DOI: 10.5061/dryad.q83bk3jvv
title: Data for: A short-snouted "sphenosuchian” with unusual feeding anatomy demonstrates that ecological specialization occurred early in crocodylomorph evolution

description: The early evolution and diversification of Crocodylomorpha is a key
 component of vertebrate evolution on land but is somewhat poorly
 understood as a result of limited data. We describe Eosphorosuchus
 lacrimosa gen. et sp. nov., an early crocodylomorph from the Late Triassic
 of Ghost Ranch, New Mexico, whose cranial anatomy is divergent from that
 of other early crocodylomorphs (including Hesperosuchus agilis, to which
 it had been tentatively assigned), featuring an unusually short and
 osteologically reinforced facial region. A robust upper temporal arch and
 prominent surangular ridge indicate the presence of well-developed
 superficial external adductor musculature, which is divergent relative to
 pseudosuchians generally. These autapomorphies suggest specialization for
 a powerful bite. Bayesian and maximum parsimony phylogenetic analyses find
 E. lacrimosa outside of an H. agilis clade, near the base of
 Crocodylomorpha. The specializations of E. lacrimosa therefore represent
 the beginnings of ecological diversification within Crocodylomorpha among
 animals of a similar size, predating the Late Triassic appearance of
 Crocodyliformes and the Jurassic radiation of mesoeucrocodylians.
 Coexistence in the same single-event death assemblage of E. lacrimosa and
 H. agilis—two small-bodied early crocodylomorphs with functionally
 significant anatomical differences—suggests partitioning of terrestrial
 carnivorous niches within the “sphenosuchian” grade.
description: # Data for: A short-snouted "sphenosuchian” with unusual feeding
 anatomy demonstrates that ecological specialization occurred early in
 crocodylomorph evolution Dataset DOI:
 [10.5061/dryad.q83bk3jvv](https://doi.org/10.5061/dryad.q83bk3jvv) ##
 Description of the data and file structure Data for: A short-snouted
 “sphenosuchian” with unusual feeding anatomy demonstrates that ecological
 specialization occurred early in crocodylomorph evolution ### Files and
 variables #### File: Appendix1.zip **Description:** Appendix1 contains YPM
 VP 41198 uCT scan data. * VP.041198 scan data.xlsx contains metadata
 including scan settings. The specimen was uCT scanned three times; column
 D of the spreadsheet contains metadata for the scan used in this study
 (collected 2/3/2022). Metadata includes the specimen position (Axes),
 detector location, power (kV) and current (uA), dimensions of the copper
 filter used, number of frames and images collected, and number of
 projections.  * YPM_VP_41198_02.vgl is a VGSTUDIO MAX file for viewing the
 CT scan. When opened in VGSTUDIO MAX, including in the free "demo
 mode," it will call on the two subfolders in Appendix1 (see below). 
 * The folder [vg-data] YPM_VP_41198_02 contains the .tif stack for this
 scan. It will be automatically called when opening the .vgl file.
 Alternatively, the .tif stack can be imported into any open source viewer
 for uCT data, such as 3D Slicer or Horos.  * The folder [vg-project]
 YPM_VP_41198_02 was generated in VGSTUDIO MAX and contains the project
 information for this scan. It will be automatically called when opening
 the .vgl file. Use of this folder is not necessary to view the data
 directly from the .tif stack.  #### File: Appendix2.zip
 **Description:** Appendix2 contains 3D meshes of all extracted skull
 elements of YPM VP 41198. Segmentation was performed in VGSTUDIO MAX. Each
 .stl file is named with the element name and either L (left side of the
 skull) or R (right side of the skull). A list of the files in this
 appendix, representing all skull elements extracted for use in this study,
 is as follows: angularL.stl, ectopterygoidL.stl, ectopterygoidR.stl,
 frontalL.stl, frontalR.stl, jugalR.stl, lacrimalR.stl, maxillaL.stl,
 maxillaR.stl, nasalR.stl, palatineR.stl, palpebralR.stl, postorbitalR.stl,
 prefrontalR.stl, premaxillaR.stl, pterygoidL.stl, pterygoidR.stl,
 quadrateL.stl, quadrateR.stl, surangularL.stl, vomers.stl.  #### File:
 Appendix3.zip **Description:** Appendix3 contains all materials necessary
 to reproduce our phylogenetic analysis. * Eos_matrix_REVISED.nex is the
 character matrix, which contains a taxon list and scores for each numbered
 character (see Wang et al 2025 character list.pdf for character
 descriptions). It was edited in the free software Mesquite and can be
 viewed or edited in any .nex viewer. * Eos_matrix_REVISED.tnt is a
 formatted version of the matrix ready for import into the free
 phylogenetic software TNT. * Wang et al 2025 character list.pdf contains
 the full character information used in this matrix, including character
 descriptions. The substance of this list has not been modified from: Wang
 L, Clark JM, Li H, Ruebenstahl A, Bi S. A new specimen of the early
 branching crocodyliform *Platyognathus* *hsui* extends the record of
 gobiosuchids back 67 million years. *Zool J Linn Soc.*
 2025;204(2):zlaf032. doi:10.1093/zoolinnean/zlaf032 #### File:
 Appendix4.zip **Description:** Appendix4 contains 3D meshes of the
 maxillae and jugals of comparative taxa. Specimen information is listed in
 "Appendix 4.pdf," including specimen numbers and
 institutions. Segmentation was performed in VGSTUDIO MAX and meshes were
 processed in Geomagic Wrap. Appendix4 contains all new, unpublished meshes
 generated for this study. For reproducibility, it also includes all meshes
 after they have been processed for analysis. Each .stl file contains a
 single element and is named with the genus name, element name, and
 "raw" for an unprocessed segmentation or "clean" for a
 processed segmentation. A list of the files in this appendix, representing
 all comparative taxa used in this study, is as follows:
 dibothrosuchus_maxilla_clean.stl, eosphorosuchus_jugal_clean.stl,
 eosphorosuchus_maxilla_clean.stl, gracilisuchus_jugal_clean.stl,
 gracilisuchus_jugal_raw.stl, gracilisuchus_maxilla_clean.stl,
 gracilisuchus_maxilla_raw.stl, hesperosuchus_jugal_clean.stl,
 hepserosuchus_jugal_raw.stl, hesperosuchus_maxilla_clean.stl,
 hesperosuchus_maxilla_raw.stl, junggarsuchus_jugal_clean.stl,
 junggarsuchus_maxilla_clean.stl, litargosuchus_maxilla_clean.stl,
 litargosuchus_maxilla_raw.stl, terrestrisuchus_jugal_clean.stl.  ##
 Code/software Appendix1: uCT data can be viewed in VGSTUDIO MAX demo mode,
 3D Slicer, Horos, and other open source software.  Appendix2 and
 Appendix4: Meshes can be viewed in Windows built-in 3D Viewer, MeshLab,
 Blender, and other open source software.  Appendix3: The character matrix
 is intended to be opened in Mesquite but can be viewed and edited in any
 text editor. The .tnt file is formatted for the free phylogenetic software
 TNT.