This fossilized fish cranium is full of feces


View of the fossilized skull of an extinct species of stargazer fish, showing preserved fecal pellets in the brain.
Enlarge / View of the fossilized cranium of an extinct species of stargazer fish, displaying preserved fecal pellets within the mind.

Calvert Marine Museum

A fossilized skull of an extinct species of stargazer fish was filled with tiny fecal pellets generally known as coprolites, in accordance with a latest paper revealed within the journal Rivista Italiana di Paleontologia e Stratigrafia—the primary recognized cranium within the fossil document to be utterly full of fecal pellets. That is a joint examine by paleontologists on the College of Pisa in Italy, and the Calvert Marine Museum in Maryland, who proposed that tiny scavenging worms ate their manner into the lifeless fish’s cranium and pooped out the pellets.

It was a nineteenth century British fossil hunter named Mary Anning (not too long ago portrayed by Kate Winslet within the 2020 movie Ammonite) who first seen the presence of so-called “bezoar stones” within the abdomens of ichthyosaur skeletons round 1824. When she broke open the stones, she usually discovered the fossilized stays of fish bones and scales. A geologist named William Buckland took observe of Anning’s observations 5 years later, suggesting that the stones have been really fossilized feces. He dubbed them coprolites.

Coprolites aren’t fairly the identical as paleofeces, which retains lots of natural parts that may be reconstituted and analyzed for chemical properties. Coprolites are fossils, so most natural parts have been changed by mineral deposits like silicate and calcium carbonates. It may be difficult to differentiate the smallest coprolites from eggs, for instance, or different kinds of inorganic pellets, however they sometimes boast spiral or annular markings, and, as Anning found, usually include undigested fragments of meals.

Scanning electron micrograph of a single fecal pellet (coprolite) found in the cranial cavity of a fossilized fish
Enlarge / Scanning electron micrograph of a single fecal pellet (coprolite) discovered within the cranial cavity of a fossilized fish

S.J. Godfrey et al., 2022

For archaeologists eager on studying extra concerning the well being and eating regimen of previous populations—in addition to how sure parasites developed within the evolutionary historical past of the microbiome—coprolites and paleofeces is usually a veritable goldmine of knowledge. As an illustration, final 12 months we reported on an evaluation of preserved paleo-poop revealing that the traditional Iron Age miners in what’s now Austria have been fairly keen on beer and blue cheese.

In 2020, we reported on a brand new methodology (dubbed coproID) for figuring out whether or not fecal samples are human or have been produced by different animals, significantly canine.  (Canine poo bears a strikingly shut resemblance to human feces in each measurement and form, is incessantly discovered on the similar archaeological websites, and has an identical composition). The tactic combines host DNA and intestine microbiome evaluation with open supply machine-learning software program.

Samples of fecal pellets (coprolites) found in various fossils collected from the Calvert Cliffs in Maryland.
Enlarge / Samples of fecal pellets (coprolites) present in numerous fossils collected from the Calvert Cliffs in Maryland.

S.J. Godfrey et al., 2022

If a coprolite accommodates bone fragments, chances are high the animal who excreted it was a carnivore, and if there are tooth marks on these fragments, it could inform us one thing about how the animal might have eaten its prey. The scale and form of coprolites can even yield helpful insights. If it is spiral-shaped, as an example, the coprolite may need been excreted by an historical shark, since some fashionable fish (like sharks) have spiral-shaped intestines.

This new joint examine examined a number of fossil samples the museum’s assortment containing coprolites. The fossils have been recovered from the Calvert Cliffs in Maryland, with rocks fashioned from the sediment of the coastal ocean that after coated the area. The so-called Calvert Formation is a wealthy trove for fossil hunters, and whereas the cliffs are closed to the general public, folks often comb the seashore for fossilized shark enamel, that are particularly plentiful.

Essentially the most thrilling of the fossils the scientists examined was the cranium of an extinct species of stargazer fish referred to as Astroscopus countermani, discovered in 2011 and courting again to the Miocene epoch. Immediately’s surviving Astroscopus species are venomous and might produce electrical shocks. They hunt by camouflaging themselves and ambushing prey, and have been referred to as “the meanest issues in creation” by ichthyologist William Leo Smith.

SEM images of the neurocranium of an extinct species of stargazer fish, stuffed with fecal pellets (coprolites)
Enlarge / SEM photographs of the neurocranium of an extinct species of stargazer fish, filled with fecal pellets (coprolites)

S.J. Godfrey et al., 2022

The workforce recognized two varieties of coprolites. The primary have been tiny micro-coprolites about 1/eighth of an inch lengthy and grey or brownish black in shade. They have been present in snail shells, clamshells, barnacles, and burrows, in addition to the stargazer fish cranium, often stuffed into tiny areas that shelled invertebrates would not have been capable of entry. So it is probably they have been deposited by small, soft-bodied worms—in all probability an annelid worm like a polychaete—who might have navigated these tight areas.

There have been additionally a lot bigger coprolites discovered alongside the Calvert Cliffs, most definitely fossilized crocodile dung, which confirmed proof of tunneling by different animals. The authors recommend that the animals engaged in “coprophagy“: i.e., feces-eating, which sounds gross, however would have been an environment friendly technique of recycling any vitamins current within the feces, in addition to guaranteeing that the ocean flooring wasn’t utterly buried in feces.

The pellet-stuffed fish cranium can be prominently featured on the Calvert Marine Museum’s inaugural Common Coprolite Day on Sunday, February 20, 2022, described as a celebration of “excrement pleasure.” Additionally on show: shark and fish-bitten coprolites, a coprolite preserving the impression of a child turtle shell, and partially eaten coprolites, all demonstrating “the significance of coprolites within the fossil document and within the examine of prehistoric life.”

DOI: Rivista Italiana di Paleontologia e Stratigrafia, 2022. 10.54103/2039-4942/17064  (About DOIs).