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Naidids are tiny, transparent freshwater oligochaetes, which are well known for their ability to propagate asexually. Despite the fact that sexually mature individuals and cocoons with embryos are sometimes found in nature, in long-period laboratory cultures, worms reproduce agametically only. In this paper, we showed, for the first time, the expression of Vasa, Piwi, and Pl10 homologs in mature Pristina longiseta worms with well-developed reproductive system structures and germ cells. Although the animals have been propagated asexually by paratomic fission for over 20 years in our lab, some individuals become sexualized under standard conditions for our laboratory culture and demonstrate various stages of maturation. The fully matured animals developed a complete set of sexual apparatus including spermatheca, atrium, seminal vesicles, and ovisac. They also had a clitellum and were able to form cocoons. The cues for the initiation of sexual maturation are still unknown for P. longiseta; nevertheless, our data suggest that the laboratory strain of P. longiseta maintains the ability to become fully sexually mature and to establish germline products even after a long period of agametic reproduction. On the other hand, many of the sexualized worms formed a fission zone and continued to reproduce asexually. Thus, in this species, the processes of asexual reproduction and sexual maturation do not preclude each other, and Vasa, Piwi, and Pl10 homologs are expressed in both somatic and germline tissue including the posterior growth zone, fission zone, nervous system, germline cells, and gametes. [ABSTRACT FROM AUTHOR]

Aquatic worms are considered a suitable group to evaluate the effects of contaminants on the environment, although one of the main challenges is to use the species of local occurrence. Recently, Pristina longiseta was suggested to be used in acute bioassays. In this context, this study aimed to establish a chronic exposure for ecotoxicological bioassays using the cosmopolitan species of occurrence in Brazilian freshwater P. longiseta. Firstly, we tested three exposure times (4, 7, and 10 days) under the presence or absence of aeration for reproduction outputs. After determining the best configuration (7 days without aeration), we assessed the effects of the chronic exposures using the standardized reference substance potassium chloride (KCl), the antibiotic sulfamethoxazole (SMX), the flame retardant tetrabromobisphenol A (TBBPA), and the sugarcane vinasse. Our results showed suitability for applying the chronic exposure using P. longiseta and indicated the sensitivity of the offspring to KCl (EC50-7d = 0.51 g/L). Sulfamethoxazole and TBBPA caused a significant decrease in the offspring of P. longiseta (EC50-7d = 59.9 µg/L and < 62.5 µg/L, respectively). Sugarcane vinasse showed high toxicity for the species, and 4.26% of vinasse was calculated as EC50-7d. Therefore, the described protocol was successfully applied as an ecotoxicological bioassay to evaluate the effects of environmental contaminants on the reproduction rate of the freshwater worm P. longiseta. [ABSTRACT FROM AUTHOR]

Exploring the effectiveness of DNA barcoding in species identification is a prerequisite for biodiversity conservation and environmental monitoring. Aquatic oligochaetes could serve as excellent indicators in aquatic monitoring programmes. However, few studies have examined the effectiveness of DNA barcoding in these specific organisms. The mitochondrial cytochrome C oxidase (COI) gene of 83 specimens belonging to 40 species of 18 genera were sequenced in this study. The results showed that there was a barcode gap between species of Naididae and the intraspecific genetic distances of each species were smaller than interspecific genetic distances. The classification results of ABGD (Automatic Barcode Gap Discovery) were consistent with those of morphological identification, except for Tubifex tubifex and Lumbriculus variegatus. All species were successfully distinguished in the phylogenetic tree, based on the ITS2 region, which was coincident with the morphological result. Our results provided evidence that DNA barcoding can be used as an effective and convenient tool for species identification of the family Naididae and even for other aquatic oligochaetes.

