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Twenty-two marine species of Dalytyphloplanida from Cuba, Panama, and Lanzarote are presented, sixteen of which are new to science. Five known species are recorded from Cuba: Kytorhynchus microstylus, Ceratopera paragracilis, Trigonostomum armatum, T. franki, and T. vanmecheleni. Neokytorhynchus pacificus is recorded for the first time in the Atlantic (Lanzarote). For one species, a new genus is erected to be included in a new family. A new genus and thirteen new species from Cuba and three new species from Panama are described. The new species are mainly distinguished from their congeners by the specific morphology of the copulatory structures. The new taxa are discussed in the context of a new phylogenetic analysis of Dalytyphloplanida. This analysis includes sequences of 238 species, 14 of which were sequenced for the first time. The phylogenetic analysis and the detailed morphology suggest that K. microstylus may constitute a complex of cryptic species. The internal phylogenetic relationships of Trigonostomum and Promesostoma were separately analysed to include new sequence data of the mitochondrial cox1 gene. These genera are shown to consist of several diagnosable clades, concurring with the results of early morphological studies of these taxa. Morphological and molecular data support the notion that Trigonostomum sinensis is a junior synonym of T. vanmecheleni, and we therefore propose their synonymisation. A new family is erected, Schockaertiidae fam. n., to include a monophyletic clade of neodalyellids with a pharynx rosulatus and a copulatory bulb devoid of hard structures (Schockaertia aprostatica gen. n. sp. n. and Einarella argillophyla). We propose a new classification into families of Thalassotyphloplanida, which envolves elevating the status of Adenorhynchinae to family level (Adenorhynchidae status novus). All previously recognised thalassotyphloplanid families are recovered as monophyletic (Kytorhynchidae, Byrsophlebidae, Promesostomidae, and Trigonostomidae). No support was found for the previously described subfamilies, except Paramesostominae, and we, therefore, propose to suppress these taxa. [ABSTRACT FROM AUTHOR]

Whereas most cnidarians are macrofaunal, a few microscopic lineages have evolved, and some of them inhabit marine sediments. The meiofaunal genus with the most species is Halammohydra, comprising nine nominal species. Species are described with high intraspecific variability in, e.g., the number of tentacles and statocysts and the shape and length of tentacles and body, complicating morphological identification to species level. Additionally, there is not much molecular data available. This study aims to revise already described species with morphological and molecular methods, as well as, to delineate potential new species answering questions about their geographical distribution. For this, specimens were sampled at 16 locations in the Northwest Atlantic and two localities in the East Atlantic, documented with light microscopy, and fixed individually for sequencing (16S, 18S, and CO1). Herewith, morphological characters were linked to a specific sequence, enabling the testing of character variation within one molecular phylogenetic group. Phylogenetic analyses were conducted (Bayesian Interference and Maximum Likelihood) in combination with species delimitation tests (ABGD, GMYC, and bPTP). Four already described species were identified in the data sets, and all of these were found at multiple localities. Four new species are described. Overall, the combined molecular and morphological data acquisition revealed multiple new species and a high degree of sympatry in Halammohydra. This, together with the confirmed excessive intraspecific variation in morphological traits, underlines the necessity of molecular sequencing for the taxonomy and species identification of Halammohydra. [ABSTRACT FROM AUTHOR]

Within meiofauna, cnidarians are represented by only a few species most of which are in the genus Halammohydra Remane, 1927. It represents highly modified medusae. Information about this group is limited, which complicates its placement in the Cnidarian tree and the relationship to another meiofaunal cnidarian, Otohydra Swedmark & Teissier, 1958. This needs to be clarified with molecular, but also with morphological methods. In this study, the internal organization of H. vermiformis Swedmark & Teissier, 1957 from Sylt and Helgoland (Germany) was examined using transmission electron microscopy (TEM). The ultrastructure of both sexes is documented in this study, i.e. the gastric tube including gonadal compartment, aboral cone, statocysts and tentacles. It is proposed that spermatozoa and oocytes are not released into the water through the gastrodermis, but by rupture of the epidermis, because of structural changes in the epidermis. In both, male and female, there is an indent in the gastric tube and a gap of the mesoglea at the same position. Additionally, we describe the complex structure of the aboral cone with the specialized adhesive organ as well as the accumulation of myofibrils and neurites in the orally directed part of the cone, which indicates high controllability and ability to move in this region. [ABSTRACT FROM AUTHOR]

We report here a specimen of the horsehair worm (Gordiida, Nematomorpha) Spinochordodes bacescui (Căpuşe, 1965) found in a patient´s urine. This is the first record of this species from Serbia and the sixth gordiid species known in Serbia. It is discussed that there is no evidence that gordiids are parasites of humans. Instead, gordiids parasitize terrestrial insects, which release their mature gordiid parasite into water and may thereby also use containers in human surroundings. Pseudoparasites, such as Spinochordodes bacescui, do not pose a threat to human health nor are they a serious public health issue. [ABSTRACT FROM AUTHOR]

