DOI: 10.5061/dryad.8kprr4z0m
title: Data from: Functional morphology and biomechanics of an ontogenetic series of the Triassic cynodont <em>Brasilodon quadrangularis</em> and bite performance in the sister taxon of Mammaliformes

description: The Santa Maria Supersequence in Brazil has yielded numerous cynodont
 species from the Late Triassic, including derived probainognathians, which
 are relevant for the understanding of the cynodont-mammal transition. One
 of these cynodonts is Brasilodon quadrangularis, considered to be the
 sister taxon to Mammaliaformes due to a suite of apomorphic features in
 the skull, dentition, and postcranium. Specimens referred to this species
 have been described in detail, representing different ontogenetic stages.
 However, we know little of the functional performance and skull mechanics
 of this species and how this relates to recent studies of
 cynodont-mammaliaform skull mechanics. Here, we use beam analysis and
 finite element analysis (FEA) to assess the function of the skulls of
 *Brasilodon and compare their functional performance to that of the early
 mammaliaforms Morganucodon and Kuehneotherium. The ontogenetic series of
 Brasilodon shows a trend of increasing overall jaw strength and
 resistance, potentially indicating a change in diet and feeding behaviour
 through ontogeny. Beam analysis suggests that this taxon is more
 similar in bite performance to Morganucodon than to Kuehneotherium,
 regarding jaw strength and torsion resistance. Additionally, one
 of the studied skulls (UFRGS-PV-1043-T) was chosen for digital restoration
 and muscular reconstruction to increase understanding of the jaw muscle
 modifications in the cynodont-mammal transition. The muscular
 reconstruction revealed that the relative force contributions of the
 temporalis and masseter muscles of the Brasilodon ontogenetic series are
 more similar to non-mammaliaform cynodonts, such as Chiniquodon, *than to
 mammaliaforms. Our results provide further insight into cranial
 musculoskeletal anatomy and biomechanics in derived non-mammaliaform
 cynodonts.
description: # Data from: Functional morphology and biomechanics of an ontogenetic
 series of the Triassic cynodont *Brasilodon quadrangularis* and bite
 performance in the sister taxon of Mammaliformes Dataset DOI:
 [10.5061/dryad.8kprr4z0m](10.5061/dryad.8kprr4z0m) ## Description of the
 data and file structure CT scans were taken of five specimens of
 *Brasilodon* (UFRGS-PV-628-T, UFRGS-PV-760-T, UFRGS-PV-929-T,
 UFRGS-PV-1030-T, and UFRGS-PV-1043-T) representing different ontogenetic
 stages. The dentary bones of these specimens were segmented to be used in
 functional morphological and biomechanical analyses and to determine
 changes in the ontogenetic series and compare bite performance.
 Interdental slices of all of these specimens were used in beam analysis to
 determine the strength of the mandible. The skull (i.e., cranium and
 mandible) of UFRGS-PV-1043-T was used to reconstruct temporalis and
 masseter muscles for finite element analysis on the most complete
 segmented dentary meshes of the juvenile and adult specimens
 (UFRGS-PV-1030-T and UFRGS-PV-1043-T respectively) to compare bite
 performance between the two. ### Files and variables #### File:
 1030_vol_canine2.inp **Description:** the input file for finite element
 analysis of Brasilodon specimen UFRGS-PV-1030-T dentary with the bite
 point constraint on the last postcanine tooth and the input muscle forces
 from the temporalis and masseter muscles. This was initially made in the
 software Abaqus but can be potentially imported into other finite element
 analysis software. #### File: 1030_vol_pc2.inp **Description:** the input
 file for finite element analysis of Brasilodon specimen UFRGS-PV-1030-T
 dentary with the bite point constraint on the canine tooth and the input
 muscle forces from the temporalis and masseter muscles. This was initially
 made in the software Abaqus but can be potentially imported into other
 finite element analysis software. #### File: 1043_vol_pc2.inp
 **Description:** the input file for finite element analysis of Brasilodon
 specimen UFRGS-PV-1043-T dentary with the bite point constraint on the
 last postcanine tooth and the input muscle forces from the temporalis and
 masseter muscles. This was initially made in the software Abaqus but can
 be potentially imported into other finite element analysis software. ####
 File: 1043_vol_canine2.inp **Description:** the input file for finite
 element analysis of Brasilodon specimen UFRGS-PV-1043-T dentary with the
 bite point constraint on the canine tooth and the input muscle forces from
 the temporalis and masseter muscles. This was initially made in the
 software Abaqus but can be potentially imported into other finite element
 analysis software. #### File: UFRGS-PV-628-T_Interdental_Slices.pdf
 **Description:** file containing images of the segmented interdental
 slices of Brasilodon specimen UFRGS-PV-628-T that were used for the beam
 analysis. The dentary bone and the dentition were segmented separately
 resulting in different colors for better differentiation. These slices
 will also be available in the Bristol Data Repository. #### File:
 UFRGS-PV-929-T_Interdental_Slices.pdf **Description:** file containing
 images of the segmented interdental slices of Brasilodon specimen
 UFRGS-PV-929-T that were used for the beam analysis. The dentary bone and
 the dentition were segmented separately resulting in different colors for
 better differentiation. These slices will also be available in the Bristol
 Data Repository. #### File: UFRGS-PV-760-T_Interdental_Slices.pdf
 **Description:** file containing images of the segmented interdental
 slices of Brasilodon specimen UFRGS-PV-760-T that were used for the beam
 analysis. The dentary bone and the dentition were segmented separately
 resulting in different colors for better differentiation. These slices
 will also be available in the Bristol Data Repository. #### File:
 UFRGS-PV-1030-T_Interdental_Slices.pdf **Description:** file containing
 images of the segmented interdental slices of Brasilodon specimen
 UFRGS-PV-1030-T that were used for the beam analysis. The dentary bone and
 the dentition were segmented separately resulting in different colors for
 better differentiation. These slices will also be available in the Bristol
 Data Repository. #### File: UFRGS-PV-1043-T_Interdental_Slices.pdf
 **Description:** file containing images of the segmented interdental
 slices of Brasilodon specimen UFRGS-PV-1043-T that were used for the beam
 analysis. The dentary bone and the dentition were segmented separately
 resulting in different colors for better differentiation. These slices
 will also be available in the Bristol Data Repository. ## Access
 information Other publicly accessible locations of the data: *
 Morphosource
 ([https://doi.org/10.17602/M2/M764418](https://doi.org/10.17602/M2/M764418); [https://doi.org/10.17602/M2/M764341](https://doi.org/10.17602/M2/M764341)) Data was derived from the following sources: * Museums: Departamento de Paleontologia e Estratigrafia, Instituto de Geociencias, Universidade Federal do Rio Grande do sul, Porto Alegre, Brasil * Data acquisition was taken from CT-scanned specimens that were scanned either at the University of Bristol or the University of Helsinki