A phylogenetic approach to species delimitation in freshwater Gastrotricha from Sweden

Abstract

Gastrotricha is a cosmopolitan group ofaquatic invertebrates. To date, approximately 765species have been described. This study is the first todeal with species delimitation and cryptic species offreshwater Gastrotricha. Three commonly encounteredspecies, Heterolepidoderma ocellatum, Lepidochaetuszelinkai, and Lepidodermella squamata, areinvestigated for cryptic speciation. Most of thematerial is based on Swedish specimens but closelyrelated species from other parts of the world are alsoincluded. Taxonomic revisions are supported byphylogenies based on 18S rRNA, 28S rRNA, andCOI mtDNA of freshwater Chaetonotidae from severalgenera and inferred from Bayesian and maximumlikelihood approaches. Heterolepidoderma ocellatumf. sphagnophilum is raised to species level, under thename H. acidophilum n. sp. Moreover, genetic databased on COI indicate large variation between twomorphologically very similar groups of Lepidodermellasquamata. The extent of cryptic speciation inL. zelinkai appears low. Based on the phylogenetichypothesis presented in this article, the new species,Lepidodermella intermedia n. sp., from northernSweden is also described. The phylogenetic hypothesisgenerated shows that Chaetonotidae is a nonmonophyleticgroup

The phylogenetic position of Neogosseidae (Gastrotricha: Chaetonotida) and the origin of planktonic Gastrotricha

“…DNA extraction, amplification, and sequencing of 18S rDNA, 28S rDNA, and COI mtDNA follow the protocol presented in Kånneby et al (2012). The new sequences were analyzed together with most of the sequences obtained by Kånneby et al (2013).…”

Neogosseidae (Gastrotricha, Chaetonotida) from the iSimangaliso Wetland Park, KwaZulu-Natal, South Africa

“…Kisielewski 1991), it may be cautious not to regard this trait alone as a discriminatory character. Future studies, accounting for morphological and/or molecular marker differences on a statistical basis could support or disprove this hypothesis (e.g., Todaro et al 1996, Leasi and Todaro 2009, Kånneby et al 2012, Kieneke et al 2012). …”

Structure, function and evolution of somatic musculature in Dasydytidae (Paucitubulatina, Gastrotricha)

“…Furthermore, there is almost no statistic node support for internal branches. None of the DNA sequence-based phylogenetic inferences published to date include a single sequence of a member of Dasydytidae apart from the most recent one (Kånneby et al 2012). In that study, sequences of two species of Stylochaeta form a monophylum within paraphyletic Chaetonotidae, with close relationships to Polymerurus.…”