A cluster of tapeworm eggs discovered in 270-million-year-old fossilized shark feces suggests that intestinal parasites in vertebrates are much older than previously known, according to research published January 30 in the open access journal PLOS ONE by Paula Dentzien-Dias and colleagues from the Federal University of Rio Grande, Brazil.
Remains of such parasites in vertebrates from this era are rare- of 500 samples examined, only one revealed the tapeworm eggs. This particular discovery helps establish a timeline for the evolution of present-day parasitic tapeworms that occur in foods like pork, fish and beef. The fossilized eggs were found in a cluster very similar to those laid by modern tapeworms. Some of them are un-hatched and one contains what appears to be a developing larva. According to the study, "This discovery shows that the fossil record of vertebrate intestinal parasites is much older than was previously known and occurred at least 270-300 million years ago."
The fossil described in this study is from Middle-Late Permian times, a period followed by the largest mass extinction known, when nearly 90% of marine species and 70% of terrestrial species died out.
Citation: Dentzien-Dias PC, Poinar G Jr, de Figueiredo AEQ, Pacheco ACL, Horn BLD, et al. (2013) Tapeworm Eggs in a 270 Million-Year-Old Shark Coprolite. PLoS ONE 8(1): e55007. doi:10.1371/journal.pone.0055007
Financial Disclosure: Financial support was provided by the Conselho Nacional de Desenvolvimento Cientıfico e Tecnologico - Brazil (CNPq) through a study grant (PCD-D, AEQF and BH) and the Project 478914/2006-7 (Edital MCT/CNPq 02/2006 - Universal). This work was also partially funded by the Conselho Nacional de Desenvolvimento Cientıfico e Tecnologico (http://www.cnpq.br/) through scholarships granted to AEQF, BH and CLS. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Competing Interest Statement: The authors have declared that no competing interests exist.
PLEASE LINK TO THE SCIENTIFIC ARTICLE IN ONLINE VERSIONS OF YOUR REPORT (URL goes live after the embargo ends): http://dx.plos.org/10.1371/journal.pone.0055007