"So, naturalists observe, a flea has smaller fleas that on him prey; and these have smaller still to bite ’em; and so proceed ad infinitum."
- Jonathan Swift
January 20, 2010
January 20 - Neoechinorhynchus emyditoides
Neoechinorhynchus emyditoides is a species of acanthocephalan, or thorny-headed worm. These parasites often have very complex life cycles involving multiple trophic levels. The vertebrate host of this species is a turtle and, as the picture shows, a single turtle can have hundreds of worms – in some cases, more than 1000! - filling its intestine. The acanthocephalan eggs are expelled in the turtle’s feces and are eaten by ostracods, tiny crustaceans, where they develop into a stage called an acanthella. When fish eat the ostracods, the acanthella travel to the fish’s liver and await the fish’s ingestion by a turtle. There are 10 species in this genus and they are extremely difficult to tell apart. This photo likely contains a mix of both N. emyditoides and Neoechinorhynchus pseudemydis. The host in this case was a red-eared slider (Trachemys scripta) collected from Reelfoot Lake, Tennessee.
Nomination and photo by Mike Barger.