DOI: 10.5061/dryad.cq376
title: Data from: The early evolution of synapsids, and the influence of sampling on their fossil record

description: Synapsids dominated the terrestrial realm between the late Pennsylvanian
 and the Triassic. Their early evolution includes some of the first
 amniotes to evolve large size, herbivory, and macro-predators. However,
 little research has focused on the changes in diversity occurring during
 this early phase in their evolutionary history, with more effort
 concentrating on later events such the Permo-Triassic extinction. Here we
 assess synapsid diversity, at both the species and genus levels, between
 the Carboniferous (Moscovian) and the Middle Permian (Capitanian). A raw,
 taxic diversity (richness) estimate is generated, and we use two separate
 methods to correct for sampling biases in this curve. To remove the effect
 of anthropogenic sampling bias, we apply a recently published modification
 of the residual diversity method, and then generate a supertree, using
 matrix representation with parsimony to infer ghost lineages and obtain a
 phylogenetic diversity estimate. The general diversity pattern reflects
 the initial diversification of synapsids in the late Pennsylvanian and
 early Cisuralian, which was followed by an extinction event during the
 Sakmarian. Diversity recovered during the Artinskian and Kungurian,
 coinciding with the radiation of Caseidae, although other families begin
 to decline. A second extinction event occurred across the
 Kungurian/Roadian boundary, in which Edaphosauridae and Ophiacodontidae
 died out although Caseidae and Therapsida diversified. The
 sampling-corrected curves reveal further extinction during the Roadian,
 although therapsids were again unaffected. Pelycosaurian-grade synapsids
 survived during the Wordian and Capitanian, but were a minor part of an
 otherwise therapsid-dominated fauna. Evidence of significant anthropogenic
 sampling bias calls into question previous diversity studies that have not
 employed sampling correction.
description: Supplementary table
 1List
 of all taxa included in the diveristy curves, and their affinities, ranges
 and the countries in which they are foundSupplementary table
 2List
 of phylogenetic hypotheses included in the creation of the supertree, and
 reasons for removal of thise hypotheses not includedSupplementary figure
 1Supertree used in the
 creation of the Phylogenetic diversity curve. Black lineages – known
 ranges, Gray lineages – temporal uncertainty in the dating of localities
 (included in the phylogenetic diversity estimate), Red lineages – ghost
 lineages. Timescale representing millions of years ago appears at the
 bottomSupplementary figure
 2Supertree in which
 temporal uncertainty is not taken into account, and each locality is
 restricted to two or fewer substages. Timescale representing millions of
 years ago appears at the bottom.Supplementary figure
 3The
 diversity curves produced when taxa of uncertain age are assigned to the
 full possible stratigraphic range (dashed-dotted lines) compared to the
 diversity curves produced when each locality of uncertain ages is
 restricted to two or less time bins (solid line). A, Taxic diversity
 curves. B, Phylogenetic diversity curves. Timescale representing millions
 of years ago appears at the bottom