Profiles

Inga Martinek

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Arbetar vid Zoologiska institutionen
E-post inga.meyer-wachsmuth@nrm.se
Besöksadress Frescativägen 40, Naturhistoriska riksmuseet
Postadress Zoologiska institutionen Box 50007, 104 05 Stockholm

Publikationer

I urval från Stockholms universitets publikationsdatabas
  • Inga Meyer-Wachsmuth, Ulf Jondelius.

    Here we present a comprehensive phylogeny of Nemertodermatida, a taxon of microscopic marine worms, based for the first on molecular marker with consideration of morphological characters. Our dataset comprises three nuclear genes and most nominal and putative species including recently described cryptic species; only species of the genus Ascoparia could not be obtained. We show that the two families of Nemertodermatida, Ascopariidae and Nemertodermatidae, are retrieved as separate clusters, although not in all analyses as sister groups. We also validate sequences published before 2013 against our dataset; some sequences are shown to be chimeric and have falsified prior hypotheses about nemertodermatid phylogeny, other sequences should be assigned new names. We also show that the genus Nemertoderma needs revision. 

  • Olga I. Raikova, Inga Meyer-Wachsmuth, Ulf Jondelius.

    Nemertodermatida are microscopic marine worms likely to be the sister-group to acoels and the earliest extant bilaterian animals. The nervous system of Flagellophora apelti, Sterreria sp. and Nemertoderma westbladi has been investigated by immunohistochemistry and confocal microscopy using anti-tubulin, anti-5-HT and anti-FMFRamide antibodies as well as by phalloidin staining.

    The nervous system of Flagellophora apelti is composed of a large brain neuropile at the level of the statocysts with several fibres surrounding it and innervating the broom organ. Sterreria sp. shows a commissural-like brain and several nerve cords going frontad and caudad from this. At the level of the statocysts there is also a thicker aggregation of IR fibres. The nervous system of N. westbladi consists of a nerve ring lying outside the body wall musculature at the level of the statocyst and a pair of ventro-lateral nerve cords, from which extend numerous fibres innervating the ventral side of the animal. Numerous bottle-shaped glands were observed, innervated by fibres starting both from the brain and the cords. Those nemertodermatids studied to-date display no common nervous system pattern. This study demonstrates that the nemertodermatid nervous system possesses a number of plesiomorphic features and appears more primitive than the nervous system in other worms, except Xenoturbellida. The musculature of Sterreria sp., as revealed by phalloidin-TRITC staining, shows diagonal muscles in the anterior quarter of the body and a simple orthogonal grid in the posterior three quarters. It is more primitive than that of the other nemertodermatids. High-resolution differential contrast microscopy permitted to better visualise some morphological characters such as statocysts, sperm and glands. 

  • 2016. Inga Meyer-Wachsmuth, Ulf Jondelius. Organisms Diversity & Evolution 16 (1), 73-84

    Nemertodermatida is a small taxon of microscopic marine worms, which were originally classified within Platyhelminthes. Today they are hypothesized to be either an early bilaterian lineage or the sister group to Ambulacraria within Deuterostomia. These two hypotheses indicate widely diverging evolutionary histories in this largely neglected group. Here, we analyse the phylogeny of Nemertodermatida using nucleotide sequences from the ribosomal LSU and SSU genes and the protein coding Histone 3 gene. All currently known species except Ascoparia neglecta and Ascoparia secunda were included in the study in addition to several yet undescribed species. Ascopariidae and Nemertodermatidae are retrieved as separate clades, although not in all analyses as sister groups. Non-monophyly of Nemertodermatida was rejected by the Approximately Unbiased test. Nemertodermatid nucleotide sequences deposited in Genbank before 2013 were validated against our dataset; some of them are shown to be chimeric implying falsification of prior hypotheses about nemertodermatid phylogeny: other sequences should be assigned new names. We also show that the genus Nemertoderma needs revision.

Visa alla publikationer av Inga Martinek vid Stockholms universitet

Senast uppdaterad: 13 april 2018

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