Records of horsehair worms from Scandinavia are comparably few, although there are indications that the existing diversity of taxa is higher. We report here the occurrence of Gordius cf. spiridonovi Schmidt-Rhaesa, 2010 from two locations in Sweden and of Gordionus wolterstorffii (Camerano, 1888) from Norway. This is the first record from Norway. Gordionus wolterstorffii is a common species in Northern Europe. Gordius spiridonovi was described from Estonia. The newly reported Swedish specimens resemble G. spiridonovi in several characters, but G. terminosetosus Schmidt-Rhaesa, 2010 in others. This can be explained either by character plasticity or by the Swedish specimens representing an own species. This question cannot be resolved with the current material. [ABSTRACT FROM AUTHOR]

We report here a female specimen of Parachordodes sp. from Iran. This is the first report of the genus from Iran. The cuticle shows the characteristic feature of the genus Parachordodes, superareoles. Remarkable is the variety of shape in the areoles, which includes megareoles, which are characteristic for the genus Paragordionus. The variety of areoles also includes patterns that resemble characteristic structures of two Central Asian species. The new specimen opens up new perspectives for the future description of cuticular patterns in the genus Parachordodes and stresses the need for molecular data to resolve the relationship between the genera Parachordodes and Paragordionus. [ABSTRACT FROM AUTHOR]

We report a female Chordodes anthophorus from a Giant Asian Mantis (Hierodula membranacea) for the first time from Iran. Scanning electron microscopy (SEM) was used to describe the characters and substructures precisely. We demonstrate characteristic cuticular patterns for Chordodes anthophorus. The presence of five types of areoles including simple, tubercle, crowned and circumcluster areoles and also crowned areoles with long fi laments which is a common feature in females, confi rm our investigation. [ABSTRACT FROM AUTHOR]

The nematode phylum Nematomorpha contains organisms which are also known as horsehair worms or Gordian worms. We report here a male specimen of Gordian worm from a horse farm in Balıkesir province, Turkey. The body of the specimen was brown in color and the length was about 38 cm. After fixed in ethyl alcohol (80%) scanning electron microscopic (SEM) observations were carried out. Based on macroscopic and SEM findings the specimen was identified as Gordius sp. As merely little data is available on these organisms in Turkey, our finding will contribute to the existing knowledge in terms of the local diversity of this taxon. [ABSTRACT FROM AUTHOR]

The 19 genera within the phylum Nematomorpha contain approximately 350 species. The cosmopolitan genus Gordionus Müller, 1926 contains about 58 species, 6 of which occur in the contiguous United States of America. Recently, 2 new Gordionus species were described from high-altitude streams within the southern Rocky Mountains, near Santa Fe, New Mexico. Here we describe another new Gordionus species, from a high-altitude stream in the southern Rocky Mountains, from near Taos, New Mexico. The sites consisted of temporary puddles and a small human-made stream at 3,175-3,250-m altitude in aspen/pine woodland. Gordionus lokeri n. sp. has 1 areole type, which varies in shape and size between and within body regions. Midbody areoles are elongated, polygonal, or triangular, shingled, with the raised side of the areole serrated. The interareolar space is narrow, containing few bristles. The male cloacal opening is surrounded inside and outside by narrow branching bristles that bifurcate or trifurcate deeply; the furcae then subdivide several times terminally. Adhesive warts are lacking. Genetic data, consisting of partial cytochrome c oxidase subunit I (COI) gene sequences, clearly separated G. lokeri n. sp. from other Nearctic species. This is the third Gordionus species described from high-elevation streams in the Rocky Mountains. It appears that this high-altitude habitat represents the preferential niche for numerous species of this genus, and thus future work should focus on describing gordiid diversity in other parts of the Rocky Mountains. [ABSTRACT FROM AUTHOR]

Freshwater hairworms (class Gordiida) are members of the phylum Nematomorpha that use terrestrial arthropods as definitive hosts but reside as free-living adult worms in rivers, lakes, or streams. The genus Gordius consists of 90 described species, of which three species were described from freshwater habitats in North America. In this paper we describe a new species of Gordius from terrestrial habitats in Oklahoma, Texas, and Louisiana, United States. Oddly, each year hundreds of adult free-living worms appear after bouts of heavy rain on streets, sidewalks, and lawns during the winter season, when terrestrial arthropod hosts are not active. The new species is described based on morphological characters of adults and nonadult stages including the egg strings, eggs, larvae, and cysts. Adult males have a unique row of bristles on the ventral inner side of each tail lobe and a circular pattern of bristles on the terminal end of each lobe, which distinguishes them from all other described North American species of Gordius. The egg string, larval, and cyst morphology of this new species conform to previous descriptions of non-adult hairworm stages for the genus Gordius. However, the eggs of this new species of hairworm are unique, as they contain an outer shell separated by distinct space from a thick inner membrane. The consistent occurrence of this gordiid in terrestrial habitats, along with its distinct egg morphology, suggests that this new species of hairworm has a terrestrial life cycle. [ABSTRACT FROM AUTHOR]