[Display omitted] • Characterization of novel aurantiactinomyxon types from Ilyodrilus templetoni. • Naidids reinforced as preferred hosts for aurantiactinomyxon development. • New types are likely counterparts to Paramyxidium spp. infecting European eel. • Aurantiactinomyxon interspecific genetic variability may be lower than 1% • Phylogeny supports high functionally of aurantiactinomyxon in estuarine habitats. Three new aurantiactinomyxon types are described from the oligochaete Ilyodrilus templetoni (Southern, 1909) (Naididae) collected from a northern Portuguese estuary, based on light microscopy and sequencing of the 18S rDNA. The addition of I. templetoni to the group of freshwater annelids known to be permissive for aurantiactinomyxon development reinforces the crucial role of naidids in the evolution and settlement of myxozoans in estuarine environments. Maximum likelihood and Bayesian inference analyses of a comprehensive 18S rDNA dataset placed the novel types within the Paramyxidium clade. This positioning suggests them as probable life cycle counterparts to Paramyxidium spp. that most likely infect the European eel Anguilla anguilla , as the sole representative of Elopomorpha in Portuguese rivers. Although distance estimation revealed a genetic difference of only 0.4 % between Aurantiactinomyxon types 1 and 3, this value was determined to be representative of interspecific variability based on the consistent matching of both genotypes with distinct actinospore morphologies, and potential richness of closely related species of Paramyxidium infecting the European eel in Portuguese waters. The clustering of aurantiactinomyxon types within distinct myxosporean lineages, representative of the suborders Variisporina and Platysporina, demonstrates that the aurantiactinomyxon morphotype is highly functional in promoting myxozoan infections in estuarine environments. [ABSTRACT FROM AUTHOR]

Ecotoxicological bioassays have been widely utilized to evaluate the toxicity of substances to organisms. However, the main challenge for researchers is finding native species to assess the effects of pollutants on aquatic biota. The tropical Oligochaeta, Allonais inaequalis, can be used as a test organism in bioassays to understand the effects of toxicants on aquatic ecosystems and their impact on native aquatic biota. In this study, we tested four methodological designs to validate the use of our "Allonais inaequalis reproduction test" as an ecotoxicological bioassay. For each sample, the assay consisted of a bottle containing 10 mg of sterilized fine sand, 60 mL of dechlorinated tap water and 6 organisms, fed at the beginning of the test and again after 5 days. The assay was first established in a controlled environment and then used to evaluate a stressed environment containing one of the following three toxicants suggested by the OECD (2008) and Corbi et al. (2015): zinc chloride, copper sulfate, or potassium chloride. Our results showed that the best experimental design for reproduction analysis was a static, long-term bioassay, which lasted 10 days without aeration and allowed for the reproduction of multiple generations (10 ± 5 new organisms). The observed inhibition reproduction by toxicants (EC50 ranging between 0.2 mg L−1 and 1.36 g L−1) validated the methods used in this paper. The use of a reproduction endpoint is a new contribution to the ecotoxicological toolbox, examining responses from a native organism to predict the effects of pollutants in an aquatic environment. [ABSTRACT FROM AUTHOR]

In the current study aquatic oligochaetes worms were collected monthly from five sites along AL- Abbasyia river / Al-Najaf province, South Iraq for a period between February 2018 to January 2019. Physical and chemical parameters for river water were examined which include: Air and Water temperature, pH ,Electrical conductivity ,Salinity, Dissolved oxygen , Biological oxygen demand and Sediment texture. The results showed a number of 5039 individuals of aquatic Oligochaeta were identified as three families Naididae ,Lumbriculdae and Enchytraaeidae .Tow species of Naididae Allonais pectinata (Stephenson, 1910) and Dero (Dero) dorsalis Forroniere, 1899 are considered as a new records in Euphrates River . Results showed the site S4 was highest number of worms site, 1323 worms of 17 species were found, while the lowest number of 579 individuals of 11 species were recorded in S2. J-card index for similarity showed that the highest similarity was between site S2 and site S3. Temporally, the highest individual numbers were recorded during September, while in April the lowest individual's number was recorded. [ABSTRACT FROM AUTHOR]

