DOI: 10.5061/dryad.v9s4mw773
title: Original dataset, coded matrix, and Bayesian phylogenetic trees of three Late Ordovician brachiopod genera (Atrypida: Anazygidae)

description: The Late Ordovician was a pivotal interval in Earth’s history, marked by
 rapid diversification and a significant accumulation of biodiversity
 across marine ecosystems. This period witnessed the flourishing of
 brachiopods, which were a dominant component of the Paleozoic Evolutionary
 Fauna—a group primarily composed of filter-feeding, sessile benthic
 organisms that played a critical role in the structure and function of
 Paleozoic marine communities. In this study, we focus on reconstructing
 the evolutionary relationships and biodiversity dynamics of a key lineage
 within this group: the atrypid brachiopods of the family Anazygidae. This
 family includes the genera Anazyga, Catazyga, and Zygospira, which are
 particularly important for understanding morphological innovation,
 biogeographic patterns, and ecological adaptation during a time of major
 evolutionary expansion. By integrating phylogenetic analysis with
 biodiversity assessments, our study sheds light on the evolutionary
 history and ecological significance of these brachiopods during the Late
 Ordovician radiation.
description: # Original and coded matrix for Zygospirinids; and alternative tree
 topologies Dataset DOI: [10.5061/dryad.v9s4mw773](10.5061/dryad.v9s4mw773)
 ## Description of the data and file structure Multiple datasets of
 internal and external characters were incorporated into one single file
 (Excel file, Supplementary Data 1). Characters were coded in an original
 dataset with continuous (measured in millimeters) and discrete characters;
 more information about the character states is found on the
 "Metadata" sheet (Supplementary Data 1). Later, all characters
 were converted to categorical character states (0-6), missing (?), or
 absent/gap (-) (NEXUS and NEXUS Metadata sheets, Supplementary Data
 1). The created NEXUS file was incorporated into a Bayesian phylogenetic
 framework under the fossilized birth-death (FBD) in BEAST2. If you wish to
 access more information on the rates used and statistics involving the
 model, please contact me at
 [mandrad2@vols.utk.edu](mailto:mandrad2@vols.utk.edu), and I will be happy
 to share the files with you. The model recovered topologies that were most
 robust when incorporating only external characters (Paper text), however,
 alternative topologies are equally available (PDF file, Supplementary Data
 2). Moreover, all recovered topologies indicate that species previously
 assigned to *Anazyga* and *Zygospira* do not separate into discrete clades
 but are intermixed within a single monophyletic group. Consequently, we
 propose a systematic revision based on external characters that recognizes
 two monophyletic genera: *Catazyga*, which includes most species
 historically assigned to *Catazyga*, and *Zygospira*, which includes most
 species historically assigned to *Zygospira* and *Anazyga*. One new
 species, *Zygospira idahoensis* is described, and one former subspecies is
 elevated to species status as *Zygospira multicostata*. The Anazygidae is
 estimated to have originated around 453 million years ago in the Sandbian
 Stage. Recovered diversification rates indicate that the highest
 speciation and extinction rates occurred in the late Katian (Katian 3)
 state, when the total number of species in the clade reached its peak.
 This was followed by an abrupt decline in biodiversification rates lead to
 an extinction episode in the Katian 4 Stage for all lineages. Therefore,
 *Catazyga* and *Zygospira* are interpreted as early Late Ordovician
 atrypids that experienced both rapid radiation and extinction during the
 last phase of the Ordovician Radiation in the Katian Stage.   ### Files
 and variables #### File: Supplementary\_Data\_1.xlsx
 **Description:** Supplementary Data 1 is an Excel file with four sheets.
 The first (Data) includes the raw measurements per specimen and their
 associated museum code, the second (Metadata) is the metadata with the
 character names and character states. The continuous measurements are all
 in millimeters when appropriate, or in angles; no conversions were made.
 In addition, I also incorporated the coded NEXUS file (NEXUS) and the
 associated metadata (NEXUS Metadata). NEXUS file was used in BEAST2.6.6
 #### File: Supplementary\_Data\_2.pdf **Description:** Supplementary data
 2 is a PDF file with screenshots of the alternative tree topologies. ####
 File: Topology1\_w\_external\_internal.tre Description: Bayesian phylogeny
 estimated using both external and internal morphological data and without
 constraints within the subfamily Anazygidae. The former taxonomic
 nomenclature is shown. Posterior probability: -327.56. #### File:
 Topology2\_wt\_internal.tre Description: Bayesian phylogeny
 estimated using external morphological data only and without constraints
 within the subfamily Anazygidae. The former taxonomic nomenclature is
 shown. Posterior probability: -318.77. #### File:
 Topology3\_grouping\_constraints.tre Description: Bayesian
 phylogeny estimated using both internal and external characters with
 grouping constraints reflecting the previously published generic
 assignments. The former clade’s taxonomic nomenclature is shown. Posterior
 probability: -342.19. #### File: Final\_topology.tre 
 Description: The .tre preferred topology. A better view of the tree can be
 seen on Figure 3.