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- Appeltans, W., et al.
(författare)
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The Magnitude of Global Marine Species Diversity
- 2012
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 22:23, s. 2189-2202
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Tidskriftsartikel (refereegranskat)abstract
- Background: The question of how many marine species exist is important because it provides a metric for how much we do and do not know about life in the oceans. We have compiled the first register of the marine species of the world and used this baseline to estimate how many more species, partitioned among all major eukaryotic groups, may be discovered. Results: There are similar to 226,000 eukaryotic marine species described. More species were described in the past decade (similar to 20,000) than in any previous one. The number of authors describing new species has been increasing at a faster rate than the number of new species described in the past six decades. We report that there are similar to 170,000 synonyms, that 58,000-72,000 species are collected but not yet described, and that 482,000-741,000 more species have yet to be sampled. Molecular methods may add tens of thousands of cryptic species. Thus, there may be 0.7-1.0 million marine species. Past rates of description of new species indicate there may be 0.5 +/- 0.2 million marine species. On average 37% (median 31%) of species in over 100 recent field studies around the world might be new to science. Conclusions: Currently, between one-third and two-thirds of marine species may be undescribed, and previous estimates of there being well over one million marine species appear highly unlikely. More species than ever before are being described annually by an increasing number of authors. If the current trend continues, most species will be discovered this century.
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- Kånneby, Tobias, 1981-, et al.
(författare)
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A new species of Aspidiophorus (Gastrotricha: Chaetonotidae) from the Swedish west coast
- 2017
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Ingår i: Zootaxa. - : Magnolia Press. - 1175-5326 .- 1175-5334. ; 4290:2, s. 390-394
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Tidskriftsartikel (refereegranskat)abstract
- Gastrotricha is a group of small aquatic acoelomate animals with more than 820 species worldwide (Balsamo et al. 2015). The Swedish gastrotrich fauna today comprises 94 nominal species of which 40 are marine and 54 are freshwater (Curini-Galletti et al. 2012; Kånneby 2011). Of these, 69 species belong to the order Chaetonotida Remane, 1925 and 25 species belong to the order Macrodasyida Remane, 1925. Compared to other relatively well investigated countries in the region, the Swedish marine Gastrotrich fauna of the west coast appears fairly surveyed. In fact, 38 species have been recorded from Norway (Clausen 2004; Schmidt 1972), while 15 species have been recorded from the seas surrounding the Danish mainland (Grilli et al. 2010). The Swedish brackish waters of the Baltic have a lower diversity and so far only 7 species are known from this area (Kånneby 2011; unpublished observations). By comparison, 31 species have been recorded from the Polish Baltic coast (Hummon 2008; Kolicka et al. 2015). In this paper we describe a new species of Aspidiophorus found during an intensive research on the gastrotrich fauna of the surroundings of the Sven Lovén Centre for Marine Sciences (Kristineberg) on the Swedish west coast carried out in the summer of 2009.
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- Kånneby, Tobias, 1981-, et al.
(författare)
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A Phylogenetic approach to species delimitation in freshwater Gastrotricha from Sweden
- 2012
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Ingår i: Hydrobiologia. - : Springer Science and Business Media LLC. - 0018-8158 .- 1573-5117. ; 683:1, s. 185-202
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Tidskriftsartikel (refereegranskat)abstract
- 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, becoming H. acidophilum n. sp. Moreover, genetic data based on COI indicates high 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 paper the new species, Lepidodermella intermedia n. sp., from northernSweden is also described. The phylogenetic hypothesis generated show that Chaetonotidae is a non-monophyletic group.
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- Kånneby, Tobias, 1981-
(författare)
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Gastrotricha of Sweden - Biodiversity and Phylogeny
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- 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 non-monophyletic. 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.
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