Data from: Evidence for clinging arboreality in a Middle Jurassic stem lepidosaur
Data files
Mar 12, 2025 version files 470.68 KB
Abstract
Lepidosaurs are an ecologically diverse and speciose group with more that 11,000 living species (squamates and the tuatara). Stem lepidosaurs are known from the Early Triassic onwards, but primarily from very incomplete specimens. Therefore, we have little information on their ecological diversity or the ecological context of deep evolutionary divergences of Lepidosauria. Marmoretta oxoniensis, from the Middle Jurassic of the UK, is one of the most completely known candidate stem lepidosaurs. Previous studies proposed that it may have been semiaquatic, based primarily on its abundance in marginal marine rocks. We show here that Marmoretta was adapted for climbing, based on the postcranial anatomy of a partial skeleton, visualised using micro-computed tomography (µCT), in particular, the steep angles of thoracic zygapophyses, ungual phalanx morphology, and elongate penultimate manual phalanges that curve distoventrally along their lengths. Linear discriminant analysis of the partial hand, using a training dataset of hand skeleton measurements and habitat use in extant squamates, returns strong evidence for clinging arboreality and Marmoretta clusters among scansorial/arboreal iguanians in manus shape space. Evidence of arboreality in Marmorettaprovides the first information about habitat use in a probable stem lepidosaur and illuminates the vertical structure of ecological communities of the mid Mesozoic.
https://doi.org/10.5061/dryad.t4b8gtjc8
Description of the data and file structure
Description of the data and file structure
- Fontanarrosa et al. 2018 subset.csv - squamate forelimb bone measurements with subset of manus only measurements. for use as a training set to evaluate habitat use in Marmoretta.
- Fossil measurements for Marmoretta.csv - measurements of the manus obtained from 3D models of Marmoretta.
- Marmoretta postcranial skeleton script 07Jan2025.R - R script used for phylogenetic regression, PCA, and LDA.
- Tonini_et_al_trees for Marmoretta post crania.tre - 50 trees randomly taken from the tree distribution of Tonini et al. 2016 to provide a phylogenetic framework for phylogenetic regression.
- MrBayes_script_for_Mkv_run_new_Marmoretta - text file with script for MrBayes run, based on the phylogenetic analysis in Ford et al. 2021 with revisions for the coding of Marmoretta after 17 changes to the coding for the postcranial skeleton (see S5 for further details).
Files and variables
File: Ford_et_al._2025_MrBayes_script_for_Mkv_run_new_Marmoretta.zip
Description: contains Fontanarrosa et al. subset.csv, Fossil Measurements 18Nov2024.csv, Marmoretta postcranial skeleton script.R and Tonini et al tress for Marmoretta post crania.tre. These files contain the script and data used are used for linear discriminant analysis and principal components analysis.
The variables in the tabular data file Fossil Measurements 18Nov2024.csv are linear measurements of the length and width of the metacarpals and phalanges of individual digits for Marmoretta oxoniensis (NMS G.1992.47.1). The variables in the tabular data file Fontanarrosa et al. 2018 subset.csv are also linear measurements of the length and width of the metacarpals and phalanges of the digits of the selected taxa, when available. This file also contains linear measurements of the length and width of the ulna, radius and distal carpals. Units for both files are in millimetres (mm).
In Fontanarrosa et al. 2018 subset.csv the column descriptions are below:
- Index - An index number used for sorting the columns
- Genera - Genus name (from Fontanarrosa et al. 2018)
- sp - Species name (from Fontanarrosa et al. 2018)
- Specimen - Institution code and specimen number from which measurements were taken (from Fontanarrosa et al 2018)
- Family - Family name (from Fontanarrosa et al. 2018)
- Taxon - Higher taxon assignment (from Fontanarrosa et al. 2018)
- Meiri et al. 2018 - The verbatim habitat use classification from Meiri et al. (2024), sometimes including alternatives e.g. Arboreal & Terrestrial"
- Meiri2 - A refined habitat use classification based on Meiri et al. (2024), including only a single habitat use term.
- Notes - Notes on habitat use classification (from Meiri et al. 2024),
- Common_name - The vernacular name of the species
File: Ford_et_al._2025_Marmoretta_postcranial_script_and_data_07Jan2025.zip
Description: contains MrBayes script for the phylogenetic analysis of the affinities of Marmoretta after 17 changes to the coding of Ford et al. 2021.
Code/software
Code/software
Phylogenetic regressions were implemented using the procD.pgls function of the R packages geomorph version 4.0.7 [49] and RRPP version 2.0.0
LDA was implemented using the function lda, from the R package MASS
PCA was implemented via the 'princomp' function of the R package stats (R Core Team 2022).
The revised matrix of Ford et al. 2021 was analysed using a non-time calibrated Bayesian Mkv model in MrBayes v.3.2.5 (Ronquist et al. 2012).