During surveys of the Gastrotricha of the Tropical Northwestern Atlantic (TNWA, Caribbean Sea), we came across numerous specimens of the uncommon macrodasyidan, Xenodasys riedli (Xenodasyidae). Abundance data on gastrotrichs is rare and entirely absent for this species; moreover, there are no data on morphological variation of X. riedli outside its type locality (North Carolina, USA). Here, we provide new abundance data on specimens collected from St. John Island (US Virgin Islands), as well as new metric and morphological data from specimens collected on San Salvador Island (Bahamas), Tobago, and a sublittoral environment on the Atlantic Coast of Florida (USA). In the interstitial environments of St. John, X. riedli was most abundant at 0.8 m depth in moderately well-sorted sediments. It reached maximum abundance of 89.5 ± 42.7 ind./102 cm and made up 69.7% of the total taxocoenosis. Metric variation revealed that specimens at all sites in the TNWA and Florida had smaller body sizes than those recorded at the type locality, but showed only limited variation in the size and number of taxonomic characters. Observations of specimen from Florida using scanning electron microscopy (SEM) revealed details that were overlooked in the type description. For example, we observed 8 dorsal head plates (11 in the original description), 1 pair of anterior medial plates, and 3 ventral plates, the latter of which were not described in the type specimens. We confirm the existence of round scales on the dorsolateral margins, and note that spineless-scales are also present in between the spined scales on the lateral body wall. We also determined that the lateral spined scales possess dorsal and ventral spines instead of anterior and posterior spines, which was their original assumed position. This research reveals that SEM remains the best diagnostic tool for characterizing gastrotrich morphology, and should be part of all future studies of gastrotrich taxonomy. [ABSTRACT FROM AUTHOR]

Only four species of freshwater Nematomorpha (Gordiida) and one undeterminedGordiussp. are known from New Zealand. During recent surveys in the South Island we discovered a new species belonging to the genusGordionus, a genus new to New Zealand. Scanning electron microscopic observations of seven collected specimens revealed that the species is clearly morphologically distinct from all other members of the genus and is characterised by the presence of an extensive row of large bristles on the ventral side of the posterior end in males. This row is much larger than in any knownGordionusspecies. Analysis of the mitochondrial CO1 gene and of the nuclear 18S rRNA gene showed that the newGordionusspecimens form a monophyletic clade, but with partly extensive internal genetic difference. This indicates that cryptic species might be present, for although there are minor variations in cuticular areoles, other morphological characters indicate little difference between specimens. LSIDurn:lsid:zoobank.org:pub:E6E436C0-9032-4D4B-B08C-1C7B6948291A [ABSTRACT FROM AUTHOR]

Gordiids, or freshwater hairworms, are members of the phylum Nematomorpha that use terrestrial definitive hosts (arthropods) and live as adults in rivers, lakes, or streams. The genus Paragordius consists of 18 species, one of which was described from the Nearctic in 1851. More than 150 years later, we are describing a second Paragordius species from a unique habitat within the Nearctic; the Madrean Sky Island complex. The Madrean Sky Islands are a series of isolated high mountains in northern Mexico and the southwestern United States (Arizona and New Mexico), and are well known for their high diversity and endemicity. The new species is described based on both molecular data (COI barcoding) and morphological characters of the eggs, larvae, cysts, and adults. Adult females have unique small oblong mounds present on the interior of the trifurcating lobes with randomly dispersed long hairs extending from the furrows between the mounds. Marked genetic differences support observed morphological differences. This species represents the second new hairworm to be described from the Madrean Sky Islands, and it may represent the first endemic hairworm from this biodiversity hotspot. [ABSTRACT FROM AUTHOR]

Nematodes are a large and diverse monophyletic taxon with about 20,000 known species. They are part of the taxon Ecdysozoa, some of which possess a characteristic type of brain called the cycloneuralian brain. Because animals with a cycloneuralian brain likely are not a monophyletic group, it is important to describe and understand the structure of cyloneuralian brains and associated nervous system structures. With respect to nematodes, most studies focus on model organisms, such as Caenorhabditis elegans and immunohistochemical data in general, are rare. To expand the knowledge, we investigated two species of the family Plectida, Plectus acuminatus and Plectus aquatilis by immunohistochemical experiments combined with confocal laser-scanning microscopy. In comparison with C. elegans and further nematodes, our results reveal a conserved architecture of the nervous system and several structures can be homologized with known counterparts. Nevertheless, in detail, some striking differences can be demonstrated, which become visible in the arrangement of longitudinal and transverse neurites as well as in specialized neurons, such as the neurosecretory motor neurons within the pharynx. Compared to C. elegans, the branching pattern of these neurons in Plectus spp. is more complex. Overall, there are indications that the nervous system among nematodes is more diverse in structure than originally expected and further studies on taxonomically basal, free-living nematodes needs to be in focus on future investigations. [ABSTRACT FROM AUTHOR]

