A new nemertean species: what are the useful characters for ribbon worm descriptions?

Abstract

In recent years the Norwegian Taxonomy Initiative started thorough investigations of poorly known organism groups. In this context, several marine inventories have rendered a number of marine invertebrate species new to science. Within the phylum Nemertea (ribbon worms) a characteristic hoplonemertean was encountered on two different occasions. We describe the new species Amphiporus rectangulus sp. nov. with a combination of histology and DNA data (COI). For the morphological description we use a previously proposed character matrix and, in a context given by the results, also provide a brief discussion on benefits and drawbacks with both methods. We argue that for small animals with soft bodies external characters can be more informative than hitherto expected.

Assessing the diversity and distribution ofCephalothrixspecies (Nemertea: Palaeonemertea) in European waters by comparing different species delimitation methods

“…In recent years, DNA‐based analyses gained increasing importance in identifying and describing nemertean species (Strand, Herrera‐Bachiller, Nygren, & Kånneby, ; Strand & Sundberg, ; Sundberg & Strand, ). Accordingly, a combination of external characters and genetic markers is presently regarded as sufficient to describe nemertean species (Strand & Sundberg, ; Strand et al., ; Sundberg & Strand, ; Sundberg, Andrade, et al., ). In order to delimit and identify nemertean species that exhibit only few discernible diagnostic morphological characters, genetic markers like the barcoding gene COI are commonly employed (Bucklin, Steinke, & Blanco‐Bercial, ; Hart & Sunday, ; Hebert & Gregory, ; Sundberg, Kvist, & Strand, ).…”

“…increasing importance in identifying and describing nemertean species (Strand, Herrera-Bachiller, Nygren, & Kånneby, 2014;Strand & Sundberg, 2011;. Accordingly, a combination of external characters and genetic markers is presently regarded as sufficient to describe nemertean species (Strand & Sundberg, 2011;Strand et al, 2014;Sundberg, Andrade, et al, 2016).…”

A new member of the genus Antarctonemertes (Hoplonemertea, Nemertea) from Antarctic waters

“…Here we follow the current trend in nemertean 1 3 taxonomy of combining external morphological characters with molecular data to place the species within its phylogenetic context (e.g. Sundberg and Strand 2010;Strand et al 2013;Taboada et al 2013;Herrera-Bachiller et al 2015).…”

“…Gibson 1985;Roe et al 2007), proposed that histological features should not be included as a prerequisite to describe/ redescribe new nemertean fauna and that they instead should only be used to address questions about internal organ systems functionality and evolution. To support this statement, Strand et al (2013) suggested that there is no strong evidence that nemertean identifications are more accurate when based on internal features, rather than in external. In fact, several internal characters used to differentiate between species and genera of nemerteans can sometimes show high levels of intraspecific variation (Envall and Sundberg 1993).…”

DNA barcoding supports identification of Malacobdella species (Nemertea: Hoplonemertea)

“…DNA barcoding accelerated the discovery ratio of new species (Wiens 2007) and identified some inconsistencies between species assignment and previously sequenced specimens (Kvist et al 2013). Nevertheless, only a small number of nemerteans have been analysed through DNA barcoding (Sundberg et al 2009;Chen et al 2010;Fernández-Álvarez and Machordom, 2013;Kvist et al 2013;Strand et al 2014). The potential use of DNA barcoding needs to be substantiated in well-established taxonomic groups before it can be fully exploited in all nemertean genera.…”