Change search
Refine search result
1 - 21 of 21
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Kolicka, Malgorzata
    et al.
    Department of Animal Taxonomy and Ecology, Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University in Poznań, Umultowska 89, 61–614 Poznan, Poland.
    Dabert, Miroslawa
    Molecular Biology Techniques Laboratory, Faculty of Biology, Adam Mickiewicz University in Poznań, Umultowska 89, 61–614 Poznań, Poland. .
    Dabert, Jacek
    Department of Animal Morphology, Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University in Poznań, Umultowska 89, 61–614 Poznań, Poland..
    Kånneby, Tobias
    Swedish Museum of Natural History, Department of Zoology.
    Kisielewski, Jacek
    Department of Animal Taxonomy and Ecology, Institute of Environmental Biology, Faculty of Biology, Adam Mickiewicz University in Poznań, Umultowska 89, 61–614 Poznan, Poland. .
    Bifidochaetus, a new Arctic genus of freshwater Chaetonotida (Gastrotricha) from Spitsbergen revealed by an integrative taxonomic approach2016In: Invertebrate systematics, ISSN 1445-5226, E-ISSN 1447-2600, ISSN 1445-5226, Vol. 30, no 4, p. 398-419, article id IS16001Article in journal (Refereed)
    Abstract [en]

    Gastrotricha is a cosmopolitan phylum of aquatic and semi-terrestrial invertebrates that comprises ~820 described species. To date, freshwater gastrotrichs have not been the subject of faunistic or taxonomic research in the polar regions. In this paper, we present the first species-level description of a freshwater gastrotrich from the Arctic (Svalbard Archipelago). Evidence from morphology, morphometry and molecular analyses reveals that the species represents a new genus in Chaetonotidae: Bifidochaetus arcticus, gen. et sp. nov. Taking into consideration many morphological similarities to Chaetonotus (Primochaetus) veronicae Kånneby, 2013 we propose to include C. (P.) veronicae in the newly established genus under the new combination Bifidochaetus veronicae (Kånneby, 2013), comb. nov. In the phylogenetic analysis based on nuclear 18S rRNA, 28S rRNA and mitochondrial cytochrome c oxidase subunit I sequence data, B. arcticus, gen. et sp. nov. is nested within the family Chaetonotidae, as the sister group to the genus Lepidochaetus Kisielewski, 1991. In this paper we also present new taxonomic characters useful for gastrotrich taxonomy: the pharynx-to-intestine length ratio (I) and the spine bifurcation ratio (B).

  • 2.
    Kånneby, Tobias
    Swedish Museum of Natural History, Department of Zoology.
    A redescription of Chaetonotus (Primochaetus) veronicae Kånneby, 2013 (Gastrotricha: Chaetonotidae)2015In: Zootaxa, ISSN 1175-5326, E-ISSN 1175-5334, Vol. 4027, no 3, p. 442-446Article in journal (Refereed)
  • 3.
    Kånneby, Tobias
    Swedish Museum of Natural History, Department of Zoology.
    Gastrotricha of Sweden - Biodiversity and Phylogeny2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Gastrotricha are small aquatic invertebrates with approximately 770 known species. The group has a cosmopolitan distribution and is currently classified into two orders, Chaetonotida and Macrodasyida. The gastrotrich fauna of Sweden is poorly known: a couple of years ago only 29 species had been reported. In Paper I, III, and IV, 5 freshwater species new to science are described. In total 56 species have been recorded for the first time in Sweden during the course of this thesis. Common species with a cosmopolitan distribution, e. g. Chaetonotus hystrix and Lepidodermella squamata, as well as rarer species, e. g. Haltidytes crassus, Ichthydium diacanthum and Stylochaeta scirtetica, are reported. In Paper II molecular data is used to infer phylogenetic relationships within the morphologically very diverse marine family Thaumastodermatidae (Macrodasyida). Results give high support for monophyly of Thaumastodermatidae and also the subfamilies Diplodasyinae and Thaumastodermatinae. In Paper III the hypothesis of cryptic speciation is tested in widely distributed freshwater gastrotrichs. Heterolepidoderma ocellatum f. sphagnophilum is raised to species under the name H. acidophilum n. sp. The results indicate that L. squamata may be a complex of at least two species. In Paper III and V the phylogeny of Chaetonotidae (Chaetonotida), the largest family within Gastrotricha, is inferred. The group suffers from a troubled taxonomy and is hypothesized to be nonmonophyletic. Results show that members of Dasydytidae are nested within the group. Since only 3 of 17 sampled genera are monophyletic, it is hypothesized that the cuticular structures used in current classification do not reflect phylogenetic relationships. The phylogenetic hypothesis generated in Paper V indicates a marine origin of the predominantly limnic Chaetonotidae with a subsequent secondary invasion to marine environments of some taxa.