Three horsehair worms (Nematomorpha) are recorded from Nagaland, India. The first species is Chordodes combiareolatus, which was recently described from Nagaland. The second is Chordodes cf. furnessi, earlier reported from Meghalaya, and some new observations are added. The third is a new species, described as Beatogordius nagalandis sp. n. This is the first report of the genus Beatogordius in India and this observation fits well into the Gondwana distribution of the genus. The species is quite similar to B. chinensis, reported from South China. [ABSTRACT FROM AUTHOR]

Three females and one male specimen of a previously unconfirmed species of horsehair worms (Nematomorpha) from South Africa are described using Scanning Electron Microscopy. The females correspond to the description of Chordodes ferox Camerano, 1897, a species previously described from the Democratic Republic of the Congo (Congo-Kinshasa) and an adjacent, not further specified region of the Republic of Congo (Congo-Brazzaville). Characteristic is the presence of enlarged and elevated simple areoles around the base of a thorn areole, in combination with further cuticular characters. This is the latest of a total of six species of horsehair worms reported from South Africa so far. Two species of praying mantids, Polyspilota aeruginosa (Goeze, 1778) and Sphodromantis gastrica Stål, 1858, have been identified as hosts of C. ferox, while its distribution range in the region and the period of adult emergence from the host remain largely unknown. [ABSTRACT FROM AUTHOR]

The members of the phylum Nematomorpha, called as horsehair or gordian worms, are the parasites of arthropods and emerge from their host for reproduction and early development in water. There are about 360 species of nematomorphs described till date. Although, horsehair worms are parasites of arthropod species, sporadic cases of their occurrence have also been reported from several other hosts, including man. This paper describes a case history of the occurrence of two nematomorph worms in the meat of a pig in Shillong, India. The worms were reported to have emerged in live condition from pork bought by a consumer from local market in Shillong. One of the recovered specimens was studied by scanning electron microscopy for species determination and identified as Gordius sp., mainly on the basis of flat polygonal areoles and fine bristles on the cuticle. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Zoology is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The nervous system of invertebrates is considered to be a very conservative organ system and thus can be helpful to elucidate questions of phylogenetic relationships. Up to now, comparative neuroanatomical studies have been mainly focused on arthropods, where in-depth studies on major brain structures are abundant. In contrast, except for Gastropoda and Cephalopoda, the nervous system of representatives of the second largest phylum of invertebrates, the Mollusca, is as yet hardly investigated. We therefore initiated an immunohistochemical survey to contribute new neuroanatomical data for several molluscan taxa, especially the lesser known Caudofoveata, Solenogastres, Polyplacophora, and Scaphopoda, focusing on the cellular architecture and distribution of neurotransmitters in the brain. Antisera against the widespread neuroactive substances FMRFamide and serotonin were used to label subsets of neurons. Both antisera were additionally used in combination with acetylated α-tubulin and the nuclear marker DAPI. This enables us to describe the morphology of the nervous system at a fine resolution and to compare its cellular architecture between different species of one taxon, as well as between different taxa of mollusks. On the basis of these results, the nervous system of caudofoveates seems to be most highly derived within the so-called basal (non-conchiferan) mollusks, and a monophyly of a clade Aplacophora could not be confirmed. In general, the brain as well as the remaining nervous system of the molluscan taxa investigated shows a great variability, suggesting a deep time origin of the diversification of this prominent protostome clade. [ABSTRACT FROM AUTHOR]

Despite the severe fitness costs associated with sexual reproduction, its persistence and pervasiveness among multicellular organisms testifies to its intrinsic, short-term advantages. However, the reproductive assurance hypothesis predicts selection favoring asexual reproduction in sparse populations and when mate finding is difficult. Difficulties in finding mates is especially common in parasites, whose life cycles involve multiple hosts, or being released from the host into the external environment where the parasite can find itself trapped without a sexual partner. To solve this problem and guarantee reproduction, parasites in numerous phyla have evolved reproductive strategies, as predicted by the reproductive assurance hypothesis, such as hermaphroditism or parthenogenesis. However, this type of strategy has not been reported from species in the phylum Nematomorpha, whose populations have often been described as sparse. A new Nematomorpha species, Paragordius obamai n. sp., was discovered from Kenya, Africa, and appears to have solved the problem of being trapped without a mate by eliminating the need for males. Paragordius obamai n. sp. represents the first and only known species within this phylum to reproduce asexually. To determine the mechanism of this mating strategy, we ruled out the involvement of reproduction manipulating endosymbionts by use of next generation sequencing data, thus suggesting that parthenogenesis is determined genetically and may have evolved as a means to assure reproduction. Since this new parthenogenetic species and a closely related gonochoristic North American congener, P. varius, are easy to propagate in the laboratory, these gordiids can be used as model systems to test hypotheses on the genetic advantages and disadvantages of asexual reproduction and the genetic determinants of reproductive strategies in parasites. [ABSTRACT FROM AUTHOR]

