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Fossil discovery reveals how trilobites ate

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  • Fossil discovery reveals how trilobites ate

    In a study conducted on the fossilized remains of a trilobite found near Prague over a century ago, which dated to roughly 465 mya (Middle Ordovcian period), a team composed of researchers from the Czech Republic and Sweden discovered that the specimen who's guts had been mostly preserved intact -- the first of its kind in the fossil record.

    Scientific America provides the background:

    The trilobite specimen hails from a well-known fossil deposits found in the shales of the Šárka Formation fossil near Prague. The area’s fossils, which are often preserved in three dimensions inside of nodules nicknamed Rockycany balls, offer a glimpse into a marine ecosystem that existed during the Middle Ordovician period between 470 million and 458 million years ago. When a local fossil hunter cracked into one of these nodules in 1908, they discovered the nearly intact trilobite entombed inside.

    The stunning find ended up at a local museum, where paleontologist Petr Kraft came across the trilobite as a child and noticed something crammed inside it. Kraft, now a researcher at Charles University in Prague and lead author of the new study, spent decades wondering what was inside the trilobite. Until recently, however, he lacked a way to peer inside the fossil without destroying the specimen.

    Paleontologists Valéria Vaskaninova, also of Charles University, and Per Ahlberg from Uppsala University in Sweden, recommended that they try using synchrotron microtomography, an imaging technique that creates detailed three-dimensional scans of internal anatomy. This involves a large electron accelerator that produces powerful laser-like x-rays to create high quality, detailed 3-dimensional scans of the fossil without damaging it.

    The team discovered the a wide array of partially digested shell fragments tightly packed in to both of the trilobite’s two tube-like stomachs when they looked at a high-resolution 3-D scan. The contents included fragments of thin-walled shells such as small clams, bivalve crustaceans called ostracods, cone-shaped animals known as hyoliths, as well as stylophorans -- which are precursors to starfish. It appeared that the trilobite (Bohemolichas incola) pretty much opportunistically hoovered up virtually any bottom-dwellers that were small enough to swallow whole (trilobites had no teeth or sturdy mouth parts).

    As Ahlberg noted, "It seems to have been going along like a living version of one of those little automatic vacuum cleaners, [sucking up] small animals that could be swallowed whole or crushed up easily," adding "What is remarkable is just how stuffed full it is. It seems to have been really gorging itself, eating very rapidly."

    IOW, that the packed stomachs indicated that they foraged almost constantly.

    Further, the calcium-rich shells in the trilobite's guts revealed little indication of any damage from being dissolved that usually occurs when calcium carbonate shells are soaked in stomach acid. This indicates that the trilobite probably had a gut environment with an alkaline or neutral pH, similar to what we find in the stomachs of living mud crabs and horseshoe crabs.

    Because these animals are only distantly related to trilobites, Ahlberg thinks that a neutral gut was likely a condition found in ancestral arthropods. Vaškaninová noted that sort of biochemistry was beneficial in that it would have reduced the amount of dissolved calcium entering its bloodstream, something that is metabolically difficult to get rid of.

    The team is searching for more specimens realizing with over 20,000 known specimens over a roughly 290 million year existence, they shouldn't consider Bohemolichas incola as representative of all trilobites.

    A fossilized trilobite stomach can show us clues to Cambrian cuisine
    About 465 million years ago, a now extinct arthropod called a trilobite was eating its way across the present day Czech Republic. After it died, the passage of time actually preserved the plentiful contents of this specimen’s prehistoric guts. A team of paleontologists is using this full fossilized belly to learn more about the feeding habits and lifestyle of these common fossilized arthropods. The findings are detailed in a study published September 27 in the journal Nature.

    More than 20,000 species of trilobite lived during the early Cambrian to the end-Permian period roughly 541 to 252 million years ago. They are some of the most common fossil specimens from this time period, yet paleontologists do not know much about their feeding habits since gut contents usually disappear over time, and until recently there were no known fossil specimens with them intact.

    In the study, a team from institutions in Sweden and the Czech Republic examined a fossil specimen of Bohemolichas incola first uncovered near Prague over 100 years ago. Study co-author and paleontologist Petr Kraft from Charles University in Prague had long suspected that this specimen may have a gut full of food intact, but did not have a suitable technique to look inside the trilobite’s innards. Study co-authors and paleontologists Valéria Vaskaninova and Per Ahlberg from Uppsala University in Sweden suggested using a synchrotron in one of their fossil scanning sessions. This machine is a large electron accelerator that produces powerful laser-like x-rays to take high-quality scans of the fossil

    “The results were fantastic, showing all the gut contents in detail so that we could identify what the trilobite had been eating,” Ahlberg tells PopSci. “Remains of ostracods (small shell-bearing crustaceans, still around today), hyoliths (extinct cone-shaped animals of uncertain affinities) and stylophorans (extinct echinoderms that look like little armor-plated electric guitars). These are all kinds of animals that lived in the local environment.”

