Vestibular labyrinth diversity in diprotodontian marsupial mammals

概要

論文の詳細を見る
The bony labyrinth of specimens representing eight diprotodontian species were visualized by high-resolution computed tomography. Linear measurements of the labyrinth were taken, e.g., the height and width of the arc of each semicircular canal. The relative sizes and spatial arrangements of the semicircular canals were compared and some of the variation was atomized into 17 characters, which were then phylogenetically interpreted. There has been a change both in size and in relative arrangement of the semicircular canals that for some aspects maps onto the ecological change from arboreality to terrestriality. In particular, there are differences among diprotodontians in the height of the anterior semicircular canal in relation to the posterior one. In arboreal species, the lateral semicircular canal is relatively longer than the equivalent semicircular canals of terrestrial species. A rounder anterior semicircular canal is widespread for Diprotodontia with a shift in Pseudocheiridae, where it is more flattened. Dendrolagus shows features typical of terrestrial species in spite of its arboreal lifestyle. The fact that it shows the derived character state is congruent with the fact that it has secondarily and only recently evolved an arboreal lifestyle.
日本哺乳類学会の論文
2007-12-01