Gastrotricha of Sweden – Biodiversity and Phylogeny

Tobias Kånneby

Department of Stockholm University 2011 Gastrotricha of Sweden – Biodiversity and Phylogeny Doctoral dissertation 2011

Tobias Kånneby Department of Zoology Stockholm University SE-106 91 Stockholm Sweden

Department of Zoology Swedish Museum of Natural History PO Box 50007 SE-104 05 Stockholm Sweden [email protected] [email protected]

©Tobias Kånneby, Stockholm 2011

ISBN 978-91-7447-397-1 Cover Illustration: Therése Pettersson Printed in Sweden by US-AB, Stockholm 2011 Distributor: Department of Zoology, Stockholm University

Till Mamma och Pappa

ABSTRACT Gastrotricha are small aquatic with approximately 770 known species. The group has a cosmopolitan distribution and is currently classified into two orders, and . The 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. hystrix and squamata, as well as rarer species, e. g. Haltidytes crassus, diacanthum and Stylochaeta scirtetica, are reported. In Paper II molecular data is used to infer phylogenetic relationships within the morphologically very diverse marine family (Macrodasyida). Results give high support for monophyly of Thaumastodermatidae and also the subfamilies Diplodasyinae and Thaumastoder- matinae. In Paper III the hypothesis of cryptic speciation is tested in widely distributed freshwater gastrotrichs. 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 (Chaetonotida), the largest family within Gastrotricha, is inferred. The group suffers from a troubled and is hypothesized to be non- monophyletic. Results show that members of 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.

Keywords: taxonomy, systematics, phylogeny, new species, cryptic species, Chaetonotidae, Dasydytidae, Thaumastodermatidae.

Swedish Gastrotricha Tobias Kånneby

CONTENTS

AVHANDLINGEN I KORTHET ...... 2 LIST OF PAPERS ...... 4 1. INTRODUCTION ...... 5 1.1 Historical overview...... 5 1.2 Morphology...... 8 1.2.1 Size and shape...... 8 1.2.2 Cuticle and body wall ...... 9 1.2.3 Alimentary canal...... 10 1.2.4 Nervous system and sense organs...... 10 1.2.5 Excretory organs ...... 11 1.2.6 Respiration and circulation ...... 11 1.2.7 Reproduction and cycle ...... 11 1.3 Biogeography...... 13 1.3.1 Dispersal ...... 13 1.4 Aims...... 14 2. METHODS ...... 14 2.1 Collection and documentation ...... 14 2.2 Further treatment...... 15 2.3 Molecular studies...... 15 3. SWEDISH FAUNA...... 16 3.1 Freshwater fauna...... 16 3.2 Marine fauna ...... 17 4. GASTROTRICH RELATIONSHIPS...... 17 4.1 Gastrotrich interrelationships...... 18 4.2 Cryptic species...... 19 5. FUTURE PERSPECTIVES...... 20 6. SUMMARY OF PAPERS ...... 21 7. LITERATURE CITED ...... 23 8. ACKNOWLEDGEMENTS...... 28 APPENDIX I – GASTROTRICHA REPORTED FROM SWEDEN...... 30 APPENDIX II – REFERENCES FIGURE 1 AND FIGURE 2 ...... 34 Swedish Gastrotricha Tobias Kånneby

AVHANDLINGEN I KORTHET Bukhårsdjur (Gastrotricha) är mycket små maskformiga ryggradslösa djur som lever i både sötvatten och marina miljöer. Gruppen utgör en del av det man brukar kalla meiofauna, ett samhälle av små djur som ofta lever mellan sandkorn och andra partiklar i akvatiska miljöer. I sötvatten kan bukhårsdjuren också leva på växter, ovanpå bottnen eller till och med i den fria vattenmassan. De lever av små organiska partiklar, bakterier eller alger och äts i sin tur av lite större ryggradslösa djur. Bukhårsdjur kännetecknas av att de har små hår, så kallade cilier, på undersidan som de använder för att ta sig fram. De har också häftrör med vilka de kan klistra fast sig mot underlaget om något skulle störa dem. Djuren är relativt vanliga men kan oftast inte ses med blotta ögat, de minsta bukhårsdjuren är bara en tiondels millimeter långa. Därför behöver man mikroskop för att dokumentera och artbestämma dem. Hittills har man hittat nästan 770 arter i hela världen men det finns fortfarande många delar av jordklotet som inte är undersökta. Bukhårsdjur delas in i två grupper. Den ena gruppen (Macrodasyida) innehåller nästan uteslutande marina avlånga maskar med häftrör på bakkroppen, på sidorna och kanske även på ryggen och i framändan. De är hermafroditer, samma individ är samtidigt både hane och hona eller så alternerar individen mellan hona och hane. Den andra gruppen (Chaetonotida) innehåller både marina och sötvattenslevande maskar som med få undantag har en kägelformad kropp. Hos denna grupp finns häftrören oftast bara på bakkroppen och sitter på en gaffelliknande struktur som kallas furka. Många arter inom gruppen förökar sig genom jungfrufödsel, vilket innebär att avkomman utvecklas ur obefruktade ägg, men hermafroditer förekommer också hos marina arter. I Sverige är bukhårsdjur en dåligt studerad grupp och 2007 kände man bara till 22 marina och 7 sötvattenslevande arter. Det enklaste sättet att samla in bukhårsdjur är att ta upp bottenmaterial, växter eller sand med en mycket finmaskig håv eller för hand. Proverna letas därefter igenom under en stereolupp och djuren kan plockas ut. Oftast måste man söva djuren med magnesiumklorid, som sätter nervsystemet ur spel, och hindrar dem från att häfta fast vid olika ytor. För att identifiera djuret måste det studeras levande under ett speciellt mikroskop, ett så kallat differential interferens kontrast mikroskop (DIC) som ökar kontrasten på de viktiga strukturerna hos det mer eller mindre transparenta djuret. När djuret är fotograferat och väl dokumenterat kan det sugas upp från objektsglaset och sparas för till exempel genetiska studier. Släktskapen inom gruppen är dåligt kända och klassificeringen grundar sig, främst hos Chaetonotida, på utbredning och form av fjäll och taggar. Dessa karaktärer är väldigt variabla och verkar inte fungera för högre klassificering inom gruppen. Många av de nuvarande grupperna inom Chaetonotida är förmodligen inte monofyletiska, det vill säga de härstammar inte från en gemensam förfader. Problemen är mest påtagliga i den stora familjen Chaetonotidae, som förutom variationen hos fjäll och taggar är en homogen grupp. Vissa släkten inom denna familj är enbart definierade på fjällens utseende. Ett bra exempel är det största släktet Chaetonotus, som både har marina och sötvattenslevande representanter. Denna grupp är en löst sammansatt grupp som kännetecknas av fjäll med taggar, vilket också finns hos andra släkten inom familjen. Inom Macrodasyida verkar nuvarande klassificering vara mer stabil. Den grundar sig inte i lika stor utsträckning på de variabla strukturerna på kroppsytan utan istället på reproduktionssystemets uppbyggnad, utbredning och antal häftrör samt bakkroppens form. Syftet med denna avhandling är att undersöka hur många arter av bukhårsdjur som finns i Sverige, främst med fokus på mångfalden hos sötvattenslevande djur. Vidare undersöks också släktskapen mellan grupper av bukhårsdjur med hjälp av olika gener. En del av avhandlingen tar också upp kryptiska arter, det vill säga arter som ser väldigt lika ut men skiljer sig åt genetiskt. Idag är 90 arter av bukhårsdjur kända från Sverige, vilket innebär att antalet arter mer än tredubblats under en period av knappt fyra år. Av dessa arter återfinns 52 i sötvatten medan resterande 38 är marina. Många av de sötvattenslevande arterna samt 5 nya arter för vetenskapen presenteras i Papper I, III och IV. Det finns fortfarande mycket obestämt material och en del av detta utgör förmodligen nya arter. Om man bara tittar på antalet sötvattenslevande arter i Sverige och jämför det med andra närliggande länder, så finns det mycket kvar att upptäcka. I Polen har man hittat 98 arter och i Tyskland 90 arter, och som Europas femte största land till ytan bör det finnas 2 Swedish Gastrotricha Tobias Kånneby

åtminstone lika många eller kanske till och med fler arter i Sverige. De flesta arter har hittats i ganska näringsrika eller stillastående vatten där andmat, vitmossa, vass eller näckrosor är vanliga. De kargare subarktiska norra och nordvästra delarna av landet har visat sig hysa många ovanliga arter. Den vanligaste marina arten i Sverige är Turbanella cornuta, som hittats både i Östersjön och på västkusten. Lepidodermella squamata, Lepidochaetus zelinkai och Chaetonotus hystrix är de vanligaste sötvattenslevande arterna och har troligen en stor utbredning, kanske över hela landet. I denna avhandling ingår också tre arbeten som behandlar släktskapen inom bukhårsdjur. I Papper II undersöks den största familjen inom Macrodasyida, Thaumastodermatidae. Denna grupp uppvisar en stor variation i morfologiska karaktärer men definieras utifrån karaktärer hos reproduktionsorganen. Med hjälp av tre gener visas att gruppen är monofyletisk, alltså härstammar från en gemensam förfader. Vidare har familjen delats in i två undergrupper, även de definierade utifrån reproduktionsorganens uppbyggnad. Dessa grupper erhålls också som monofyletiska. Studien visar dock på att det största släktet Tetranchyroderma förmodligen inte härstammar från en gemensam förfader. Studien tyder också på att Turbanellidae, en av de andra större familjerna inom Macrodasyida, verkar vara en monofyletisk grupp. I Papper III presenteras den första analysen av flera gener för att utröna förekomsten av kryptiska arter och släktskap inom den största familjen Chaetonotidae. Många arter inom denna grupp har en stor geografisk utbredning. Resultaten tyder på att den vanliga arten Lepidodermella squamata i själva verket kan bestå av åtminstone två kryptiska arter. Det finns vissa yttre karaktärer som möjligen kan användas för att identifiera dessa. För Heterolepidoderma ocellatum har även formen sphagnophilum, som kännetecknas av en rad av taggar på ryggsidan, beskrivits. Resultaten visar att denna form skiljer sig så pass mycket genetiskt från H. ocellatum att den bör utgöra en egen art. Därför beskrivs den som ny under namnet Heterolepidoderma acidophilum. Släktskapsanalysen inom Chaetonotidae visar att endast tre av sex släkten verkar härstamma från en gemensam förfader, vilket visar att nuvarande klassificering skapar onaturliga grupper och behöver revideras. I Papper V angrips också släktskapen inom familjen Chaetonotidae, som i denna studie inkluderar många fler arter än Papper III. Vi använder samma gener som för Thaumastodermatidae och visar att gruppen även inkluderar den semi-planktoniska familjen Dasydytidae. Den marina familjen Xenotrichulidae utgör en systergrupp, det vill säga den närmast besläktade nu levande gruppen, till Chaetonotidae och Dasydytidae. Av släkten representerade av mer än en art så är det endast tre stycken, samma som erhålls i Papper III, som verkar härstamma från en gemensam förfader. Vidare visar det sig att arter som har olika typer av fjäll och taggar grupperar tillsammans vilket tyder på att dessa strukturer inte reflekterar släktskap i så stor utsträckning som man tidigare trott. Inom Chaetonotidae och Dasydytidae verkar marina arter av släktet vara en systergrupp till alla andra arter vilket tyder på ett marint ursprung för familjen. Aspidiophorus kännetecknas av fjäll som bärs upp av en stjälk, dessa återfinns också hos arter inom familjen Xenotrichulidae. Sammantaget har denna avhandling avsevärt ökat vår förståelse och kunskap om bukhårsdjurens biodiversitet och spridning i Sverige. Studier av släktskapen inom gruppen har gett viktiga evolutionära såväl som taxonomiska insikter.

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LIST OF PAPERS

This thesis is based on the following papers, referred to in the text by their roman numerals:

I. Kånneby, T., Todaro, M. A., Jondelius, U. 2009. One new species and records of Ichthydium Ehrenberg, 1830 (Gastrotricha: Chaetonotida) from Sweden with a key to the . Zootaxa, 2278, 26–46.

II. Todaro, M. A., Kånneby, T., Dal Zotto, M., Jondelius, U. 2011. Phylogeny of Thaumastodermatidae (Gastrotricha: Macrodasyida) inferred from nuclear and mitochondrial sequence data. PLoS ONE, 6(3), e17892. doi:10.1371/journal.pone. 0017892.

III. Kånneby, T., Todaro, M. A., Jondelius, U. A phylogenetic approach to species delimitation in freshwater Gastrotricha from Sweden. Submitted to Hydrobiologia.*

IV. Kånneby, T. New species and new records of freshwater Chaetonotida (Gastrotricha) from Sweden. Accepted for publication in Zootaxa.*

V. Kånneby, T., Todaro, M. A., Jondelius, U. Phylogeny of Chaetonotidae (Gastrotricha) inferred from nuclear and mitochondrial genes. Manuscript.

Paper I. © Magnolia Press *Species descriptions in this thesis are not issued for permanent scientific records or purposes of Zoological Nomenclature and are not regarded as published within the meaning of the International Code of Zoological Nomenclature (ICZN), Ed. 4, Article 8.2 and 8.3.