Paranais litoralis, a euryhaline aquatic oligochaete, was recently recorded in the middle stretch of the Danube River basin. This study provides more details about population abundance and habitat preferences of the species, inhabiting a lowland stretch of the Váh River in Slovakia. For the first time, few specimens were identified at one sampling site in September 2015, whereas in May 2016 the species was found at three sampling sites, with abundance ranging from 86 to 614 individuals per square meter. Regarding its habitat distribution, P. litoralis prefers sandy substrata but occurs also on muddy and stony substrata. The possible origin of this isolated population is discussed. [ABSTRACT FROM AUTHOR]

A new species of naidid oligochaete, Dero rwandae, detected in the bladder and the Wolffian ducts of reed frogs Hyperolius kivuensis from Rwanda, is described. Until now, D. bauchiensis was the only endoparasitic Dero known to infect African frogs infesting the eyes and Harderian glands. To the best of our knowledge, the finding of D. rwandae is the first record of an African Dero species infecting the urinary tract of anurans. In general morphology, the two African Dero parasites resemble each other, but differences in the features of ventral setae morphology exist. Parts of the mitochondrial 16S rRNA locus and the nuclear 18S and 28S rRNA loci were sequenced to assess the phylogenetic relationships to other Dero spp. Among those few species, that are barcoded so far, the closest relative of the new taxon is D. superterrenus, a free-living South American species. The species groups formerly termed subgenera Allodero, Aulophorus and Dero within the genus Dero do not represent distinct evolutionary lineages and the genus is paraphyletic including Branchiodrilus. [ABSTRACT FROM AUTHOR]

Both N deposition and changes in precipitation amount are important components of global change and affect aquatic ecosystem functioning by altering the detrital quality and detrital processing rates by macroinvertebrates and microorganisms. Changes in precipitation pattern can also modify the physical structure of the ecosystem, determining habitat availability for aquatic organisms. Although these drivers can individually affect ecosystem structure and functioning, their interactive effects are poorly understood.To better understand the combined effects of detritus quality and precipitation regime on the structure and function of aquatic ecosystems we manipulated litter quality, by modifying N:P stoichiometry and rainfall amount on tropical natural aquatic microcosms (water‐holding epiphytic bromeliads). We performed an orthogonal manipulation of litter N:P ratio (natural N:P and high N:P) and rainfall levels (current level and predicted 40% increase for south‐eastern Brazil)Changes in litter quality affected the abundance of the aquatic organisms inhabiting bromeliads, including algae and bacteria. However, changes in litter quality combined with changes in precipitation levels affected only one group of macroinvertebrates, the Naididae worms (Oligochaeta) an important group of detritivores in the bromeliad systems. These combined drivers also affected the decomposition of organic matter by changing coloured organic matter concentrations, fine particulate matter biomass, and NH4+ concentrations in bromeliad tanks. The NH4+ concentration in bromeliad water was positively related with Naididae abundance, suggesting that these worms can act as ecosystem engineers by boosting N cycling. In both N:P treatments we observed a 50% decrease in N flux from litter to bromeliad leaves due to increases in nutrient leaching from the tanks caused by rainfall.The combined effects of litter quality and changes in precipitation regimes altered the decomposition process and nutrient cycling in tank bromeliads, probably through changes in the abundance of some keystone species (e.g. Naididae). Aquatic macroinvertebrate community structure remained similar after manipulating precipitation, despite changes in the abundance of some species. Although some microorganisms were washed out of the system, their abundance inside the bromeliads remained stable. We conclude that the abundance of individuals belonging to aquatic communities in bromeliad phytotelmata are generally stable and resistant to changes in rainfall levels, but are sensitive to changes in litter quality.This experiment showed that the interactive effects of increased precipitation and N concentrations differed from the effects of either factor alone. As responses to changes in these factors were complex rather than additive, caution is required in predicting the outcomes of changes in both factors in freshwater ecosystems. [ABSTRACT FROM AUTHOR]

