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  • 1.
    Envall, Ida
    Stockholm University, Faculty of Science, Department of Zoology.
    Evolutionary Perspectives on Naidinae (Annelida, Clitellata, Naididae): Molecular and Morphological Revelations2009Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Naidinae is a group of tiny oligochaetous clitellates, common all over the world, primarily in freshwater. The taxon includes about 180 nominal species. In this thesis it is shown (using molecular data) that Naidinae (sensu Erséus and Gustavsson, 2002) is non-monophyletic, since one genus, Pristina, formerly regarded as part of Naidinae, is well-separated from the remaining naidines by some genera of another clitellate subfamily, Rhyacodrilinae. The ultrastructure of coelomocytes from several naidine and rhyacodriline species are described and compared with each other and with coelomocytes previously studied, from other clitellate taxa. The naidine and rhyacodriline coelomocytes are similar, differing from those of other groups, which corroborates the hypothesis of a close relationship between Rhyacodrilinae and Naidinae.

    Features of the chaetae are important taxonomic characters of Naidinae. However, the significance of chaetotaxy has been questioned. The correlation between genetic variation and chaetal morphology within the genus Nais is investigated. Principally, chaetal character patterns are congruent with the evolutionary lineages revealed by genetic data, but at least nine lineages correspond to at most six nominal species. The species complex Nais communis/variabilis appears to be a gathering of at least five separately evolving lineages. That is, cryptic speciation is revealed.

    Finally, six molecular markers are used to elucidate the phylogenetic relationships within the group, and the resulting tree is used to track the evolution of morphological characters commonly used in naidine taxonomy. The tropical genera Dero, Branchiodrilus, and Allonais branch off from the base of the naidine tree of life, suggesting that Naidinae originally evolved in the tropics. Chaetal characters are shown to be homoplastic to a great extent within the group, most certainly contributing to the overall confusion in naidine systematics.

  • 2.
    Envall, Ida
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Erséus, Christer
    Zoologiska institutionen, Göteborgs universitet.
    Gustavsson, Lena
    Avdelningen för evertebratzoologi, Naturhistoriska riksmuseet.
    Ultrastructural investigation of coelomocytes in representatives of Naidinae and Rhyacodrilinae (Annelida, Clitellata, Tubificidae)2008In: Journal of Morphology, Vol. 269, no 9, p. 1157-1167Article in journal (Refereed)
    Abstract [en]

    Various types of free-floating cells are found in the coelomic fluid of representatives of several annelid groups. The ultrastructure of these "coelomocytes," however, has been studied to a limited degree. In this study, we used a transmission electron microscope to investigate the coelomocytes in specimens of five species of Naidinae and three species of Rhyacodrilinae (all oligochaetous clitellates within the family Tubificidae). These were compared with each other and with previously described coelomocytes of representatives of other oligochaete taxa. Only one distinguishable coelomocyte type was found in the studied specimens: a round to oblong cell without pseudopodia or other appendages, primarily containing membrane-bound granules of varying electron density, a prominent network of rough endoplasmic reticulum, and free ribosomes. This type differs to a great extent from most of the previously described coelomocytes, but shows similarities to certain types found in members of Enchytraeidae and Megascolecidae. Although we noticed some variation, we did not find any ultrastructural characters in these cells obviously useful for phylogenetic studies within Tubificidae.

  • 3.
    Envall, Ida
    et al.
    Stockholm University, Faculty of Humanities, Centre for the Study of Cultural Evolution.
    Gustavsson, Lena M.
    Erseus, Christer
    Genetic and chaetal variation in Nais worms (Annelida, Clitellata, Naididae)2012In: Zoological Journal of the Linnean Society, ISSN 0024-4082, E-ISSN 1096-3642, Vol. 165, no 3, p. 495-520Article in journal (Refereed)
    Abstract [en]