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1. INTRODUCTION Gastrotricha are small vermiform or tenpin- structure of the gastrotrich community shaped acoelomate invertebrate (Kisielewski, 1981). common to most aquatic environments. The Gastrotricha is considered a monophyletic group constitutes an important part of the group based on the following apomorphies: meiofauna and has a cosmopolitan distribution (i), a multilayered cuticle; (ii), locomotory and (Todaro & Hummon in Artois et al., 2011). To sensory cilia covered by epicuticle; (iii), outlet date almost 770 species have been described. of adhesive duo-gland system covered by Although the group is abundant and can reach cuticle; and (iv), peculiar helicoidal muscles high densities, especially in marine habitats, surrounding the alimentary canal (Hochberg & the minute size and the soft body of the Litvaitis, 2001a; Todaro et al., 2006). Another animals, make them hard to work with. important trait for the group is the ventral Because of this gastrotrichs have been ciliation, although not an apomorphy, this somewhat neglected by taxonomists and the single feature gave the group its name, group is in great need of taxonomic revisions. Gastrotricha (G. gaster, stomach; trichos, Gastrotrichs are among the smallest metazoans hair). The group is currently divided into two known and certain species can have a total orders, the almost exclusively marine body length of only 70 µm. However, most Macrodasyida and the marine and freshwater species attain larger sizes, some freshwater Chaetonotida. Macrodasyida are vermiform species can reach body lengths of up to 600 or animals with anterior, lateral, dorsal and 700 µm, while marine species are generally posterior adhesive tubes (Figure 1). They are larger and bulkier and can reach body lengths and usually possess of up to 3.5 mm (Remane, 1935–36; Todaro & pharyngeal pores that help expelling excess Hummon in Artois et al., 2011). water taken in with the food. Chaetonotida are In marine environments most species live tenpin-shaped and characterized by their interstitially and are found in fine to medium bifurcated posterior end carrying 0 to 4 grained clean sand (Hummon, 1982). adhesive tubes, but usually 2 are present. Most Freshwater species are usually epibenthic or species have a very elaborate cuticle epiphytic but can also be found interstitially. sculptured into various arrangements of scales Freshwater habitats especially rich in and/or spines (Figure 2). gastrotrichs are Sphagnum bogs and small still waters with Lemna (Schwank, 1990). 1.1 Historical overview Although the group is represented in almost all With the invention of the microscope by environments, distribution can be patchy and Antonie van Leeuwenhoek in the 1670s a new is probably controlled by food resources such world opened to the naturalists of that time. as particulate organic material and biofilms The microscope was an important tool in the (Kisielewski, 1981; Balsamo et al., 2004). The study of what the scientists of those days ecological role of gastrotrichs is not fully called “Animalcules”, a term including small understood but they are hypothesized to be an animals or microorganisms seen through a important link between larger invertebrates microscope. and the microbial loop (Balsamo & Todaro, The first known observations of 2002). Certain freshwater species may be gastrotrichs were made by Joblot in 1718. He sensitive to environmental change as they referred to the tenpin-shaped animals as small prefer still nutrient rich waters, and can thus fishes (Murray, 1913). More than half a act as important bioindicators. However, most century later the first species were described. species can cope with harsh environments (e. Müller (1773) regarded the gastrotrichs he g. drought or low temperatures) by production found in freshwater as and , of resting eggs. These eggs are characterized hence the names Trichoda larus and Cercaria by a thick ornamented shell and their podura (Figure 3). In the 1830s the animals durability is dependent on species and does that Müller described were classified as not only affect abundance but also the 5 Swedish Gastrotricha Tobias Kånneby

Figure 1. Families and genera of the Macrodasyida. 1. Dactylopodola, 2. Dendrodasys, 3. Dendropodola, 4. Chordodasiopsis, 5. Xenodasys, 6. Crasiella, 7. Planodasys, 8. Lepidodasys, 9. Cephalodasys, 10. Dolichodasys, 11. Megadasys, 12. Mesodasys, 13. Paradasys, 14, Pleurodasys, 15. Macrodasys, 16. Urodasys, 17. Desmodasys, 18. Dinodasys, 19. Paraturbanella, 20. Prostobuccantia, 21. Pseudoturbanella, 22. Turbanella, 23. Marinellina, 24. Redudasys, 25. Acanthodasys, 26. Diplodasys, 27. Hemidasys (extinct), 28. Oregodasys, 29. Pseudostomella, 30. Ptychostomella, 31. Tetranchyroderma, 32. Thaumastoderma. Bold italic numbers indicate genera present in Sweden. Not to scale. Modified from various sources (Appendix II).

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Figure 2. Families and genera of the order Chaetonotida. 1. Neodasys, 2. Draculiciteria, 3. Heteroxenotrichula, 4. Xenotrichula, 5. Dichaetura, 6. Proichthydioides, 7. Proichthydium, 8. Anacanthoderma, 9. Chitonodytes, 10. Dasydytes, 11. Haltidytes, 12. Ornamentula, 13. Setopus, 14. Stylochaeta, 15. Kijanebalola, 16. Neogossea, 17. Diuronotus, 18. Musellifer, 19. Arenotus, 20. Aspidiophorus, 21. Caudichthydium, 22. Chaetonotus, 23. Fluxiderma, 24. Halichaetonotus, 25. Heterolepidoderma, 26. Ichthydium, 27. Lepidochaetus, 28. Lepidodermella, 29. Rhomballichthys, 30. Polymerurus, 31. Undula. Bold italic numbers indicate genera present in Sweden. Not to scale. Modified from various sources (Appendix II).

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Rotatoria by Ehrenberg (1838). The genera Chaetonotus and Ichthydium were erected already in 1830, hence Trichoda larus became Chaetonotus larus and Cercaria podura became Ichthydium podura. The first marine gastrotrich, Turbanella hyalina, was described in the 1850s (Schultze, 1853), but it would take more than half a century until marine environments were thoroughly studied with regard to gastrotrichs. Metschnikoff (1865) was the first to acknowledge the ventral ciliation, which has become the hallmark for the group, and assigning the name Gastrotricha. Zelinka (1889) published the first monograph of the group dealing with biology, classification and morphology. At that time there were four different views of gastrotrich relationships to other groups: (i), gastrotrichs are as proposed by Ehrenberg (1838); (ii), they are flatworms as proposed by Schultze (1853); Figure 3. Fac-simile of the original description of (iii), gastrotrichs are related to rotifers as Cercaria podura, now Ichthydium podura, from Müller (1773). proposed by Metschnikoff (1865); and (iv), they are closely related to as late 1800s the interest for gastrotrichs was proposed by Ludwig (1875). limited in North America. In the 1940s and Zelinka (1889) regarded gastrotrichs as a 50s Brunson paved the way for gastrotrich group within Trochelminthes together with research in America, focusing mainly on rotifers. During the early 1900s species were freshwater gastrotrichs. mostly described and reported from freshwater. Until the works of Remane in the 1.2 Morphology mid 1920s only a handful of species had been The following sections give a brief reported from marine environments. The introduction to gastrotrich morphology. pioneering work of Adolf Remane is summarized in Bronn’s Klassen und 1.2.1 Size and shape Ordnungen des Tierreichs (1935-36). Remane Gastrotrichs are very small. As a rule of thumb regarded gastrotrichs as a class within Macrodasyida are generally larger and bulkier “Aschelminthes”, an assemblage of triplo- than Chaetonotida. The macrodasyidan blastic vermiform animals that contained Megadasys pacificus can attain lengths of up Rotatoria, Nematoda, , Acan- to 3.5 mm while the largest chaetonotidan, thocephala, and . This Polymerurus elongatum can reach lengths of view was retained by Hyman (1951) and up to 770 µm. Heterolepidoderma lamellatum Ruppert (1991). “Aschelminthes” is now is the smallest gastrotrich known to date and known to be a non-monophyletic group (e. g. adult animals are only 70 µm in total body Winnepenninckx et al., 1995). length (Remane, 1935–36; Todaro & By tradition of research most gastrotrichs Hummon in Artois et al., 2011). have been described from Europe. During the th Chaetonotida are, with exception for first half of the 20 century researchers were Neodasys, bottle or tenpin-shaped (Figure 4, mainly active in Germany, Italy and Poland. 5). The head usually takes the shape of one to However, at that time scientific expeditions five lobes, each lobe often covered by were also undertaken to colonies or former cuticular plates known as cephalion, epi- and colonial areas in Africa, South America and hypopleuria (Figure 5). The head is often Asia. Except for the works of Stokes in the separated from the trunk by a neck

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richly sculptured into various arrangements of scales, spines and hooks or combinations of these (e. g. most Chaetonotida and Thaumastoderma- tidae) (Figure 6C, E). In Chaetonotida the nature of the cuticular structures are important taxonomic cha- racters on species level. Species with a thin and smooth cuticle are often more flexible than species with a thick and orna- mented cuticle. In many species the scales and spines generally increase in size towards the Figure 4. Habitus of Xenotrichula velox showing some morphological characters. posterior end (Figure 6E). constriction. In the trunk region the lateral The epidermis is cellular in most body sides may be parallel in small and thin Macrodasyida and syncytial with few cells in species or elongated species, or convex in Chaetonotida (Ruppert, 1991). On the ventral stouter species. The body gradually tapers of side the epidermis consists of ciliated cells into the base of the furca. The furca is a fork- used for locomotion. In some gastrotrich taxa like structure that carries distal adhesive tubes these epidermal cells are monociliated, but in (Figure 4, 5). Usually two adhesive tubes are most they are multiciliated. The ciliation may present, but may also be absent (e. g. cover the whole ventral surface but can also Dasydytidae). The ventral side is more or less form patterns, e. g. transverse or longitudinal flat while the dorsal side is arched but the bands, patches or tufts. In Xenotrichulidae whole body can be rounded in some semi- groups of cilia form thicker structures called planktonic species. cirri (Figure 4). The epidermis also contains In Macrodasyida the body is more sensory cells, nerve cells, gland cells and elongated and vermiform than in Chaeto- (d’Hondt, 1971). The adhesive tubes notida. The body sides are usually parallel and are fed by a duo-gland system, where one hold lateral adhesive tubes (Figure 6A). A gland produces an adhesive substance and the neck may be present but it is not as prominent other a releasing substance (Tyler & Rieger, as in Chaetonotida. The posterior end is 1980; Ruppert, 1991) (Figure 5). usually lobed, bi-lobed or tail-like and holds The muscular system consists of both several adhesive tubes. In addition to the longitudinal and circular muscles. From the anterior and posterior adhesive tubes, lateral outside to the inside the muscular system is and dorsal adhesive tubes may also be present. composed of circular muscles and 4 to 12 Some groups (e. g. Thaumastoderma) and pairs of longitudinal muscle bands (Figure 5). certain other species have tentacles in the The alimentary canal is surrounded by a series anterior end (Figure 4). of circular muscles that form the splanchnic musculature and the digestive tract may also 1.2.2 Cuticle and body wall possess helicoidal muscles (Remane, 1935– The gastrotrich body, including cilia, is 1936; Hochberg & Litvaitis, 2001a). In covered by a thin bilayered cuticle that gives Macrodasyida an additional pair of somatic support (Ruppert, 1991). The cuticle can be longitudinal muscles is present as ventrolateral smooth (e. g. Arenotus, Ichthydium and most muscle bands aiding body movement. Some marine families) (Figure 6B) but is usually Chaetonotida possess dorsoventral muscle

9 Swedish Gastrotricha Tobias Kånneby bands that antagonize the movements of the innervates the and intestine; and (iii), longitudinal muscle bands (Leasi et al., 2006). the peripheral nervous system that innervates sensory structures of the head and body. 1.2.3 Alimentary canal The gastrotrich alimentary canal is generally complete. The round to oval mouth is situated terminally or subterminally. The mouth ring may contain ridges, denticles and other sharp structure to facilitate digestion (Schwank, 1990; Balsamo & Todaro, 2002). In Chaetonotida a short buccal capsule is present, containing longitudinal ridges and sometimes sharp teeth, between the mouth and the pharynx (Hyman, 1951; Schwank, 1990). The pharynx is an elongated muscular tube, 1/6 to 1/3 of total body length, and similar to the pharynx (Figure 4, 5). Food particles are sucked in by powerful contra- ctions of the pharynx musculature. The pharynx lumen is Y-shaped in Chaetonotida and inverted Y-shaped in Macrodasyida. Members of Macrodasyida (except Lepido- dasyidae) have pharyngeal pores, situated in the posterior part of the pharynx, that help expel excess water taken in with food particles. In Chaetonotida bulbous enlarge- ments may be present anteriorly and/or posteriorly. The pharynx is in turn connected to a straight intestine via the pharyngeal intestinal junction (Hyman, 1951) (Figure 5). This structure acts as a valve preventing food particles from the intestine to enter the pharynx when it is contracted to suck in new food particles. The anterior part of the intestine in freshwater Chaetonotidae sometimes has a granulated appearance. Bennett (1978) reported that, at least freshwater gastrotrichs may have a well developed lipid metabolism because of the presence of lipid globules in the intestine. The intestine ends in a subterminal ventral and is usually covered by the ventral terminal scales in Chaetonotida (Figure 5).

1.2.4 Nervous system and sense Figure 5. Gastrotrich morphology. 1) Cephalion. 2) organs Anterior sensory ciliary tuft. 3) Epipleuria. 4) Posterior sensory ciliary tuft. 5) Hypopleuria. 6) Cerebral According to Hochberg (2007) the gastrotrich ganglion. 7) Anterior lateral longitudinal muscle. 8) nervous system can be divided into three Salivary gland. 9) Pharynx. 10) Pharyngeal intestinal components: (i), the central nervous system junction. 11) Protonephridium. 12) Intestine. 13) Posterior lateral longitudinal muscle. 14) Egg. 15) that consists of the circumpharyngeal cerebral Dorsal muscles. 16) Anus. 17) Adhesive/releasing ganglion and paired or multiple nerve cords; glands. 18) Adhesive tube muscle. 19) Adhesive tube. (ii), the stomatogastric nervous system that Modified from Remane (1927a). 10 Swedish Gastrotricha Tobias Kånneby

