Subterranean Fishes of the World

915

1971

Journal of Morphology

179-188

133

The morphology of the Weberian ossicles of Astyanax mexicanus, an eyed river fish, and A. jordani, the Mexican blind cave fish, was investigated and the results were correlated with behavioral data on the auditory capacities of the two species. Several characteristics of the ossicles of the two species were inter‐specifically significantly different while other characteristics varied as much intra‐specifically as inter‐specifically. The ascending arm of the scaphium was shorter in the blind fish than in the river fish and the ascending arm of the intercalarium was further from the distal end of the base of the bones in the blind fish than in the river fish. A previously unreported ligament between the scaphium and the sinus atrium impar was found in Astyanax. It was hypothesized that this connective tissue retained perilymphatic fluid within the inner ear, helped the ossicles return to an anterior position after moving posteriorly, and might protect the inner ear during intense acoustical stimulation.

1