  • 4.
    Kånneby, Tobias
    Swedish Museum of Natural History, Department of Zoology.
    New species and new records of freshwater Chaetonotida (Gastrotricha) from Sweden2011In: Zootaxa, ISSN 1175-5326, E-ISSN 1175-5334, Vol. 3115, p. 29-55Article in journal (Refereed)
    Abstract [en]

    Gastrotricha is a small phylum of acoelomatic aquatic invertebrates common in both marine and freshwater environments. The freshwater gastrotrich fauna of Sweden is poorly known and so far only 20 species have been reported. In this study two species, Heterolepidoderma joermungandri n. sp. and H. trapezoidum n. sp., are described as new to science. Moreover, 9 species are presented as new to the Swedish fauna. Additional taxonomic information is also given for 4 species previously reported from the country. In total 7 genera of two families, Chaetonotidae and Dasydytidae, are presented and the number of reported freshwater gastrotrichs from the country is increased to 31.

  • 5.
    Kånneby, Tobias
    Swedish Museum of Natural History, Department of Zoology.
    New species and records of freshwater Chaetonotus (Gastrotricha: Chaetonotidae) from Sweden2013In: Zootaxa, ISSN 1175-5326, E-ISSN 1175-5334, Vol. 3701, no 5, p. 551-588Article in journal (Refereed)
    Abstract [en]

    Chaetonotus is the most speciose genus of the family Chaetonotidae within Gastrotricha, a small phylum of aquatic acoe-lomate invertebrates. The freshwater gastrotrich fauna of Sweden has been studied during the last five years and so far 44 species have been reported in the literature from the country. This study describes the new species, Chaetonotus (Pri-mochaetus) veronicae n. sp., and reports 9 species new to the Swedish fauna raising the known number of freshwater spe-cies from the country to 54. Some records stand out from a biogeographic point of view: Chaetonotus (Primochaetus) soberanus is reported for the first time from Europe and Chaetonotus (Chaetonotus) arethusae, Chaetonotus (Chaetonotus) naiadis and Chaetonotus (Hystricochaetonotus) euhystrix are reported for the first time outside the countries from which they were originally described.

  • 6.
    Kånneby, Tobias
    Swedish Museum of Natural History, Department of Zoology.
    Phylum Gastrotricha2016In: Keys to Nearctic Fauna: Thorp and Covich's Freshwater Invertebrates / [ed] Thorp, J., Rogers, D.C., Academic Press, 2016, 4, p. 115-130Chapter in book (Other academic)
  • 7.
    Kånneby, Tobias
    et al.
    Swedish Museum of Natural History, Department of Zoology.
    Atherton, Sarah
    Department of Biology, University of Massachusetts Lowell, Lowell, MA 01854, USA.
    Hochberg, Rick
    Department of Biology, University of Massachusetts Lowell, Lowell, MA 01854, USA.
    Two new species of Musellifer (Gastrotricha: Chaetonotida) from Florida and Tobago and the systematic placement of the genus within Paucitubulatina2014In: Marine Biology Research, ISSN 1745-1000, E-ISSN 1745-1019, Vol. 10, no 10, p. 983-995Article in journal (Refereed)
    Abstract [en]