Gastrotrichs have a rather large cerebral paired protonephridia are made up by one ganglion that forms a lobe on each side of the and a contorted mass of tubules that pharynx (Figure 5). The lobes are connected surface on the ventral side (Kieneke et al., dorsally and by a small commissure ventrally, 2008a). Neodasys and Macrodasyida possess with each lobe giving rise to lateral nerve several pairs of protonephridia (Kieneke et al., cords that extend to the posterior part of the 2007). The number of flame cells varies body (Teuchert, 1977). In addition the cerebral between the different genera and may increase ganglion gives rise to nerve cords that extend with age (Teuchert, 1967; d’Hondt, 1971). In anteriorly and connect to the sensory ciliary some cases glands on the body surface may tufts. The sensory structures are usually simple also help excrete waste products (Schwank, and often tactile or rheoreceptive (Bullock & 1990). Horridge, 1965). They occur as spines, setae, cilia and tentacles and are often concentrated 1.2.6 Respiration and circulation on the head but present all over the body. In There are no special respiratory or circulatory Chaetonotids the setae are present in the neck organs in gastrotrichs. They are small animals region and the posterior trunk region. The and respiration takes place by diffusion posterior pair is often anchored by a special through the body wall. Hemoglobin containing scale that differs from the other scales of the cells, adjacent to muscle and nervous tissue, same region. The setae may also be anchored are known from Neodasys and may facilitate by small papillae. Ciliary tufts on the head storage or diffusion of oxygen (Colacino & work as tactile receptors but are also used for Kraus, 1984). locomotion (Figure 5). Certain taxa also have ciliated depressions or furrows on the head 1.2.7 Reproduction and life cycle which may have chemosensory function Species within Macrodasyida are sequential or (Remane, 1927b; Schwank, 1990). In some simultaneous hermaphrodites with a complex species, e. g. Heterolepidoderma ocellatum reproduction system (Balsamo et al., 2002). and Chaetonotus oculifer, pseudocelli are They have one or two testes and one or two present (Figure 6F). These structures consist ovaries. The testes lie laterally along the of pigment granules that are enclosed in the anterior part of the intestine, each giving rise cerebral ganglion. Balsamo (1980) showed to a canal which emerges through a common that Lepidodermella squamata preferred pore (Hummon & Hummon, 1983). colored light over white light. The sensitivity Spermatozoa are usually filiform but differ on for light is probably facilitated by some kind species and genus level (Fregni, 1998a). of dermal light sense analogous to that in Ovaries lie laterally and ventrally on either some rotifers. side of the anterior or posterior part of the In Macrodasyida sensorial organs may intestine. A single ovary is present in take the form of tentacles (e. g. Xenodasys and Lepidodasyidae and some Thaumastoderma- Chordodasiopsis), piston pits (e. g. Macro- tidae (d’Hondt, 1971; Balsamo & Todaro, dasys), spatulate- or antenna-like tentacles (e. 2002). Secondary reproductive structures are g. Tetranchyroderma and Thaumastoderma). also present in the form of a frontal organ and Recently Marotta et al. (2008) investigated the a caudal organ, their name referring to their drumstick-like sensory organs of Pleurodasys relative position in the body (Ruppert & Shaw, helgolandicus, and proposed them to be 1977). The sac-like frontal organ is situated putative gravireceptors. In Dactylopodola close to the mature eggs and acts as a seminal baltica photoreceptors with simple pigment receptacle, like in Gnathostomulida, receiving cups are situated just below the epidermis from other individuals. The caudal (Hochberg & Litvaitis, 2003). organ ejects sperm through a cuticular tube into the frontal organ of another individual 1.2.5 Excretory organs (Ruppert, 1991). Although self fertilization is Waste substances are probably excreted by possible, it does not seem to take place means of protonephridia, which also have an (Balsamo, 1992). osmoregulatory function. In

11 Swedish Gastrotricha Tobias Kånneby

Figure 6. Representatives of Gastrotricha showing some important morphological characters. A) Macrodasyida, B–H) Chaetonotida. A) Turbanella cornuta, habitus showing distribution of adhesive tubes. B) Ichthydium squamigerum, habitus. Note the smooth cuticle. C) Aspidiophorus tetrachaetus, dorsal view showing distribution of scales. D) Heterolepidoderma macrops, habitus showing a large egg. E) Lepidochaetus zelinkai, lateral view showing the increase in spine length from anterior to posterior body end. F) Chaetonotus oculifer, dorsal view of head showing ocellar granule (arrow head). G) Heterolepidoderma ocellatum, posterior portion of body showing the X-organ (arrow) and packets of spermatozoa (arrow head). H) Lepidodermella squamata, habitus of juvenile specimen. Note the length of the pharynx and the lack of reproductive structures. Scale bars: B, F and G, 10 µm; C, 20 µm; D and H, 25 µm; E, 50 µm; A, 100 µm. Photo A: M. A. Todaro.

12 Swedish Gastrotricha Tobias Kånneby

In Chaetonotida reproduction is less complex four phases (Balsamo & Todaro, 1987; 1988). than in Macrodasyida. Most species are First is the embryonic phase which starts when parthenogenetic females, but some brackish the egg is laid. In Chaetonotus maximus the and marine species are simultaneous or embryo starts to develop after one hour. proterogynic hermaphrodites (e. g. Muselli- Development lasts for about one day and feridae and Xenotrichulidae). In Neodasyidae muscular contractions in the embryo facilitate a pair of testes is situated on either side of the hatching (Balsamo & Todaro, 1987). The anterior part of the intestine (d’Hondt, 1971; second, postembryonic or prereproductive Balsamo, 1992). The ovaries are situated in a phase (Figure 6H), is characterized by rapid ventrolateral position close to the intestine. growth and ends when the animal is capable of Based on the structure of the reproduction reproduction. In this phase there may be an system and embryological studies Balsamo increase of the cuticular structures (Hyman, (1992) claimed that the general trend in 1951; Amato & Weiss, 1982). During the Chaetonotida is a reduction or loss of male reproductive phase, 3 to 6 eggs are produced reproductive structures, from hermaphroditism by apomictic and laid one at a to parthenogenesis. Secondary structures are time by rupture of the body wall (Hummon, reduced to an organ called the X-organ (Figure 1984a). The last phase is the postpartheno- 6G), which is situated ventrally at the genetic phase during which both spermatozoa posterior part of the intestine (Balsamo, 1992, and eggs may be present in the body at the Weiss, 2001). It is unclear if this organ same time (see e. g. Weiss, 2001) (Figure 6G). functions as a seminal receptacle, like the The X-organ, reported from several genera, frontal organ in Macrodasyida. Most fresh- also develops during this phase (Kisielewska, water Chaetonotida produce 4 to 5 eggs, one at 1981; Hummon, 1984b; Balsamo & Todaro, a time. The eggs are among the biggest in the 1987; 1988; Weiss, 2001). animal compared to body size and more than 75% of the trunk may be occupied 1.3 Biogeography by the egg (Figure 5, 6D). The last egg Like many other small metazoan animals produced by a female is usually a dormant egg Gastrotricha has a cosmopolitan distribution. that can endure harsh environmental cond- They are known from all continents with a itions (Balsamo, 1992). bias of species reported from Europe. Many The eggs undergo a modified type of areas of the world still remain unexplored and radial that differs between the two lots of species still remain to be discovered. orders. In a few Macrodasyida an oviduct is The freshwaters of tropical areas are visible but a female pore is lacking, the egg is especially neglected and may give important thereby laid through rupture of the body wall insights in the evolution of the group. (Balsamo, 1992). In Chaetonotida the eggs are Kisielewski (1991) made exhaustive studies in laid through the ventral-caudal end of the Brazil, which contributed significantly to the body, a genital pore is sometimes present as in knowledge of the freshwater fauna, but also Gnathostomulida. The eggs are oval and raised many questions. Additionally very usually ornamented (Figure 6D), sometimes harsh environments should not be neglected. only on one side, not unlike eggs, Recently the genus Desmodasys was reported and are often positioned in the surface film or from a hydrothermal vent (Kieneke & Zekely, close to an object (grain of sand, parts of 2007) and the genera Chaetonotus and etc.). The ornamentation may help the Thaumastoderma have been reported from egg to adhere to the substratum (Hyman, Antarctica (Sudzuki, 1964; Kieneke, 2010). 1951; Balsamo, 1992). The gastrotrich life cycle is short and development is direct. The 1.3.1 Dispersal life span is usually a couple of weeks but the Many morphological species of gastrotrichs marine chaetonotid Aspidophorus polystictos are known to be cosmopolitan. Gastrotrichs has been shown to live for up to 50 days in the have direct development and hence lack larval laboratory (Balsamo & Todaro, 1988). The stages for dispersal. In marine environments life cycle of freshwater gastrotrichs consists of they live interstitially and in freshwaters they 13 Swedish Gastrotricha Tobias Kånneby are usually isolated from other areas. Paper III – The extent of cryptic species According to Sterrer (1973) a marine species within some commonly reported freshwater can be considered as cosmopolitan if it is gastrotrichs are examined. In addition the first found in two or more including multi gene approach for elucidating part of the connected seas. In Gastrotricha it is estimated phylogenetic relationships within the largest that up to 10% of the marine species on either family Chaetonotidae is presented. side of the Atlantic can be regarded as cosmopolitan species. Many gastrotrichs have Paper IV – This study presents new a very small body size as well as long spines species and new Swedish records of fresh- which may aid dispersal by means of flotation water Chaetonotidae and Dasydytidae. Each with sea currents (Ruppert, 1977a). species is accompanied by photographs of Many freshwater species also have a taxonomically important characters. cosmopolitan distribution (e. g. Chaetonotus (C.) maximus and Lepidodermella squamata). Paper V – Both nuclear and mito- At species level 30% of the European and chondrial genes are used to investigate the 50% of the South American gastrotrich phylogenetic relationships within Chaeto- freshwater fauna appear to be cosmopolitan notidae. Special attention is given to the (Balsamo et al., 2008). Most freshwater largest genus, Chaetonotus. The evolution of gastrotrichs have resting eggs, with a thick Chaetonotidae is discussed in the light of the ornamented durable shell, which ensures obtained results. survival of offspring in harsh environments. These eggs can perhaps be dispersed as 2. METHODS aerosols during drought. Moreover birds and other animals that spend lots of their time 2.1 Collection and documentation searching for food in wetlands and migrate Gastrotrichs can basically be collected from from one area to another may also carry all kinds of aquatic environments, but they are dormant and perhaps also living stages of most common in clean medium to fine grained small animals in their feathers or fur marine sands or still nutrient rich freshwater (Schwank, 1990). When introduced to a new ponds. In freshwater habitats bogs with suitable habitat a single individual can give Sphagnum and ponds with Lemna are rise to a new population by means of especially rich in gastrotrichs (Figure 7). parthenogensis.

1.4 Aims The purpose of this thesis is to investigate the Swedish gastrotrich biodiversity and relation- ships within the group. The main focus lies on freshwater taxa but data on marine taxa is also presented. This thesis is part of the Swedish Taxonomy Initiative (STI), aiming to map Swedish metazoan biodiversity.

Paper I – New species and new records of freshwater Gastrotricha of the genus Ichthydium are presented together with a key to the genus. Figure 7. Small ponds with duckweed (Lemna spp.) are usually rich in gastrotrichs.

Paper II – Relationships of the morpho- In marine habitats collection is usually logically diverse marine family Thaumasto- done by scooping up the top layer of sand dermatidae are investigated using the first from the littoral or sublittoral. In freshwaters multi gene approach for phylogenetic studies samples can be collected with a net within Gastrotricha.

14 Swedish Gastrotricha Tobias Kånneby with a mesh size of 25 µm. It is also a very pharynx, should be documented at a high good idea to collect benthic material, aquatic magnification. plants or by hand. Freshwater samples are preferably stored in small aerated aquaria 2.2 Further treatment from which subsamples can be sucked up with When the animal has been sufficiently a pipette. Clean marine samples that contain recorded it can usually be recovered from the only a small amount of organic matter can be slide for further treatment, including stored in a refrigerator. Samples yield the permanent mounting and molecular studies. highest number of species just after collection. This is a very tricky part but by adding water However, gastrotrichs can survive for as long the cover slip can be gently lifted with a small as a year in freshwater aquaria only adding tap needle. Usually the animal is stuck to the water and supplying oxygen (own obser- underside of the cover slip and can easily be vations). Fregni (1998b) gives a detailed sucked up with a small addition of water. account on how to extract gastrotrichs from However, in many cases a deep examination marine and freshwater sediments. of the animal destroys it and other specimens Subsamples are usually treated with a 1 to are needed for further treatment. 7% solution of MgCl2, to anaesthetize the For preservation as whole mounts the animals, depending on which habitat the animal is fixed in 10% borax buffered original sample was collected from. formalin and can be stored at 4ºC. Anaesthetization is not necessary but it is Subsequently it is put through a series of recommended as it prevents the animal to use glycerol and alcohol to pure glycerol (see its adhesive tubes to adhere to surfaces and Paper I). By adding a small amount of immobilizes it. Subsequently the individual formalin to the glycerol the risk of bacterial subsamples are scanned under a good growth and degeneration of the specimen dissecting microscope, preferably in trans- decreases. The cover slip can be sealed with mitted light. Individual gastrotrichs are sucked either nail-polish or asphalt varnish. up with a micropipette and put on a clean glass slide. To avoid interference with dust particles 2.3 Molecular studies the cover slip needs to be carefully wiped. A For genetic studies the specimen is put in a small amount of modeling clay should also be small vial with 95% ethanol and stored at -18– applied to the edges of the cover slip as it 20ºC until further treatment. For marine prevents squashing of the animal. The cover samples it is very important to get rid of as slip is then gently put on the drop of water much water as possible, otherwise salt crystals holding the animal. It is a good idea to do this may form and specimens will be very hard to procedure under the dissecting microscope as find again. The whole specimen needs to be it may be hard to find the animal again. After processed for DNA extraction but photographs mounting the gastrotrich needs to be may be used as vouchers. In Paper II and III orientated in a dorso-ventral fashion for proper reliable methods and new primers are documentation. The easiest way to do this is to provided for extraction of DNA and add small amounts of water or suck it up with amplification of 18S rDNA, 28S rDNA and filter paper, which creates small currents under COI mtDNA from single specimens of the cover slip. When the animal is properly Gastrotricha. mounted it can be photographed under a For such small animals as gastrotrichs it differential interference contrast (DIC) is important to verify that the obtained microscope. If water evaporates during this sequences are correct. The easiest way to do procedure more can be added to the side of the this is by using the BLAST (Basic Local cover slip. Documentation should include Alignment Search Tool) available online on pictures of the habitus, which can be used for GenBank. Since previous molecular studies measurements of width and length of the body have only dealt with 18S rDNA it is trickier to as well as other structures. Subsequently verify 28S rDNA and COI mtDNA. Using taxonomically important characters, such as BLAST for these sequences as well is a good distribution of adhesive tubes, scales and way to start as common contaminants like 15 Swedish Gastrotricha Tobias Kånneby fungi or mould can be detected. Phylogenetic trees for individual genes should also be compared to look for conflicts and in the light of this evaluate the quality of sequences. Moreover alignments and analyses with other phyla can be done to look for monophyly of obtained sequences. For COI mtDNA extra care should be taken as primers for commonly amplified regions (see Folmer et al., 1994) are universal. Contaminants can usually be discovered by BLAST but it is also a good idea to translate sequences into amino acid sequences, using the general invertebrate mitochondrial code, and look for stop codons. 3. SWEDISH FAUNA The gastrotrich fauna of Sweden is poorly known and only a handful of studies have actually focused on Gastrotricha present in Sweden. In the past marine species has generally gained more attention than freshwater species. In 2007 only 22 marine and 7 freshwater species had been recorded from the country. To date the total number of species has more than tripled and 90 species have been found; of these 5 are new to science and 56 are new to the Swedish fauna. Macrodasyida is represented by 24 species from 16 of the 32 described genera, while Chaetonotida is represented by 66 species from 11 of the 31 described genera. In addition more than 20 species are not yet identified, because of lack of material. A full list of Swedish species as well as their distribution is given in Appendix I and Figure