    The genus Nais is a group of oligochaetous clitellates, common in eutrophic freshwater habitats. About 30 species are described. Species identification is based primarily on chaetal characters, which are often subtle, inconsistent, and even overlapping between nominal species. We investigated the correlation between genetic variation and chaetal morphology in this genus. Eighty-one individuals from Europe, North America, and China were included in the study. Seventy-five of these were preserved as vouchers. They were scrutinized with regard to chaetal morphology, and ten different morphotypes were identified. Three molecular markers, two mitochondrial (the COI gene and 16S rDNA) and one nuclear (the ITS region), were used to establish the genetic lineages in the material. Genetic variation was found to be largely congruent with chaetal character patterns. However, at least nine separately evolving lineages (all supported by mitochondrial as well as nuclear data) correspond to at most six nominal species. Four morphotypes/lineages are recognized as Nais barbata, Nais christinae, Nais elinguis, and Nais stolci, respectively, whereas five, or possibly more, lineages represent a morphological continuum covering the variation of the Nais communis/variabilis complex. Thus, cryptic speciation is revealed. Our results indicate that a taxonomic revision of the genus will be needed in the future.

  • 4.
    Envall, Ida
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Gustavsson, Lena M.
    Swedish Museum of Natural History.
    Erséus, Christer
    University of Gothenburg.
    Genetic and morphological variation in “cosmopolitan” Nais worms (Annelida, Clitellata, Naididae): species diversity beyond that of current taxonomyManuscript (Other academic)
  • 5.
    Envall, Ida
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Gustavsson, Lena M.
    Swedish Museum of Natural History.
    Erséus, Christer
    University of Gothenburg.
    Naidine tree of life (Annelida, Clitellata, Naididae) revisited – a multigene approachManuscript (Other academic)
  • 6.
    Envall, Ida
    et al.
    Stockholm University, Faculty of Science, Department of Zoology.
    Källersjö, Mari
    Erséus, Christer
    University of Gothenburg.
    Molecular evidence for the non-monophyletic status of Naidinae (Annelida, Clitellata, Tubificidae)2006In: Molecular Phylogenetics and Evolution, ISSN 1055-7903, E-ISSN 1095-9513, Vol. 40, no 2, p. 570-584Article in journal (Refereed)
    Abstract [en]

    Naidinae (former Naididae) is a group of small aquatic clitellate annelids, common worldwide. In this study, we evaluated the phylogenetic status of Naidinae, and examined the phylogenetic relationships within the group. Sequence data from two mitochondrial genes (12S rDNA and 16S rDNA), and one nuclear gene (18S rDNA), were used. Sequences were obtained from 27 naidine species, 24 species from the other tubificid subfamilies, and five outgroup taxa. New sequences (in all 108) as well as GenBank data were used. The data were analysed by parsimony and Bayesian inference. The tree topologies emanating from the different analyses are congruent to a great extent. Naidinae is not found to be monophyletic. The naidine genus Pristina appears to be a derived group within a clade consisting of several genera (Ainudrilus, Epirodrilus, Monopylephorus, and Rhyacodrilus) from another tubificid subfamily, Rhyacodrilinae. These results demonstrate the need for a taxonomic revision: either Ainudrilus, Epirodrilus, Monopylephorus, and Rhyacodrilus should be included within Naidinae, or Pristina should be excluded from this subfamily. Monophyly of four out of six naidine genera represented by more than one species is supported: Chaetogaster, Dero, Paranais, and Pristina, respectively

  • 7.
    Erséus, Christer
    et al.
    University of Gothenburg.
    Envall, Ida
    Stockholm University, Faculty of Science, Department of Zoology.
    Marchese, Mercedes
    Instituto Nacional de Limnología (CONICET-UNL), Ciudad Universitaria, Santa Fe, Argentina.
    Gustavsson, Lena M.
    Swedish Museum of Natural History.
    The systematic position of Opistocystidae (Annelida, Clitellata) revealed by DNA data2010In: Molecular Phylogenetics and Evolution, ISSN 1055-7903, E-ISSN 1095-9513, Vol. 54, no 1, p. 309-313Article in journal (Refereed)
    Abstract [en]

    Opistocystidae Cernosvitov, 1936 is a largely Neotropical oligochaete taxon containing seven species. its familial status has never been formally challenged, although possible close relationships with Naididae and Phreodrilidae have been noted. Mitochondrial 12S and 16S rDNA, and nuclear 18S rDNA, of a range of aquatic oligochaete taxa, including Trieminentia corderoi (Opistocystidae), were analysed by Bayesian inference. This showed that T. corderoi is a derived lineage within Naididae, closely related to Pristina and its monotypic subfamily Pristininae. Opistocystidae as a whole (with its three genera, Opistocysta, Trieminentia, and Crustipellis) is thus likely to be a group within Naididae.