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The clitellate branchiate genus Branchiodrilus presently includes three nominal species with a mainly tropical distribution. A recent molecular phylogeny of the subfamily Naidinae suggested that species complexes may occur within the genus. In order to delimit species, we studied a total of 91 Branchiodrilus specimens collected in Asia, Africa and Europe; the genus is introduced in the latter area. We used an integrative approach, where genetic data were analysed for 42 specimens (single‐locus and multiple‐locus methods) and then compared with patterns shown by morphology. Ten Molecular Operational Taxonomic Units could be identified within Branchiodrilus, potentially representing 10 different species. Most of the delimited species are genetically well separated. In contrast, morphological scrutiny identified only three non‐overlapping clusters of specimens, one of them grouping all specimens from the Palaearctic region and belonging to the same species. Other morphological groups are mostly consistent with the biogeographic distribution of species. The Oriental region harbours six species and might be the centre of origin from which Branchiodrilus species have dispersed and radiated. Two other species are present in the Afrotropical region, among them B. cleistochaeta newly obtained from the type locality and genetically characterized, but the presence of B. hortensis in Africa is queried. The taxonomic relevance of the morphological criteria traditionally used to distinguish nominal species is useless at the species level. B. hortensis and B. semperi are now considered as species inquirenda. To document the genital organs of species remains highly desirable, although hardly practicable for this species complex with a primarily asexual reproductive mode. [ABSTRACT FROM AUTHOR]

In surveys conducted during 2000-2005, 39 taxa of aquatic oligochaetes belonging to the families Enchytraeidae and Naididae were found in Lake Tonle Sap in the Mekong River Basin, Cambodia. Dominated by naidines and pristinines (29 taxa), they mainly comprised widely distributed species as well as South Asian and Southeast Asian species. Among the four areas studied, the littoral regions of the lake—where inundated forests and aquatic vegetation developed during the flooded seasons—presented the highest number of species. Submerged vegetation in the littoral Lake Tonle Sap harbored abundant epiphytic oligochaetes, especially Stylaria fossularis. In contrast to the rich abundance of naidine and pristinine fauna, tubificines and ryhacodrilines were scarce in and around the lake, irrespective of the vegetation in their habitats. Several Aulodrilus species and Branchiura sowerbyi were the main representatives of the benthic oligochaete assemblages throughout the offshore zone of the lake without vegetation. It is noteworthy that the widely distributed tubificines Tubifex tubifex and Limnodrilus hoffmeisteri were not found in any surveyed locality. [ABSTRACT FROM AUTHOR]

We investigated the involvement of oligochaetes in the life cycles of fresh water myxozoan parasites in Brazil. In a fish farm in the State of Mato Grosso do Sul, we examined 192 oligochaetes and found that two (1%) released Aurantiactinomyxon type actinospores. We identified infected oligochaetes by morphology: both were Pristina synclites, from family Naididae. This is the first report of the involvement of this species in the life cycle of myxozoans. Small-subunit ribosomal DNA sequences of Aurantiactinomyxon type 1 (1882 nt) and Aurantiactinomyxon type 2 (1900 nt) did not match any previously sequenced myxozoan in the NCBI database, with the highest BLAST search similarities of 83% with Myxobolus batalhensis MF361090 and 93% with Henneguya maculosus KF296344, respectively, and the two aurantiactinomyxons were only 75% similar to each other (over ~ 1900 bases). Phylogenetic analyses showed that Aurantiactinomyxon type 1 had closest affinities with myxozoans from fish hosts in Order Characiformes, and Aurantiactinomyxon type 2 had affinities with myxozoans from fish of Order Siluriformes. [ABSTRACT FROM AUTHOR]

The genera Dero and Allonais belong to the family Naididae. Most species in the genus Dero have unique morphological characters including a branchial fossa and/or gills at the posterior end of the body. The genus Allonais has no eyes unlike its close relative the genus Nais. Of these genera, one species of Dero, D. obtusa, was recently reported in Korea. However, the genus Allonais has not been recorded in Korea. Here, we report Dero dorsalis Ferroni$\grave{e}$ 수식 이미지re, 1899 and Allonais pectinata (Stephenson, 1910) with a diagnosis and illustrations.