8 shows all localities sampled in Sweden. Turning to other Scandinavian countries Figure 8. Map of Sweden showing all localities the Norwegian marine fauna is comparatively sampled for gastrotrichs from 1923 to 2011. Red and well studied (see e. g. Clausen, 1992; 1996; blue dots show localities sampled during the course of this research (2007-2011), indicating freshwater and 2000) but almost nothing is known about the marine localities respectively. Black dots show both freshwater fauna and only a handful of species marine and freshwater localities sampled prior to this have been recorded (Schwank, 1990). research. Lepidochaetus zelinkai has been found close e. g. Todaro et al., 2005; Grilli et al., 2009; to the Swedish border at Riksgränsen (own 2010). observations) and on Svalbard (D. Fontaneto, pers. comm.). The Finnish fauna is also poorly 3.1 Freshwater fauna studied but Karling (1954) reported a few Macrodasyida from Hangö and Tvärminne. The first Swedish Gastrotricha, Chaetonotus Moreover, a few freshwater species have been (H.) macrochaetus, C. (C.) maximus and reported (Schwank, 1990). The Danish fauna, Lepidodermella squamata, were reported by especially the freshwater, is better known (see Hofsten (1923) when studying the fauna of northern Sweden. Moreover, 16 Swedish Gastrotricha Tobias Kånneby

Schwank (1990) reported C. (P.) chuni, C. than the freshwater fauna. In 2007, 22 species (H.) longispinosus and C. (S.) schultzei as had been recorded, most from the west coast present in Sweden. Fauna Europaea also lists (Swedmark, 1950; Karling, 1954; Boaden, Aspidiophorus squamulosus. 1960; Swedmark & Teissier, 1967) but also During the past couple of years the from the Baltic coast (Karling, 1954; Wieser, freshwater fauna has been extensively studied 1954). Lang (1936) reported Urodasys and has increased more than sevenfold. The mirabilis, a species characterized by its known number of freshwater species from peculiar posterior end, from Öresund. Sweden is currently 52. New species and new Todaro and Kånneby reported 32 species records for the Swedish fauna are presented in of which 13 were new to the Swedish fauna Paper I, III and IV. The most common and 7 apparently new to science (Willems et species found in Sweden usually also have a al., 2009). The total number of marine species cosmopolitan distribution, e. g. C. (H.) hystrix, has almost doubled since 2007. Currently 37 and L. squamata. Other species that are fairly species, of which 24 belong to Macrodasyida common and have been found in large and 13 to Chaetonotida, are known. Most numbers on several occasions are C. (C.) species collected in Sweden are widely microchaetus and Lepidochaetus zelinkai. distributed while others are restricted to the More uncommon records include members of North Atlantic and connected seas. Rare Ichthydium, some of which previously have records include the macrodasyidan Thau- only been reported from Italy. Additionally, mastoderma moebjergi and the chaetonotidan the poorly described Lepidodermella minor Chaetonotus (C.) tempestivus which were minor and the semi-planktonic Haltidytes previously only known from their respective crassus and Stylochaeta scirtetica have also type localities. Most species have been found been reported from the country. in fine clean sand while muddy sand yielded Comparing the Swedish freshwater fauna fewer species. In brackish waters biodiversity to other well investigated countries, e. g. is generally lower but certain species can be Poland, 98 spp. (Kisielewski, 1981; 1998); found in very high densities. The fine and very Italy, 92 spp. (Balsamo & Tongiorgi, 1995); clean calcareous sand of the south east coast Russia, 91 spp. (Balsamo et al., 2008); of Sweden holds very high numbers of the Romania, 90 spp. (Rudescu, 1967); and macrodasyidan Turbanella cornuta (own Germany, 90 spp. (Remane, 1935-1936; observations). This species seems very Schwank, 1990), it seems likely that the tolerant to fluctuations in temperature as it has country can hold close to 100 freshwater been found in high abundances during the species. Sweden hosts a wide array of winter months, also reported by Jansson different habitats, ranging from deciduous (1968). The chaetonotidans Xenotrichula velox forest in the south to coniferous forests and and Halichaetonotus spp. are also common in subarctic habitats in the north. these habitats (own observations). Most species have so far been reported from Sphagnum bogs and small nutrient rich 4. GASTROTRICH ponds or lakes, but a couple of species have RELATIONSHIPS also been found in interstitial freshwater habitats of larger lakes. Sphagnum bogs are The phylogenetic position of Gastrotricha is common in Sweden and single samples can unclear. Some groups (e. g. Dactylopodolidae yield as much as 15 species of which one or and Neodasyidae) possess a monociliated two species are more dominant than the rest. epidermis, a character state shared with However, other habitats should not be Gnathostomulida. This trait is especially neglected as they may harbor few but interesting as it is believed to be a plesio- uncommon species. morphic character state and occurs in Porifera and . Except for and 3.2 Marine fauna possibly and all other are multiciliate or secondarily Until a couple of years ago the Swedish monociliated (Balsamo, 1992; Hochberg & marine gastrotrich fauna was better known

17 Swedish Gastrotricha Tobias Kånneby

Litvaitis, 2000; Zrzávy, 2003). Recent 1961). Recently Neodasys has been morphological studies suggest Gastrotricha to hypothesized to be a group within the be the sister-group of (Schmidt- Macrodasyida based on 18S rDNA (Todaro et Rhaesa et al., 1998; Peterson et al., 2000). al., 2006; Petrov et al., 2007). Both This hypothesis is based on the muscular morphological and molecular studies agree on pharynx with a triradiate lumen, a terminal a monophyletic Paucitubulatina (Hochberg & mouth opening and a bilayered cuticle. Zrzávy Litvaitis, 2000; Zrzávy, 2003; Todaro et al., (2003) suggested that Ecdysozoa may have 2003; Manylov et al., 2004; Todaro et al., originated from a gastrotrich-like ancestor that 2006; Petrov et al., 2007). This group contains subsequently lost the ventral ciliation and both marine and freshwater tenpin-shaped obtained periodical molting. gastrotrichs, often characterized by their Molecular data is not congruent with sculptured cuticle. Leasi & Todaro (2008) morphological data. Analyses based on 18S erected Muselliferidae, a strictly marine group, rDNA have placed gastrotrichs as basal to all formerly classified as Chaetonotidae based on (Littlewood et al., 1998), basal to the hypothesized plesiomorphic character Platyhelminthes (Giribet et al., 2000), or in a states of the muscular system. The basal sister-group relation to Platyhelminthes position of Muselliferidae is also supported by (Garey, 2001). Todaro et al. (2006) used an other morphological and molecular data based extensive sampling of gastrotrich taxa and on 18S rDNA (Hochberg & Litvaitis, 2000; found them in a clade together with Todaro et al., 2006). The strictly marine Micrognathozoa, Rotifera and Cycliophora Xenotrichulidae has been proposed as the based on 18S rDNA. Petrov et al. (2007) sister-group of Chaetonotidae (Todaro et al., rejected a relationship of Gastrotricha to 2006; Kieneke et al., 2008b). Nematoda and Ecdysozoa. Phylogenomic Chaetonotidae is the largest family within studies also suggest that Gastrotricha is not Gastrotricha. It is most probably a non- affiliated to Ecdysozoa but instead a group monophyletic assemblage of marine and fresh- within the (Dunn et al., 2008; Hejnol water taxa. In this group current classification et al., 2009). From the above it seems likely is to a great extent based on cuticular that Gastrotricha is a sister-group of morphology. In Paper V (see also Paper III) Platyhelminthes in Platyzoa within the an extensively sampled phylogeny based on . 18S rDNA, 28S rDNA and COI mtDNA is presented and shows that the group is non- 4.1 Gastrotrich interrelationships monophyletic since members of Dasydytidae Most studies agree on a monophyletic are nested within the group. The hypothesized Gastrotricha. However, Manylov et al. (2004) non-monophyly of Chaetonotidae has figured suggested the group to be non-monophyletic in previous studies (e. g. Hochberg & based on 18S rDNA. Interrelationships are Litvaitis, 2000; Kieneke et al., 2008b). Since poorly understood and have only been the only 3 out of 17 sampled genera are mono- subject of a handful studies. Traditionally phyletic according to current classification, the Gastrotricha have been classified into two group is in great need of taxonomic revision. orders, the Chaetonotida and Macrodasyida Genera with both marine and freshwater (Remane, 1925a). Chaetonotida is in turn representatives are never monophyletic, divided into the two suborders Multi- pointing toward convergent evolution of tubulatina, with the single genus Neodasys, cuticular structures within the group. Marine and Paucitubulatina (d’Hondt, 1971). The Aspidiophorus are indicated as the sister group strictly marine Neodasys has been considered of all other Chaetonotidae and Dasydytidae, the sister group of Paucitubulatina, sharing also in part proposed by Todaro et al. (2006). many characters with Macrodasyida (e. g. a This is however in conflict with the results of vermiform body and lateral adhesive tubes). Leasi & Todaro (2008) indicating a basal However, because of the organization of the position of Polymerurus, based on the pharynx and ventral ciliation the group has architecture of the muscular system. been classified as Chaetonotida (Remane,

18 Swedish Gastrotricha Tobias Kånneby

Several genera are defined solely on 1983; Hochberg & Litvaitis, 2001b). Recent cuticular morphology (e. g. Chaetonotus, molecular studies based on 18S rDNA have Ichthydium, Lepidodermella). Chaetonotus is shown Neodasys to be nested within Macro- one of the more problematic genera and with dasyida thus rendering the group non- more than 200 species this group is defined on monophyletic according to current classi- the presence of spined scales. The group is fication (Todaro et al., 2006; Petrov et al., divided into subgenera based on the 2007). Within Macrodasyida Dactylopodo- evolutionary trends of cuticular structures lidae has retained the plesiomorphic character (Kisielewski, 1997). In Paper V the phylo- state of a monociliated epidermis. Moreover genetic hypothesis generated shows that this members of this group are suggested to have a genus is non-monophyletic. Moreover, many muscle architecture similar to the of the subgenera appear non-monophyletic. hypothesized ground pattern in Gastrotricha Relationships within Chaetonotidae are (Travis, 1983; Hochberg & Litvaitis, 2001c). hard to discern as the group is homogenous In Paper II relationships within the largest (except for the cuticular structures). Both family Thaumastodermatidae are investigated morphological and molecular studies have together with other macrodasyid taxa based on failed to successfully resolve deeper 18S rDNA, 28S rDNA and COI mtDNA. relationships within the group. Results Although morphologically very diverse, this obtained from molecular studies indicate that family is retained as monophyletic. Previous scales and spines do not reflect phylogenetic studies have also suggested monophyly based relationships within Chaetonotidae. These on cuticle ultrastructure (Rieger & Rieger, characters should be evaluated together with 1977) and on the structure of the reproductive other morphological characters to establish a apparatus (Ruppert, 1978). Within Thaumasto- solid classification for the group. A good dermatidae both subfamilies defined on example of this is the more or less smooth morphological differences of the male cuticle of Ichthydium and the completely reproductive system are also retained as smooth cuticle of Arenotus strixinoi, taxa that monophyletic. Paper II also gives high do not group together based on molecular support for a monophyletic Turbanellidae studies. Moreover pedunculated scales are while Cephalodasyidae is non-monophyletic. known for Aspidiophorus as well as species within Xenotrichulinae and Polymerurus. 4.2 Cryptic species Aspidiophorus is a polyphyletic taxon based The extent of cryptic species is poorly studied on molecular data where marine species within Gastrotricha. Todaro et al. (1996) appear to be in a sister group relationship to studied four different populations of Chaetonotidae and Dasydytidae, while Xenotrichula intermedia from the freshwater species nests within Chaetonotidae. Mediterranean Sea, the Gulf of Mexico and Whether the pedunculated scales of the Atlantic Ocean respectively. The study Xenotrichulinae and marine Aspidiophorus are found differences in pharynx length between homologous is still an open question. In Paper populations, but no other morphological V marine representatives of the subgenus C. differences. Analyses of COI mtDNA showed (Schizochaetonotus) figures as the second a divergence of up to 11.5% for the different group, marine Aspidiophorus being the first, to populations, indicating the presence of sibling branch off in the Chaetonotidae and species within this taxon. Different Dasydytidae clade. Although not well populations of X. intermedia also exhibit supported this clade is clearly separated from morphological differences of the muscular Halichaetonotus and marine Heterolepido- system, but external characters do not differ derma, which are therefore hypothesized to (Leasi & Todaro, 2009). Kisielewski (1991) have invaded marine environments second- studied the inland water gastrotrichs of Brazil darily. and found that several nominal species also The order Macrodasyida is a well defined found in Europe differed in size. In Paper III group and is considered monophyletic based the extent of cryptic species is investigated in on morphology (Ruppert, 1982; 1991; Travis, some commonly occurring freshwater gastro-

19 Swedish Gastrotricha Tobias Kånneby trichs. Lepidodermella squamata is one of the utilized to resolve deeper nodes of most commonly recorded gastrotrichs with a Chaetonotidae. Preferably protein coding cosmopolitan distribution. This species nuclear genes like (e. g. EF-1α) can be used. exhibits morphological variation in the New sequencing techniques will allow a much number and shape of scales. COI mtDNA has higher throughput and facilitate sequencing of shown a high ingroup variation and the additional genes. possibility of cryptic speciation within this Also more ecological questions could be widely distributed species is probably high. addressed. Experiments dealing with dispersal Lepidochaetus zelinkai is another commonly of freshwater gastrotrichs could be set up in reported species and for Swedish specimens the laboratory and also studied in the field by uncorrected pairwise distances and phylo- sequencing of different populations. Since genetic distances are low, around 3 to 4% for gastrotrichs are common their impact as COI mtDNA. This species may prove very grazers and microvores could also be useful for future DNA taxonomical studies as examined. it is large and can be easily identified with a good dissecting microscope. L. brasilense, a taxon described from Brazil is morpho- logically and genetically clearly separated from L. zelinkai. Moreover it is shown that there are differences in the COI mtDNA gene between Heterolepidoderma ocellatum and H. ocellatum f. sphagnophilum. As a consequ- ence, also taking the morphological diff- erences between the two taxa into account, H. ocellatum f. sphagnophilum is raised to species.

