Figure 1.
Avian caudal skeleton in left lateral (A) and dorsal (B) views.
Abbreviations: fcv, free caudal vertebra; pyg, pygostyle; syn, synsacrum. Scale bar equals 5 mm.
Figure 2.
(A) Northern Fulmar (Fulmaris glacialis – AMNH 20697), (B) American White Pelican (Pelecanus erythrorhynchos – USNM 535930), (C) Great Cormorant (Phalacrocorax carbo – USNM 553884), (D) Adélie Penguin (Pygoscelis adeliae – AMNH 623439), (E) Common Loon (Gavia immer – FMNH 444970), and (F) Great Frigatebird (Fregata minor – FMNH 339432). Scale bar equals 5 mm.
Figure 3.
Free caudal vertebra in dorsal (A), ventral (B), left lateral (C), and anterior (D) views.
Skeletal metrics collected: Centrum length (CL), centrum width (CW), centrum height (CH), transverse process length (TPL), transverse process width (TPW), spinous process length (SPL), spinous process width (SPW), spinous process height (SPH), ventral process length (VPL, ventral process width (VPW), ventral process height (VPH). Scale bar equals 2 mm.
Figure 4.
Outline reconstruction using Elliptical Fourier Descriptors.
Black contours represent the original outline shape of the pygostyle of Phoebastria immutabilis. Red contours represented the reconstructed shape using the corresponding number of harmonics. Increasing the number of harmonics increases the detail of the reconstructed shape and the accuracy with which it approximates the true shape.
Table 1.
Phylogenetic Signal.
Table 2.
Phylogenetic MANOVA Results: Free Caudal Vertebrae.
Table 3.
Phylogenetic MANOVA Results: Principal Components of Pygostyle Shape.
Figure 5.
5a: Flight Style pFDA Plot: First Caudal Vertebra. Misclassification Rate = 41.18%. 5b: Flight Style pFDA Plot: Middle Free Caudal Vertebra. Misclassification Rate = 37.25%. 5c: Flight Style pFDA Plot: Last Free Caudal Vertebrae. Misclassification Rate = 37.25%.
Figure 6.
6a: Foraging Style pFDA Plot: First Free Caudal Vertebrae. Misclassification rate = 39.22%. 6b. Foraging Style pFDA Plot: Middle Free Caudal Vertebrae. Misclassification rate = 31.37%. 6c: Foraging Style pFDA Plot: First Last Caudal Vertebrae. Misclassification rate = 23.52%.
Figure 7.
Flight Style pFDA Plot: Pygostyle Shape.
Misclassification rate = 13.73%.
Figure 8.
Foraging Style pFDA Plot: Pygostyle Shape.
Misclassification rate = 3.92%.
Figure 9.
Foraging style and pygostyle shape mapped onto the phylogenetic topology of Hackett [46], [48].
Branch colors represent foraging style; internal branches are colored gray to indicate that ancestral foraging style is uncertain. Node 1, Aequornithes (waterbirds); Node 2, Charadriiformes (shorebirds).