TY - JOUR
T1 - Molecular fingerprints resolve affinities of Rhynie chert organic fossils
AU - Loron, C. C.
AU - Rodriguez Dzul, E.
AU - Orr, P. J.
AU - Gromov, A. V.
AU - Fraser, N. C.
AU - McMahon, S.
N1 - Funding Information:
This research was supported by The Royal Society (UK) and the Belgium Wallonia Brussels programme WBI.WORLD (C.C.L.) and the CONACYT (National Council of Science and Technology of Mexico) Postgraduate Scholarship for Studying Abroad (E.R). We thank J. Parnell at the University of Aberdeen, the National Museums Scotland and the University of Oxford Museum of Natural History for facilitating access to samples. I. Febbrari is thanked for the preparation of thin sections. S. Hetherington and M. Krings are thanked for their help identifying cyanobacterial and plant taxa. D. Marosi-McMahon is thanked for the help with statistical comparison tests.
Funding Information:
This research was supported by The Royal Society (UK) and the Belgium Wallonia Brussels programme WBI.WORLD (C.C.L.) and the CONACYT (National Council of Science and Technology of Mexico) Postgraduate Scholarship for Studying Abroad (E.R). We thank J. Parnell at the University of Aberdeen, the National Museums Scotland and the University of Oxford Museum of Natural History for facilitating access to samples. I. Febbrari is thanked for the preparation of thin sections. S. Hetherington and M. Krings are thanked for their help identifying cyanobacterial and plant taxa. D. Marosi-McMahon is thanked for the help with statistical comparison tests.
Publisher Copyright:
© 2023, The Author(s).
PY - 2023/3/13
Y1 - 2023/3/13
N2 - The affinities of extinct organisms are often difficult to resolve using morphological data alone. Chemical analysis of carbonaceous specimens can complement traditional approaches, but the search for taxon-specific signals in ancient, thermally altered organic matter is challenging and controversial, partly because suitable positive controls are lacking. Here, we show that non-destructive Fourier Transform Infrared Spectroscopy (FTIR) resolves in-situ molecular fingerprints in the famous 407 Ma Rhynie chert fossil assemblage of Aberdeenshire, Scotland, an important early terrestrial Lagerstätte. Remarkably, unsupervised clustering methods (principal components analysis and K-mean) separate the fossil spectra naturally into eukaryotes and prokaryotes (cyanobacteria). Additional multivariate statistics and machine-learning approaches also differentiate prokaryotes from eukaryotes, and discriminate eukaryotic tissue types, despite the overwhelming influence of silica. We find that these methods can clarify the affinities of morphologically ambiguous taxa; in the Rhynie chert for example, we show that the problematic “nematophytes” have a plant-like composition. Overall, we demonstrate that the famously exquisite preservation of cells, tissues and organisms in the Rhynie chert accompanies similarly impressive preservation of molecular information. These results provide a compelling positive control that validates the use of infrared spectroscopy to investigate the affinity of organic fossils in chert.
AB - The affinities of extinct organisms are often difficult to resolve using morphological data alone. Chemical analysis of carbonaceous specimens can complement traditional approaches, but the search for taxon-specific signals in ancient, thermally altered organic matter is challenging and controversial, partly because suitable positive controls are lacking. Here, we show that non-destructive Fourier Transform Infrared Spectroscopy (FTIR) resolves in-situ molecular fingerprints in the famous 407 Ma Rhynie chert fossil assemblage of Aberdeenshire, Scotland, an important early terrestrial Lagerstätte. Remarkably, unsupervised clustering methods (principal components analysis and K-mean) separate the fossil spectra naturally into eukaryotes and prokaryotes (cyanobacteria). Additional multivariate statistics and machine-learning approaches also differentiate prokaryotes from eukaryotes, and discriminate eukaryotic tissue types, despite the overwhelming influence of silica. We find that these methods can clarify the affinities of morphologically ambiguous taxa; in the Rhynie chert for example, we show that the problematic “nematophytes” have a plant-like composition. Overall, we demonstrate that the famously exquisite preservation of cells, tissues and organisms in the Rhynie chert accompanies similarly impressive preservation of molecular information. These results provide a compelling positive control that validates the use of infrared spectroscopy to investigate the affinity of organic fossils in chert.
U2 - 10.1038/s41467-023-37047-1
DO - 10.1038/s41467-023-37047-1
M3 - Article
SN - 2041-1723
VL - 14
SP - 1
EP - 7
JO - Nature Communications
JF - Nature Communications
IS - 1
M1 - 1387
ER -