The origins of mammal growth patterns during the Jurassic mammalian radiation
Data files
Jun 28, 2024 version files 312.94 MB
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Borealestes.zip
15.75 MB
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Dryolestes.zip
43.24 MB
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Dryolestoids.zip
16.16 MB
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Guimarota_multituberculates.zip
47.65 MB
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Haldanodon.zip
115.98 MB
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Krusatodon.zip
15.17 MB
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Kuehneotherium.zip
19.45 MB
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Morganucodon.zip
17.01 MB
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Palaeoxonodon.zip
11.63 MB
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Phascolotherium.zip
10.90 MB
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README.md
1.61 KB
Abstract
We use synchrotron X-ray tomography of annual growth increments in the dental cementum of mammaliaforms (stem and crown fossil mammals) from three faunas across the Jurassic to map the origin of patterns of determinate growth, which is intrinsically related to mammalian endothermy. Although all fossils studied exhibited slower growth rates, longer lifespans, and delayed sexual maturity relative to comparably sized extant mammals, the earliest crown mammals developed significantly faster growth rates in early life that reduced at sexual maturity (determinate growth), compared to stem mammaliaforms. Estimation of basal metabolic rates (BMRs) suggests some fossil crown mammals had BMRs approaching the lowest rates of extant mammals. We suggest mammalian determinate growth first evolved during their mid-Jurassic adaptive radiation, although growth remained slower than in extant mammals.
https://doi.org/10.5061/dryad.b2rbnzsp2
Description of the data and file structure
This archive contains example data for X-ray tomographic scans of fossilised cementum from Mesozoic mammaliaform taxa studied for this research project, which was collected during several tomographic experiments at synchrotron X-ray sources.
Each folder contains Three subfolders representing the preservational category.
- Category A comprises the best-preserved specimens.
- Category B comprises specimens of less preservational quality than Category A but was still used in analyses.
- Category C comprises specimens deemed of too low preservational quality to use in analyses.
Each subfolder contains a PDF document for each specimen, comprising:
- an example of a tomographic slice of the tooth root of the respective fossil specimen.
- an image highlighting the region selected for analysing preserved cementum increments (in yellow).
- the Region highlighted in (b), is isolated and straightened, with an example radial transect (yellow line) through the cementum.
- grayscale values along the transect highlighted in (c), with the mean, upper, and lower standard deviations of values within 5 sections along the transect highlighted.
Sharing/Access information
This data has also been uploaded to Figshare and will become publically available at: https://doi.org/10.6084/m9.figshare.21959828 upon acceptance of this manuscript.