November 15 - Pharyngodon australis

I was on my way home from grocery shopping when I spotted something in the middle of the road near where I live. As I got closer I saw that it was a dead lizard. So like any good parasitologist, I quickly got home, parked my car, grabbed some plastic bags and dashed across the road, scooping up the lizard in the process. It must have only just been recently killed because rigor mortis hasn't even set in. So I thought I'd make something worthwhile out of an otherwise senseless death, drove to work and started dissecting the dead lizard, and sure enough, found this parasite! Pharyngodon australis is a species of nematode found in the large intestine of Eastern blue-tongue lizard (Tiliqua scincoides), a large ominvorous skink from Australia. Thousands of nematodes live in the gastrointestinal tract of skinks and other lizards. Stable isotope studies have indicate that some of these nematodes might be consuming microbes living in the host's gut, while other experiments showed that they might even contribute to gut fermentation. So this might be a case of what would normally be assumed to be a parasitic organism actually being a welcome guest!

Contributed by Tommy Leung.