  • 8.
    Isaksson, Sven
    et al.
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Archaeological Research Laboratory.
    Funcke, Alexander
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution. University of Pennsylvania, USA.
    Envall, Ida
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution.
    Enquist, Magnus
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution.
    Lindenfors, Patrik
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Centre for the Study of Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    A Novel Method to Analyze Social Transmission in Chronologically Sequenced Assemblages, Implemented on Cultural Inheritance of the Art of Cooking2015In: PLoS ONE, ISSN 1932-6203, E-ISSN 1932-6203, Vol. 10, no 5, article id e0122092Article in journal (Refereed)
    Abstract [en]

    Here we present an analytical technique for the measurement and evaluation of changes in chronologically sequenced assemblages. To illustrate the method, we studied the cultural evolution of European cooking as revealed in seven cook books dispersed over the past 800 years. We investigated if changes in the set of commonly used ingredients were mainly gradual or subject to fashion fluctuations. Applying our method to the data from the cook books revealed that overall, there is a clear continuity in cooking over the ages - cooking is knowledge that is passed down through generations, not something (re-) invented by each generation on its own. Looking at three main categories of ingredients separately (spices, animal products and vegetables), however, disclosed that all ingredients do not change according to the same pattern. While choice of animal products was very conservative, changing completely sequentially, changes in the choices of spices, but also of vegetables, were more unbounded. We hypothesize that this may be due a combination of fashion fluctuations and changes in availability due to contact with the Americas during our study time period. The presented method is also usable on other assemblage type data, and can thus be of utility for analyzing sequential archaeological data from the same area or other similarly organized material.

  • 9.
    Lindenfors, Patrik
    et al.
    Stockholm University, Faculty of Humanities, Centre for Cultural Evolution. Stockholm University, Faculty of Science, Department of Zoology, Animal Ecology.
    Envall, Ida
    Stockholm University, Faculty of Humanities, Centre for Cultural Evolution.
    Isaksson, Sven
    Stockholm University, Faculty of Humanities, Centre for Cultural Evolution. Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Archaeological Research Laboratory.
    Enquist, Magnus
    Stockholm University, Faculty of Humanities, Centre for Cultural Evolution.
    An empirical study of cultural evolution: the development of European cookery from medieval to modern times2015In: Cliodynamics, ISSN 2373-7530, E-ISSN 2308-4294, Vol. 6, no 2, p. 115-129Article in journal (Refereed)
    Abstract [en]

    We have carried out an empirical study of long-term change in European cookery to test if the development of this cultural phenomenon matches a general hypothesis about cultural evolution: that human cultural change is characterized by cumulativity. Data from seven cookery books, evenly spaced across time, the oldest one written in medieval times (~1200) and the most recent one dating from late modernity (1999), were compared. Ten recipes from each of three categories (‘poultry recipes’, ‘fish recipes,’ and ‘meat recipes’) were arbitrarily selected from each cookery book by selecting the first ten recipes in each category, and the numbers (per recipe) of steps, separate partial processes, methods, ingredients, semi-manufactured ingredients, compound semi-manufactured ingredients (defined as semi-manufactured ingredients containing no less than two raw products), and self-made semi-manufactured ingredients were counted. Regression analyses were used to quantitatively compare the cookery from different ages. We found a significant increase in the numbers (per recipe) of steps, separate partial processes, methods, ingredients, and semi-manufactured ingredients. These significant increases enabled us to identify the development of cookery as an example of the general trend of cumulativity in long-term cultural evolution. The number of self-made semi-manufactured ingredients per recipe, however, tended to decrease over time, which may reflect the cumulative characteristics of cultural evolution at the level of society, considering the accumulation of knowledge that is required to industrialize food production.

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