CAREER: Investigating the Role of Modularity in the Diversification of the Acanthomorph Skull

William Marsh Rice University, Houston TX

Investigators

Abstract

The fish skull is a highly complex biological structure. It is highly multi-functional, and accommodates the need to perform multiple tasks at the same time, including feeding, sensing, and communication. Over its 300-million-year history, the skull has undergone dramatic changes as different species have adapted it to respond to differing and unique environmental pressures. Amongst this diversity, spiny ray-finned fishes (Acanthomorpha) have emerged as one of the most diverse animal groups, representing over 25% of all vertebrate species diversity. This project will be first of its kind to analyze patterns of skull shape evolution in its proper anatomical context. This study will advance the understanding of how complex structures evolve. The results of this project would also provide a framework for study of shape change across other complex biological structures. The broader impacts of this project also feature a Marine Biology Science Co-op and summer REU program in collaboration with San Jacinto College. The study will produce a compilation of a large open source micro-CT scan dataset for 1084 species of acanthomorph fishes while aiding in digitizing efforts for museum collections worldwide. Modularity is thought to play a key role in the evolution of complex morphologies by reducing the “cost of complexity” which can reduce the rate of adaptation in populations that exhibit strong integration between traits. This study will advance the understanding of how complex structures evolve and the role that modularity plays in this process. The research objectives of this work are (1) to quantify the tempo and mode of skull shape evolution across 1084 acanthomorph fish species using three dimensional geometric morphometrics collected from micro-computed-tomography (micro-CT) scan data, (2) test for evolutionary modularity across the acanthomorph skull, and (3) test for differences in the rate and model of evolution across different modules of the acanthomorph fish skull. The education component will consist of the development of a hands-on course module to teach undergraduates about modularity in biological systems that will produce an open-access anatomical review of the skull morphology of 308 families of acanthomorph fishes. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.