Meeting Abstract

P1.87  Friday, Jan. 4  In vivo measurement of cranial kinesis in Gekko gecko using XROMM methodology MONTUELLE, SJ*; VESSEL, C; WILLIAMS, SH; Ohio University; Ohio University; Ohio University montuell@ohio.edu

Kinetic skulls are characterized by moveable joints within the cranium. While cranial kinesis is a variable feature among vertebrates, the skull of gekkotan lizards is a textbook model for studying cranial kinesis. However, most evidence for cranial kinesis is extracted from manipulating skeletal specimens and experimental data quantifying kinetic movements are rare. Because of the lack of in vivo evidence, the ecological relevance of cranial kinesis (i.e., biological role) remains poorly understood. We used the X-ray Reconstruction Of Moving Morphology (XROMM) methodology to quantify mesokinesis, or the movements of the snout with respect to the braincase, in Gekko gecko during two routine behaviors: mouth-gaping displays and aggressive biting. We chose G. gecko because they are territorial animals that use gaping display and biting to protect their territory daily. During biting, we simultaneously recorded bite force using a bite force transducer. Our first hypothesis is that cranial kinesis may enhance maximum gape by rotating the snout dorsally when threatening predators. Our secondary hypothesis is that the snout can also rotate ventrally during biting to puncture the food item or the predator, thus potentially increasing bite force. Preliminary results confirm dorsoflexion of the snout during mouth-gaping display as well as ventroflexion during biting. This reveals that mesokinesis in the gekkotan skull may be a key adaptation for the defensive behaviors associated with territoriality.