    The team believes that Bohemolichas incola was likely an opportunistic scavenger. It also was potentially a light crusher and a chance feeder, which means that it ate both dead or living animals, which either disintegrated easily or were actually small enough to be swallowed whole. However, after this particular Bohemolichas incola died, the circle of life continued and the scavenger became the scavenged. Vertical tracks of other scavengers were found on the specimen. These unknown creatures burrowed into this trilobite’s carcass and targeted its soft tissue, but avoided its gut. Staying away from the gut implies that there were some noxious conditions inside Bohemolichas incola’s digestive system and potentially ongoing enzymatic activity.

    “We were able to draw conclusions about the chemical environment inside the gut of the living trilobite. The shell fragments on the gut have not been etched by stomach acids, and this shows that the gut pH must have been close to neutral, similar to the condition in modern crabs and horseshoe crabs,” says Ahlberg. “This may indeed be a very ancient shared characteristic of trilobites and these modern arthropods.”

    Future studies into trilobites could use similar techniques to look for more gut fills. Since this group is a very diverse group of animals, it can’t be assumed that this particular species is representative of the feeding habits for all.

    “This project shows how cutting-edge technology can come together with really old museum specimens. The trilobite was collected in 1908, and has been in a museum ever since, but it is only now that we have the technology to unlock its secrets,” says Ahlberg. “This illustrates not only the rapid technological progress of our time, but also the importance of well-maintained museum collections.”

    The full paper, Uniquely preserved gut contents illuminate trilobite palaeophysiology can be read by clicking the hyperlink, and I made the abstract from it available below


    Trilobites are among the most iconic of fossils and formed a prominent component of marine ecosystems during most of their 270-million-year-long history from the early Cambrian period to the end Permian period1. More than 20,000 species have been described to date, with presumed lifestyles ranging from infaunal burrowing to a planktonic life in the water column2. Inferred trophic roles range from detritivores to predators, but all are based on indirect evidence such as body and gut morphology, modes of preservation and attributed feeding traces; no trilobite specimen with internal gut contents has been described3,4. Here we present the complete and fully itemized gut contents of an Ordovician trilobite, Bohemolichas incola, preserved three-dimensionally in a siliceous nodule and visualized by synchrotron microtomography. The tightly packed, almost continuous gut fill comprises partly fragmented calcareous shells indicating high feeding intensity. The lack of dissolution of the shells implies a neutral or alkaline environment along the entire length of the intestine supporting digestive enzymes comparable to those in modern crustaceans or chelicerates. Scavengers burrowing into the trilobite carcase targeted soft tissues below the glabella but avoided the gut, suggesting noxious conditions and possibly ongoing enzymatic activity.

    a,b, Distribution of trace fossils in right lateral view with hypostome (a) and transparent exoskeleton (b). c, Ventral view with ‘crumble’.
    df, Details of head region in left lateral (d); ventral (e) and oblique ventrolateral (f) views. Color coding as in Fig. 1,
    trace fossils in brown, exoskeleton and hypostome transparent. Scale bars, 5 mm (ac), 1 mm (df).

    Last edited by rogue06; 11-29-2023, 10:03 AM. Reason: fix trilobite link

    I'm always still in trouble again

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  • #2
    Forgot the one of the guts & contents

    I'm always still in trouble again

    "You're by far the worst poster on TWeb" and "TWeb's biggest liar" --starlight (the guy who says Stalin was a right-winger)
    "Overall I would rate the withdrawal from Afghanistan as by far the best thing Biden's done" --Starlight
    "Of course, human life begins at fertilization that’s not the argument." --Tassman


    • #3
      Originally posted by rogue06 View Post
      Forgot the one of the guts & contents

      Homey swallowed a rainbow.


      • #4
        Originally posted by whag View Post

        Homey swallowed a rainbow.

        I'm always still in trouble again

        "You're by far the worst poster on TWeb" and "TWeb's biggest liar" --starlight (the guy who says Stalin was a right-winger)
        "Overall I would rate the withdrawal from Afghanistan as by far the best thing Biden's done" --Starlight
        "Of course, human life begins at fertilization that’s not the argument." --Tassman


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