5. FUTURE PERSPECTIVES New gastrotrich species are recorded at a regular basis from all around the world. This work is of great importance as new species can give new insights of the evolution of the group. The findings of Redudasys fornerise (Kisielewski, 1987) showed that macro- dasyidans could also successfully colonize freshwater habitats. The gastrotrich fauna of the southern hemisphere and the tropics need more attention and several interesting taxa (e. g. Arenotus, Kijanebalola, Ornamentula and Undulinae) have been reported from these regions (Kisielewski, 1991). Future molecular studies should include both Chaetonotida and Macrodasyida to test the hypothesis of a non-monophyletic Gastrotricha presented by Manylov et al. (2004), who included only few taxa. Current classification within Gastrotricha should also be scrutinized, especially within Chaeto- notidae. Morphological characters need to be optimized in conjunction with robust phylogenies, to evaluate homology. Additional genetic markers should be sequenced and 20 Swedish Gastrotricha Tobias Kånneby

6. SUMMARY OF PAPERS

Paper I approach. The sampled Thaumastodermatidae formed a monophyletic group, as did the two Kånneby, T., Todaro, M. A., Jondelius, U. subfamilies Diplodasyinae and Thaumasto- 2009. One new species and records of dermatinae. Within Thaumastodermatinae Ichthydium Ehrenberg, 1830 (Gastrotricha: Oregodasys is retained as sister group to the Chaetonotida) from Sweden with a key to the remaining species. Tetranchyroderma is non- genus. Zootaxa, 2278, 26–46. monophyletic and nested in two groups, one in a sister group relation to Pseudostomella and During field trips in 2008 several specimens of the other in a cluster together with the genus Ichthydium were found. Among the Ptychostomella. The other less sampled representatives was a new species, Ichthydium families are all monophyletic except for skandicum n. sp., found in a Sphagnum bog Cephalodasyidae. between Åre and Storlien in Jämtland. The Results are congruent with the current same species was also found in high numbers classification of Thaumastodermatidae. Future in 2009 in small Sphagnum rock pools in studies should focus on Tetranchyroderma, Fiskebäckskil on the Swedish west coast. In Ptychostomella and Pseudostomella where addition, the first records of I. diacanthum, I. revisions may be necessary. squamigerum and I. tanytrichum, previously only reported from Italy, were recorded as new to the Swedish fauna. These species are Paper III briefly presented and the accompanying gastrotrich fauna including the genera Kånneby, T., Todaro, M. A., Jondelius, U. Aspidiophorus, Chaetonotus, Lepidodermella A phylogenetic approach to species delimit- and Polymerurus is also mentioned. The tation in freshwater Gastrotricha from publication includes a dichotomous key, Sweden. Submitted to Hydrobiologia. accompanied by illustrations, of all the valid species of Ichthydium. Many of the commonly recorded freshwater gastrotrichs have a cosmopolitan distribution. Certain species exhibit a wide range of Paper II morphological and morphometric characters and this raises the question of cryptic species Todaro, M. A., Kånneby, T., Dal Zotto, M., within the group. The commonly reported Jondelius, U. 2011. Phylogeny of Thaumasto- Lepidodermella squamata, Lepidochaetus dermatidae (Gastrotricha: Macrodasyida) zelinkai, Heterolepidoderma ocellatum and the inferred from nuclear and mitochondrial form H. ocellatum f. sphagnophilum are sequence data. PLoS ONE, 6(3), e17892. investigated for cryptic speciation and based doi:10.1371/journal.pone.0017892. mainly on Swedish material but also on other populations. Three genes, 18S rDNA, 28S Phylogenetic relationships within Gastrotricha rDNA and COI mtDNA are used and are poorly understood and had this far only uncorrected pairwise distances and been based on a single gene, 18S rDNA, phylogenetic distances were calculated for and/or morphological data. After extensive each group. The obtained results show that L. sampling of the morphologically diverse squamata forms two clades, also indicated in family Thaumastodermatidae and several their morphology. L. zelinkai form a single other marine Macrodasyida, 18S rDNA, 28S clade that is clearly separated from L. rDNA and COI mtDNA were used to elucidate brasilense. Ingroup variation within L. zelinkai phylogenetic relationships within the group. is low and based on the data at hand no The data sets were analyzed using both a indication of cryptic speciation was detected. Bayesian and a maximum likelihood H. ocellatum and H. ocellatum f. sphagno- 21 Swedish Gastrotricha Tobias Kånneby philum form two clearly separated clades and Paper V can also be separated based on their morph- ology. Consequently we propose H. ocellatum Kånneby, T., Todaro, M. A., Jondelius, U. f. sphagnophilum to be raised to species level, Phylogeny of Chaetonotidae (Gastrotricha) under the name H. acidophilum n. sp. Based inferred from nuclear and mitochondrial on analyses of the combined dataset and genes. Manuscript. nuclear gene distances we also propose a new species of Lepidodermella, L. intermedia n. This study deals with the phylogeny of the sp. largest gastrotrich family Chaetonotidae. This The low samples obtained for each group group is known to suffer from a troubled did not allow more robust statistical speciation taxonomy and genera are to a great extent methods, such as the GMYC-model or the 4x- based on the morphology and distribution of rule, to be applied. Future more densely cuticular scales, which are highly variable sampled studies can surely benefit from these characters. Three genes, 18S rDNA, 28S methods in conjunction with the results of our rDNA and COI mtDNA are used to study. reconstruct phylogenetic relationships within the group and both marine and freshwater representatives are sampled. Paper IV Results show that Chaetonotidae is non- monophyletic as members of Dasydytidae Kånneby, T. New species and new records of nests within the group in a sister group freshwater Chaetonotida (Gastrotricha) from relationship to Chaetonotus (Zonochaeta). Sweden. Accepted for publication in Zootaxa. Xenotrichulidae is obtained as a sister group of the Chaetonotidae and Dasydytidae clade. This paper presents freshwater species of all Following current classification only 3 genera, genera, except Chaetonotus and Ichthydium, Lepidochaetus, Polymerurus and Stylochaeta, collected in Sweden during the period 2007– out of a total 17 genera sampled are indicated 2011. Two new species, Heterolepidoderma as monophyletic. Genera containing both joermungandri n. sp. and H. trapezoidum n. freshwater and marine species group with sp. are described. Detailed accounts for other other species depending on habitat. Marine species from the genera Aspidiophorus, Aspidiophorus appears as the sister group of Heterolepidoderma, Lepidochaetus, Lepido- all other Chaetonotidae and Dasydytidae dermella, Polymerurus, Haltidytes and indicating a marine origin of the family. A Stylochaeta are also given, raising the total secondary invasion to marine habitats may number of reported freshwater gastrotrichs have taken place at least once as marine from Sweden to 31. Moreover, each presented Heterolepidoderma and the strictly marine species is accompanied by a plate of Halichaetonotus are in a sister group relation taxonomically important characters. to freshwater Chaetonotus. In addition only Future taxonomic studies should focus on one of the proposed subgenera of Chaetonotus Chaetonotus present in Sweden and is indicated as monophyletic. gastrotrichs of the freshwater interstitial, Chaetonotidae is in need of taxonomic larger lakes and lotic waters. revision. The current classification, to a great extent based on distribution and shape of cuticular scales, does not reflect phylogenetic relationships. Future studies should focus on additional genetic markers to resolve deeper nodes within the family as well as a more extensive sampling.

22 Swedish Gastrotricha Tobias Kånneby

7. LITERATURE CITED Amato, J. A., Weiss, M. J. 1982. Developmental M. (eds.). Freshwater meiofauna: biology and flexibility in the cuticular pattern of a cell-constant ecology. Backhuys Publishers, Leiden, pp. 45–61. organism, Lepidodermella squammata (Gastro- Balsamo, M., Todaro, M. A., Tongiorgi, P. 2004. tricha). Transactions of the American Micro- Gastrotricha. In: Yule, C. M., Yong, H. S. (eds.). scopical Society, 101, 229–240. Freshwater invertebrates of the Malaysian region. Artois, T., Fontaneto, D., Hummon, W. D., McInnes, S. Academy of Science Malaysia, pp. 127–135. J., Todaro, M. A., Sørensen, M. V., Zullini, A. Balsamo, M., Tongiorgi, P. 1995. Gastrotricha. In: 2011. Ubiquity of microscopic animals? Evidence Minelli, A., Ruffo, S., La Posta, S. (eds.). Checklist from the morphological approach in species delle Specie della Fauna d’Italia. Calderini, identification. In: Fontaneto, D. (ed.). Biogeo- Bologna, 7, 1–11. graphy of Microscopic Organisms: Is Everything Bennett, L. W. 1978. Lipid globules in fresh-water Small Everywhere? Cambridge University Press, Gastrotricha. Transactions of the American pp. 245–249. Microscopical Society, 97, 390–392. Balsamo, M. 1978. Prime ricerche sui Gastrotrichi Boaden, P. J. S. 1960. Three new gastrotrichs from the dulciacquicoli italiani. Atti della Societa Toscana Swedish west cost. Cahiers de Biologie Marine, 1, di Scienze Naturali Memorie, Serie B, 84, 87–150. 397–406. (1977). Brehm, V. 1917. Ergebnisse einiger im Franzensbader Balsamo, M. 1980. Spectral sensitivity in a Moor unternommener Exkursionen. Archiv für Gastrotrich (Lepidodermella squamatum Dujardin). Hydrobiologie, 11, 306–323. Experientia 36, 830–831. Brunson, R. B. 1950. An introduction to the taxonomy Balsamo, M. 1982. Three new gastrotrichs from a of the Gastrotricha with a study of eighteen species Tuscan-Emilian Apennine Lake. Bollettino di from Michigan. Transactions of the American Zoologia, 49, 287–295. Microscopical Society, 69, 325–352. Balsamo, M. 1983. Gastrotrichi. Consiglio Nazionale Bullock, T. H., Horridge, G. A. 1965. Gastrotricha, In: delle Ricerche, Guide per il riconoscimento delle Structure and Function of the Nervous System of specie animali delle acque interne italiane, 20, 92 Invertebrates, Vol. 1. Freeman, San Francisco, p. pp. 604. Balsamo, M. 1992. Hermaphroditism and partheno- Clausen, C. 1965a. Desmodasys phocoides gen. et. sp. genesis in lower Bilateria: Gnathostomulida and n., family Turbanellidae (Gastrotricha: Macro- Gastrotricha. In: Dallai, R. (ed.). Sex origin and dasyoidea). Sarsia, 21, 17–21. evolution. Selected symposia and monographs Clausen, C. 1965b. New interstitial species of the U.Z.I., 6. Mucchi, Modena, pp. 309–327. family Thaumastodermatidae (Gastrotricha Macro- Balsamo, M., Ferraguti, M., Guidi, L., Todaro, M. A., dasyoidea). Sarsia, 21, 23–36. Tongiorgi, P. 2002. Reproductive system and Clausen, C. 1968. Crasiella diplura gen. et sp. n. spermatozoa of Paraturbanella teissieri (Gastro- (Gastrotricha, Macrodasyoidea). Sarsia, 33, 59–63. tricha, Macrodasyida): implications for sperm Clausen, C. 1992. Two new species of Thaumastoderma transfer modality in Turbanellidae. Zoomorph- (Gastrotricha, Macrodasyida) from the west coast ology, 121, 235–241. of Norway. Sarsia, 76, 157–165. Balsamo, M., Fregni, E. 1995. Gastrotrichs from Clausen, C. 1996. Three new species of Gastrotricha interstitial fresh water, with a description of four Macrodasyida from the Bergen area, western new species. Hydrobiologia, 302, 163–175. Norway. Sarsia, 81, 119–129. Balsamo, M., d’Hondt, J.L., Kisielewski, J., Pierboni, Clausen, C. 2000. Gastrotricha Macrodasyida from the L. 2008. Global diversity of gastrotrichs Tromsø region, northern Norway. Sarsia, 85, 357– (Gastrotricha) in fresh waters. Hydrobiologia, 595, 384. 85–91. Clausen, C. 2004. Gastrotricha from the Faroe Bank. Balsamo, M., Todaro, M. A. 1987. Aspidiophorus Sarsia, 89, 423–458. polystictos, a new marine species (Gastrotricha, Colacino, J. M., Kraus, D. W. 1984. Hemoglobin- Chaetonotida) and its life cycle. Bollettino di containing cells of Neodasys (Gastrotricha, Chaeto- Zoologia, 54, 147–153. notida)-II. Respiratory significance. Comparative Balsamo, M., Todaro, M. A. 1988. Life history traits of biochemistry and physiology, 79, 363–369. two chaetonotids (Gastrotricha) under different Dujardin, F. 1841. Histoire Naturelle des Zoophytes, experimental conditions. Invertebrate Reproduction Infusoires. Librairie Encyclopedique de Roret, and Development, 14, 161–176. Paris, 684 pp. and atlas p. 12, pl. 18. Balsamo, M., Todaro, M. A. 1995. Gastrotrichi del Dunn, C. W., Hejnol, A., Matus, D. Q., Pang, K., Trentino: le Viotte del Monte Bondone. Studi Browne, W. E., Smith, S. A., Seaver, E., Rouse, G. Trentini di Scienze Naturali–Acta Biologica, 70, 9– W., Obst, M., Edgecombe, G. D., Sørensen, M. V., 22. Haddock, S. H. D., Schmidt-Rhaesa, A., Okusu, A., Balsamo, M., Todaro, M. A. 2002. Gastrotricha. In: Kristensen, R. M., Wheeler, W. C., Martindale, M. Rundle, S. D., Roberston, A. L., Schmid-Araya, J. Q., Giribet, G. 2008. Broad phylogenomic

