In a primary for paleontology, scientists have discovered a whole bunch of tiny, fossilized fecal pellets crammed inside a fish braincase relationship to about 9 million years in the past. The wee fossil poops, also called coprolites, had been deposited by scavengers — in all probability worms — that devoured the fish’s decaying head, together with its mind.
As they munched the flesh from the cranium, the worms pooped out chains and clusters of oval coprolite beads, every measuring about 0.1 inches (2.5 millimeters) lengthy. Small as they had been, these pellets added up over time. When the hungry scavengers had been executed, they’d left behind a whole bunch of pellets — sufficient poop to fill the fish’s braincase completely.
Researchers discovered the coprolite-filled fossil at Calvert Cliffs, a website in southern Maryland that accommodates fossils relationship from about 18 million to eight million years in the past, in the course of the Miocene epoch. The cranium belonged to the fish Astroscopus countermani, a kind of bottom-dwelling ambush predator generally generally known as a stargazer, and small, rectangular coprolite pellets similar to these are identified collectively as Coprulus oblongus. Along with the fecal-stuffed cranium, the scientists additionally examined different coprolite pellet deposits that had been clustered in sandy sediments, caught to fossilized snail and bivalve shells, and grouped round preserved barnacles on the website.
One other notable fossil within the group was a a lot bigger coprolite measuring 7 inches (18 centimeters) lengthy, that had been pooped by a vertebrate, probably an historic crocodilian. Threading by way of the preserved poop had been deep tunnels that had been dug out by unknown animals consuming the poop or digging a house — or each, researchers reported within the March 2022 situation of the journal Rivista Italiana di Paleontologia e Stratigrafia (Analysis in Paleontology and Stratigraphy).
Many Miocene marine creatures have beforehand been described from Calvert Cliffs fossils, together with sharks and different fish, turtles, crocodiles, seabirds and seals, in keeping with the research. A wide range of coprolites have additionally been collected close to the cliffs, although microcoprolites which are produced by invertebrates — such because the coprolites within the fish cranium — have not been as well-studied as poop from animals with backbones, in keeping with the research.
Scientists decided that the tiny beads contained in the cranium had been fecal pellets “on the premise of their very attribute dimension, form and chemical composition,” mentioned lead research writer Stephen Godfrey, a curator of paleontology on the Calvert Marine Museum in Solomons, Maryland. Nondestructive X-ray spectroscopy revealed that these microcoprolites had comparatively excessive concentrations of calcium and phosphate, that are generally present in fossilized feces, Godfrey informed Dwell Science in an e-mail. (Whereas there’s no option to inform for certain if the scavengers munched on fish brains, the poop-filled braincase means that brains had been in all probability on the dinner menu.)
However whose poo was it? A lifeless animal’s corpse attracts quite a few scavengers, a lot of which “will likely be completely pleased to eat your brains and fill your cranium with feces,” Godfrey mentioned. Micropellets similar to these are produced by bugs, worms, sea squirts, snails and clams; however because the coprolites got here from a marine surroundings, “we are able to safely rule out terrestrial bugs because the producers,” Godfrey mentioned. Sea squirts is also dominated out, as a result of they spend most of their grownup lives hooked up to rocks, and acorn worms had been additionally crossed off the checklist because of their behavior of defecating exterior their burrows.
As a result of the fecal pellets had been discovered within the innermost elements of a fish cranium that measured not more than 2 inches (5 cm) broad, they had been in all probability pooped out by an invertebrate that would squeeze its delicate physique into tight areas. “This might in all probability then rule out snails and clams, leaving polychaete worms and different kinds of worms because the almost certainly candidates,” Godfrey mentioned within the e-mail.
The researchers additionally seen that each one the wee pellets had been related of their dimension and form, Godfrey mentioned. In truth, he was “most stunned and really impressed” by the coprolites’ uniformity, in comparison with the inconsistently formed fecal output of most vertebrates.
“How and why is it that some worm might produce such uniform and wonderfully-shaped feces is exceptional to me,” he mentioned.
Initially revealed on Dwell Science.