Nematode Mouths...The Scary Bits

This week, I have been exploring the differences between nematode genera (plural of Genus), or simply put, how to tell the difference between nematodes. A lot of the differences are not-so-subtle like the shape of different structures, but sometimes I have to look for internal ridges, or the presence of really small teeth, or sometimes the pattern in cuticular ornamentation (think of stick and poke tattoo ornamentation).

However, sometimes the differences are really easy to see and I have included two pictures this week to show some of the more apparent differences between nematodes. Nematode teeth, or lack thereof, provide information regarding their diets and how they feed. Nematodes with large and apparent teeth, like the picture here, are predators and use their teeth for feeding and killing. They may feed on other nematodes or on small animals that also live between grains of sand. Other nematodes may have teeth that are set further back in their mouths and they may use these teeth to scrape bacteria off of sand grains, which may be the case for the nematode pictured below. 

Under the microscope, these along with the numbers of setae (hair-like structures) and their orientation, and the shape of their sensory organ are indicators of the nematode Genus, though putting all of the puzzle pieces together can take a while. On Wednesday, Dr. Ingels and I spent nearly two hours identifying 20 nematodes. He says that I will get better at it, and I sure hope so.

Next week, I am going to hopefully get some good pictures of the cuticular ornamentation so that you can see the differences in nematode skin patterns, because some of them are so incredibly complex, that I wonder what evolutionary role they play. Until then...

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