Table 1 Best supported PGLS models from AIC analysis, with adjusted R2 and Pagel’s λ, a measure of phylogenetic signal.
From: Aquatic birds have middle ears adapted to amphibious lifestyles
Species included in analysis | Anatomical category | Dependent variable | Model | Adjusted R2 | λ |
|---|---|---|---|---|---|
All species | Impedance-matching | log(tympanic membrane area) | log(head mass) + ecology | 0.7 | 0.56 |
log(footplate area) | log(head mass) + ecology | 0.67 | 0.75 | ||
log(tympanic membrane area/footplate area) | log(head mass) × ecology | 0.27 | 0.16 | ||
log(columella offset) | log(head mass) + ecology | 0.53 | 0.4 | ||
log(umbo height) | log(head mass) + ecology | 0.34 | 0.43 | ||
log(tympanic membrane angle) | log(head mass) + ecology | 0.27 | 0.011 | ||
log(extrastapedius length) | log(head mass) + ecology | 0.59 | 0.65 | ||
log(round window area) | log(head mass) + ecology | 0.67 | 0.61 | ||
Cochlear aqueduct | log(cochlear aqueduct area) | log(head mass) | 0.31 | 0.85 | |
Air volume | log(cranial air volume) | log(head mass) + ecology | 0.82 | 0.011 | |
Columella | log(columella length) | log(head mass) × ecology | 0.85 | 0.65 | |
log(columella volume) | log(head mass) | 0.78 | 0.46 | ||
Aquatic only | Impedance-matching | log(tympanic membrane area) | log(head mass) + dive score | 0.78 | 0.0011 |
log(footplate area) | log(head mass) + dive score | 0.79 | 0.7 | ||
log(tympanic membrane area/footplate area) | log(head mass) + dive score | 0.22 | 0.045 | ||
log(columella offset) | log(head mass) + dive score | 0.4 | 0.63 | ||
log(umbo height) | log(head mass) + dive score | 0.13 | 0.0011 | ||
log(tympanic membrane angle) | log(head mass) | 0.024 | 0.0011 | ||
log(extrastap-edius length) | log(head mass) + aquatic foraging lifestyle | 0.5 | 0.75 | ||
log(round window area) | log(head mass) | 0.62 | 0.51 | ||
Cochlear aqueduct | log(cochlear aqueduct area) | log(head mass) + dive score | 0.55 | 0.92 | |
Air volume | log(cranial air volume) | log(head mass) + aquatic foraging lifestyle | 0.78 | 0.2 | |
Columella | log(columella length) | log(head mass) × aquatic foraging lifestyle | 0.87 | 0.8 | |
log(columella volume) | log(head mass) + aquatic foraging lifestyle | 0.85 | 0.0011 |