    Two new species of marine Gastrotricha, Musellifer reichardti sp. nov. and Musellifer tridentatus sp. nov. (Chaetonotida: Paucitubulatina: Muselliferidae), are described from the Atlantic coast of Florida (USA) and the west coast of Tobago (Trinidad and Tobago), respectively. Both new species are peculiar in that they lack a muzzle bearing the mouth, which is a diagnostic character of the genus. They correspond well to the diagnosis of Musellifer in other morphological features, and genetic data from the 18S rDNA gene of M. reichardti sp. nov. further support the inclusion of the new species in the genus Musellifer. Musellifer reichardti sp. nov. is distinguished by the following combination of characters: blunt head with reduced muzzle; dorsal patches of naked cuticle bearing sensory cilia on either side of the head; ventral locomotory cilia restricted to the pharyngeal region; spined scales; caudal furca with naked adhesive tubes. The new species is a simultaneous hermaphrodite with posterior paired ovaries, paired testes located at mid-body length, and a posterior frontal organ. M. tridentatus sp. nov. is the first species within the genus exhibiting two types of dorsal/lateral scales: anteriormost dorsal and lateral trident-shaped scales and smooth strongly overlapping dorsal scales. The systematic placement of Musellifer within the Paucitubulatina is discussed and emended diagnoses are given for Muselliferidae and Musellifer.

  • 8. Kånneby, Tobias
    et al.
    Bernvi, David C
    Swedish Museum of Natural History, Department of Zoology. Stockholm University.
    Jondelius, Ulf
    Swedish Museum of Natural History, Department of Zoology. Stockholm University.
    Distribution, delimitation and description of species of Archaphanostoma (Acoela)2014In: Zoologica Scripta, ISSN 0300-3256, E-ISSN 1463-6409, Vol. 44, no 2, article id 218-231Article in journal (Refereed)
  • 9.
    Kånneby, Tobias
    et al.
    Swedish Museum of Natural History, Department of Zoology.
    Hochberg, Rick
    Department of Biology, University of Massachusetts Lowell, Lowell, MA 01854, USA.
    Phylum Gastrotricha2015In: Ecology and General Biology: Thorp and Covich's Freshwater Invertebrates / [ed] Thorp, J. and Rogers, D. C., Academic Press, 2015, 4, p. 211-223Chapter in book (Other academic)
  • 10.
    Kånneby, Tobias
    et al.
    Swedish Museum of Natural History, Department of Zoology.
    Jondelius, Ulf
    Swedish Museum of Natural History, Department of Zoology.
    Four new species of Acoela from Chile2013In: Zootaxa, ISSN 1175-5326, E-ISSN 1175-5334, Vol. 3736, no 5, p. 471-485Article in journal (Refereed)
    Abstract [en]

    Acoels are with few exceptions marine worms and a common component of the interstitial meiofauna. In this study we present new species to science belonging to Isodiametridae and Solenofilomorphidae. The new species, Isodiametra finkei n. sp., Postaphanostoma nilssoni n. sp., Pseudaphanostoma hyalinorhabdoida n. sp. and Solenofilomorpha pellucida n. sp. were all collected in Chile during March 2012. Nucleotide sequences for the ribosomal genes 18S rDNA and 28S rDNA as well as COI mtDNA have been determined for the new species and used in a maximum likelihood analysis to further support their classification.

  • 11.
    Kånneby, Tobias
    et al.
    Swedish Museum of Natural History, Department of Zoology.
    Todaro, M. Antonio
    Department of Biology, University of Modena and Reggio Emilia, Modena, Italy.
    The phylogenetic position of Neogosseidae (Gastrotricha: Chaetonotida) and the origin of planktonic Gastrotricha2015In: Organisms Diversity & Evolution, ISSN 1439-6092, E-ISSN 1618-1077, Vol. 15, no 3, p. 459-469Article in journal (Refereed)
    Abstract [en]

    Planktonic forms of Gastrotricha have been known since the 1850s, despite the fact that they are rather uncommon and difficult to collect. They are characterized by a round sack-shaped body, an absence of furcal adhesive tubes, and a different distribution of the locomotory ciliation compared to epibenthic and periphytic gastrotrichs. Today, planktonic gastrotrichs are classified into the three taxa—Dasydytidae, Neogosseidae, and Undula—but their origin and whether they share a recent common ancestor remain largely unknown. A long-held view is that planktonic taxa are derived from benthic ancestors related to Chaetonotus (Zonochaeta), but the hypothesis has never been properly tested. Here, in order to elucidate the phylogeny and origin of planktonic Gastrotricha, we provide the first molecular data on the very rare genera Kijanebalola and Neogossea, both members of the family Neogosseidae. We use Bayesian and maximum likelihood phylogenetics to analyze sequences of 18S rDNA, 28S rDNA, and COI mtDNA spanning 71 taxa in total. We find high support for a common origin of planktonic gastrotrichs, with monophyly of both Dasydytidae and Neogosseidae. Planktonic forms have evolved from epibenthic or periphytic ancestors, and the closest extant clade comprises members of Chaetonotus (Zonochaeta) + Chaetonotus heteracanthus Remane, 1927. These results further imply that the motile spines and underlying muscle patterns that control them in species of Dasydytidae are adaptations to the planktonic environment that evolved independently of those in other species of Gastrotricha.

