Polymorphism hides cryptic species in Oerstedia dorsalis (Nemertea, Hoplonemertea)

Abstract

The marine hoplonemertean Oerstedia dorsalis is considered to be a highly polymorphic species with extensive geographic distribution. We show, based on mitochondrial cytochrome c oxidase subunit I, 16S and nuclear internal transcribed spacer sequences, that there are genetic subsets withing this species. Seventy-one specimens of various colours from different geographic localities (in Europe) were sequenced and analysed using statistical parsimony and Bayesian analysis. Both analyses supported nine major clades. We conclude that O. dorsalis hides different species with geographic resolution. These species, however, appear to be polymorphic as well, and we find no diagnostic features in pigmentation or external characters to separate species within this complex.

Worms without borders: genetic diversity patterns in four Brazilian Ototyphlonemertes species (Nemertea, Hoplonemertea)

“…Ototyphlonemertes genetic variability and demographic history Previous genetic surveys have shown the existence of cryptic lineages in nemerteans (Strand and Sundberg 2005a;Mateos and Giribet 2008;Sundberg et al 2009;Chen et al 2010;Mahon et al 2010). In the present study, the mitochondrial gene COX3 produced a mosaic of outcomes with respect to differentiation within and among Ototyphlonemertes species, including potential cryptic speciation in O. lactea and O. parmula (Figs.…”

“…All phylomorphs (Envall and Norenburg 2001) seem to be monophyletic, taking into account that the cryptic lineages found are also part of the phylomorph previously determined. Finding cryptic lineages is not surprising in light of several studies on nemerteans showing lack of concordance between morphological and molecular diversity (e.g., Envall and Sundberg 1998;Strand and Sundberg 2005a, b;Sundberg et al 2009;Chen et al 2010 and references therein;Sundberg and Strand 2010). Clearly, the use of morphological traits alone is impractical for characterizing Ototyphlonemertes species.…”

“…Several of the traits used to distinguish varieties among established species are plastic and would rather diagnose ecological morphs than represent monophyletic units (Envall and Sundberg 1998;Envall and Norenburg 2001). The lack of correspondence between morphology and evolutionary lineages in several genera of nemerteans could result from the presence of multiple sibling species (Envall and Sundberg 1998;Sundberg et al 2009;Chen et al 2010). In recent years, the number of molecular studies addressing the cryptic diversity in nemerteans has increased substantially (e.g., Strand and Sundberg 2005a;Mateos and Giribet 2008;Thornhill et al 2008;Sundberg et al 2009;Chen et al 2010;Mahon et al 2010).…”

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

“…The difficulty of morphological recognition of a great part of the more than 1,280 species included in the phylum Nemertea has been previously discussed (Andrade et al 2012;Kvist et al 2013, among others), and different authors have advocated new tools and comprehensive studies for correctly identifying species and thus providing accurate biodiversity knowledge. The combination of molecular and morphological methods has been useful in elucidating nemertean taxonomy in other genera (Sundberg et al 2009;Junoy et al 2010;Puerta et al 2010;Kajihara et al 2011;Taboada et al 2013). 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).…”

“…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.…”