We present a reconstruction of the nervous system of Neodasys chaetonotoideus Remane, (Gastrotricha, Chaetonotida) based on different microscopical methods: (1) immunohistochemistry (anti-acetylated α- and β-tubulin-, anti-5-HT- and anti-FMRFamide labelling) and (2) histochemistry (labelling of musculature and nuclei) by the means of confocal laser scanning microscopy (cLSM) and (iii) ultrastructure by means of transmission electron microscopy (TEM). All parts of the nervous system contain structures with an immunoreaction against the used immunohistochemical markers and labelling of histochemical markers. Results of both techniques (cLSM, TEM) reveal that the nervous system of N. chaetonotoideus is composed of a 'dumb-bell-shaped' brain and one pair of posterior longitudinal neurite bundles. The brain is made up of a pair of laterally located clusters of neuronal somata, a large dorsal interconnecting dorsal commissure and two tiny ventral commissures in the region of the lateral clusters. From this, it follows that the brain is circumpharyngeal in position. The innervation of the head region is conducted by three pairs of anterior-directed neurite bundles. We describe here the gross anatomy of the nervous system and give additional details of the ultrastructure and the 5-HT and RFamide-like IR components of the nervous system. We compare our newly obtained data with already published data on the nervous system of gastrotrichs to reconstruct the hypothetical ground pattern of the nervous system in Gastrotricha, respectively, in Macrodasyida. [ABSTRACT FROM AUTHOR]

Chordodes mizoramensis, a new species of freshwater gordiid horsehair worm, is described from Mizoram, NE India on the basis of scanning electron microscopic and morphometric studies. Th e new species can be distinguished from its congeners in that the apical filaments of the crowned areoles are branched several times, a pattern that has not been observed in other species. An additional distinguishing character is that it has more bulging areoles, which are distributed among simple areoles alone or in groups, do not form clear patterns. [ABSTRACT FROM AUTHOR]

Copyright of Estonian Journal of Ecology is the property of Teaduste Akadeemia Kirjastus and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The nervous system of the meiobenthic priapulid species Tubiluchus troglodytes is described by immunohistochemistry and confocal laser scanning microscopy. The brain is circumpharyngeal, consisting of a central ring of neuropil and both anterior and posterior somata. From the brain emerges a ventral nerve cord, which shows ganglion-like swellings in the neck and caudal region. The introvert includes longitudinal neurite bundles running below and between the rows of scalids, with a small cluster of sensory cells under each scalid. In the body wall of the neck and trunk region, longitudinal and circular neurite bundles are present in an orthogonal pattern. The tail is innervated from the caudal swelling of the ventral nerve cord; it also includes longitudinal and circular bundles in an orthogonal pattern. The pharynx has a reticulated system of neurite bundles running between the pharyngeal teeth and fimbrillae. Below each tooth and fimbrilus is a ganglion-like cluster of somata. The intestine is surrounded by a nerve net. The data on the nervous system are compared within other priapulids and with other species of Scalidophora (Kinorhyncha and Loricifera). [ABSTRACT FROM AUTHOR]

Background: Invertebrate nervous systems are highly disparate between different taxa. This is reflected in the terminology used to describe them, which is very rich and often confusing. Even very general terms such as 'brain', 'nerve', and 'eye' have been used in various ways in the different animal groups, but no consensus on the exact meaning exists. This impedes our understanding of the architecture of the invertebrate nervous system in general and of evolutionary transformations of nervous system characters between different taxa. Results: We provide a glossary of invertebrate neuroanatomical terms with a precise and consistent terminology, taxon-independent and free of homology assumptions. This terminology is intended to form a basis for new morphological descriptions. A total of 47 terms are defined. Each entry consists of a definition, discouraged terms, and a background/comment section. Conclusions: The use of our revised neuroanatomical terminology in any new descriptions of the anatomy of invertebrate nervous systems will improve the comparability of this organ system and its substructures between the various taxa, and finally even lead to better and more robust homology hypotheses. [ABSTRACT FROM AUTHOR]

Six species of the genus Chordodes from Africa were investigated in order to certify their taxonomic descriptions and verify the species status. Scanning electron microscopy demonstrated that the female of Chordodes congolensis has seven types of areoles, while the females of C. ferox have six and the male and females of C. madagascariensis have four and five areolar types, respectively. The females of these three species have polymorphic crowned areoles with both short and long filaments, these areoles are only observed along the ventral groove. The female of Chordodes mobensis has five areolar types and we found that crowned areoles were present in clusters of 10-12 areoles. Chordodes maculatus has been synonymized with C. kolensis and C. kakandensis with C. schoutedeni, because no differences could be detected that justify these species as valid. [ABSTRACT FROM AUTHOR]