  • 12.
    Kånneby, Tobias
    et al.
    Swedish Museum of Natural History, Department of Zoology.
    Todaro, M. Antonio
    Department of Biology, University of Modena and Reggio Emilia, Modena, Italy.
    Jondelius, Ulf
    Swedish Museum of Natural History, Department of Zoology.
    A phylogenetic approach to species delimitation in freshwater Gastrotricha from Sweden2012In: Hydrobiologia, ISSN 0018-8158, E-ISSN 1573-5117, Vol. 683, p. 185-202Article in journal (Refereed)
    Abstract [en]

    Gastrotricha is a cosmopolitan group of aquatic invertebrates. To date, approximately 765 species have been described. This study is the first to deal with species delimitation and cryptic species of freshwater Gastrotricha. Three commonly encountered species, Heterolepidoderma ocellatum, Lepidochaetus zelinkai, and Lepidodermella squamata, are investigated for cryptic speciation. Most of the material is based on Swedish specimens but closely related species from other parts of the world are also included. Taxonomic revisions are supported by phylogenies based on 18S rRNA, 28S rRNA, and COI mtDNA of freshwater Chaetonotidae from several genera and inferred from Bayesian and maximum likelihood approaches. Heterolepidoderma ocellatum f. sphagnophilum is raised to species level, under the name H. acidophilum n. sp. Moreover, genetic data based on COI indicate large variation between two morphologically very similar groups of Lepidodermella squamata. The extent of cryptic speciation in L. zelinkai appears low. Based on the phylogenetic hypothesis presented in this article, the new species, Lepidodermella intermedia n. sp., from northern Sweden is also described. The phylogenetic hypothesis generated shows that Chaetonotidae is a nonmonophyletic group.

  • 13.
    Kånneby, Tobias
    et al.
    Swedish Museum of Natural History, Department of Zoology.
    Todaro, M. Antonio
    Department of Biology, University of Modena and Reggio Emilia, Modena, Italy.
    Jondelius, Ulf
    Swedish Museum of Natural History, Department of Zoology.
    One new species and records of Ichthydium Ehrenberg, 1830 (Gastrotricha: Chaetonotida) from Sweden with a key to the genus2009In: Zootaxa, ISSN 1175-5326, E-ISSN 1175-5334, Vol. 2278, p. 26-46Article in journal (Refereed)
    Abstract [en]

    The freshwater gastrotrich fauna of Sweden is poorly known. Only seven species of freshwater gastrotrichs have been reported so far. This paper is the first in a series of contributions about the Swedish freshwater gastrotrich fauna. Here we describe one new species, Ichthydium skandicum n. sp., from Jämtland, northern Sweden. The new species falls within the boundary of the subgenus Forficulichthys and is morphologically closest to Ichthydium tanytrichum from which it can be differentiated based on the presence of four pairs of dorsal, keeled scales in the posterior trunk region. Moreover, we provide morphometric data for three additional Ichthydium species: I. diacanthum, I. squamigerum and I. tanytrichum, Italian species all of which are reported for the first time outside Italy. Considering the accompanying fauna, a total of thirteen freshwater Gastrotricha are reported for the first time from Sweden. Finally we present a dichotomous key for Ichthydium along with distributional data of the species considered.

