Date of Award


Degree Name

Biological Sciences


College of Science

Type of Degree


Document Type


First Advisor

Frank R. O’Keefe

Second Advisor

Suzanne Strait

Third Advisor

Andy Grass


The relationships of pterosaurs have been previously inferred from observed traits, depositional environments, and phylogenetic associations. A great deal of research has begun to analyze pterosaur ontogeny, mass estimates, wing dynamics, and sexual dimorphism in the last two decades. The latter has received the least attention because of the large data set required for statistical analyses. Analyzing pterosaurs using osteological measurements will reveal different aspects of size and shape variation in Pterosauria (in place of character states) and sexual dimorphism when present. Some of these variations, not easily recognized visually, will be observed using multivariate allometry methods including Principle Component Analysis (PCA) and bivariate regression analysis. Using PCA to variance analysis has better visualized ontogeny and sexual dimorphism among Pterodactylus antiquus, and Aurorazhdarcho micronyx. Each of the 24 (P. antiquus) and 15 (A. micronyx) specimens had 14 length measurements used to assess isometric and allometric growth. Results for P. antiquus analyses show modular isometric growth in the 4th metacarpal, phalanges I-II, and the femur. Bivariate plots of the ln-geometric mean vs ln-lengths correlate with the PCA showing graphically the relationship between P. antiquus and A. micronyx which are argued here to be sexually dimorphic and conspecific. Wing schematic reconstructions of all 39 specimens were done to calculate individual surface areas and scaled to show relative intraspecific wing shape and size. Finally, Pteranodon, previously identified having sexually dimorphic groups, was compared with ln-4 th metacarpal vs ln-femur data, bivariately, revealing differences likely due to the constraints of size (P. antiquus and A. micronyx = group 1; Pteranodon = group 2).



Pterodactyls -- Anatomy.