Inner ear of the coelacanth fish Latimeria has tetrapod affinities
Abstract
Auditory reception in elasmobranchs, teleosts and amphibians may be mediated by various inner-ear sensory epithelia1-3, including the basilar papilla, which seems to be the precursor of the cochlea in mammals. The origin of the basilar papilla remains a major unsolved problem for understanding the evolution of hearing in terrestrial vertebrates4-6. Study of living species indicates that the basilar papilla is a unique feature of tetrapods6,7, but palaeonto-logical data indicate that this epithelium as well as a middle ear, is already present in crossopterygian fish8-10. However, no basilar papilla has been found in the only living crossopterygian species, the coelacanth Latimeria chalumnae11. I have re-examined the inner ear of adult and embryonic Latimeria and find a membranous specialization which resembles in structure, position and innerva-tion pattern the basilar papilla of tetrapods, in particular amniotes. No epithelium comparable to the basilar papilla was found in lungfish. I suggest that the basilar papillae of Latimeria and tetrapods are homologous and evolved only once in their common ancestor.
- Publication:
-
Nature
- Pub Date:
- May 1987
- DOI:
- 10.1038/327153a0
- Bibcode:
- 1987Natur.327..153F