"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

August 29, 2010

August 29 - Linguatula taenioides

Linguatula taenioides is a species of pentastomid worm that alternates between an herbivorous mammal (e.g. sheep) and a carnivorous mammal (e.g. wolf). The adults, which can be quite large - we're talking females that can be 4 inches or so! - live in the nasal passages. The eggs are sneezed out where they get eaten by grazing or browsing animals. Once into the gut of this intermediate host, the larvae, armed with two short claw-like arms, bore through the tissue of this host until they find a place to reside such as the liver or the lungs. There they encyst and wait for the host to be eaten, when they will repeat this process until they get to the lungs or nasal passages of the carnivore and mature into sexually reproducing adults.


  1. I've read that these guys are more recently considered crustaceans, which is extra peculiar.

  2. Right. Where pentastomids fit in the the tree of life has long been controversial. A recent paper (see http://pdfserve.informaworld.com/834248__920088485.pdf), puts them with brachiuran crustaceans, but does not recover Crustacea as a monophyletic group. I don't think we've heard the last on this issue, though.