Oldest fossilised vomit of land animal tells us about menu of predator that lived 290 million years ago

Berlin, Feb 8 (The Conversation) We were already familiar with fossilised droppings, called coprolites. But a recent discovery shows that regurgitation can also become fossilised. At the Bromacker paleontological site in Germany, a very unusual fossil was unearthed: a regurgitalith, that is, a fossilised vomit.
     This regurgitation comprises bone remains belonging to three different animals and comes from a predator belonging to the synapsids (a group of animals including modern mammals), which had already been discovered at this site.
     The rocks at this site, dating back approximately 290 million years (Early Permian), have already yielded exceptionally well-preserved plants, amphibians, and reptiles, as well as numerous footprints.
     This time, our team discovered a small cluster of partially digested bones, lacking any structure or regular shape, suggesting that it was not excrement but rather the remains regurgitated by a predator. This discovery has just been published in Scientific Reports.

     How did we determine that it was fossilised vomit?
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     This fossil is a compact mass of bones. Such a grouping of bones has never been discovered at Bromacker and suggests that these remains were ingested and then excreted by a predator, either through defecation or regurgitation.
     In the case of coprolites (fossilised droppings), the bone remains are generally preserved within a visible sedimentary matrix of organic origin (faecal matter), rich in phosphorus, resulting from bacterial activity related to bone digestion. However, in this specimen, the bone remains are not surrounded by such a matrix.
     A chemical analysis using micro-XRF ( X-ray fluorescence spectrometry ) confirmed a near absence of phosphorus in this matrix. This lack of phosphorus is characteristic of regurgitalites (fossilised regurgitations) compared to coprolites, which are highly concentrated in phosphorus due to a longer digestion time.
     We also scanned the fossil in 3D (CT scan). This non-destructive approach allowed us to virtually reconstruct each bone and identify it precisely. The regurgitalith notably contains:

     • a maxilla of a small quadrupedal reptile ( Thuringothyris ), with most of the teeth still in position;
     • a humerus belonging to Eudibamus, a bipedal reptile;
     • a metapodial (foot or hand bone) of a diadectid, a herbivore of significantly larger size.

     In total, three different animals of varying sizes were ingested and then partially regurgitated by the same predator.

     Why is this discovery important?
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     Regurgitalites are very rare in the fossil record, and none had yet been described in such an ancient terrestrial environment. This discovery thus represents the oldest known fossil vomit of a terrestrial vertebrate.
     It also opens a new window onto the feeding behaviour of Early Permian predators. Two carnivores large enough to have ingested these prey are known from Bromacker: Dimetrodon, recognisable by its dorsal crest, and another carnivorous synapsid of comparable size, Tambacarnifex.
     The diversity of remains found in this regurgitate suggests opportunistic behaviour, where these predators ingested whatever was within reach. Furthermore, this regurgitation acts as a veritable time capsule, containing the remains of several animals that lived
     This specimen thus allows us to verify the actual coexistence of these three animals.

     What follow-up actions should be taken in this research?
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     This study invites us to reconsider certain accumulations of fossil bones, sometimes interpreted as coprolites or sedimentary deposits. It shows that regurgitation could be more frequent than previously thought, but still largely under-identified.
     In the future, the combination of 3D scans, chemical analyses, and detailed anatomical comparisons could allow researchers to identify other fossil vomits and better link these remains to the predators that produced them.
     This research opens new perspectives for reconstructing ancient food webs (the network of feeding interactions between living organisms in an ecosystem ) and better understanding the functioning of terrestrial ecosystems nearly 300 million years ago. (The Conversation) SKS
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(This story has not been edited by THE WEEK and is auto-generated from PTI)