The phylogenetic relationships within Naidinae (Annelida, Clitellata, Naididae) were investigated, using six molecular markers, both mitochondrial (12S rDNA, 16S rDNA, the COI gene) and nuclear (18S rDNA, 28S rDNA, the ITS region). Thirty-seven nominal species, representing 16 of the 22 genera recognized in the subfamily, were included, and the Nais communis/variabilis species complex was represented by six different morphotypes. Ten other species of Naididae were selected as outgroups. The data were analysed by Bayesian inference and Maximum Likelihood. The phylogeny corroborates monophyly of the Naidinae, and the separate status of the genus Pristina (Pristininae) and the Opistocystinae. Relationships within Naidinae are largely well supported, but in some parts unexpected: (1) A clade containing the largely tropical genera Dero and Branchiodrilus is sister to the rest of the subfamily, and together with a third tropical genus, Allonais , they form a basal paraphyly. All these genera show morphological adaptations to environmental hypoxia, leading to the conclusion that Naidinae originated in tropical freshwaters. (2) The genera Dero , Nais and Piguetiella are paraphyletic. (3) At least Branchiodrilus , Paranais , Chaetogaster , Nais , Stylaria appear to contain cryptic species. Morphological characters, especially those associated with chaetae, are to a great extent homoplastic within Naidinae, which certainly has contributed to the overall taxonomic confusion of this subfamily. [ABSTRACT FROM AUTHOR]

One of the goals of urban ecology is to link community structure to ecosystem function in urban habitats. Pollution-tolerant wetland invertebrates have been shown to enhance greenhouse gas ( GHG) flux in controlled laboratory experiments, suggesting that they may influence urban wetland roles as sources or sinks of GHG. However, it is unclear if their effects can be detected in highly variable conditions in a field setting. Here we use an extensive data set on carbon dioxide ( CO2), methane ( CH4), and nitrous oxide (N2O) flux in sediment cores ( n = 103) collected from 10 urban wetlands in Melbourne, Australia during summer and winter in order to test for invertebrate enhancement of GHG flux. We detected significant multiplicative enhancement effects of temperature, sediment carbon content, and invertebrate density on CH4 and CO2 flux. Each doubling in density of oligochaete worms or large benthic invertebrates (oligochaete worms and midge larvae) corresponded to ~42% and ~15% increases in average CH4 and CO2 flux, respectively. However, despite exceptionally high densities, invertebrates did not appear to enhance N2O flux. This was likely due to fairly high organic carbon content in sediments (range 2.1-12.6%), and relatively low nitrate availability (median 1.96 μmol/L NO3−-N), which highlights the context-dependent nature of community structural effects on ecosystem function. The invertebrates enhancing GHG flux in this study are ubiquitous, and frequently dominate faunal communities in impaired aquatic ecosystems. Therefore, invertebrate effects on CO2 and CH4 flux may be common in wetlands impacted by urbanization, and urban wetlands may make greater contributions to the total GHG budgets of cities if the negative impacts of urbanization on wetlands are left unchecked. [ABSTRACT FROM AUTHOR]

