. Integrative and Comparative Biology 56:1310-1322. DOI:10.1093/icb/icw121

Rivera, G., J. N. Davis, J. C. Godwin, and D. C. Adams. 2014. Repeatability of habitat-associated divergence in shell shape of turtles. Evolutionary Biology 41:29-37. DOI:10.1007/s11692-013-9243-6

Rivera, A. R. V., G. Rivera, and R. W. Blob. 2013. Forelimb kinematics during swimming in the pig-nosed turtle, Carettochelys insculpta, compared with other turtle taxa: Rowing versus flapping, convergence versus intermediacy. Journal of Experimental Biology 216:668-680. DOI:10.1242/jeb.079715

Husak, J. F., G. Ribak, R. H. Baker, G. Rivera, G. S. Wilkinson, and J. G. Swallow. 2013. Effects of ornamentation and phylogeny on the evolution of wing shape in stalk-eyed flies (Diopsidae). Journal of Evolutionary Biology 26:1281-1293. DOI:10.1111/jeb.12133

Rivera, G., and C. T. Stayton. 2013. Effects of asymmetry on the strength of the chelonian shell: A comparison of three species. Journal of Morphology 274:901-908. DOI:10.1002/jmor.20146

Rivera, G., A. R. V. Rivera, and R. W. Blob. 2011. Hydrodynamic stability of the painted turtle (Chrysemys picta): Effects of four-limbed rowing versus forelimb flapping in rigid-bodied tetrapods. Journal of Experimental Biology 214:1153-1162. DOI:10.1242/jeb.046045

Rivera, G., and C. T. Stayton. 2011. Finite element modeling of shell shape in the freshwater turtle Pseudemys concinna reveals a trade-off between mechanical strength and hydrodynamic efficiency. Journal of Morphology 272:1192-1203. DOI:10.1002/jmor.10974

Dougherty, E., G. Rivera, R. Blob, and J. Wyneken. 2010. Hydrodynamic stability in posthatchling loggerhead (Caretta caretta) and green (Chelonia mydas) sea turtles. Zoology 113:158-167. DOI:10.1016/j.zool.2009.10.001

Gosnell, J. S., G. Rivera, and R. W. Blob. 2009. A phylogenetic analysis of sexual size dimorphism in turtles. Herpetologica 65:70-81. DOI:10.1655/07-057R2.1

Blob, R. W., and G. Rivera. 2008. Going with the flow: Ecomorphological variation across aquatic flow regimes: An introduction to the symposium. Integrative and Comparative Biology 48:699-701. DOI:10.1093/icb/icn093

Rivera, G., and J. Claude. 2008. Environmental media and shape asymmetry: A case study on turtle shells. Biological Journal of the Linnean Society 94:483-489. DOI:10.1111/j.1095-8312.2008.01008.x

Rivera, G. 2008. Ecomorphological variation in shell shape of the freshwater turtle Pseudemys concinna inhabiting different aquatic flow regimes. Integrative and Comparative Biology 48:769-787. DOI:10.1093/icb/icn088

Rivera, G., A. R. V. Rivera, E. E. Dougherty, and R. W. Blob. 2006. Aquatic turning performance of painted turtles (Chrysemys picta) and functional consequences of a rigid body design. Journal of Experimental Biology 209:4203-4213. DOI:10.1242/jeb.02488

Rivera, G., A. H. Savitzky, and J. A. Hinkley. 2005. Mechanical properties of the integument of the common gartersnake, Thamnophis sirtalis (Serpentes: Colubridae). Journal of Experimental Biology 208:2913-2922. DOI:10.1242/jeb.01715