23 Swedish Gastrotricha Tobias Kånneby

sampling improves resolution of the animal tree of methods. Proceedings of the Royal Society B, 276, life. Nature, 452, 745–749. 4261–4270. Ehrenberg, C. G. 1832. Über die Entwickelung und Hochberg, R. 2007. Comparative immunohisto- Lebensdauer der Infusionsthiere. Abhandlung der chemistry of the cerebral ganglion in Gastrotricha: Akademie der Wissenschaftes zu Berlin, 1–154. an analysis of FMRFamide-like immunoreactivity (1831). in Neodasys cirritus (Chaetonotida), Xenodasys Ehrenberg, C. G. 1838. Die Infusionstierchen als riedli and Turbanella cf. hyalina (Macrodasyida). vollkommene Organismen. Ein Blick in des tiefere Zoomorphology, 126, 245–264. organische Leben der Natur. pp. 386–390; Tafel Hochberg, R., Litvaitis, M. K. 2000. Phylogeny of the 48. Nebst Atlas. Leopold Voss, Leipzig. Gastrotricha: a morphology-based framework of Evans, W. A., Hummon, W. D. 1991. A new genus and gastrotrich relationships. Biological Bulletin, 198, species of Gastrotricha from the Atlantic coast of 299–305. Florida, U.S.A. Transactions of the American Hochberg, R., Litvaitis, M. K. 2001a. A muscular Microscopical Society, 110, 321–327. double helix in Gastrotricha. Zoologischer Folmer, O., Black, M., Hoeh, W., Lutz, R., Vrijenhoek, Anzeiger, 240, 61–68. R. 1994. DNA primers for amplification of Hochberg, R., Litvaitis, M. K. 2001b. Macrodasyida mitochondrial cytochrome c oxidase subunit I from (Gastrotricha): A cladistic analysis of morphology. diverse metazoan invertebrates. Molecular Marine Invertebrate Zoology, 120, 124–135. Biology and Biotechnology, 3, 294–299. Hochberg, R. Litvaitis, M. K. 2001c. The muscular Fregni, E. 1998a. The spermatozoa of macrodasyid system of Dactylopodola baltica and other gastrotrichs: observations by scanning electron macrodasyidan gastrotrichs in a functional and microscopy. Invertebrate Reproduction and phylogenetic perspective. Zoologica Scripta, 30, Development, 34, 1–11. 325–336. Fregni, E. 1998b. A practice in the extraction of Hochberg, R., Litvaitis, M. K. 2003. Ultrastructural and gastrotrichs from marine and freshwater sediments. immunocytochemical observations of the nervous Italian Journal of Zoology, 65, 203–206. systems of three macrodasyidan gastrotrichs. Acta Gagné, G. D. 1977. Dolichodasys elongatus n.g., n. sp. Zoologica (Stockholm), 84, 171–178. a new macrodasyid gastrotrich from New England. Hofsten, N. von. 1923. Rotatorien der Nord- Transactions of the American Microscopical schwedischen Hochgebirge. Naturwissen- Society, 96, 19–27 schaftliche Untersuchungen des Sarekgebirges in Garey, J. R. 2001. Ecdysozoa: the relationship between Swedish-Lappland geleitet von A. Hamberg, and . Zoologischer Zoologie, 4, 829–894. Anzeiger, 240, 321–330. d'Hondt, J. L. 1968. Contribution a la connaissance des Gerlach, S. A. 1953. Gastrotrichen aus dem Küsten- intercotidaux du Golfe de Gascogne. grundwasser des Mittelmeeres. Zoologischer Cahiers de Biologie Marine, 9, 387–404. Anzeiger, 150, 203–211. d'Hondt, J. L. 1971. Gastrotricha. Oceanography and Giribet, G., Distel, D., Polz, M., Sterrer, W., Wheeler, Marine Biology: An Annual Review, 9, 141–192. W. C. 2000. Triploblastic relationships with Horlick, R. 1975. Dasydytes monile, a new species of emphasis on the Acoelomates and the positions of gastrotrich from Illinois. Transactions of the Gnathostomulida, Cycliophora, Plathelminthes and Illinois State Academy of Sciences, 68, 61–64. : a combined approach of 18S rRNA Hummon, M. R. 1984a. Reproduction and sexual sequences and morphology. Systematic Biology, 49, development in a freshwater gastrotrich. 1. 539–562. Oogenesis of parthenogenic eggs (Gastrotricha). Greuter, A. 1917. Beiträge zur Systematik der Gastro- Zoomorphology, 104, 33–41. trichen in der Schweiz. Revue Suisse de Zoologie, Hummon, M. R. 1984b. Reproduction and sexual 25, 35–76. development in a freshwater gastrotrich. 3. Post- Grilli, P., Kristensen, R. M., Balsamo, M. 2009. parthenogenic development of primary oocytes and Heterolepidoderma caudosquamatum (Gastro- the X-body. Cell and Tissue Research, 236, 629– tricha. Chaetonotida), a new species from brackish 636. waters of Denmark. Zootaxa, 2173, 49–54. Hummon, M. R., Hummon W. D. 1983. Gastrotricha. Grilli, P., Kristensen, R. M., Balsamo, M. 2010. In: Adiyodi, K. G., Adiyodi, R. G. (eds.). Contribution to the knowledge of the freshwater Reproductive Biology of Invertebrates 2, Gastrotricha from Denmark. Steenstrupia, 32, 79– Spermatogenesis and Sperm function. John Wiley 92. & Sons Ltd, New York, pp. 195–205. Grünspan, T. 1908. Beiträge zur Systematik der Hummon, W. D. 1982. Gastrotricha, In: Parker, S. P. Gastrotrichen. Zoologische Jahrbücher Abteilung (ed.). Synopsis and Classification of Living für Systematik, 26, 214–256. Organisms, 1. McGraw-Hill, New York, pp. 857– Hejnol, A., Obst, M., Stamatakis, A., Ott, M., Rouse, G. 863. W., Edgecombe, G. D., Martinez, P., Baguñá, J., Hummon, W. D., Todaro, M. A. 2010. Analytic Bailly, X., Jondelius, U., Wiens, M., Müller, W. E. taxonomy and notes on marine, brackish-water and G., Seaver, E., Wheeler, W. C., Martindale, M. Q., estuarine Gastrotricha. Zootaxa, 2392, 1–32. Giribet, G., Dunn, C. W. 2009. Assessing the roots Hummon, W. D., Todaro, M. A., Tongiorgi, P. 1993. of bilaterian animals with scalable phylogenomic Italian Marine Gastrotricha: II. One new genus and 24 Swedish Gastrotricha Tobias Kånneby

ten new species of Macrodasyida. Bollettino di Kisielewski, J. 1997. On the subgeneric division of the Zoologia, 60, 109–127. genus Chaetonotus Ehrenberg (Gastrotricha). Hyman, L. H. 1951. Gastrotricha, In: The Invertebrates, Annales Zoologici, 46, 145–151. Vol. III , Aschelminthes and Kisielewski, J. 1998. Brzuchorzeski (Gastrotricha). Ectoprocta. McGraw-Hill, New York, pp. 150– Fauna Slodkowodna Polski, Zeszyt 31. 169. Windawnictwo Uniwersytetu Lodzkiego, Lódz, Jansson, B-O. 1968. Quantitative and experimental 157 pp. studies of the interstitial fauna of four Swedish Lang, K. 1936. Undersökningar över Öresund. sandy beaches. Ophelia, 5, 1–71. Kungliga Fysiografiska Sällskapets Handlingar, N. Karling, T. G. 1954. Über einige Kleintiere des F., 46, 1–8. Meeressandes des Nordsee-Ostsee- Gebietes. Arkiv Leasi, F., Rothe, B. H., Schmidt-Rhaesa, A., Todaro, M. för Zoologi, 14, 241–249. A. 2006. The musculature of three species of Kieneke, A. 2010 A new species of Thaumastoderma gastrotrichs surveyed with confocal laser scanning (Gastrotricha: Macrodasyida) from the Antarctic microscopy (CLSM). Acta Zoologica (Stockholm), deep sea with a phylogenetic analysis of the whole 87, 171–180. genus. Journal of the Marine Biological Leasi, F., Todaro, M. A. 2008. The muscular system of Association of the United Kingdom, 90, 575–584. Musellifer delamarei (Renaud-Mornant, 1968) and Kieneke, A., Ahlrichs, W. H., Arbizu, P. M., other chaetonotidans with implications for the Bartolomaeus, T. 2008a. Ultrastructure of phylogeny and systematization of the protonephridia in Xenotrichula carolinensis Paucitubulatina (Gastrotricha). Biological Journal syltensis and Chaetonotus maximus (Gastrotricha : of the Linnean Society, 94, 379–398. Chaetonotida): comparative evaluation of the Leasi, F., Todaro, M. A. 2009. Meiofaunal cryptic gastrotrich excretory organs. Zoomorphology, 127, species revealed by confocal microscopy: the case 1–20. of Xenotrichula intermedia (Gastrotricha). Marine Kieneke, A., Arbizu, P. M., Ahlrichs, W. H. 2007. Biology, 156, 1335–1346. Ultrastructure of the protonephridial system in Lévi, C. 1950. Contribution a l'etude des gastrotriches Neodasys chaetonotoideus (Gastrotricha : Chaeto- de la region de Roscoff. Archives de Zoologie notida) and in the ground pattern of Gastrotricha. Experimentale et Generale, 87, 31–42. Journal of Morphology, 268, 602–613. Littlewood, D. T. J., Telford, M. J., Clough, K. A., Kieneke, A., Riemann, O., Ahlrichs, W. H. 2008b. Rohde, K. 1998. Gnathostomulida–An enigmatic Novel implications for the basal internal metazoan from both morphological and relationships of Gastrotricha revealed by an molecular perspectives. Molecular analysis of morphological characters. Zoologica and Evolution, 9, 72–79. Scripta, 37, 429–460. Ludwig, H. 1875. Über die Ordnung Gastrotricha Kieneke, A., Zekely, J. 2007. Desmodasys abyssalis sp. Metschn. Zeitschrift für Wissenschaftliche nov. – first record of a deep sea gastrotrich from Zoologie, 26, 193–226. hydrothermal vents. JMBA2 – Biodiversity records, Luporini, P., Magagnini, G., Tongiorgi, P. 1973. 5895, 1–8. Chaetonotoid gastrotrichs of the Tuscan Coast. Kisielewska, G. 1981. Hermaphroditism of freshwater Bollettino di Zoologia, 40, 31–40. gastrotrichs in natural conditions. Bulletin de Manylov, O. G., Vladychenskaya, N. S., Milyutina, I. L’Académie Polonaise des Sciences, 29, 167–172. A., Kedrova, O. S., Korokhov, N. P., Kisielewski, J. 1981. Gastrotricha from raised and Dvoryanchikov, G. A, Aleshin, V. V., Petrov, N. B. transitional peat bogs in Poland. Monografie Fauny 2004. Analysis of 18S rRNA gene sequences Polski, 11. Polska Akademia Nauk, Warszawa, 143 suggests significant molecular differences between pp. Macrodasyida and Chaetonotida (Gastrotricha). Kisielewski, J. 1986. Taxonomic notes on freshwater Molecular Phylogenetics and Evolution, 30, 850– gastrotrichs of the genus Aspidiophorus Voigt 854. (Gastrotricha, Chaetonotoidea) with description of Marcolongo, I. 1910. Primo contributo allo studio dei four new species. Fragmenta Faunistica, 30, 139– Gastrotrichi del lago-stagno craterico di Astroni. 156. Monitore Zoologico Italiano, 21, 315–318. Kisielewski, J. 1987. Two new interesting genera of Marotta, R., Todaro, M. A., Ferraguti, M. 2008. The Gastrotricha (Macrodasyida and Chaetonotida) unique gravireceptor organs of Pleurodasys helgo- from the Brazilian freshwater psammon. landicus (Gastrotricha : Macrodasyida). Zoomorph- Hydrobiologia, 153, 23–30. ology, 127, 111–119. Kisielewski, J. 1988. New records of marine Metschnikoff, E. 1865. Über einige wenig bekannte Gastrotricha from the French coasts of Manche and niedere Thierformen. Zeitschrift für Wissen- Atlantic. II Chaetonotida, with descriptions of four schaftliche Zoologie, 15, 450–463. new species. Cahiers de Biologie Marine, 29, 187– Mock, H. 1979. Chaetonotoidea (Gastrotricha) der 213. Nordseeinsel Sylt. Mikrofauna des Meeresbodens, Kisielewski, J. 1991. Inland-water Gastrotricha from 78, 405–507. Brazil. Annales Zoologici Warszawa, 43, Murray, J. 1913. Gastrotricha. Journal of the Quekett Supplement 2, 1–168. Microscopical Club, 12, 211–238.

25 Swedish Gastrotricha Tobias Kånneby

Müller, O. F. 1773. Vermium terrestrium et fluviatilium Remane, A. 1935-36. Gastrotricha und Kinorhyncha. saeu animalium infosoriorum, helminthicorum et In: Bronn, H. G. (ed.). Klassen und Ordnungen des testaceorum non marinorum, succincta historia. Tierreichs, Band 4, Abteilung 2, Buch 1, Teil 2, Heineck et Faber, Havniae et Lipsiae, 135 pp. Lieferungen 1–2. Akademie Verlagsgesellschaft, Peterson, K. J., Cameron, R. A., Davidson, E. H. 2000. Leipzig, pp. 1–385. Bilaterian origins: Significance of new experi- Remane, A. 1951. Mesodasys, ein neues Genus der mental observations. Developmental Biology, 219, Gastrotricha Macrodasyoidea aus der Kieler Bucht. 1–17. Kieler Meeresforschungen, 8, 102–105. Petrov, N. B., Pegova, A. N., Manylov, O. G., Remane, A. 1952. Zwei neue Turbanella-Arten aus dem Vladychenskaya, N. S., Mugue, N. S., Aleshin, V. marinen Küstengrundwasser. Kieler Meeres- V. 2007. Molecular phylogeny of Gastrotricha on forschungen, 9, 62–65. the basis of a comparison of the 18S rRNA genes: Remane, A. 1961. Neodasys uchidai nov. spec., eine Rejection of the hypothesis of a relationship zweite Neodasys-Art (Gastrotricha Chaeto- between Gastrotricha and Nematoda. Molecular notoidea). Kieler Meeresforschungen, 17, 85–88. Biology, 41, 445–452. Rieger, G. E., Rieger, R. M. 1977. Comparative fine Preobrajenskaja, E. N. 1926. Zur Verbreitung der structure study of the Gastrotrich cuticle and Gastrotrichen in den Gewässern der Umgebung aspects of cuticle evolution within Aschelminthes. von Kossino. Arbeiten der Biologischen Station zu Zeitschrift für Zoologische Systematik und Kossino (Moskau), 4, 1–14. Evolutionsforschung, 15, 81–124. Rao, G. C. 1981. Three new gastrotrichs from Orissa Rieger, R. M., Ruppert, E. E., Rieger, G. E., Schoepfer- coast, India. Bulletin of the Zoological Survey of Sterrer, C. 1974. On the fine structure of India, 3, 137–143. gastrotrichs, with description of Chordodasys Rao, G. C., Clausen, C. 1970. Planodasys marginalis antennatus sp. n. Zoologica Scripta, 3, 219–237. gen. et sp. nov. and Planodasyidae fam. nov. Roszczak, R. 1936. Brzuchorzeski (Gastrotricha) (Gastrotricha Macrodasyoidea). Sarsia, 42, 73–82. zbiornikow wodnych okolic Poznania, Spraw. Remane, A. 1924. Neue aberrante Gastrotrichen. I. Towarzystwo Przyjaciół Nauk, 9, 109–111. (1935). Macrodasys buddenbrocki nov. gen. nov. spec. Rudescu, L. 1967. Gastrotricha. In: Fauna Republicii Zoologischer Anzeiger, 61, 289–297. Socialiste Romania, Trochelminthes, 2. Academia Remane, A. 1925a. Organisation und systematische Republicii Socialiste Romania, Bucharest, 292 pp. Stellung der aberranten Gastrotrichen. Verhand- Ruppert, E. E. 1977a. Zoogeography and speciation in lungen der deutschen zoologischen Gesellschaft, marine Gastrotricha. Mikrofauna Meeresbodens, 30, 121–128. 61, 231–251. Remane, A. 1925b Neue aberrante Gastrotrichen II: Ruppert, E. E. 1977b. Ichthydium hummoni n. sp., a Turbanella cornuta n. sp. und T. hyalina M. new marine chaetonotid gastrotrich with a male Schultze, 1853. Zoologischer Anzeiger, 64, 309– reproductive system. Cahiers de Biologie Marine, 314. 18, 1–5. Remane, A. 1926a. Morphologie und Verwandtschaft- Ruppert, E. E. 1978. The reproductive system of beziehungen der aberranten Gastrotrichen I. Gastrotrichs. III. Genital organs of Thaumasto- Zeitschrift für Morphologie und Oekologie der dermatinae subfam. n. and Diplodasyinae subfam. Tiere, 5, 625–754. n. with discussion of reproduction in Macro- Remane, A. 1926b. Marine Gastrotrichen aus der dasyida. Zoologica Scripta, 7, 93–114. Ordnung der Chaetonotoidea. Zoologischer Ruppert, E. E. 1982. Comparative ultrastructure of the Anzeiger, 66, 243–252. Gastrotrich pharynx and the evolution of Remane, A. 1927a. Gastrotricha. In: Grimpe, G., myoepithelial foreguts in Aschelminthes. Wagler, E. (eds.). Die Tierwelt der Nord- und Zoomorphology, 99, 181–220. Ostsee. Lieferung X. VII (d) Akademische Ruppert, E. E. 1988. Gastrotricha. In: Higgins, R. P., Verlagsgesellschaft, Lepizig. pp. 1–56. Thiel, H. (eds.). Introduction to the study of Remane, A. 1927b. Beiträge zur Systematik der meiofauna. Smithsonian Institution Press, Süsswassergastrotrichen. Zoologische Jahrbücher Washington, D.C., pp. 302–311. Abteilung für Systematik Oekologie und Ruppert, E. E. 1991. Gastrotricha. In: Harrison, F. W., Geographie der Tiere, 53, 269–320. Ruppert, E. E. (eds.) Microscopic Anatomy of Remane, A. 1927c. Xenotrichula velox nov. gen. nov. Invertebrates, Vol. 4, Aschelminthes. Wiley-Liss, spec., ein chaetonotoides Gastrotrich mit New York, pp. 41–109. männlichen Geschlechtsorganen. Zoologischer Ruppert, E. E., Shaw, K. 1977. The reproductive system Anzeiger, 71, 289–294. of gastrotrichs I. Introduction with morphological Remane, A. 1927d. Neue Gastrotricha Macrodasyoidea. data for two new Dolichodasys species. Zoologica Zoologischer Jahrbücher Abteilung für Systematik Scripta, 6, 185–195. (Jena), 54, 203–242. Ruttner-Kolisko, A. 1955. Rheomorpha neiswestnovae Remane, A. 1934. Die Gastrotrichen des Küsten- und Marinellina flagellata, zwei phylogeneticsh grundwassers von Schilksee. Schriften des interessante Wurmtypen aus dem Süsswasser- Naturwissenschaftlichen Vereins für Schleswig- psammon. Österreichische Zoologische Zeitschrift, Holstein, 20, 473–478. 6, 55–69.

