Thylacocephalans are an enigmatic group of marine arthropods allied with crustaceans. Their fossil record consists predominantly of isolated carapaces which contain relatively few systematically useful characteristics besides the hard-to-quantify outline.
The micro-ornamentation patterns contribute a new suite of systematically useful characters that seem to be invariant within species and easily segregated into one of three types - linear, polygonal or scale-like - using scanning electron microscope analysis. The patterns for 13 species of thylacocephalans are documented and analysed.
One new genus (Paraconcavicarisgen. nov.) and three new species (Concavicaris martinaesp. nov.,C. woodruffensissp. nov. andC. pikaesp. nov.) are erected. :