DOI: 10.5061/dryad.dr7sqvb6m
title: Data from: Individual, ontogenetic, and phylogenetic variation in the dentition of hadrosaurids (Iguanodontia: Ornithischia)

description: Phylogenetic analyses of Hadrosauroidea are generally well-resolved, but
 finer resolution within Hadrosauromorpha remains contentious. This lack of
 resolution is due in part to the inability of discrete traits to
 illustrate their natural variation, particularly relating to the dental
 tooth battery. Not only has the variation not been properly examined, but
 the character definitions fluctuate throughout the literature. Here, we
 evaluate individual, ontogenetic, and phylogenetic variation in four
 fundamental tooth characters at the subfamily level to better establish
 their use in future analyses: number of tooth rows, tooth aspect ratio,
 secondary enamel ridges, and marginal enamel denticles. Factor analysis of
 mixed data and linear discriminant analysis were used to evaluate how
 accurately these four characters together identified the phylogenetic
 groups. We then used these data to predict phylogenetic relationships for
 a select few historically problematic taxa. We found that although the
 number of tooth rows is phylogenetically informative, it is related to
 size and is only useful in separating hadrosaurids from non-hadrosaurid
 iguanodontians. Tooth aspect ratio was found to be highly variable, and
 phylogenetic groups cannot be separated reliably from one another.
 Secondary ridges are individually variable, and their presence or absence
 should be grouped into a single character instead of being separated.
 Lastly, the presence and shape of marginal denticles in hadrosaurids is
 similarly variable, though rounded mammillations are almost exclusive to
 Lambeosaurinae, with some variation in their presence and prevalence
 within the group. When used in combination, these characters can
 accurately identify dentary teeth below Hadrosauridae, providing new
 options for identifying poorly preserved specimens and isolated teeth from
 microsites. Taken together, these characters may still be informative, but
 the individual variation described here must be accounted for when
 constructing character states, and we recommend several modifications to
 their coding.
description: # Data from: Individual, ontogenetic, and phylogenetic variation in the
 dentition of hadrosaurids (Iguanodontia: Ornithischia) Thomas W. Dudgeon,
 Gillian Gallimore, David C. Evans The supplementary data consists of five
 csv files: S1_-_Tooth_row_number.csv: The number of tooth rows (NTR) and
 dental battery tooth row length (DBTRL, measured in millimeters) for each
 specimen, and associated taxonomic data and references. Blanks for
 'Ontogenetic Reference' indicate the assessment was made by us.
 S2_-_Tooth_aspect_ratio_-_analogous_positions.csv: Tooth aspect ratio for
 analogous segments of the dentary tooth battery for each specimen, and
 associated taxonomic data and references. Analogous segments of the
 dentary tooth battery are defined in 10% increments, where teeth in the
 anterior 10% of tooth positions are in column '0-10%', the next
 10% of tooth positions are in column '10-20%', etc. Values
 reported in the columns are the average tooth aspect ratios for that
 segment of the dental battery. Blanks for the relative tooth positions
 indicate data are not available. Blanks for 'Ontogenetic
 Reference' indicate the assessment was made by us.
 S3_-_SER_by_position.csv: The presence or absence of secondary ridges for
 each tooth position of each specimen, and associated taxonomic data and
 references. Absences are indicated by '0' and presences are
 indicated by '1'. 'NA' indicates the trait could not
 be observed due to damage. Specimens varied in the number of tooth rows,
 so data are reported for tooth positions ranging from 1 at the anterior
 end of the jaw up to the posterior-most tooth position, and blanks in the
 subsequent tooth position columns indicate that the specimen did not have
 that many teeth (i.e., the number of columns with data reported match the
 number of tooth rows). Blanks for 'Ontogenetic Reference'
 indicate the assessment was made by us. S4_-_MED_by_position.csv: The
 presence and shape of marginal enamel denticles for each tooth position of
 each specimen, and associated taxonomic data and references. Blanks for
 'Ontogenetic Reference' indicate the assessment was made by us.
 '0' represents wedge-shaped denticles, '1' represents
 rounded mammillations, '2' represents small papillae, and
 '3' represents absence of denticles (smooth tooth
 margin). Specimens varied in the number of tooth rows, so data are
 reported for tooth positions ranging from 1 at the anterior end of the jaw
 up to the posterior-most tooth position, and blanks in the subsequent
 tooth position columns indicate that the specimen did not have that many
 teeth (i.e., the number of columns with data reported match the number of
 tooth rows). 'NA' indicates the trait could not be observed due
 to damage. S5_-_Combined_dataset.csv: The number of tooth positions,
 average tooth aspect ratio, secondary ridges, and marginal enamel denticle
 shape for each specimen included in the combined analysis. Blanks indicate
 absence of data for that specimen. For secondary ridges, Absences are
 indicated by '0' and presences are indicated by '1'.
 For denticle character state, '0' represents wedge-shaped
 denticles, '1' represents rounded mammillations, '2'
 represents small papillae, and '3' represents absence of
 denticles (smooth tooth margin). NTR = number of tooth rows, TRL = tooth
 row length (measured in millimeters).