  • 14.
    Kånneby, Tobias
    et al.
    Swedish Museum of Natural History, Department of Zoology.
    Todaro, M. Antonio
    Department of Biology, University of Modena and Reggio Emilia, Modena, Italy.
    Jondelius, Ulf
    Swedish Museum of Natural History, Department of Zoology.
    Phylogeny of Chaetonotidae and other Paucitubulatina (Gastrotricha: Chaetonotida) and the colonization of aquatic ecosystems2013In: Zoologica Scripta, ISSN 0300-3256, E-ISSN 1463-6409, Vol. 42, no 1, p. 88-105Article in journal (Refereed)
    Abstract [en]

    Chaetonotidae is the largest family within Gastrotricha with almost 400 nominal species represented in both freshwater and marine habitats. The group is probably non-monophyletic and suffers from a troubled taxonomy. Current classification is to a great extent based on shape and distribution of cuticular structures, characters that are highly variable. We present the most densely sampled molecular study so far where 17 of the 31 genera belonging to Chaetonotida are represented. Bayesian and maximum likelihood approaches based on 18S rDNA, 28S rDNA and COI mtDNA are used to reconstruct relationships within Chaetonotidae. The use of cuticular structures for supra-specific classification within the group is evaluated and the question of dispersal between marine and freshwater habitats is addressed. Moreover, the subgeneric classification of Chaetonotus is tested in a phylogenetic context. Our results show high support for a clade containing Dasydytidae nested within Chaetonotidae. Within this clade, only three genera are monophyletic following current classification. Genera containing both marine and freshwater species never form monophyletic clades and group with other species according to habitat. Marine members of Aspidiophorus appear to be the sister group of all other Chaetonotidae and Dasydytidae, indicating a marine origin of the clade. Halichaetonotus and marine Heterolepidoderma form a monophyletic group in a sister group relationship to freshwater species, pointing towards a secondary invasion of marine environments of these taxa. Our study highlights the problems of current classification based on cuticular structures, characters that show homoplasy for deeper relationships.

  • 15.
    Kånneby, Tobias
    et al.
    Swedish Museum of Natural History, Department of Zoology.
    Wicksten, Mary K.
    First record of the enigmatic genus Redudasys Kisielewski, 1987 (Gastrotricha: Macrodasyida) from the Northern hemisphere2014In: Zoosystema, Vol. 36, no 4, p. 723-733Article in journal (Refereed)
    Abstract [en]

    Gastrotricha Metschnikoff, 1865 is a small phylum of acoelomatic animals common in both marine and freshwater environments. To date, close to 800 species are known from all over the world. The order Macrodasyida Remane, 1925 [Rao & Clausen, 1970] is almost exclusively marine except for the rare genera Marinellina Ruttner-Kolisko, 1955 and Redudasys Kisielewski, 1987. In this study, we present morphological and molecular data for a potentially new species of Redudasys from the Edwards Aquifer, Texas, USA. It is the first record of the genus from the Northern hemisphere. It has only previously been reported from Brazil. The Texan specimen, designated as Redudasys sp., has a single pair of anterior adhesive tubes and is considerably shorter than the specimens reported from Brazil. Molecular data from the 18S rRNA and COI mtDNA genes support a close relationship of Redudasys sp. to Redudasys fornerise Kisielewski, 1987. Barcodes are provided for both Redudasys sp. and R. fornerise. The limited material obtained does not justify the description of a new species, but the record is certainly important from a biogeographical standpoint. The colonization and invasion of marine species into freshwater habitats, in particular those of the Edwards Aquifer, is discussed. Although certain marine gastrotrichs appear to have an astonishing ability to adapt to changes in salinity Redudasys is likely to be a marine relic.

  • 16. Schwank, Peter
    et al.
    Kånneby, Tobias
    Swedish Museum of Natural History, Department of Zoology.
    Contribution to the freshwater gastrotrich fauna of wetland areas of southwestern Ontario (Canada) with redescriptions of seven species and a check-list for North America2014In: Zootaxa, ISSN 1175-5326, E-ISSN 1175-5334, Vol. 3811, no 4, p. 463-490Article in journal (Refereed)
    Abstract [en]

    This study gives additional, detailed information on the freshwater gastrotrich species described and reported from the southwestern regions of Ontario and New Brunswick, Canada by Schwank (1990). Aspidiophorus ontarioniensis, Chaetonotus (Chaetonotus) furculatus, Chaetonotus (Chaetonotus) ontariensis, Chaetonotus (Primochaetus) annae, Ich-thydium malleum, Lepidodermella forficulata and Setopus lemnicola are all redescribed. In addition, a complete list of freshwater species currently known from North America is given.

