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Image Gallery: Parasite Eggs Lurk in Fossilized Shark Poop

Fossil Poop

fossilized shark poop

(Image credit: Luiz Flavio Lopes.)

Fossilized shark poop, called a coprolite (shown here), was found to contain ancient tapeworm eggs.

tapeworm eggs

tapeworm eggs in fossilized shark poop

(Image credit: Bruno Horn.)

Researchers found a cluster of 270-million-year-old tapeworm eggs (shown here) in fossilized shark poop.

Perfect Ovals

tapeworm eggs in fossilized shark poop

(Image credit: Bruno Horn.)

The eggs were perfect oval shapes, with each spanning only about 150 microns long, or about one-and-a-half times the average width of a human hair. The researchers discovered the eggs by cutting coprolites into thin slices.

Growing Larva

tapeworm eggs in fossilized shark poop

(Image credit: PLoS ONE 8(1): e55007. )

One of the tapeworm eggs even contained a probable developing larva (E), which held a cluster of fiberlike objects that may have been the beginnings of hooklets used to attach to a host's intestines as adults.

Tapeworm Details

tapeworm eggs in fossilized shark poop

(Image credit: PLoS ONE 8(1): e55007.)

Here a schematic of the tapeworm egg showing: the shell (C), embryo or larva (E), developing hooklets (H), inner envelope (I) and outer envelope (O).

Today's tapeworms

tapeworm in human intestine

(Image credit: Juan Gaertner | Shutterstock)

Like today's tapeworms, these ancient parasites would have clung to the intestines of the shark or other vertebrate (animal with a backbone). When the parasite reached adulthood, it would unleash its eggs on the world via the feces of its host. Here, a tapeworm attached to a human intestine.

Graspers

(Image credit: Claire J. Healy)

Here, a scanning electron micrograph of the scolex (anterior attachment organ) of Rhinebothrium sp., an extant tapeworm.