Data from: Individual, ontogenetic, and phylogenetic variation in the dentition of hadrosaurids (Iguanodontia: Ornithischia)
Data files
Dec 05, 2025 version files 34.31 KB
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README.md
3.34 KB
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S1_-_Tooth_row_number.csv
6.79 KB
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S2_-_Tooth_aspect_ratio_-_analogous_positions.csv
6.89 KB
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S3_-_SER_by_position.csv
7.91 KB
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S4_-_MED_by_position.csv
6.29 KB
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S5_-_Combined_dataset.csv
3.10 KB
Abstract
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.
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).
- Dudgeon, Thomas W.; Gallimore, Gillian; Evans, David C. (2024). Individual, ontogenetic, and phylogenetic variation in the dentition of hadrosaurids (Iguanodontia: Ornithischia). Journal of Systematic Palaeontology. https://doi.org/10.1080/14772019.2024.2419422