Limnodrilus species are annelid worms distributed worldwide in various freshwater sediments. The systematics of Limnodrilus has chiefly been based on morphology, but the genus has not been subject to any closer phylogenetic studies over the past two decades. To reconstruct the evolutionary history of Limnodrilus , and to assess the monophyly of this genus and its systematic position within the subfamily Tubificinae (Annelida: Clitellata: Naididae), 45 Limnodrilus specimens, representing 19 species, and 35 other naidid species (representing 24 genera) were sampled. The data consisted of sequences of three mitochondrial genes (COI, 12S and 16S rDNA) and four nuclear markers (18S and 28S rDNA, Histone 3, and ITS). The phylogeny was estimated, using Maximum Likelihood and Bayesian analyses of concatenated data of seven DNA loci, as well as a multi-locus coalescent-based approach. All analyses strongly suggest that Limnodrilus is monophyletic, but only if the morphospecies L. rubripenis is removed from it. Limnodrilus rubripenis and (at least) Baltidrilus , Lophochaeta and some species attributed to Varichaetadrilus comprise the sister group to the clade Limnodrilus sensu stricto , and the latter is further divided into three well-supported groups. One of them contains morphospecies characterized by short cuticular penis sheaths and enlarged chaetae in anterior segments ( L. udekemianus , L. silvani and L. grandisetosus ). The second is a small group of species with moderately long penis sheaths, i.e., L. sulphurensis and L. profundicola . The third, and largest group, includes not only the multitude of cryptic species in the L. hoffmeisteri complex, but also other, morphologically distinct, species nested within this complex. All studied species in this large group have long penis sheaths, which are exceptionally long in L. claparedianus , L. maumeensis , and a form morphologically intermediate between L. claparedianus and L. cervix . The identification and classification of these groups provide a framework for directed sampling in further phylogenetic studies, and for revisionary work on the L. hoffmeisteri complex and other unresolved Limnodrilus species. [ABSTRACT FROM AUTHOR]

The involvement of oligochaetes in the life cycles of fresh water myxozoan parasites in Brazil was investigated. Of 333 oligochaetes collected in a fish farm in the State of São Paulo, three (0.9%) released Aurantiactinomyxon type spores. From 86 worms collected in a fish farm in Mato Grosso do Sul State, 1 (0.9%) released actinospores with a novel morphology for which we propose the name Seisactinomyxon. Infected oligochaetes were identified by morphology: all belonged to family Naididae, with Pristina americana the host for Aurantiactinomyxon and Slavina evelinae the host of Seisactinomyxon. This is the first report of the involvement these two species of oligochaetes in the life cycle of myxozoans. Small subunit rDNA sequences of the Aurantiactinomyxon (1204 nt) and Seisactinomyxon (1877 nt) did not match any previously sequenced myxozoan. Phylogenetic analyses showed that both actinospore types fell in a clade formed by six Myxobolus spp. that parasitize Characiformes fishes. [ABSTRACT FROM AUTHOR]

Despite the importance of Oligochaeta to the dynamics of aquatic ecosystems and to studies of the biology of pollution, there is currently a dearth of information on this group's ecology in Brazil. The aim of this study was to describe the Oligochaeta fauna in four watercourses - three urban and one rural - in the state of São Paulo: the Pinheirinho stream, the Água Branca stream, the Monjolinho River and the Gouveia stream, respectively. Sediment samples were taken with a Van Veen grab in two areas from each watercourse, during the summer and winter of 2001. In all collection areas, measurements of the pH, electrical conductivity, dissolved oxygen and turbidity of the water were made with a Horiba U-10 device. Principal component analysis showed that axes 1 and 2 explained 68.18% of the results' variability, with the first axis predominantly associated with the granulometric data and the second one with the limnological data. Cluster analysis indicated that area II of the Monjolinho River differed from the other collection sites. In the present study, the Oligochaeta group was represented by Tubificidae, Naididae, Alluroididae, Narapidae and Enchytraeidae. Among the three species of Tubificidae, Limnodrilus hoffmeisteri Claparede, 1862, was the most abundant and most frequent species. The results provided important information on the ecology and distribution of limnic Oligochaeta.Apesar da importância dos Oligochaeta para a dinâmica dos ecossistemas aquáticos e para os estudos sobre a biologia da poluição, existe atualmente, no Brasil, uma carência de informação sobre a ecologia desse grupo. O objetivo do estudo foi caracterizar a fauna de Oligochaeta em três córregos urbanos e um córrego rural, localizados na região central do Estado de São Paulo, sendo estes o córrego do Pinheirinho, Água Branca, rio Monjolinho e o córrego do Gouveia, respectivamente. Amostras do sedimento foram obtidas com um pegador Van Veen em duas áreas, durante o verão e inverno de 2001, em cada um dos ambientes estudados. Em todas as áreas de coletas foram tomadas medidas de pH, condutividade elétrica, oxigênio dissolvido e turbidez da água com o aparelho U-10 Horiba. A análise de componentes principais mostrou que os eixos I e II explicaram 68,18% da variabilidade dos resultados, sendo que, o primeiro eixo foi predominantemente explicado pelas variáveis granulométricas e o segundo eixo pelas variáveis limnológicas. A análise de agrupamento indicou que a área II do rio Monjolinho diferiu dos demais pontos de coleta. No presente estudo, o grupo Oligochaeta foi representado pelas famílias Tubificidae, Naididae, Alluroididae, Narapidae e Enchytraeidae. Entre as três espécies de Tubificidae, Limnodrilus hoffmeisteri Claparede, 1862 foi a mais abundante e mais freqüente. Os resultados forneceram informações importantes sobre a ecologia e distribuição de Oligochaeta límnicos.

