Meeting Abstract

P1.84A  Tuesday, Jan. 4  Getting Inside a Weasel’s Head: Frontal Sinus Size and Shape in Mustelidae ECKERT, Kirsten*; CURTIS, Abigail A.; VAN VALKENBURGH, Bliare; Univ. of California, Los Angeles; Univ. of California, Los Angeles; Univ. of California, Los Angeles kirsteneckert@gmail.com

Frontal sinuses are one of the four mammalian paranasal sinuses that form during ontogeny when nasal epithelium escapes the nasal cavity and invades surrounding bones including the maxilla, sphenoid, ethmoid, and frontal. Sinuses are highly diverse among species, and have evolved and/or been lost numerous times within Mammalia. For nearly two millennia, the function of frontal sinuses has remained an evolutionary mystery. Myriad functions have been proposed, including warming and humidifying air, absorbing shock during feeding and intraspecific combat, as well as contributing to skull growth and development, and many more. Few studies have tested these hypotheses because the sinuses were inaccessible without destroying the skull. Thus, little is known about variation in sinus presence, size, or shape among species, despite their potentially important physiological or biomechanical role in skull function. Recent advances in imaging technologies, such as x-ray computed tomographic (CT) scanning have greatly increased our ability to study these enigmatic cavities. In this study, we utilize CT technology to conduct the first quantitative study of frontal sinus size and shape in Mustelidae (e.g., weasels, otters, badgers). We use specialized 3D imaging software and spherical harmonics (SPHARM) to quantify size and three-dimensional shape variation in the sinuses. Results show that sinuses are highly diverse among mustelids, and that their presence is the ancestral state in Mustelidae, but they are reduced or lost with the acquisition of an aquatic lifestyle.