Abstract
Exceptional preservation of fossils has often been attributed to the actions of bacteria that aid in the preservation of soft tissues that normally decay rapidly. However, it is well known that fungi play a major role in organic matter decomposition, biogeochemical cycling of elements, and metal-mineral transformations in modern ecosystems. Although the fungal fossil record can be traced back over a billion years, there are only a few recorded examples of fungal roles in fossilization. In this research, we have carried out a detailed geobiological investigation on early Pleistocene hyena coprolites (fossilized dung) in an attempt to ascertain possible fungal involvement in their formation. Using an advanced microscopic and mineralogical approach, we found that numerous hydroxyapatite nanofibers (25-34 nm on average), interwoven to form spheroidal structures, constituted the matrix of the coprolites in addition to food remains. These structures were found to be extremely similar in texture and mineral composition to biominerals produced during laboratory culture of a common saprophytic and geoactive fungus, Aspergillus niger, in the presence of a solid source of calcium (Ca) and phosphorus (P). This observation, and our other data obtained, strongly suggests that fungal metabolism can provide a mechanism that can result in fossil biomineralization, and we hypothesize, therefore, that this may have contributed to the formation of well-preserved fossils (Lagerstätten) in the geological record. The characteristic polycrystalline nanofibers may also have served as a potential biosignature for fungal life in early Earth and extraterrestrial environments.
| Original language | English |
|---|---|
| Pages (from-to) | 2417-2424.e2 |
| Journal | Current Biology |
| Volume | 33 |
| Issue number | 12 |
| Early online date | 17 May 2023 |
| DOIs | |
| Publication status | Published - 24 May 2023 |
Bibliographical note
Funding Information:Many thanks to Suping Wu for her assistance with CT scanning at NIGPAS. Peisong Xie, Qian Chen, Tingting Qiu, and Jiani Chen (Nanjing University) are acknowledged for technical support in TEM sample preparation and FIB SEM analyses. M.L. was funded by the talent program from the Chinese Academy of Sciences (2018-039), National Natural Science Foundation of China (42072004), and Strategic Priority Research Program of the Chinese Academy of Sciences (no. XDB26000000). Zhen Li acknowledges funding by State Key Laboratory of Palaeobiology and Stratigraphy, Nanjing Institute of Geology and Palaeontology, CAS (no. 223116). G.M.G. gratefully acknowledges financial support from the Natural Environment Research Council, UK (NE/M010910/1 [TeaSe]; NE/M011275/1 [COG3]). M.L. conceived the project. D.Z. collected the coprolite specimens. M.L. performed the CT scanning, SEM imaging, Raman spectrometry, and TEM analyses. Y.P. and T.Z. conducted the FTIR analysis. Zhen Li and M.S. performed the fungi incubation experiments. M.L. Z.Y. Zhen Li, M.S. D.Z. and G.M.G. interpreted the data. All authors wrote the paper and approved the final version of the manuscript. The authors declare no competing interests. We support inclusive, diverse, and equitable conduct of research.
Funding Information:
Many thanks to Suping Wu for her assistance with CT scanning at NIGPAS. Peisong Xie, Qian Chen, Tingting Qiu, and Jiani Chen (Nanjing University) are acknowledged for technical support in TEM sample preparation and FIB SEM analyses. M.L. was funded by the talent program from the Chinese Academy of Sciences ( 2018-039 ), National Natural Science Foundation of China ( 42072004 ), and Strategic Priority Research Program of the Chinese Academy of Sciences (no. XDB26000000 ). Zhen Li acknowledges funding by State Key Laboratory of Palaeobiology and Stratigraphy , Nanjing Institute of Geology and Palaeontology , CAS (no. 223116 ). G.M.G. gratefully acknowledges financial support from the Natural Environment Research Council , UK ( NE/M010910/1 [TeaSe]; NE/M011275/1 [COG 3 ]).
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