Abstract  Immunohistochemical stainings have become standard tools to describe the nervous system, but usually only singular or few markers are used and consequently show only subsets of neurons within the nervous system. We investigated two species of Dactylopodola (Gastrotricha, Macrodasyida) with a broad set and combination of markers, to represent the nervous system in a more holistic approach. We suggest that markers for both neurotubuli (tubulin) and neurotransmitters (e.g. serotonin, FMRF-amides, histamine) should be used. Combinations with markers for the musculature (phalloidin) and nuclei (propidiumiodide or other markers) help to reveal spatial patterns and when used with TEM can provide a more precise picture of the spatial relationships of particular nerves. Species of Dactylopodola have a brain consisting of a solid dorsal commissure and a fine ventral commissure. Cell somata of brain cells are arranged lateral to the dorsal commissure and form a dumbbell-like brain. Additionally, projections into the head region, head sensory organs, one pair of lateroventral nerve cords with three commissures and stomatogastric nerves are described. Obviously, some longitudinal transmitter-specific fibres run in parallel to the main longitudinal nerve and represent additional longitudinal fibres. In comparison with the nervous system architecture of other gastrotrich species and that of different bilaterian animals it is speculated that the gastrotrich nervous system retains several ancestral features, such as being commissural and not a compact brain. [ABSTRACT FROM AUTHOR]

Long-held ideas regarding the evolutionary relationships among animals have recently been upended by sometimes controversial hypotheses based largely on insights from molecular data. These new hypotheses include a clade of moulting animals (Ecdysozoa) and the close relationship of the lophophorates to molluscs and annelids (Lophotrochozoa). Many relationships remain disputed, including those that are required to polarize key features of character evolution, and support for deep nodes is often low. Phylogenomic approaches, which use data from many genes, have shown promise for resolving deep animal relationships, but are hindered by a lack of data from many important groups. Here we report a total of 39.9 Mb of expressed sequence tags from 29 animals belonging to 21 phyla, including 11 phyla previously lacking genomic or expressed-sequence-tag data. Analysed in combination with existing sequences, our data reinforce several previously identified clades that split deeply in the animal tree (including Protostomia, Ecdysozoa and Lophotrochozoa), unambiguously resolve multiple long-standing issues for which there was strong conflicting support in earlier studies with less data (such as velvet worms rather than tardigrades as the sister group of arthropods), and provide molecular support for the monophyly of molluscs, a group long recognized by morphologists. In addition, we find strong support for several new hypotheses. These include a clade that unites annelids (including sipunculans and echiurans) with nemerteans, phoronids and brachiopods, molluscs as sister to that assemblage, and the placement of ctenophores as the earliest diverging extant multicellular animals. A single origin of spiral cleavage (with subsequent losses) is inferred from well-supported nodes. Many relationships between a stable subset of taxa find strong support, and a diminishing number of lineages remain recalcitrant to placement on the tree. [ABSTRACT FROM AUTHOR]

Abstract  The architecture of the musculature of the eutardigrade species Milnesium tardigradum Doy�re, 1840, Hypsibius sp. and Ramazzottius oberhaeuseri (Doy�re in Ann Sci Nat Zool S�r 2(14):269–369, 1840) is investigated by phalloidin staining and confocal laser scanning microscopy. There are methodological problems in staining eutardigrades due to physiological alterations under stress (anhydrobiosis) and due to penetration problems of the cuticle. It is helpful to fix specimens in the state of asphyxy, where animals are stretched following an oxygen shortage in their environment. The musculatures of all three species correspond in their general architecture, but differ in detail, such as in the number of muscles. All muscles are isolated muscle strands. There are on each body side two dorsal and one ventral muscle strands, in addition to a system of dorsoventral, lateral and lateroventral muscles. Seven median ventral attachment points give rise to dorsoventral, ventrolateral and appendage muscles. The appendages receive several muscles originating dorsally and ventrally. The number of muscles and the arrangement differ in each appendage. The fourth appendage shows the greatest differences with a far smaller number of muscles compared to other species. The musculature shows comparably few strict segmental patterns, for example, the musculature of each appendage differs from the other ones. By comparison with literature data on the same species and data of Macrobiotus hufelandi it can be shown that eutardigrades have a roughly comparable muscular architecture, but that there are several differences in detail. [ABSTRACT FROM AUTHOR]

Larvae of Paragordius varius (Leidy, 1851) were investigated using transmission electron microscopy, providing new observations concerning the cuticular structures of the preseptum, the postseptal gland and the pseudointestine. The cuticle is three-layered but the basal layer is variable in structure. The hooks possess long, intracuticular roots and the stylets have apical teeth. Both postseptal gland and pseudointestine are secretory in function. The postseptal gland is composed of eight cells, which are all connected by a duct leading through the septum into the preseptum. Inside the postseptal gland, the duct wall has numerous pores. The pseudointestine is composed of four cells surrounding a cavity with an amorphous content. A flattened duct within a syncytium with five nuclei leads to a ventral pore close to the posterior end. [ABSTRACT FROM AUTHOR]

Six species of the genus Chordodes from Africa are investigated in order to certify the taxonomic descriptions and verify the species status. Scanning electron microscopy demonstrates that the males of Chordodes clavatus and C. digitatus have five types of areoles, while the females of C. clavatus have seven areolar types and the females of C. digitatus have six areolar types. Chordodes capensis also shows this sexual dimorphism, as males have four types of areoles and females have five areolar types. The cuticle of Chordodes tuberculatus contains three areolar types. Chordodes ibembensis and C. uncinatus are synonimized with C. clavatus, because no differences can be detected that justify these species as valid. [ABSTRACT FROM AUTHOR]

