DOI: 10.5061/dryad.4xgxd25nh
title: Predicting body length and assessing the shape of tail-propelled Mesozoic marine reptiles

description: Body length is a crucial ecological predictor in vertebrates, yet total
 body length proxies have seldom been assessed for ancient marine top
 predators. Here, we test the strength of phylogenetic imputation and 23
 linear measurements, sampling both broad skeletal regions and frequently
 fossilised elements (such as vertebral centra), in predicting the body
 length of the main clades of tail-propelled Mesozoic marine reptiles
 (Ichthyosauria, Mosasauridae, and pelagic thalattosuchians). We embed this
 marine reptile sample within a comparative framework with raptorial
 cetaceans, and analyse the evolution of body proportions in these clades.
 We find that trunk length and centrum dimensions are strong predictors of
 body length, opening up the possibility to build vast datasets of body
 length estimations for Mesozoic marine reptiles from minimal preserved
 remains. We provide body length calculation equations for all traits and
 all clades. Proxies fared much better and often had distinct slopes when
 applied clade-wide rather than when applied to the global dataset. We also
 show that body length in Mesozoic marine reptiles is more labile than
 their skeletal architectures, rendering phylogenetic imputation methods
 less effective than skeletal proxies for assessing body lengths.
description: # Predicting body length and assessing the shape of tail-propelled
 Mesozoic marine reptiles Dataset DOI:
 [10.5061/dryad.4xgxd25nh](10.5061/dryad.4xgxd25nh) ## Description of the
 data and file structure The .zip file (SuppInfo.zip) is a compressed
 folder which can be uncompressed with software like winzip, winrar, the
 unarchiver. It contains: * The raw data (linear measurements in mm of
 total bodies and body parts, per species, in an Excel file:
 `SuppData1.xslx`). This is an Excel file that can be opened with Microsoft
 Excel, Open Office, Google Sheets, or R. * The phylogenetic data trees
 (one dataset for each focal clade, in the .tre format:
 `SuppData2_Cetacea.tre` [Cetacea], `SuppData3_Ichthyosauria.tre`
 [Ichthyosauria], `SuppData4_Mosasauridae.tre` [Mosasauridae],
 `SuppData5_Thalattosuchia.tre` [Thalattosuchia]). These are files
 containing information on the phylogenetic relationships of the species of
 interest. Such a file can be opened with Mesquite, R. These data are
 dimensionless. * The results from all analyses (coefficient of
 correlation: R2, slope of the regression line, intercept of the regression
 line, standard error of the correlation, for both the ordinary least
 square [OLS] and phylogenetic generalised least square [PGLS] analyses)
 and each clade, in a .csv format (`SuppData6.csv` [all species combined],
 `SuppData7.csv` [all reptiles combined], `SuppData8.csv` [Cetacea],
 `SuppData9.csv` [Ichthyosauria], `SuppData10.csv` [multivariate
 regressions; Ichthyosauria], `SuppData11.csv` [Mosasauridae],
 `SuppData12.csv` [multivariate regressions; Mosasauriae], `SuppData13.csv`
 [Thalattosuchia], `SuppData14.csv` [multivariate regressions;
 Thalattosuchia]). CSV is an efficient way to store information from a
 matrix into a text file. It can be opened using Microsoft Excel, Open
 Office, Google Sheets, R. These data are dimensionless. * The R
 script, `SuppData15_Rscript.R`,  (in .r format) used to call all the
 necessary packages, import the data, and generate all results and the base
 of all figures. The script contains explanations throughout and can be
 opened in R, Rstudio. The following packages are used: AICcmodavg, ape,
 dplyr, FSA, ggalt, ggplot2, ggpubr, ggtern, paleotree, phylolm, phytools,
 picante, psych, readxl, Rphylopars #optional, just to test if results are
 similar to those of picante, strap, tidyr, viridis. ## Access information
 Other publicly accessible locations of the data: *
 [https://hdl.handle.net/2268/331290](https://hdl.handle.net/2268/331290)