Table 3. Dimensions of vestibular elements and orientations of semicircular canalsa.
| Taxon | Aqueduct Length | Stapedial Ratio | Labyrinth Index | Semicircular Canal Angles | ||
| A–L | A–P | L–P | ||||
| Marsupialia | ||||||
| Didelphis | 2.58 | 1.6 | 0.0 | 109 | 102 | 104 |
| Eutheria | ||||||
| Kulbeckia | 1.24 | 2.0 | 0.0 | 79.9 | 79.9 | 89.6 |
| Ukhaatherium | NA | 1.5 | 0.0 | 88.8 | 105 | 88.4 |
| Zalambdalestes | 1.74 | 1.7 | 0.0 | 81.0 | 93.6 | 85.6 |
| Zhelestid | 1.06 | 1.6 | 0.0 | 88.8 | 96.8 | 93.1 |
| Afrotheria | ||||||
| Chrysochloris | 0.37 | 2.8 | 21.7 | 65.6 | 86.9 | 96.7 |
| Elephantimorpha | 13.9 | 1.6 | 0.0 | 66.3 | 73.7 | 92.6 |
| Hemicentetes | NA | 1.6 | 4.1 | 79.3 | 87.9 | 87.0 |
| Macroscelides | 2.08 | 1.9 | 32.7 | 100 | 90.7 | 95.7 |
| Orycteropus | 8.25 | 1.8 | 0.0 | 78.5 | 91.9 | 87.4 |
| Procavia | 3.39 | 2.1 | 44.9 | 87.4 | 112 | 86.3 |
| Trichechus | 12.3 | 1.6 | 0.0 | 52.2 | 84.9 | 77.5 |
| Xenarthra | ||||||
| Dasypus | 2.63 | 1.7 | 23.0 | 62.4 | 67.7 | 87.3 |
| Laurasiatheria | ||||||
| Atelerix | NA | 1.8 | 26.4 | 82.2 | 91.7 | 92.1 |
| Balaenopteridae | 3.83 | 1.5 | 0.0 | 71.6 | 105 | 75.6 |
| Bathygenys | NA | NA | 45.2 | 86.0 | 99.6 | 91.3 |
| Canis | NA | 1.3 | 0.0 | 80.4 | 101 | 89.1 |
| Equus | 11.7 | 1.7 | 10.5 | 84.7 | 93.3 | 90.1 |
| Eumetopias | 2.26 | 1.5 | 0.0 | 79.7 | 105 | 90.6 |
| Felis | 3.77 | 1.9 | 13.1 | 76.8 | 91.4 | 96.7 |
| Manis | 2.45 | 1.7 | 20.5 | 77.0 | 84.8 | 88.6 |
| Nycteris | NA | 1.0 | 0.0 | 85.9 | 112 | 94.9 |
| Pteropus | 1.62 | 1.8 | 29.7 | 84.9 | 98.3 | 90.4 |
| Rhinolophus | 1.40 | 1.4 | 38.3 | 79.9 | 104 | 87.9 |
| Sorex | 1.58 | 1.7 | 11.9 | 75.3 | 89.6 | 89.3 |
| Sus | 3.18 | 1.3 | 16.5 | 82.8 | 96.0 | 87.9 |
| Tadarida | 1.42 | 2.0 | 22.1 | 74.7 | 98.4 | 98.4 |
| Tursiops | 2.23 | 1.4 | 0.0 | 52.2 | 84.9 | 77.5 |
| Euarchontoglires | ||||||
| Cavia | 3.82 | 2.9 | 25.3 | 77.2 | 105 | 85.5 |
| Cynocephalus | 1.80 | 2.0 | 30.8 | 92.2 | 90.0 | 91.8 |
| Homo | 5.47 | 3.0 | 55.8 | 98.9 | 100 | 89.8 |
| Lepus | 3.71 | 1.7 | 32.4 | 84.2 | 94.0 | 88.6 |
| Macaca | 3.76 | 2.5 | 50.1 | 83.1 | 100 | 89.0 |
| Mus | 1.28 | 1.9 | 25.8 | 88.8 | 94.4 | 95.6 |
| Sylvilagus | 2.08 | 1.5 | 33.9 | 92.7 | 97.5 | 77.9 |
| Tupaia | 2.61 | 2.6 | 13.1 | 82.3 | 106 | 102 |
a
Measurements: Aqueduct Length, length of bony channel for vestibular aqueduct (mm); Stapedial Ratio, height of fenestra vestibuli over width; Labyrinth Index, sagittal labyrinthine index [34]; Semicircular Canal Angles, formed between planes of anterior (A), lateral (L) and posterior (P) canals (°). Values for extinct eutherians are averages [83].