  • 17.
    Strand, Malin
    et al.
    Swedish Species Information Centre, Swedish University of Agricultural Sciences, Sven Lovén Centre for Marine Sciences, Tjärnö, SE-452 96 Strömstad, Sweden.
    Herrera-Bachiller, Alfonso
    EU–US Marine Biodiversity Research Group, Instituto Franklin, Universidad de Alcalá & Departamento de Ciencias de la Vida, Universidad de Alcalá, 28871 Alcalá de Henares, Madrid, Spain.
    Nygren, Arne
    Department of Biology and Environmental Sciences, University of Gothenburg, Box 463, SE-405 30 Gothenburg, Sweden.
    Kånneby, Tobias
    Swedish Museum of Natural History, Department of Zoology.
    A new nemertean species: what are the useful characters for ribbon worm descriptions?2014In: Journal of the Marine Biological Association of the United Kingdom, ISSN 0025-3154, E-ISSN 1469-7769, Vol. 94, no 02, p. 317-330Article in journal (Refereed)
    Abstract [en]

    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.

  • 18. Sundberg, Per
    et al.
    Andrade, Sonia
    Bartolomaeus, Thomas
    Beckers, Patrick
    von Döhren, Jörn
    Krämer, Daria
    Gibson, Ray
    Giribet, Gonzalo
    Herrera-Bachiller, Alfonso
    Junoy, Juan
    Kajihara, Hiroshi
    Kvist, Sebastian
    Kånneby, Tobias
    Swedish Museum of Natural History, Department of Zoology.
    Sun, Shi-Chun
    Thiel, Martin
    Turbeville, James
    Strand, Malin
    University of Gothenburg, Department of Zoology, P.O. Box 463, SE-405 30 Gothenburg, Sweden.
    The future of nemertean taxonomy (phylum Nemertea) — a proposal2016In: Zoologica Scripta, ISSN 0300-3256, E-ISSN 1463-6409, ISSN 0300-3256, Vol. 45, no 6, p. 579-582Article in journal (Refereed)
  • 19.
    Sundberg, Per
    et al.
    University of Gothenburg, Department of Zoology, P.O. Box 463, SE-405 30 Gothenburg, Sweden.
    Chernyshev, Alexey V.
    A.V. Zhirmunsky Institute of Marine Biology, Far East Division, Russian Academy of Sciences,.
    Kajihara, Hiroshi
    Faculty of Science, Hokkaido University, Sapporo 060-0810, Japan.
    Kånneby, Tobias
    Swedish Museum of Natural History, Department of Zoology.
    Strand, Malin
    University of Gothenburg, Department of Zoology, P.O. Box 463, SE-405 30 Gothenburg, Sweden.
    Character-matrix based descriptions of two new nemertean (Nemertea) species2009In: Zoological Journal of the Linnean Society, ISSN 0024-4082, E-ISSN 1096-3642, Vol. 157, p. 264-294Article in journal (Refereed)
    Abstract [en]

    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.

  • 20.
    Todaro, M. Antonio
    et al.
    Department of Biology, University of Modena and Reggio Emilia, Modena, Italy.
    Dal Zotto, Matteo
    Department of Biology, University of Modena and Reggio Emilia, Modena, Italy.
    Jondelius, Ulf
    Swedish Museum of Natural History, Department of Zoology.
    Hochberg, Rick
    Department of Biology, University of Massachusetts Lowell, Lowell, MA 01854, USA.
    Hummon, William D.
    Department of Biological Sciences,Ohio University, Athens, Ohio, United States of America.
    Kånneby, Tobias
    Swedish Museum of Natural History, Department of Zoology.
    Rocha, Carlos E. F.
    Departamento de Zoologia, Instituto de Biocieˆncias, Universidade de Sa˜o Paulo, Sa˜o Paulo, Brazil.
    Gastrotricha: A Marine Sister for a Freshwater Puzzle2012In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 7, no 2, p. e31740-Article in journal (Refereed)
    Abstract [en]