26 Swedish Gastrotricha Tobias Kånneby

Schmidt, P. 1974. Interstitielle Fauna von Galapagos Todaro, M. A., Hummon, W. D. 2008. An overview and IV. Gastrotricha. Mikrofauna Meeresboden, 26, 1– a dichotomous key to genera of the phylum 76. Gastrotricha. Meiofauna Marina, 16, 3–20. Schmidt-Rhaesa, A., Bartolomaeus, T., Lemburg, C., Todaro, M. A., Littlewood, D. T. J., Balsamo, M., Ehlers, U., Garey, J. R. 1998. The position of Herniou, E. A., Cassanelli, S., Manicardi, G. C., Arthropoda in the phylogenetic system. Journal of Wirz, A., Tongiorgi, P. 2003. The interrelationships Morphology, 238, 263–285. of the Gastrotricha using nuclear small rRNA Schrom, H. 1972. Nordadriatische Gastrotrichen. subunit sequence data, with an interpretation based Helgoländer wissenschaftlicher Meeresuntersuch- on morphology. Zoologischer Anzeiger, 242, 145– ungen, 23, 286–351. 156. Schultze, M. 1853. Über Chaetonotus und Ichthydium Todaro M. A., Telford M. J., Lockyer A. E., Littlewood (Ehrb.) und eine neue verwandte Gattung D. T. J. 2006. Interrelationships of the Gastrotricha Turbanella. Müller's Archiv für Anatomie und and their place among the Metazoa inferred from Physiologie, 6, 241–254. 18S rRNA genes. Zoologica Scripta, 35, 251–259. Schwank, P. 1990. In: Brauer, A. Schwoerbel, J. Zwick, Travis, P. B. 1983. Ultrastructural study of body wall P. (eds.). Süsswasserfauna von Mitteleuropa. Band organization and Y-cell composition in the 3: Heft 1–2: Gastrotricha und Nemertini. Gustav Gastrotricha. Zeitschrift für zoologische Systematik Fischer Verlag, Stuttgart, Jena, New York. 252 pp. und Evolutionsforschung, 21, 52–68. Sterrer, W. 1973. Plate tectonics as a mechanism for Tyler, S., Rieger, G. E. 1980. Adhesive organs of the dispersal and speciation in interstitial sand fauna. Gastrotricha. I. Duo-gland organs. Zoomorpho- Netherlands Journal of Sea Research, 7, 200–222. logie, 95, 1–15. Stokes, A. C. 1887. Observations on Chaetonotus. The Voigt, M. 1901a. Mittheilungen aus der Biologischen Microscope (Detroit), 7, 1–9; 35–43. Station zu Plön, Holstein. Über einige bisher Sudzuki, M. 1964. On the microfauna of the Antarctic unbekannte Süsswasser Organismen. Zoologischer Region: -water community at Langhovde. Anzeiger, 24, 191–195. JARE Scientific Reports, Series E, Biology, 19, 1– Voigt, M. 1901b. Diagnosen bisher unbeschriebener 41. Organismen aus Plöner Gewässern. Zoologischer Sudzuki, M. 1971. Die das Kapillarwasser des Lücken- Anzeiger, 25, 35–39. systems Bewohnenden Gastrotrichen Japans. I. Voigt, M. 1902. Drei neue Chaetonotus-Arten aus Zoological Magazine (Tokyo), 80, 256–257. Plöner Gewässern. Zoologischer Anzeiger, 25, Swedmark, B. 1950. Contribution a l'etude de 116–118. microfaune des sables de Roscoff. Archives de Weiss, M. J. 2001. Widespread hermaphroditism in Zoologie Experimentale et Generale, 87, 22–24. freshwater gastrotrichs. Invertebrate Biology, 120, Swedmark, B. 1967. Trois nouveaux gastrotriches 308–341. macrodasyoides de la faune interstitielle marine des Wieser, W. 1954. Turbanella lutheri Remane var. sables de Roscoff. Cahiers de Biologie Marine, 8, scanica nov. var., ein neues Gastrotrich aus dem 323–330. Grundwasser der Schwedischen Ostseeküste. Swedmark, B., Teissier, G. 1967. Structure et Kungliga Fysiografiska Sällskapets Förhandlingar, adaptation d’Halammohydra adherens. Cahiers de Lund, 24, 151–156. Biologie Marine, 8, 63–74. Wilke, U. 1954. Mediterrane Gastrotrichen. Teuchert, G. 1967. Zum Protonephridialsystem mariner Zoologischer Jahrbücher Abteilung für Systematik Gastrotrichen der Ordnung Macrodasyoidea. (Jena), 82, 497–550. Marine Biology, 1, 110–112. Willems, W. R., Curini-Galletti, M., Ferrero, T. J., Teuchert, G. 1977. The ultrastructure of the marine Fontaneto, D., Heiner, I., Huys, R., Ivanenko, V. gastrotrich Turbanella cornuta Remane (Macro- N., Kristensen, R. M., Kånneby, T. MacNaughton, dasyoidea) and its functional and phylogenetical M. O., Martinez-Arbitzu, P., Todaro, M. A., importance. Zoomorphologie, 88, 189–246. Sterrer, W., Jondelius, U. 2009. Meiofauna of the Todaro, M. A. 1995. Paraturbanella solitaria a new Koster-area, results from a workshop at the Sven psammic species (Gastrotricha: Macrodasyida), Lovén Centre for Marine Sciences (Tjärnö, from the coast of California. Proceedings of the Sweden). Meiofauna Marina, 17, 1–34. Biological Society of Washington, 108, 553–559. Winnepenninckx, B., Backeljau, T., Mackey, L. Y., Todaro, M. A., Balsamo, M. Kristensen, R. M. 2005. A Brooks, J. M., De Wachter, R., Kumar, S., Garey, new genus of marine chaetonotids (Gastrotricha), J. R. 1995. 18S rRNA data indicate that with a description of two new species from Aschelminthes are polyphyletic in origin and Greenland and Denmark. Journal of the Marine consist of at least three distinct clades. Molecular Biological Association of the United Kingdom, 85, Biology and Evolution, 12, 1132–1137. 1391–1400. Zelinka, C. 1889. Die Gastrotrichen. Eine mono- Todaro, M. A., Fleeger, J. W., Hu, Y. P., Hrincevich, A. graphische Darstellung ihrer Anatomie, Biologie W., Folz, D. W. 1996. Are meiofaunal species und Systematik. Zeitschrift für Wissenschaftliche cosmopolitan? Morphological and molecular Zoologie, 49, 209–384. analysis of Xenotrichula intermedia (Gastrotricha: Zrzavý, J. 2003. Gastrotricha and metazoan phylogeny. Chaetonotida). Marine Biology, 125, 735–742. Zoologica Scripta, 32, 61–81.

27 Swedish Gastrotricha Tobias Kånneby

8. ACKNOWLEDGEMENTS It has been a long journey for me but finally I Pettersson, Erica Sjölin, Wim Willems and have finished this part of my work on these Anna Persson. intriguing small animals. Hopefully I can My colleagues at the entomology depart- continue in a near future. This work would not ment Tobias Malm, Marianne Espeland, Julia have been possible without the guidance and Stigenberg, Sibylle Noack and Jeanette help from many people. Nordqvist. We have had great fun teaching or It all started when I first met my attending courses. My Leffe is not stale yet. supervisor Ulf Jondelius at Kristineberg The staff at MSL, Martin Irestedt, Pia Marine Research Station. During the years Ulf Eldenäs and Bodil Kronholm. has introduced me to phylogenetics and given My friends in Uppsala: Andreas Wallberg solutions to most of my problems. We have for supplying me with filter and ali_filter. had many interesting discussions on our way Karolina Larsson, good luck at the museum. to the restaurant Stora Skuggan, and I think I Best of luck to Maria Lindström, are have even managed to learn some birds. All fun! my gratitude goes to my Italian supervisor and Per Sundberg, Malin Strand and Christer gastrotrich expert, Antonio Todaro. You have Erséus at the Department of Zoology in managed to teach me a lot and also to focus Gothenburg. I miss the nemerteans and you all my work on what is important. I am looking did your best to help me forward. Anna forward to our next field trip! Maybe you will Ansebo, Daniel Gustavsson and Pierre De beat me in table tennis this time. “Uncle” Sven Wit, we have had lots of fun. Boström, always with a joke up his sleeve, has My Italian friends and colleagues which read many of my texts with careful helped me order “carne” and break the consideration. Keyvan Mirbakhsh, the maestro language barrier. Matteo Dal Zotto we had a of squeezing the last drop of DNA from nice time in Sweden and we both learned a lot microscopic animals. A big hug to Diego in the lab. Thank you for watching my back in Fontaneto for being a very good friend and Modena. Patrizia Marchetto for taking me out your great patience when introducing me to and feeding me after a long flight from the new methods. We need to go back to Abisko U.S. Simona Ghiviriga for nice discussions of soon. Bill Hummon for raising my knowledge lab work. Thanks also go to Paulo Grilli. on gastrotrichs and for all the nice evenings I am very grateful to Carlos Rocha who we spent together in Modena and on the U.S. helped with permits and collection in Brazil. I Virgin Islands. am looking forward to our next visit to the My fellow colleagues at the department churrascaria. Many thanks to David of Invertebrate Zoology at the Swedish Figueiredo Candiani and Nancy Lo Man Hung Museum of Natural History: Lena Gustavsson for your help with collection and supplying who has provided lots of support and many transports in Belém. laughs. Anders Warén for helping me find all Several gastrotrichologists have helped kinds of stuff and for lending me screw me and special gratitude goes to Drs. Mitchell drivers. Carina Svensson helped me a lot in J. Weiss, Paulo Tongiorgi, Maria Balsamo and the lab, we started with 13 and in the end we Jacek Kisielewski. I am also very grateful to had a single specimen left. The ladies Karin Mr. James J. Kirk who has read some of my Sindemark-Kronestedt, Elin Sigvaldadottir, papers correcting my English language and Emily Dock-Åkerman, Kerstin Rignéus, Sara grammar. Paglia, Hanna Taylor and Sabine Stöhr for interesting and funny discussions in the lunch Jag hade nog inte stått ut i Stockholm utan min room. My accomplices Michel Clément, Karin allra bästa vän Kalle Wikstrand. Du, jag och Nilsson and Inga Meyer-Wachsmuth, good Kjellberg har haft många trevliga kvällar ihop. luck with all your work you will do excellent. Vi får ta en Fridays snart. Mina gamla Thanks also go to Sarah Bourlat, Thomas studiekompisar Jim Siegers, Mats Rasmusson, Kuntze, Hanna-Maria Jansson, Therése Roger Andersson, Ulf Nilsson och Gustav 28 Swedish Gastrotricha Tobias Kånneby

Svensson, vad kul vi hade! Min lilla älsklingsfågel Eva, som gjorde sitt bästa för att ta muspilen när jag satt och jobbade. Du lyckades till och med skriva en snutt en gång. Mamma och Pappa, det finns inget som är så skönt som att komma hem till Åhus och bara slappna av. Mysa i trädgården, äta gott och umgås. Jag älskar er! Min älskade Veronica. Du är det finaste jag har. Ekväkula!

