Data from: Newly discovered morphology of the Silurian sea spider Haliestes and its implications
Data files
Sep 22, 2023 version files 1.52 GB
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29571_vaxml.zip
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29571-tomograms.zip
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29656_vaxml.zip
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29656-tomograms.zip
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29661-tomograms.zip
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29661-vaxml.zip
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README.md
Abstract
The three-dimensionally preserved Haliestes dasos from the Silurian (Wenlock) Lagerstätte is the most complete fossil sea spider and the oldest unambiguous pycnogonid known from the fossil record. The discovery of two new specimens to add to the holotype reveals new features including proximal annulations of the appendages and segmentation of the trunk end, critical details for comparison with pycnogonids from the Devonian (Emsian) Hunsrück Slate and for the interpretation of the evolutionary significance of Palaeozoic genera. There is some evidence of sexual dimorphism. H. dasos was nektobenthic and its morphology indicates an unusual mode of feeding compared to living pycnogonids. The new morphological features of H. dasos are closely similar to those in Palaeoisopus problematicus from the Hunsrück Slate and it clearly belongs, together with that species, in stem Pycnogonida and not the crown group.
README: Title of Dataset
Serial tomography datasets and 3D models for three specimens of Haliestes dasos (Euarthropoda, Pycnogonida) from the Silurian of Herefordshire, UK.
Specimens are accessed in the Oxford University Museum of Natural History, and are:
OUMNH PAL 29571 (Holotype)
OUMNH PAL 29656
OUMNH PAL 29661
Description of the data and file structure
Overview
Data for all three specimens comprises:
(a) RGB images in bmp format representing tomographic datasets from 20-micron interval manual serial grinding. These have been registered and cropped to ROI. For each specimen they comprise multiple parts, each representing separate fragments of the original specimen that were subjected to serial grinding. Scaling information (pixels-per-mm of images etc) is provided in description.txt files within each archive.
(b) Mesh-models constructed from RGB images using the SPIERS software package, http://spiers-software.org. These are in VAXML format (see also http://spiers-software.org) - they can be viewed using the SPIERsview element of the SPIERS software suite, or the STL files that comprise the model can be imported into any other mesh software.
Directory structure
The archive contains this readme file and six zip achives, named as 'specimen_type.zip', where specimen is the specimen number ('29571', '29656', '29661'), and type is either 'vaxml' or 'tomograms'.
'vaxml' archives each comprise:
- one vaxml metadata file
- one directory containing STL files describing morphology
'tomograms' archives each comprise:
- one Description.txt file with information on scaling and number of images for each 'part'
- a directory for each 'part' containing tomographic images in .bmp format
Sharing/Access information
N/A
Code/Software
N/A
Methods
Specimens of Haliestes dasos were serially-ground and photographed at 20 μm intervals using a digital micropscope camera. The images were aligned, edited, and used to generate 3D virtual fossils with SPIERS software-suite (http://spiers-software.org). Data provided are (a) registered image-sets from serial-grinding, one set per 'part', and (b) VAXML/STL format models of specimens generated using SPIERS and manual editing (segmentation) and mark-up of the data into separate anatomical elements.
Usage notes
Models are in VAXML/STL format. These are ideally viewed with SPIERSview (open source and available at http://spiers-software.org), but the mesh-models comprise a series of STL format files which can be combined and viewed in any mesh-viewing software. Note that meshes are correctly positioned within a single coordinate-space to facilitate the latter mode.