    Within an evolutionary framework of Gastrotricha Marinellina flagellata and Redudasys fornerise bear special interest, as they are the only Macrodasyida that inhabit freshwater ecosystems. Notwithstanding, these rare animals are poorly known; found only once (Austria and Brazil), they are currently systematised as incertae sedis. Here we report on the rediscovery of Redudasys fornerise, provide an account on morphological novelties and present a hypothesis on its phylogenetic relationship based on molecular data. Specimens were surveyed using DIC microscopy and SEM, and used to obtain the 18 S rRNA gene sequence; molecular data was analyzed cladistically in conjunction with data from 42 additional species belonging to the near complete Macrodasyida taxonomic spectrum. Morphological analysis, while providing new information on taxonomically relevant traits (adhesive tubes, protonephridia and sensorial bristles), failed to detect elements of the male system, thus stressing the parthenogenetic nature of the Brazilian species. Phylogenetic analysis, carried out with ML, MP and Bayesian approaches, yielded topologies with strong nodal support and highly congruent with each other. Among the supported groups is the previously undocumented clade showing the alliance between Redudasys fornerise and Dactylopodola agadasys; other strongly sustained clades include the densely sampled families Thaumastodermatidae and Turbanellidae and most genera. A reconsideration of the morphological traits of Dactylopodola agadasys in light of the new information on Redudasys fornerise makes the alliance between these two taxa very likely. As a result, we create Anandrodasys gen. nov. to contain members of the previously described D. agadasys and erect Redudasyidae fam. nov. to reflect this novel relationship between Anandrodasys and Redudasys. From an ecological perspective, the derived position of Redudasys, which is deeply nested within the Macrodasyida clade, unequivocally demonstrates that invasion of freshwater by gastrotrichs has taken place at least twice, in contrast with the single event hypothesis recently put forward.

  • 21.
    Todaro, M. Antonio
    et al.
    Department of Biology, University of Modena and Reggio Emilia, Modena, Italy.
    Kånneby, Tobias
    Swedish Museum of Natural History, Department of Zoology.
    Dal Zotto, Matteo
    Department of Biology, University of Modena and Reggio Emilia, Modena, Italy.
    Jondelius, Ulf
    Swedish Museum of Natural History, Department of Zoology.
    Phylogeny of Thaumastodermatidae (Gastrotricha: Macrodasyida) Inferred from Nuclear and Mitochondrial Sequence Data2011In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 6, no 3, p. e17892-Article in journal (Refereed)
    Abstract [en]

    Background: Phylogenetic relationships within Gastrotricha are poorly known. Attempts to shed light on this subject using morphological traits have led to hypotheses lacking satisfactory statistical support; it seemed therefore that a different approach was needed.

    Methodology/Principal Findings: In this paper we attempt to elucidate the relationships within the taxonomically vast family Thaumastodermatidae (Macrodasyida) using molecular sequence data. The study includes representatives of all the extant genera of the family and for the first time uses a multi-gene approach to infer evolutionary liaisons within Gastrotricha. The final data set comprises sequences of three genes (18S, 28S rDNA and COI mtDNA) from 41 species, including 29 thaumastodermatids, 11 non-thaumastodermatid macrodasyidans and a single chaetonotidan. Molecular data was analyzed as a combined set of 3 genes and as individual genes, using Bayesian and maximum likelihood approaches. Two different outgroups were used: Xenotrichula intermedia (Chaetonotida) and members of the putative basal Dactylopodola (Macrodasyida). Thaumastodermatidae and all other sampled macrodasyidan families were found monophyletic except for Cephalodasyidae. Within Thaumastodermatidae Diplodasyinae and Thaumastodermatinae are monophyletic and so are most genera. Oregodasys turns out to be the most basal group within Thaumastodermatinae in analyses of the concatenated data set as well as in analyses of the nuclear genes. Thaumastoderma appears as the sister taxon to the remaining species. Surprisingly, Tetranchyroderma is non-monophyletic in our analyses as one group of species clusters with Ptychostomella while another appears as the sister group of Pseudostomella.

    Conclusions/Significance: Results in general agree with the current classification; however, a revision of the more derived thaumastodermatid taxa seems necessary. We also found that the ostensible COI sequences from several species do not conform to the general invertebrate or any other published mitochondrial genetic code; they may be mitochondrially derived nuclear genes (numts), or one or more modifications of the mitochondrial genetic code within Gastrotricha.

1 - 21 of 21
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf