Ashly N. Romero

The right and left side of any primate head can and will likely differ. These differences are called bilateral asymmetry. The random deviations from symmetry that are present in the cranium (fluctuating asymmetry) can tell us how well a primate was able to deal with problems occurring during their development (developmental instability). Using geometric morphometric techniques, I calculate levels of fluctuating asymmetry in primate crania to answer questions about developmental instability in primate taxa and provide better context for primate craniofacial evolution.

Though many articles have been written about stress and asymmetry, no one has used a comprehensive stress measurement to evaluate the relationship between these two factors. Allostatic load is a measure of wear and tear on the body provided by multiple biomarkers from various physiological systems. Myself and my collaborators are among the first to investigate how stress affects skeletal growth and development from the relationship between allostatic load and fluctuating asymmetry. Further, we will be the first to measure a true allostatic load index in rhesus macaques.

It is unclear how well the genetic structure of primate populations explains the fluctuating asymmetry (FA) present. Is there a lot of genetic variation for FA in the population that natural selection can act on? These questions are difficult to answer because there aren't many populations with appropriate data to allow these studies. I investigate this question in the rhesus macaques from Cayo Santiago and olive baboons from Texas Biomed (SNPRC), pedigreed populations for which a skeletal collection is present.

Some mammals have defenses that are part of their body. Armadillos have a carapace. Pangolins have keratinous scales. Porcupines have quills. All of these defenses are grown throughout ontogeny. Therefore, they are considered morphological. Growing these structures requires an enormous amount of energy, but we don't know if the energy required for morphological defenses reduces the amount of energy available for ensuring stable development of other areas of the body. I research the level of asymmetry in mammals with morphological defenses compared to mammals without in the hopes of understanding the impact of growing such costly structures.

Tablet and phone use in recent decades has increased exponentially, which adds frequent strains on the neck as it accommodates the postures required for device viewing. To assess how neck position changes with tablet use, my colleagues and I are investigating variation in cervical vertebrae position related to particular postures associated with tablet use. These same individuals provide the perfect opportunity to assess changes in hyoid position with neck extension and flexion in humans. We are additionally characterizing how the hyoid moves during these postures for tablet use.