In a unique paleontological breakthrough, the Calvert Marine Museum has revealed the discovery of an ancient coprolite, or fossilized feces, containing the impression of a previously unknown species of parasitic marine isopod. The fossil, dating back 18 million years, was found by Jason Osborne, a black-water scuba diver, during a dive in the Pamunkey River in Virginia. This discovery is exceptional, as it represents only the second coprolite ever documented to contain an impression of undigested prey.
The coprolite fossil preserves the shape of a small parasitic isopod, now identified as a new genus and species named Calverteca osbornei, in honor of Osborne, who found the specimen. These findings were published in the journal Palaeontologia Electronica and co-authored by Dr. Stephen J. Godfrey of the Calvert Marine Museum alongside Dr. Carrie E. Schweitzer and the late Dr. Rodney M. Feldmann from Kent State University, Ohio.
“This discovery is extraordinary not only for its rarity but also for what it reveals about ancient marine ecosystems,” stated Dr. Godfrey. “Impressions of ingested animals in coprolites are exceedingly rare, making this find a significant contribution to the fossil record.”
Discovery and Significance of Calverteca osbornei
This particular coprolite, which measures less than three inches in length, was formed from sediment on the prehistoric Atlantic Ocean floor during the Miocene epoch. The impression of Calverteca osbornei preserved in the fossil provides a detailed view of the parasite’s body structure, suggesting it was once lodged in the mouth of a fish. As an obligate parasite, this ancient isopod belonged to the Cymothoidae family, which consists of parasites that attach to fish, often on their tongues. This specific genus has become popularly known as “tongue-biters” due to its adaptation to living and feeding off the tongues of fish.
After the isopod detached, it was likely swallowed by the fish, passing through its digestive system without fully decomposing before being expelled. Over millions of years, it fossilized within the coprolite, creating a snapshot of an ancient marine food chain in which the parasite played a key role.
A Rare and Remarkable Find
The discovery marks a rare preservation instance within the fossil record. Among tens of thousands of coprolites that have been studied, only two documented cases exist where undigested prey parts have left an impression, underscoring the rarity of such a finding.
The research team noted that while isopods are a widely distributed group of crustaceans, boasting more than 10,000 species today, their fossil record remains relatively sparse. This scarcity is due to the isopods’ delicate exoskeletons, which are less likely to withstand the fossilization process compared to other marine organisms. The Cymothoidae family, which includes Calverteca osbornei, consists of around 380 species found primarily in tropical and subtropical waters. For anglers, these parasites are a familiar sight on fish as “tongue biters” — they not only consume the host fish’s tongue tissue but effectively replace it, functioning as the fish’s new “tongue.”
While modern anglers often encounter Cymothoidae in tropical waters, the fossil of Calverteca osbornei provides a rare glimpse into the habits of their ancient relatives. The study suggests that this parasite likely lived in the mouth of a fish, consuming nutrients from the host before becoming detached and eventually ingested by the fish itself. This fossil discovery indicates that isopods’ exoskeletons were capable of passing through a host’s digestive tract relatively intact, revealing a unique trait in ancient marine ecosystems.
Implications for Understanding Marine Ecology
The preserved fossil has broad implications for understanding the dietary and ecological relationships within ancient marine environments. By examining this parasitic interaction through fossil evidence, researchers gain insight into both predator-prey dynamics and the adaptability of marine parasites within their ecosystems.
“This fossil isopod was probably living in the mouth of a fish, became detached, swallowed, and then passed essentially undigested through the fish’s intestines,” said Dr. Godfrey. “It provides invaluable insights into the ecology of marine life in the Miocene epoch.”
For paleontologists, such findings contribute valuable data on how isopod parasites have adapted over time, offering clues on their resilience and ecological roles across millions of years. The existence of Calverteca osbornei within this fossil record underscores the complexities of ancient marine life, shedding light on both the behavior of parasites and the dietary patterns of the fish they inhabited.
Ongoing Research and Public Access
As paleontologists continue to study this coprolite fossil, further insights may emerge regarding the interactions between ancient marine species and their hosts. The paper is available to the public through Palaeontologia Electronica, offering enthusiasts and scholars alike a chance to explore this unique discovery in greater depth. The full research publication can be accessed online at: https://palaeo-electronica.org/content/2024/5363-isopod-impression-in-a-coprolite.
This extraordinary find not only expands the scientific community’s understanding of ancient ecosystems but also highlights the ongoing importance of fossil studies in uncovering hidden details about the past. The Calvert Marine Museum continues its commitment to showcasing significant paleontological discoveries, bringing the ancient world to life for future generations.