DOI: 10.5061/dryad.2b6039d
title: Data from: The effects of skeletal asymmetry on interpreting biological variation and taphonomy in the fossil record

description: Biological asymmetry is present in all bilaterally symmetric organisms as
 a result of normal developmental instability. However, fossilized
 organisms, which have undergone distortion due to burial, may have
 additional asymmetry as a result of taphonomic processes. To investigate
 this issue, we evaluated the magnitude of shape variation resulting from
 taphonomy on vertebrate bone using a novel application of fluctuating
 asymmetry. We quantified the amount of total variance attributed to
 asymmetry in a taphonomically distorted fossil taxon and compared it to
 that of three extant taxa. The fossil taxon had an average of 27% higher
 asymmetry than the extant taxa. In spite of the high amount of taphonomic
 input, the major axes of shape variation were not greatly altered by
 removal of the asymmetric component of shape variation. This presents the
 possibility that either underlying biologic trends drive the principal
 directions of shape change irrespective of asymmetric taphonomic
 distortion, or that the symmetric taphonomic component is large enough
 that removing only the asymmetric component is inadequate to restore
 fossil shape. Our study is the first to present quantitative data on the
 relative magnitude of taphonomic shape change and presents a new method to
 further explore how taphonomic processes impact our interpretation of the
 fossil record.
description: Figure
 S1Figure S1.
 Psittacosaurus lujiatunensis landmark figures showing landmarks (numbered)
 and semi-landmark curves (red) for the (A) scapula, (B) humerus in cranial
 view, (C) humerus in medial view, (D) humerus in caudal view, (E) ilium,
 (F) femur in cranial view, and (G) femur in caudal view. Scale = 25
 mm.FigS1-PsittacosaurLMFigFlat.tifFigure S2Figure S2. Red-tailed hawk (Buteo jamaicensis) landmark figures showing landmarks (numbered) and semi-landmark curves (red) for the (A) scapula, (B) humerus in cranial view, (C) humerus in medial view, (D) humerus in caudal view, (E) ilium, (F) femur in cranial view, and (G) femur in caudal view. Scale = 25 mm.FigS2-RTHLMFigFlat.tifFigure S3Figure S3. American alligator (Alligator mississippiensis) landmark figures showing landmarks (numbered) and semi-landmark curves (red) for the (A) scapula, (B) humerus in cranial view, (C) humerus in medial view, (D) humerus in caudal view, (E) ilium, (F) femur in cranial view, and (G) femur in caudal view. Scale = 50 mm.FigS3-AlligatorLMFigFlat2.tifFigure S4Figure S4. White-tailed deer (Odocoileus virginianus) landmark figures showing landmarks (numbered) and semi-landmark curves (red) for the (A) scapula, (B) humerus in cranial view, (C) humerus in medial view, (D) humerus in caudal view, (E) ilium, (F) femur in cranial view, and (G) femur in caudal view. Scale = 50 mm.FigS4-DeerLMFigureFlat.tifFigure S5Figure S5. Principal component analysis of humeri (cranial view) showing the relative divergence between left and right humeri (cranial view) in morphospace for P. lujiatunensis (A), Alligator (C), and Buteo (D). Each individual is colored with a line connecting the right and left humeri (cranial view) for P. lujiatunensis and the first five specimens are given for the extant taxa, which were randomly selected. Bones were measured three times each for inclusion in the error analysis so one animal is made up of six individual points, three for the right humerus and three for the left. To identify how shape trends were affected by removing the asymmetric component of variation, we plotted thin plate splines of the symmetric component of variation for P. lujiatunesis next to thin plate splines for the total variation (B).FigS5-FAPCAHumCranFigREVFlat.tifFigure S6Figure S6. Principal component analysis of humeri (medial view) showing the relative divergence between left and right humeri (medial view) in morphospace for P. lujiatunensis (A), Alligator (C), and Buteo (D). Each individual is colored with a line connecting the right and left humeri (medial view) for P. lujiatunensis and the first five specimens are given for the extant taxa, which were randomly selected. Bones were measured three times each for inclusion in the error analysis so one animal is made up of six individual points, three for the right humerus and three for the left. To identify how shape trends were affected by removing the asymmetric component of variation, we plotted thin plate splines of the symmetric component of variation for P. lujiatunesis next to thin plate splines for the total variation (B).FigS6-FAPCAHumMedFigREVFlat.tifFigure S7Figure S7. Principal component analysis of humeri (caudal view) showing the relative divergence between left and right humeri (caudal view) in morphospace for P. lujiatunensis (A), Alligator (C), and Buteo (D). Each individual is colored with a line connecting the right and left humeri (caudal view) for P. lujiatunensis and the first five specimens are given for the extant taxa, which were randomly selected. Bones were measured three times each for inclusion in the error analysis so one animal is made up of six individual points, three for the right humerus and three for the left. To identify how shape trends were affected by removing the asymmetric component of variation, we plotted thin plate splines of the symmetric component of variation for P. lujiatunesis next to thin plate splines for the total variation (B).FigS7-FAPCAHumCaudFigREVFlat.tifFigure S8Figure S8. Principal component analysis of ilia showing the relative divergence between left and right ilia in morphospace for P. lujiatunensis (A), Alligator (C), and Buteo (D). Each individual is colored with a line connecting the right and left ilia for P. lujiatunensis and the first five specimens are given for the extant taxa, which were randomly selected. Bones were measured three times each for inclusion in the error analysis so one animal is made up of six individual points, three for the right humerus and three for the left. To identify how shape trends were affected by removing the asymmetric component of variation, we plotted thin plate splines of the symmetric component of variation for P. lujiatunesis next to thin plate splines for the total variation (B).FigS8-FAPCAIliaFigREVFlat.tifFigure S9Figure S9. Principal component analysis of femora (cranial view) showing the relative divergence between left and right femora (cranial view) in morphospace for P. lujiatunensis (A), Alligator (C), and Buteo (D). Each individual is colored with a line connecting the right and left femora (cranial view) for P. lujiatunensis and the first five specimens are given for the extant taxa, which were randomly selected. Bones were measured three times each for inclusion in the error analysis so one animal is made up of six individual points, three for the right humerus and three for the left. To identify how shape trends were affected by removing the asymmetric component of variation, we plotted thin plate splines of the symmetric component of variation for P. lujiatunesis next to thin plate splines for the total variation (B).FigS9-FAPCAFemCranFigREVFlat.tifFigure S10Figure S10. Principal component analysis of femora (caudal view) showing the relative divergence between left and right femora (caudal view) in morphospace for P. lujiatunensis (A), Alligator (C), and Buteo (D). Each individual is colored with a line connecting the right and left femora (caudal view) for P. lujiatunensis and the first five specimens are given for the extant taxa, which were randomly selected. Bones were measured three times each for inclusion in the error analysis so one animal is made up of six individual points, three for the right humerus and three for the left. To identify how shape trends were affected by removing the asymmetric component of variation, we plotted thin plate splines of the symmetric component of variation for P. lujiatunesis next to thin plate splines for the total variation (B).FigS10-FAPCAFemCaudFigREVFlat.tifSupplemental Tables 1–9See Main Text For Table DescriptionsHedrick et al., Taphonomy SuppInfoREV.xlsx