Character-matrix based descriptions of two new nemertean (Nemertea) species

Ribbon worms (phylum Nemertea) have traditionally been described and classified based on a combination of internal and external morphological characters. The extent, and wealth of details, of these descriptions vary both over time and amongst authors. In addition, definitions of characters and character states are in many cases vague, causing problems both for identification and in phylogenetic analyses. Here, we suggest a system of describing nemerteans based on a list of characters and their states with the actual description in the form of a vector of character state symbols. We argue that this system makes it easier for other systematists to extract the necessary characters/character states for comparative and phylogenetic analyses. The proposed list of characters can also act as a checklist for nemertean description, whereby hopefully ambiguities (such as does the nonmentioning of a character actually mean 'missing' or just not looked for) can be avoided in the future. We describe two new species and one new genus Carinina ochracea sp. nov. and Raygibsonia bergi gen. et sp. nov. using this concept in combination with molecular analyses based on 18S and cytochrome oxidase I (COI) DNA sequences. (C) 2009 The Linnean Society of London, Zoological Journal of the Linnean Society, 2009, 157, 264-294.