DOI: 10.5061/dryad.0cfxpnwfq
title: Data from: The holocephalan ratfish endoskeleton shares trabecular and areolar mineralization patterns, but not tesserae, with elasmobranchs little skate and catshark

description: Abstract Specific character traits of mineralized endoskeletal tissues
 need to be clearly defined and comprehensively examined among extant
 chondrichthyans (elasmobranchs, such as sharks and skates, and
 holocephalans, such as chimaeras) to understand their evolution. For
 example, tiles of mineralized polygonal structures called tesserae occur
 at cartilage surfaces in chondrichthyans, but recent studies showing
 trabecular mineralization at elasmobranch cartilage surfaces suggest that
 tesserae are not as common as previously thought. Also, while areolar
 mineralized tissue in elasmobranchs is generally considered a unique,
 shared chondrichthyan feature, some chondrichthyan species demonstrate
 bone-like tissues in both a specific region of tesserae termed the cap
 zone and continuous (not tiled) mineralized neural arches. To clarify the
 distribution of specific endoskeletal features among extant
 chondrichthyans, adult skeletal tissues in a holocephalan chimaera
 (spotted ratfish) and two elasmobranchs (small-spotted catshark and little
 skate) were characterized using synchrotron radiation and desktop micro-CT
 imaging, and histological and immunofluorescent assays. Endoskeletal
 mineralization in the ratfish, catshark, and little skate varied both
 quantitively in tissue mineral density (TMD), and qualitatively in the
 morphology and localization of mineralized structures and tissues. For
 example, TMD of several skeletal elements was significantly lower in
 ratfish, compared to catshark and little skate. Trabecular and areolar
 mineralization were shared among these extant chondrichthyan species, but
 tesserae and bone-like tissues were not. Interestingly, three separate
 analyses argued that the adult chimaera endoskeleton has features of the
 embryonic little skate endoskeleton. Generally, this study proposes
 specific terminology for character states of the extant chondrichthyan
 endoskeleton and infers those states in ancestral chondrichthyans with
 reference to fossil data.
description: # Data from: The holocephalan ratfish endoskeleton shares trabecular and
 areolar mineralization patterns, but not tesserae, with elasmobranchs
 little skate and catshark Dataset DOI:
 [10.5061/dryad.0cfxpnwfq](https://doi.org/10.5061/dryad.0cfxpnwfq) ##
 Description of the data and file structure Data contained in the files
 listed below are desktop and Synchrotron radiation micro-CT projections of
 shark (S. canicula), skate (L. erinacea), and chimaera (H. colliei):
 **Desktop projections:** *
 Atake_et_al_chondrichMinTissuesRawData_Figs.1B-G__2C_F__3D_H__5C__6D.zip *
 Atake_et_al_chondrichMinTissuesRawData_Figs.2A_D__3B_F__5A.zip *
 Atake_et_al_chondrichMinTissuesRawData_Figs.2B_E__3C_G__5B.zip *
 Atake_et_al_chondrichMinTissuesRawData_Fig.3A_E.zip *
 Atake_et_al_chondrichMinTissuesRawData_Fig._6B.zip *
 Atake_et_al_chondrichMinTissuesRawData_Fig._6C.zip **Synchrotron
 projections:** * Atake_et_al_chondrichMinTissuesRawData_Fig._4B-E.zip *
 Atake_et_al_chondrichMinTissuesRawData_Fig._4G-J.zip *
 Atake_et_al_chondrichMinTissuesRawData_Fig._6E.zip *
 Atake_et_al_chondrichMinTissuesRawData_Fig._6F.zip *
 Atake_et_al_chondrichMinTissuesRawData_Fig._6G.zip *
 Atake_et_al_chondrichMinTissuesRawData_Fig._6H.zip All projections are
 TIFF files that can be inspected with Image J. Desktop projections can be
 reconstructed with NRecon Synchrotron projections can be reconstructed
 with UFO-KIT software
 ([https://github.com/ufo-kit/ufo-core.git](https://github.com/ufo-kit/ufo-core.git)) Reconstructed data can be viewed using Amira, Avizo, or 3D slicer Excel sheets containing Tissue Mineral Density (TMD) values computed from reconstructed projections using CT Analyzer Version 1.16.4.1 (Bruker microCT) is provided. Neural arches, synarcual, and centra are skeletal regions of interest for which TMDs were computed. NA (not applicable) in the synarcual column indicates that TMD could not be computed for the catshark because sharks do not have synarcual * Atake_et_al_chondrichMinTissuesRawData_Fig1H.xlsx * Atake_et_al_chondrichMinTissuesRawData_Fig._6L.xlsx ## Code/software Snapshot of reconstruction template containing basic parameters used for phaseCT reconstruction with the UFO-KIT software is attached as a PNG file * Synchrotron_Radiation_projection_phaseCT_Recon_Template.PNG