Comparative morphology and morphometry of the nasal fossae of four species of North American shrews (Soricinae).
The present study compares the morphology of the nasal conchae and the relative development (i.e., surface area and neurosensory cell number) of the olfactory epithelium between four species of shrews occupying different ecotopes (Blarina brevicauda, Sorex cinereus, S. fumeus, S. palustris). The number of olfactory cells was corrected for split cell error. Data were analyzed by using size indices based on the allometric method. The convoluted shape of the maxilloturbinal in Blarina, with large respiratory epithelial surface area, could not be related with certainty to the subterranean ecotope. From the comparison between Soricinae and Crocidurinae, one major difference concerned the shape and attachment of ectoturbinal 3. Differences in the relative development of the olfactory organ are discussed with regard to differences in the use of chemical signals. The semi-fossorial B. brevicauda, with the more developed olfactory organ, is reported to possess more scent-glands and to manifest active scent-marking behaviors and fecal deposits associated with territoriality. The two terrestrial species, S. cinereus and S. fumeus, have olfactory epithelia showing an intermediate development. Published accounts of fewer scent-glands and a lack of active scent-marking behavior indicate a lesser use of olfactory communication in these two species where mutual avoidance seems the rule. Indication of an even more reduced use of olfactory signals in social interactions by the semiaquatic S. palustris is suggested by its least-developed olfactory epithelium. The comparison between Soricinae and Crocidurinae supports a relationship between the development of the olfactory organ and the relative use of olfactory communication known to occur in social interactions.
Larochelle
R
R
Département des Sciences Biologiques, Université de Montréal, Québec, Canada.
Baron
G
G
D000818:Animals; D004847:Epithelial Cells; D004848:Epithelium / Q000033:anatomy & histology / Q000502:physiology; D005260:Female; D008297:Male; D009296:Nasal Cavity / Q000033:anatomy & histology* / Q000166:cytology / Q000502:physiology; D009831:Olfactory Mucosa / Q000033:anatomy & histology / Q000166:cytology / Q000502:physiology; D012788:Shrews / Q000033:anatomy & histology*