DOI: 10.5061/dryad.zpc866t8n
title: Supplemental data from: Intraspecific facial bite marks in tyrannosaurids provide insight into sexual maturity and evolution of bird-like intersexual display

description: Intraspecific aggression, or agonism, is a widespread intrasexual
 selective behavior important to understanding animal behavioral ecology
 and reproductive systems. Such behavior can be studied either by direct
 observation or inferred from wound/scar frequency in extant species, but
 is difficult to document in extinct taxa, limiting understanding of its
 evolution. Among extant archosaurs, crocodylians display extensive
 intrasexual aggression, whereas birds show extreme visual/vocal
 intersexual display. The evolutionary origin of this behavioral
 divergence, and pattern in non-avian dinosaurs, is unknown. Here we
 document the morphology, frequency, and ontogeny of intraspecific facial
 bite lesions (324 lesions) in a large sample of tyrannosaurids (202
 specimens, 528 elements) to infer patterns of intraspecific aggression in
 non-avian theropods. Facial scars are consistent in position and
 orientation across tyrannosaurid species, suggesting bites were inflicted
 due to repeated/postured behavior. Facial scars are absent in young
 tyrannosaurids, first appear in immature animals (~50% adult skull
 length), are present in ~60% of the adult-sized specimens, and show
 aggressor:victim size isometry. The ontogenetic distribution of bite scars
 suggests agonistic behavior is associated with the onset of sexual
 maturity, and scar presence in approximately half the specimens may relate
 to a sexual pattern. Considered in a phylogenetic context, intraspecific
 bite marks are consistent and widely distributed in fossil and extant
 crocodyliforms and non-maniraptoriform theropods, suggesting a potential
 plesiomorphic behavior in archosaurs. Their absence in maniraptoriform
 theropods, including birds, may reflect a transition from boney cranial
 ornamentation and crocodylian-like intrasexual aggression to avian-like
 intersexual display with the evolution of pennaceous feathers.
description: See Materials and Methods sections of the paper for methods
 details. Supplemental data consists of: supplementary text
 document, including 11 supplementary figures (Figures S1–S11), 11
 supplementary tables (Tables S1–11), legends for the eight supplementary
 datasets (Datasets S1 to S8) (as external files: .xls, .pdf), and
 supplementary references.  <b>Supplementary
 Datasets:</b> <b>Dataset</b><b>
 </b><b>S</b><b>1
 (</b><b>separate</b><b> .pdf
 </b><b>file)</b>: Line drawings of tyrannosaur cranial
 elements (1-79) showing position of healed/healing intraspecific bite mark
 lesions.  Red indicates marks that are incised and porous while orange
 indicated marks that are smooth or raised.  Multiple marks on an element
 are numbered using roman numerals from rostral to caudal.  Grey areas
 indicate reconstruction or broken surfaces. See Supplemental Dataset S2
 for quantitative data for each specimen and mark.  Only specimens with
 lesions are illustrated. Number corresponds to column I in Dataset S2.
 Data used to generate Figures 4, S4.  All scale bars equal 10
 cm. <b>Dataset</b><b>
 </b><b>S</b><b>2
 (</b><b>separate</b><b> .xls
 </b><b>file)</b>: Quantitative data on tyrannosaur
 cranial elements with and without intraspecific bite mark lesions. Sheet 1
 sorted by specimen. Sheet 2 is sorted by element. Sheet 3 is sorted by
 taxon (maxilla and dentary only). Data used to generate Tables 1, S4-S6
 and Figures 3, 6-9, S4, S5. Column I indicates number in Dataset
 S1 <b>Dataset</b><b>
 </b><b>S</b><b>3
 (</b><b>separate</b><b> .pdf
 </b><b>file)</b>: Line drawings of <i>Alligator
 </i>cranial elements showing position of healed/healing
 intraspecific bite mark lesions.  Red indicates marks that are incised and
 porous while orange indicated marks that are smooth or raised. Grey areas
 indicate reconstruction or broken surfaces. See Dataset S4 for
 quantitative data for each specimen and mark.  Only specimens with lesions
 are illustrated. Data used to generate Figures 10, S6, S7. All scale bars
 equal 10 cm. <b>Dataset</b><b>
 </b><b>S</b><b>4
 (</b><b>separate</b><b> .xls
 </b><b>file)</b>: Quantitative data on
 <i>Alligator</i> cranial elements with and without
 intraspecific bite mark lesions. Data used to generate Figure 10, Table
 S11. <b>Dataset</b><b>
 </b><b>S</b><b>5
 (</b><b>separate</b><b> .xls
 </b><b>file)</b>: Literature-derived data on
 intraspecific bite marks/tooth mark frequency in extant animals. Data
 concentrate on reported results for males and females individually.  Some
 data (highlighted) are excluded due to incompleteness or marks made by
 non-homologous structures. Data are used to generate Figure 13.
 <b>Dataset</b><b>
 </b><b>S</b><b>6 (</b><b>separate
 </b><b>.xls </b><b>file)</b>: Data for
 regression of tooth for length and mean alveolar size. Dataset of
 tyrannosaur dentary, maxilla, and premaxilla elements preserving a
 complete tooth row, and the mean alveolar length. Data are used to
 generate Figure S1, Table S1.
 <b>Dataset</b><b>
 </b><b>S</b><b>7 (</b><b>separate
 </b><b>.xls </b><b>file)</b>: Data set of
 adult sex ratio in extant bird and crocodylian species/populations. Some
 crocodylian datasets do include subadult individuals. Data are used to
 generate Figure S10.
 <b>Dataset</b><b>
 </b><b>S</b><b>9 (</b><b>separate
 </b><b>.xls </b><b>file)</b>: Data of
 intraspecific bite mark lesion occurrences in Theropoda. Data used to
 generate Figure 14.