29 Swedish Gastrotricha Tobias Kånneby

APPENDIX I – GASTROTRICHA REPORTED FROM SWEDEN

Table 1. Gastrotrich taxa reported from Sweden. The author of each species is given together with a presentation of distribution and a reference for localities. Subgeneric divisions of Chaetonotus follows Kisielewski (1997). Taxon Author Distribution Reference Order Macrodasyida

Family Cephalodasyidae Genus Cephalodasys Cephalodasys turbanelloides (Boaden, 1960) Bohuslän Boaden, 1960 Genus Dolichodasys Dolichodasys elongatus Gagne, 1977 Bohuslän Swedmark & Teissier, 1967; Willems et al., 2009 Genus Mesodasys Mesodasys laticaudatus Remane, 1951 Bohuslän Boaden, 1960 Genus Paradasys Paradasys hexadactylus Karling, 1954 Halland Karling, 1954 Paradasys subterraneus Remane, 1934 Bohuslän Willems et al., 2009

Family Dactylopodolidae Genus Dactylopodola Dactylopodola baltica (Remane, 1926a) Bohuslän Swedmark, 1950

Family Lepidodasyidae Genus Lepidodasys Lepidodasys martini Remane, 1926a Bohuslän Willems et al., 2009 Lepidodasys platyurus Remane, 1927d Bohuslän Willems et al., 2009

Family Macrodasyidae Genus Macrodasys Macrodasys buddenbrocki Remane, 1924 Bohuslän Wieser, 1954 Macrodasys caudatus Remane, 1927d Bohuslän Boaden, 1960 Genus Urodasys Urodasys mirabilis Remane, 1926a Öresund; Bohuslän Lang, 1936; Willems et al., 2009

Family Planodasyidae Genus Crasiella Crasiella diplura Clausen, 1968 Bohuslän Willems et al., 2009

Family Thaumastodermatidae Genus Acanthodasys Acanthodasys aculeatus Remane, 1927d Bohuslän Swedmark & Teissier, 1967; Willems et al., 2009 Genus Diplodasys Diplodasys ankeli Wilke, 1954 Bohuslän Swedmark & Teissier, 1967; Willems et al., 2009 Genus Ptychostomella Ptychostomella ommatophora Remane, 1927d Bohuslän Swedmark & Teissier, 1967 Genus Tetranchyroderma Tetranchyroderma cirrophorum Lévi, 1950 Bohuslän Swedmark & Teissier, 1967 Tetranchyroderma megastomum (Remane, 1927d) Bohuslän Boaden, 1960; Willems et al., 2009 Tetranchyroderma suecicum Boaden, 1960 Bohuslän Boaden, 1960 Genus Thaumastoderma Thaumastoderma heideri Remane, 1926a Bohuslän Swedmark, 1950; Willems et al., 2009 30 Swedish Gastrotricha Tobias Kånneby

Table 1 continued. Taxon Author Distribution Reference Thaumastoderma moebjergi Clausen, 2004 Bohuslän Willems et al., 2009 Family Turbanellidae Genus Dinodasys Dinodasys mirabilis Remane, 1927d Bohuslän Swedmark & Teissier, 1967; Willems et al., 2009 Genus Turbanella Turbanella cornuta Remane, 1925b Bohuslän; Skåne Karling, 1954; Boaden, 1960; Jansson, 1968; Willems et al., 2009; Kånneby unpublished Turbanella hyalina Schultze, 1853 Södermanland Karling, 1954; Jansson, 1968 Turbanella lutheri Remane, 1952 Bohuslän; Södermanland Karling, 1954; Jansson, 1968; Willems et al., 2009; Kånneby unpublished Turbanella lutheri scanica Wieser, 1954 Skåne Wieser, 1954

Order Chaetonotida Family Chaetonotidae Genus Aspidiophorus Aspidiophorus marinus Remane, 1926b Bohuslän Boaden, 1960; Swedmark & Teissier, 1967; Willems et al., 2009 Aspidiophorus oculifer Kisielewski, 1981 Lapland Paper III Aspidiophorus ophiodermus Balsamo, 1982 Bohuslän; Södermanland Paper III Aspidiophorus squamulosus Roszczak, 1936 Skåne Paper III Aspidiophorus tetrachaetus Kisielewski, 1986 Bohuslän; Jämtland Paper III Genus Chaetonotus Subgenus Captochaetus Chaetonotus (C.) arethusae Balsamo & Todaro, 1995 Stockholm Kånneby unpublished Subgenus Chaetonotus Chaetonotus (C.) benacensis Balsamo & Fregni, 1995 Dalarna Paper I Chaetonotus (C.) daphnes Balsamo & Todaro, 1995 Bohuslän; Jämtland; Skåne; Paper V; Kånneby unpublished Västmanland Chaetonotus (C.) heterospinosus Balsamo, 1978 Jämtland; Stockholm; Skåne Kånneby unpublished

Chaetonotus (C.) laroides Marcolongo, 1910 Bohuslän; Lapland Paper V Chaetonotus (C.) larus? (Müller, 1773) Bohuslän; Västmanland Kånneby unpublished Chaetonotus (C.) maximus Ehrenberg, 1831 Jämtland; Lapland?; Hofsten, 1923; Paper V; Kånneby Småland; Skåne; Stockholm unpublished

Chaetonotus (C.) microchaetus Preobrajenskaja, 1926 Bohuslän; Lapland; Paper V; Kånneby unpublished Stockholm; Stockholm archipelago; Södermanland Chaetonotus (C.) naiadis? Balsamo & Todaro, 1995 Bohuslän Kånneby unpublished Chaetonotus (C.) oculifer Kisielewski, 1981 Bohuslän; Jämtland; Lapland Paper I, V

Chaetonotus (C.) polyspinosus Greuter, 1917 Jämtland; Stockholm Paper I; Kånneby unpublished Chaetonotus (C.) similis Zelinka, 1889 Bohuslän?; Lapland; Skåne; Paper V; Kånneby unpublished Småland

Chaetonotus (C.) sphagnophilus Kisielewski, 1981 Lapland; Stockholm Kånneby unpublished archipelago Chaetonotus (C.) tempestivus Mock, 1979 Bohuslän Willems et al., 2009 Subgenus Hystricochaetonotus Chaetonotus (H.) aemilianus Balsamo, 1978 Lapland; Skåne Paper V; Kånneby unpublished Chaetonotus (H.) euhystrix Schwank, 1990 Lapland; Jämtland Kånneby unpublished Chaetonotus (H.) longispinosus Stokes, 1887 Northern Sweden Schwank, 1990

31 Swedish Gastrotricha Tobias Kånneby

Table 1 continued. Taxon Author Distribution Reference Chaetonotus (H.) hystrix Metschnikoff, 1865 Bohuslän; Dalarna; Lapland; Paper I, V; Kånneby unpublished Småland; Skåne Stockholm; Stockholm archipelago Chaetonotus (H.) macrochaetus Zelinka, 1889 Jämtland; Askö? Hofsten, 1923; Kånneby unpublished Chaetonotus (H.) persetosus? Zelinka, 1889 Lapland; Skåne; Stockholm Kånneby unpublished Chaetonotus (H.) spinulosus Stokes, 1887 Jämtland;hi l Stockholm Kånneby unpublished Subgenus Primochaetus Chaetonotus (P.) acanthodes Stokes, 1887 Bohuslän; Lapland; Småland; Paper V; Kånneby unpublished Södermanland; Chaetonotus (P.) armatus Kisielewski, 1981 Jämtland Paper V; Kånneby unpublished

Chaetonotus (P.) chuni Voigt, 1901b Unknown Schwank, 1990 Chaetonotus (P.) heideri Brehm, 1917 Bohuslän; Jämtland; Lapland Paper V; Kånneby unpublished

Chaetonotus (P.) heteracanthus Remane, 1927 Bohuslän Paper V Chaetonotus (P.) mutinensis Balsamo, 1978 Bohuslän; Lapland; Paper I; Kånneby unpublished Stockholm archipelago Subgenus Schizochaetonotus Chaetonotus (S.) atrox Wilke, 1954 Bohuslän Boaden, 1960; Willems et al., 2009 Chaetonotus (S.) dispar Wilke, 1954 Bohuslän Swedmark & Teissier, 1967; Paper V Chaetonotus (S.) inaequidentatus Kisielewski, 1988 Bohuslän Willems et al., 2009 Chaetonotus (S.) schultzei Metschnikoff, 1865 Unknown Schwank, 1990 Subgenus Zonochaeta Chaetonotus (Z.) bisacer Greuter, 1917 Västmanland Kånneby unpublished Chaetonotus (Z.) succinctus Voigt, 1902 Småland Kånneby unpublished Unknown subgenus Chaetonotus variosquamatus Mock, 1979 Bohuslän Willems et al., 2009 Genus Halichaetonotus Halichaetonotus aculifer (Gerlach, 1953) Bohuslän; Skåne? Willems et al., 2009; Kånneby unpublished Halichaetonotus atlanticus Kisielewski, 1988 Bohuslän Willems et al., 2009 Halichaetonotus paradoxus (Remane, 1927a) Bohuslän; Skåne Willems et al., 2009; Kånneby unpublished Halichaetonotus pleuracanthus (Remane, 1926b) Bohuslän Swedmark, 1950 Halichaetonotus somniculosus (Mock, 1979) Bohuslän Willems et al., 2009 Halichaetonotus euromarinus Hummon & Todaro, 2010 Bohuslän Todaro & Kånneby unpublished

Genus Heterolepidoderma Heterolepidoderma acidophilum Kånneby et al., submitted Bohuslän; Lapland; Paper III Stockholm archipelago; Södermanland; Uppland Heterolepidoderma joermungandri Kånneby in press Bohuslän Paper IV

Heterolepidoderma macrops Kisielewski, 1981 Bohuslän; Lapland Paper IV Heterolepidoderma ocellatum Metschnikoff, 1865 Bohuslän; Stockholm Paper IV archipelago; Södermanland Heterolepidoderma trapezoidum Kånneby in press Jämtland Paper IV Genus Ichthydium Ichthydium diacanthum Balsamo & Todaro, 1995 Jämtland Paper I Ichthydium maximum? Greuter, 1917 Bohuslän Kånneby unpublished Ichthydium podura (Müller, 1773) Småland; Stockholm Kånneby unpublished Ichthydium skandicum Kånneby et al., 2009 Bohuslän; Jämtland Paper I Ichthydium squamigerum Balsamo & Fregni, 1995 Dalarna; Småland; Paper I St kh l Vä t l d Ichthydium tanytrichum Balsamo, 1982 Jämtland Paper I

32 Swedish Gastrotricha Tobias Kånneby

Table 1 continued. Taxon Author Distribution Reference Genus Lepidochaetus Lepidochaetus zelinkai (Grünspan, 1908) Bohuslän; Jämtland; Lapland; Paper IV Stockholm archipelago; Södermanland Genus Lepidodermella Lepidodermella intermedia Kånneby et al., submitted Lapland Paper III Lepidodermella minor minor (Remane, 1936) Bohuslän Paper IV Lepidodermella squamata (Dujardin, 1841) Bohuslän; Gotland; Jämtland; Hofsten, 1923; Paper I; IV Lapland; Skåne; Småland; Södermanland; Västmanland

Genus Polymerurus Polymerurus nodicaudus (Voigt, 1901a) Stockholm; Södermanland; Paper III Öland Polymerurus rhomboides (Stokes, 1887) Västmanland Paper III

Family Dasydytidae Genus Haltidytes Haltidytes crassus (Greuter, 1917) Småland Paper IV Genus Stylochaeta Stylochaeta scirtetica Brunson, 1950 Småland Paper IV

Family Xenotrichulidae Genus Xenotrichula Xenotrichula punctata Wilke, 1954 Bohuslän Willems et al., 2009 Xenotrichula velox Remane, 1927c Skåne Jansson, 1968; Paper III, V

33 Swedish Gastrotricha Tobias Kånneby

APPENDIX II – REFERENCES FIGURE 1 AND FIGURE 2 Figure 1-1. Remane, 1926a Figure 2-27. Kisielewski, 1991 Figure 1-2. Wilke, 1954 Figure 2-28. Balsamo, 1983 Figure 1-3. Hummon et al., 1993 Figure 2-29. Schwank, 1990 Figure 1-4. Rieger et al., 1974 Figure 2-30. Balsamo, 1983 Figure 1-5. Swedmark, 1967 Figure 2-31. Kisielewski, 1991 Figure 1-6. Clausen, 1968 Figure 1-7. Rao & Clausen, 1970 Figure 1-8. Remane, 1926a Figure 1-9. Rao, 1981 Figure 1-10. Gagné, 1977 Figure 1-11. Schmidt, 1974 Figure 1-12. Remane, 1951 Figure 1-13. Remane, 1934 Figure 1-14. Ruppert, 1988 Figure 1-15. Remane, 1926a Figure 1-16. Remane, 1926a Figure 1-17. Clausen, 1965a Figure 1-18. Ruppert, 1988 Figure 1-19. Todaro, 1995 Figure 1-20. Evans & Hummon, 1991 Figure 1-21. d’Hondt, 1968 Figure 1-22. Remane, 1926a Figure 1-23. Ruttner-Kolisko, 1955 Figure 1-24. Kisielewski, 1987 Figure 1-25. Clausen, 2000 Figure 1-26. Wilke, 1954 Figure 1-27. Remane, 1926a Figure 1-28. Clausen, 1965b Figure 1-29. Hummon et al., 1993 Figure 1-30. Clausen, 1996 Figure 1-31. Ruppert, 1988 Figure 1-32. Clausen, 1992

Figure 2-1 Remane, 1935-36 Figure 2-2. Luporini et al., 1973 Figure 2-3. Remane, 1934 Figure 2-4. Remane, 1927c Figure 2-5. Balsamo, 1983 Figure 2-6. Sudzuki, 1971 Figure 2-7. Remane, 1935-36 Figure 2-8. Balsamo, 1983 Figure 2-9. Greuter, 1917 Figure 2-10. Horlick, 1975 Figure 2-11. Balsamo, 1983 Figure 2-12. Kisielewski, 1991 Figure 2-13. Balsamo, 1982 Figure 2-14. Balsamo, 1983 Figure 2-15. Kisielewski, 1991 Figure 2-16. Balsamo, 1983 Figure 2-17. Todaro et al., 2005 Figure 2-18. Todaro & Hummon, 2008 Figure 2-19. Kisielewski, 1987 Figure 2-20. Balsamo, 1982 Figure 2-21. Ruppert, 1977b Figure 2-22. Balsamo, 1983 Figure 2-23. Schwank, 1990 Figure 2-24. Schrom, 1972 Figure 2-25. Balsamo, 1983 Figure 2-26. Balsamo, 1983

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