A higher-level classification of Nemertea has been updated based on insights from recent phylogenetic studies. According to this classification, the phylum includes two superclasses (Pronemertea and Neonemertea), three classes (Palaeonemertea, Pilidiopho-ra,

The deep-water bathypelagic nemertean Nectonemertes mirabilis, previously found in the Atlantic and Pacific oceans, was confirmed for the first time in the Gulf of Mexico. This new record is represented by a juvenile male collected by a stratified plankton

An updated taxonomic review of Nemertea present in the Palaearctic is presented in this chapter. Dichotomous identification keys to the lowest justifiable taxonomic level based on the most recent literature are provided. These are coupled with the necessary

The nemertean order Monostilifera consists of 594 species in 127 genera and is distributed worldwide. Within the Monostilifera, two suborders have been recognized, Cratenemertea and Eumonostilifera. Within the latter, two, unranked clade names, Oerstediina

An updated taxonomic review of freshwater Nemertea found in the Neotropical region is presented in this chapter. Dichotomous identification keys to the lowest justifiable taxonomic level based on the most recent literature are provided. These are coupled