Hearing in Two Closely Related Species ( and ).

The genus has been extensively used as a model for ecological, behavioral, and evolutionary investigations. We used auditory brainstem responses (ABRs), craniofacial morphology, and pinna measurements to compare characteristics that impact hearing in two wild-caught species, . We observed significant statistical differences in craniofacial and pinna attributes between species with overall exhibiting larger features than . ABR recordings indicated that both species showed similar best frequency thresholds between 8-24 kHz. We found significant effects of intensity on amplitude ratio of wave I and IV for , but not and effects of wave number on slope of the latency-intensity function with higher wave IV and shorter wave I slope of latency intensity function in . Finally, the data showed significant differences in latency shift of the DN1 component of the BIC in relation to ITD between species, while no significant differences were observed across relative DN1 amplitude. This study supports the used of and as future model species for auditory research.