The muscular system of gastrotrichs consists of circular, longitudinal and helicoidal bands that when analysed with confocal laser scanning microscopy, provide new insights into their functional organization and phylogenetic importance. We therefore undertook a comparative study of the muscle organization in three species of Gastrotricha from the orders Macrodasyida ( Paradasys sp., Lepidodasyidae; Turbanella sp., Turbanellidae) and Chaetonotida ( Polymerurus nodicaudus, Chaetonotidae). The general muscle organization of the marine interstitial macrodasyidans, Paradasys and Turbanella, not only confirms earlier observation on other species but also adds new details concerning the organization and number of helicoidal, longitudinal and other muscle bands (e.g. semicircular band). The freshwater, epibenthic–epiphytic chaetonotid, Polymerurus nodicaudus, has a similar muscular organization to other species of Chaetonotidae, especially species of Chaetonotus, Halichaetonotus and Lepidodermella. Perhaps unique to Polymerurus is the combined presence of an unbranched Rückenhautmuskel (also in Halichaetonotus and Lepidodermella) and a specialized dorsoventral caudal muscle, which flank the splanchnic component of the longitudinal muscles (only in Chaetonotus and Lepidodermella). This combination, together with the presence of splanchnic dorsoventral muscles, known only in Xenotrichulidae, implies a unique phylogenetic position for Polymerurus, and indicates a potential basal position of this taxon among the Chaetonotidae studied so far (i.e. Aspidiophorus, Chaetonotus, Halichaetonotus and Lepidodermella). [ABSTRACT FROM AUTHOR]

We investigated the development of dorsoventral and longitudinal musculature in all postembryonic stages of the kinorhynch Pycnophyes kielensis. Although the earliest stages have only 8 externally separated trunk segments, the), already possess dorsoventral muscles for 10 (prospective) trunk segments. The last, 11th, pair is added in the third juvenile stage. Longitudinal musculature, in contrast, is slower to develop and reaches its full length only in the adult. In several juvenile individuals, single fibers project from the longitudinal musculature into the following segments, in all juvenile stages, longitudinal muscles are continuous between segments, whereas in adults they are segmentally separated from each other. Such late occurrence of a segmental pattern in the longitudinal musculature is in contrast to patterns of muscle development in arthropods and annelids. [ABSTRACT FROM AUTHOR]

Two species of horsehair worms (Nematomorpha), Gordius albopunctatus and Gordionus violaceus , are reported from eight streams on the Baltic island Bornholm. Males can be easily distinguished from each other by differing features in the posterior end, but females resemble each other and can be distinguished reliably only using scanning electron microscopy. Aquarium experiments showed that larvae and praepupae of Pomatophylax cingulatus (Trichoptera) are the host for G. albopunctatus , which is one of the few cases in which nematomorphs develop completely in aquatic animals. Both nematomorph species occur sympatrically in almost all streams, but G. albopunctatus prefers northeastern streams and G. violaceus western streams. This might be due to the distribution of hosts, because P. cingulatus is more abundant in northeastern streams. [ABSTRACT FROM AUTHOR]

Thirty‐five species of Chordodes have been reported from Africa. The original description of several of these species is incomplete and needs reinvestigation by scanning electron microscopy (SEM) which allows the observation of fine structural details. We reinvestigated five of these species: Chordodes gariazzi , C. heinzei , C. kolensis , C. muelleri , and C. ruandensis . All of them show crowned areoles occurring in clusters. These clusters are formed by crowned areoles that are surrounded by another areolar type. The females of C. kolensis and C. muelleri have polymorphic crowned areoles with both short and long filaments; these areoles are only observed along the ventral groove. Chordodes gariazzi , C. heinzei , and C. muelleri have five areole types, C. ruandensis has three different types of areole, and C. kolensis displays a sexual dimorphism where males have six types of areole and females have seven areole types. Chordodes gariazzi , C heinzei , and C. muelleri have tubercle areoles. Host data and a new distribution record of C. kolensis are reported. [ABSTRACT FROM AUTHOR]

Two questions are of interest concerning the male reproductive system in Gordiida: (1) is the epithelium surrounding the testis continuous or discontinuous and (2) is the type of spermatozoon as described at the transmission electron-microscopical level for the two species of Gordius typical for all Gordiida? An examination of the South American species Pseudochordodes bedriagae has allowed us to add new information to this poorly studied phylum. Testicular tubes are large, filled with spermatozoa, and surrounded by a continuous epithelium. The epithelial cells that line the posterior testes occasionally overlap, and their cytoplasm is narrow and contains dense granules, abundant endoplasmic reticulum, and vesicles. The plasma membrane possesses microvilli with many filaments. This epithelium rests on a basement membrane. The spermatozoa in P. bedriagae resemble the known spermatozoa of two Gordius species but differ in presenting a uniform halo layer of less dense chromatin that surrounds the dense chromatin in the nucleus. The finding that a similar type of spermatozoa occurs in both genera ( Pseudochordodes and Gordius) makes it likely that it is present in all other Gordiida and is therefore an autapomorphy of the Gordiida. [ABSTRACT FROM AUTHOR]

