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Biogenic Iron Preserves Structures during Fossilization: A Hypothesis
Author(s) -
Saleh Farid,
Daley Allison C.,
Lefebvre Bertrand,
Pittet Bernard,
Perrillat Jean Philippe
Publication year - 2020
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/bies.201900243
Subject(s) - fossilization , ferritin , ferrihydrite , anoxic waters , biology , pyrite , iron levels , evolutionary biology , paleontology , chemistry , ecology , mineralogy , biochemistry , philosophy , linguistics , organic chemistry , adsorption , endocrinology
It is hypothesized that iron from biological tissues, liberated during decay, may have played a role in inhibiting loss of anatomical information during fossilization of extinct organisms. Most tissues in the animal kingdom contain iron in different forms. A widely distributed iron‐bearing molecule is ferritin, a globular protein that contains iron crystallites in the form of ferrihydrite minerals. Iron concentrations in ferritin are high and ferrihydrites are extremely reactive. When ancient animals are decaying on the sea floor under anoxic environmental conditions, ferrihydrites may initialize the selective replication of some tissues in pyrite FeS 2 . This model explains why some labile tissues are preserved, while other more resistant structures decay and are absent in many fossils. A major implication of this hypothesis is that structures described as brains in Cambrian arthropods are not fossilization artifacts, but are instead a source of information on anatomical evolution at the dawn of complex animal life.