New Animals in the Mud

This week has been all about picking out more animals in the mesocosm muds, and I am excited to share a bit about three new animals I have discovered. When I say, 'discovered' here I don't mean that I am the first scientist to observe these animals. Instead, I mean that these animals are quite rare in my work, so I am excited to find them. When I started my dissertation and my time at FSU, I focused largely on two meiobenthic taxa: nematodes and copepods. These taxa are quite abundant in marine sediments, so I was very much aware of them throughout all of my samples. Whether I was looking for microplastics, or picking out animals, I recognized the nematodes and copepods. For the second portion of my dissertation, I learned to identify nematodes to the genus level using taxonomic keys and I learned how differences in nematode communities are representative of environmental health and disturbances in the sediment. In my microcosm experiment, I analyzed every animal I found to see if it had eaten microplastics during the experiment, but these animals were mostly nematodes. Of the nearly 10,000 animals I assessed during this work, nearly 99% were nematodes with a few copepods, kinorhynchs, polychaetes, isopods, nemerteans, and rotifers.

However, this week, I found three new (or newer) taxa, that I have not had experience working with. One of the three I have seen before, but its name is escaping me, and a quick look through the visual guide didn't lead me to any conclusions. The second taxa is brand new to me, and it looked unlike any fauna I have seen or read about, so I will have to hunt down some resources to help identify the animal. The third taxa, shown here, I believe is gnathifera, which are quite fun little animals. They remind me of a drawing a child would make if you asked them to combine a potato and a worm and then make it very small. Even the taxonomic guide calls them "more or less cylindrical," which is quite apt. Gnathifera, specifically gnathostomulids, are associated with fine sands that are detritus (dead matter) rich, hypoxic (very low oxygen), or sulfur-rich. While I'm not sure which of these features best describes the mud they came from, they are a real treat and add some novelty to my day of sifting through hundreds of nematodes. 

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