Abstract The development of Paragordius varius (Nematomorpha), in the parasitic phase of the life cycle, was followed ultrastructurally from 10days after controlled infection of crickets (Gryllus firmus) to mature animals at 30days after infection. During this time span, specimens grow from about 1cm to more than 10cm and from 93m to about 400m in diameter. A thin larval cuticle is replaced at about day 20 by a robust adult cuticle. Epidermis and intestine appear physiologically active during the early stages, but decrease in size and cytological components during further development. This is probably connected to the uptake of nutrients through the larval cuticle, whereas the adult cuticle has only protective function. The longitudinal musculature grows continuously and changes from fewer platymyarian cells to abundant coelomyarian cells. The ventral nerve cord shifts from an intraepidermal to a submuscular position during development. Additionally, basiepidermal nerves are present. Gonads develop from paired dorsolateral compact strands. It seems that in males, cells within these strands separate into epithelial and central cells, which become the gametes, while in females, gametes proliferate from the strands into the primary body cavity and fill it up completely. In males, there is a large quantity of parenchyma, restricting the body cavity to a small periintestinal space, while in females, parenchyma occurs only in the periphery of the gametes. [ABSTRACT FROM AUTHOR]

We describe new records of horsehair worms (Nemacomorpha) from Central America and islands of the Caribbean Sea, provide updated descriptions including scanning electron microscopy and include a list of all species known from this region. Three new species are described: Pseudochordodes bulbarcolatus from Mexico and Guatemala, Neochordodes chordodides from Costa Rica and Belize, and Chordodes polytubercularus from Costa Rica. From Belize and Trinidad (Gordius robustus), nemaromorphs are reported for the first time. Further records include species known from North America (Pseudochordodes manteri, Neochordodes occidentalis) or from South America (Pseudochordodes meridionalis). The actual number of species known from continental Central America is 22 species from five genera, and from Caribbean islands five species from three genera are known. [ABSTRACT FROM AUTHOR]

We describe two new species of Beatogordius Heinze, 1934 (Nematomorpha), B. australiensis and B. lineatus, from Queensland, Australia. One further species, B. abbreviatus (Villot, 1874), which was known from Reunion, is reported from Madagascar. These new reports extend the range of Beatogordius from Africa and South America to include Madagascar and Australia. Beatogordius was likely distributed over the Gondwana continent prior to the separation of continental plates in the Mesozoic. This extends the existence of the taxon Nematomorpha, which was only known from young brown coal and amber, into the Mesozoic. Adhesive warts, structures anterior of the cloacal opening in males of B. abbreviatus, were originally described as characteristic structures of Gordionus Müller, 1927, but their occurrence in B. abbreviatus and one South American species indicates a wider distribution of this character. [ABSTRACT FROM AUTHOR]

The musculature of larvae of Gordius aquaticus was investigated by laser-scanning microscopy and compared to transmission electron microscopic data for the larva of Paragordius varius. In the anterior portion of the body, the preseptum, four different muscle groups can be distinguished: (1) 12 anterior parietal muscles in the body wall, (2) six oblique muscles that function as retractors of the introvert, (3) six proboscideal muscles, which function as retractors for the proboscis, and (4) six muscles associated with spines of the outermost of the three rings of spines. The posterior portion of the body, the postseptum, possesses four pairs of longitudinal muscle strands in G. aquaticus, the postseptal parietal muscles, that are located dorsolaterally and ventrolaterally. These are not clearly visible in P. varius, where instead three pairs of parietal muscles are present. Additional small muscles are associated with the terminal spines and with the duct running from the pseudointestine to the body wall. All fibers show a cross-striated pattern although this striation is less obvious at the ends of the fibers. [ABSTRACT FROM AUTHOR]

Schmidt-Rhaesa, A. 2004. Ultrastructure of an integumental organ with probable sensory function in Paragordius varius (Nematomorpha). — Acta Zoologica (Stockholm) 85: 15–19 The cuticle of late parasitic stages of Paragordius varius (Leidy, 1851) is composed of a layer with large fibres and a second layer (often named the areolar layer) distal from it. In this paper, organs are described that start at the basal side of the epidermis, pass the epidermis and the fibrous layer of the cuticle and merge with large, cushion-like structures in the distal layer of the cuticle. The epidermal part of the organs is composed of darkly stained cells, which are probably in contact with the basi-epidermal nervous system. Up to four processes of this cell traverse the cuticle. These processes might include cilia, because they contain microtubule-like structures. The probable connection to nerve cells and the connection to the cushion-like structures in the outer cuticular layer make it likely that the organs described here are sensory in function. [ABSTRACT FROM AUTHOR]