Phylotranscriptomics of Limnognathia (Gnathifera: Micrognathozoa)

The last animal phylum to be discovered is Micrognathozoa, a rare group of limnic meiofauna. These microscopic 'jaw animals' are among the smallest metazoans yet possess highly complex jaw structures. No males have ever been found and the entire phylum is hypothesized to be parthenogenetic. There are three geographically isolated populations of Micrognathozoa. Two are at opposite poles (Greenland, Crozet Archipelago) and one in the Pyrenees. Despite the distance separating the populations, there is only one species in the phylum, Limnognathia maerski. This is the first study to investigate the intraphylum relationships within Micrognathozoa. We generated single-animal transcriptomes from multiple individuals from the three known populations of Limnognathia and tested the hypothesis of cryptic speciation using machine learning methods.