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The first Silurian trilobite with three-dimensionally preserved soft parts reveals novel appendage morphology

Citation

Sutton, Mark et al. (2021), The first Silurian trilobite with three-dimensionally preserved soft parts reveals novel appendage morphology, Dryad, Dataset, https://doi.org/10.5061/dryad.n2z34tmvv

Abstract

The first Silurian trilobite known with soft parts preserved, a Dalmanites species, is described from the Herefordshire Lagerstätte. Biramous appendages and much of the alimentary system are evident.  High-fidelity three-dimensional preservation reveals a novel, double arrangement of the exopod filaments, interconnected by a presumed membranous sheet. This morphology explains a misinterpretation of the exopod as supporting spiral structures, originally reported nearly 150 years ago. The new exopod morphology is considered primarily respiratory in function and comparison with other trilobite limbs suggests that it may be unique to Phacopida.

Methods

Tomographic data collected through physical-optical tomography at 20-micron intervals, specimen is Oxford University Museum of Natural History OUMNH C.29611. See paper associated with this data for details

3D models generated from tomographic data using the SPIERS suite - see https://spiers-software.org/ - and see paper associated with this data for details.

Usage Notes

This dataset includes 6 zip files.

AppendageDetail_VAXML.zip contains a detailed VAXML 3D model for appendage 5.

Dalmanites_sp_VAXML.zip contains a VAXML 3D model for the entire specimen, OUMNH C.29611

Section1-Cephalon.zip, Section2-AnteriorThorax.zip, Section3-PosteriorThorax.zip and Section4-Thorax-Pygidium.zip contain between them all tomograms (‘slice images’) for the specimen OUMNH C.29611. Tomograms are registered but otherwise unprocessed.

3D models are in VAXML/STL format. VAXML is an open metadata format for a combininng a series of 3D geometry files stored in the readily viewable STL format.  See https://spiers-software.org/ for freely available viewing software for VAXML datasets, and for further information.

Funding

Natural Environment Research Council, Award: NE/F018037/1

Leverhulme Trust, Award: EM-2014-068