Experimental taphonomy of Artemia reveals the role of endogenous microbes in mediating decay and fossilization

• Exceptionally preserved fossils provide major insights into the evolutionaryhistory of life. Microbial activity is thought to play a pivotal role in both thedecay of organisms and the preservation of soft tissue in the fossil record,though this has been the subject of very little experimental investigation.To remedy this, we undertook an experimental study of the decay of thebrine shrimp Artemia, examining the roles of autolysis, microbial activity,oxygen diffusion and reducing conditions. Our findings indicate thatendogenous gut bacteria are the main factor controlling decay. Followinggut wall rupture, but prior to cuticle failure, gut-derived microbes spreadinto the body cavity, consuming tissues and forming biofilms capable ofmediating authigenic mineralization, that pseudomorph tissues and structuressuch as limbs and the haemocoel. These observations explain patternsobserved in exceptionally preserved fossil arthropods. For example, gutsare preserved relatively frequently, while preservation of other internal anatomyis rare. They also suggest that gut-derived microbes play a key role in thepreservation of internal anatomy and that differential preservation betweenexceptional deposits might be because of factors that control autolysis andmicrobial activity. The findings also suggest that the evolution of a throughgut and its bacterial microflora increased the potential for exceptional fossilpreservation in bilaterians, providing one explanation for the extreme rarityof internal preservation in those animals that lack a through gut.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Annan geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Other Earth and Related Environmental Sciences (hsv//eng)

NATURVETENSKAP  -- Biologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences (hsv//eng)

Nyckelord

Cambrian explosion

palaeobiology

taphonomy

bilateria

metazoa

The changing Earth

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