The visual system is a critical portion of the sensory arsenal in many animals, since light is a fundamentally important factor that allows animals to assess and navigate their surroundings. Differences in latitude have measured effects on the quality, quantity, and consistency of daylight, and animals have adapted to these varying light levels in different ways. Research has shown that animals with larger eyes, reflected in their bony orbit dimensions, are able to perceive their environments better in more dimly lit settings. Studies have also suggested that animals at higher latitudes exhibit larger eyes for better visual performance. Our group seeks to understand if there is any significant relationship between latitude and orbital size in Canidae (wolves, foxes, and relatives) due to the difference in light levels at different latitudes. I collected several linear measurements using ImageJ and 3D Slicer from skull 3D scans of 29 species of the Canidae family over a latitude range from -104.07° - 99.02°. Additionally, our team collected data on the average tree coverage, diet, and hunting style of species, to test for additional variables that may affect orbital size. We conducted regressions and ANOVAs among the variables collected. The preliminary results show there is no significant relationship between latitude and orbital size. However, we found that both hunting style and skull length have a significant relationship with orbital volume in Canidae. These results potentially impact the field by allowing us to infer the possible evolutionary trajectories of bony orbital dimensions, and how eye size could allow for more complex hunting styles in Canidae. Future research may seek to validate these findings in other carnivore families.

Documenting plant-animal interactions allows for a better understanding of biodiversity, the behavioral ecology of frugivores, and the coevolution between plants and animals. Bats are important seed dispersers on hundreds of plant species in the tropics, but their patterns of plant use across habitats is still relatively unknown. The overarching goal of my research project is to characterize the interactions between mutualistic fruit bats and plants across different habitats at a site in Costa Rica (La Selva). My hypothesis is that bats will exhibit frequent interactions with Piper plants overall, with more variable interactions across forest Piper species over time because these species have intermittent fruiting peaks. Existing field data consist of 24h camera trap videos and nightly acoustic ultrasonic recordings taken at dozens of forest and gap Piper plants at La Selva during both rainy and dry seasons between 2019-2021. The acoustic data collected is heavy in background noise from organisms and weather conditions; therefore I developed a program in MATLAB to streamline this analysis. I am using RavenPro to identify relevant parameters of bat calls within the filtered files using focal calls as a guide to later identify the species participating in these visitations. I am comparing the number of calls across 10 P. sanctifelicis plants (open habitat) to the number of calls found across 8 P. generalense plants (closed habitat) to observe the frequency of possible fruit-bat interactions across habitats. This project is significant in the field of ecology because of its focus on plant-animal mutualistic interactions: by understanding the frequency of bat visitations to plants across habitats, we can gain a better understanding of the importance of these frugivores for seed dispersal and survival of plants.

Mosasaurs are extinct, enormous lizards that dominated the oceans in the Late Cretaceous, from 90 to 66 million years ago. They were important members of Late Cretaceous marine ecosystems, with some species being the top predators. However, there remain many uncertainties about mosasaur diets, which likely varied considerably among species. Therefore, I aim to investigate mosasaur diets to provide more information on lizard evolution and Cretaceous marine ecosystems. To infer the diets of mosasaurs, I examine the lower jaws and teeth of their closest living relatives, modern lizards, and test for correlations between craniodental morphology and diet. For example, a lizard that eats primarily hard-shelled foods will likely have more robust jaws and teeth than a lizard that primarily consumes insects. To quantify the morphologies of the lower jaw and teeth, I measured the width and height of the jaws at three points, and the height, width, length, curvatures, root length, and cusp numbers of the teeth at the same three points (n = 43 species). I then used the jaw measurements to calculate cross sectional shape values that represent the amount of stress the jaws experience during feeding. Finally, I used phylogenetic regressions and multivariate analyses to test the relationship between jaw/tooth shapes and diets. I find evidence that jawbone heights increase among diets in the following order: insectivores, carnivores, herbivores, and durophagous taxa. Further, bone width is greater in herbivores than in non-herbivorous taxa, and durophagous lizards have the most diverse tooth morphologies. These results provide a foundation for future studies to examine the relationship of jaw/tooth shapes and diet more robustly, with the goal of using modern lizards as analogs for inferring diets of mosasaurs.

 The diversification of many vertebrate groups was spurred by the use of novel food resources, and jaw functional morphology provides clues about the adaptations associated with dietary diversification. The external dimensions along the mandible reflect strength to resist bite forces, which are in turn associated with physical properties of the diet. Variation in these dimensions along the jaw and between different species therefore may reflect adaptations of the jaw to specific diets. We applied this biomechanical framework to investigate the relationship between jaw robustness and diverse diet types in bats. Using mandibles of more than 60 species, we quantified the external dimensions at interdental gaps to generate mandibular strength profiles. The strength profiles of frugivorous, insectivorous, and omnivorous bats showed similar patterns, with a trend of increasing jaw depth toward posterior teeth. All diet types showed a high level of variation in jaw shape along the toothrow, suggesting differences in the functional roles of different teeth. Insectivores showed the greatest within-guild variation in jaw shape, while nectarivores had noticeably gracile symphyses. Further, insectivorous bats showed relatively deep jaws at the canine and premolars, which may be associated with the use for prey capture, while frugivores have relatively deep jaws at the posterior molars, possibly linked to adaptations for crushing seeds and pulp. These results suggest that mandible strength profiles reflect dietary adaptations in bats.