Fissuroderes sorenseni sp. nov. and Meristoderes boylei sp. nov.: First Atlantic recording of two rare kinorhynch genera, with new identification keys

The present contribution includes the description of two new species of the phylum Kinorhyncha collected off the East coast of Florida, USA and assigned to two recently and still poorly known genera: Fissuroderes Neuhaus and Blasche, 2006 and Meristoderes Herranz et al., 2012. They both belong to the family Echinoderidae Bütschli, 1876. Species of Fissuroderes and Meristoderes have not previously been recorded from the Atlantic Ocean. This publication also provides the first SEM images and a detailed description of the introvert of a Fissuroderes species, revealing new characters of phylogenetic significance. A dichotomous key for all the known species of both genera is provided, together with discussions of their biogeographical distribution and taxonomical status.