Tobias Kånneby

Phylogeny of Thaumastodermatidae (Gastrotricha: Macrodasyida) Inferred from Nuclear and Mitochondrial Sequence Data

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.

Gastrotricha: A Marine Sister for a Freshwater Puzzle

Background 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. Methodology/Principal Findings 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. Conclusions/Significance 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.

Phylogeny of Chaetonotidae and other Paucitubulatina (Gastrotricha: Chaetonotida) and the colonization of aquatic ecosystems

Kånneby, T., Todaro, M. A., Jondelius, U. (2012). Phylogeny of Chaetonotidae and other Paucitubulatina (Gastrotricha: Chaetonotida) and the colonization of aquatic ecosystems. —Zoologica Scripta, 42, 88–105.

Nerve cells of Xenoturbella bocki (phylum uncertain) and Harrimania kupfferi (enteropneusta) are positively immunoreactive to antibodies raised against echinoderm neuropeptides

The phylogenetic position of Xenoturbella spp. has been uncertain since their discovery in 1949. It has been recently suggested that they could be related to Ambulacraria within Deuterostomia. Ambulacraria is a taxon that has been suggested to consist of Hemichordata and Echinodermata. The hypothesis that X. bocki was related to Ambulacraria as well as the hypothesis of a monophyletic Ambulacraria is primarily based on the analysis of DNA sequence data. We tested both phylogenetic hypotheses using antibodies raised against SALMFamide 1 and 2 (S1, S2), neuropeptides isolated from echinoderms, on X. bocki and the enteropneust Harrimania kupfferi. Both species showed distinct positive immunoreactivity against S1 and S2. This finding supports the Ambulacraria-hypothesis and suggests a close phylogenetic relationship of X. bocki to Ambulacraria. In particular, the presence of immunoreactivity against S2 can be interpreted as a synapomorphy of Enteropneusta, Echinodermata, and Xenoturbella spp

Two new species of Musellifer (Gastrotricha: Chaetonotida) from Florida and Tobago and the systematic placement of the genus within Paucitubulatina

Abstract 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.

A new nemertean species: what are the useful characters for ribbon worm descriptions?

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.

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

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.

The future of nemertean taxonomy (phylum Nemertea) — a proposal

Submitted: 15 January 2016 Accepted: 6 March 2016 doi:10.1111/zsc.12182 Sundberg, P., Andrade, S.C.S., Bartolomaeus, T., Beckers, P., von D€ ohren, J., Kr€amer, D., Gibson, R., Giribet, G., Herrera-Bachiller, A., Juan, J., Kajihara, H., Kvist, S., K anneby, T., Sun S.-C., Thiel, M., Turbeville, J.M. , Strand, M. (2016). The future of nemertean taxonomy (phylum Nemertea) — a proposal. —Zoologica Scripta, 45: 579–582. Corresponding author: Per Sundberg, University of Gothenburg, Department of Marine Sciences, Gothenburg, Sweden. E-mail: per.sundberg@gu.se Per Sundberg, University of Gothenburg, Department of Marine Sciences, Gothenburg, Sweden.. E-mail: per.sundberg@gu.se S onia C. S. Andrade, Departamento de Gen etica e Biologia Evolutiva, IB-Universidade de, S~ao Paulo, Brazil, S~ao Paulo, Brazil. E-mail: soniacsandrade@gmail.com Thomas Bartolomaeus, Patrick Beckers, J€orn von D€ohren, and Daria Kr€amer, University of Bonn, Institute of Evolutionary Biology and Animal Ecology, Bonn, Germany. E-mails: tbartolomaeus@evolution.uni-bonn.de, pbeckers@evolution.uni-bonn.de, jdoehren@evolution.uni-bonn.de, dkraemer@evolution.uni-bonn.de Ray Gibson, 94 Queens Avenue, Meols, Wirral, CH47 0NA, U.K. E-mail: bfginc@hotmail.co.uk Gonzalo Giribet, Museum of Comparative Zoology, Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA. E-mail: ggiribet@g.harvard.edu Alfonso Herrera-Bachiller, and Juan Junoy, Departamento de Ciencias de la Vida, Universidad de Alcal a, Madrid, Spain. E-mails: alfonso@herrerabachiller.com, juan.junoy@uah.es Hiroshi Kajihara, Faculty of Science, Hokkaido University, Sapporo, Japan. E-mail: kazi@mail.sci.hokudai.ac.jp Sebastian Kvist, Department of Natural History, Royal Ontario Museum, Toronto, Canada and Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada. E-mail: sebastian.kvist@utoronto.ca Tobias K anneby, Swedish Museum of Natural History, Department of Zoology, Stockholm, Sweden. E-mail: Tobias.Kanneby@nrm.se, tobiaskanneby@gmail.com Shi-Chun Sun, Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, China. E-mail: sunsc@ouc.edu.cn Martin Thiel, Facultad Ciencias del Mar, Centro de Estudios Avanzados en Zonas Áridas (CEAZA), Millennium Nucleus Ecology and Sustainable Management of Oceanic Island (ESMOI), Universidad Cat olica del Norte, Coquimbo, Chile. E-mail: thiel@ucn.cl James M. Turbeville, Department of Biology, Virginia Commonwealth University, Richmond, VA, USA. E-mail: jmturbeville@vcu.edu Malin Strand, Swedish Species Information Centre, The Sven Lov en Centre for Marine Sciences, Str€omstad, Sweden. E-mail: malin.strand@slu.se

Bifidochaetus, a new Arctic genus of freshwater Chaetonotida (Gastrotricha) from Spitsbergen revealed by an integrative taxonomic approach

Abstract. 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).

New species and new records of freshwater Chaetonotida (Gastrotricha) from Sweden

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.