An aquatic oligochaete species, Ripistes parasita (Schmidt, 1847) collected from Ganghwado Island in Korea, is described and illustrated. Specimens inhabiting on aquatic vegetation at the edge of the streams were collected with a plankton hand net. Morphological features of present specimens such as the number of long hair chaetae per bundle and their length in VI-VIII, and shape and size of ventral chaetae are concordant with those of previous reports on this species. The genus Ripistes contains one species, R. parasite which is distributed over, Europe, North America and eastern part of Asia including China and Japan. This is the first record of R. parasita in Korea.

Un total de 15 taxones de oligoquetos acuáticos han sido identificados en dos colecciones de la isla de Coiba del Museo Nacional de Ciencias Naturales (MNCN, Madrid) y Cuba (leg. Dra. Ana Camacho). Se aportan notas morfológicas y sistemáticas para las especies Limnodrilus variesetosus, Pristina aequiseta formas evelinae y foreli, P. breviseta, P. osborni y P. sima. Pristina cabacuensis Botea, 1983 y P. decui Botea, 1987 son propuestas como sinónimos de Pristina aequiseta Bourne. Se discute la taxonomía de Pristina osborni y P. sima y se apoya su estatus de especies independientes. El alluroidido Brinkhurstia americana se cita en la isla de Coiba ampliando la distribución actual de la especie a America Central y del Sur.

A very large collection of Naididae of the West Indies (153 localities), Suriname (15), Venezuela (2) and Florida (1) is studied. Five new species Nais barua, Dero scalariformis, D. tuna, Aulophorus kalina, A. barbatus are described. Dero magna, D. trifida, Aulophorus tridentatus, Allonais japonica, Pristina sima are redescribed. The 46 Naididae species of the West Indies are discussed by their taxonomy, distribution and habitat.

Naidid worms were sorted from 27 samples of aquatic macrophyta including ceratophyllum demersum , Potamogeton crispus and, Hydrilla verticellat with associated filamentous algae were collected from Euphrates River at Al-Mussayab city, 60 Km southwest Baghdad. The result of sorted worms revealed the presence of eight species of subfamily Naidinae, which are consider as new records for Iraq, including Stephensoniana trivandrana; Paranais frici, Ophidonais serpentine, Specaria josinae, Dero (Dero) evelinae , Dero (Aulophorus) indicus , Nais pseudobtusa and finally N. stolci. This investigation includes morphological descriptions for each species illustrated by identification criteria photos.

Heterodrilus is a group of marine Naididae, common worldwide in subtropical and tropical areas, and unique among the oligochaetes by their tridentate chaetae. The phylogenetic relationships within the group are assessed from the nuclear 18S rDNA gene, and the mitochondrial cytochrome c oxidase subunit I (COI) and 16S rDNA genes. Sequence data were obtained from 16 Heterodrilus species and 13 out-group taxa; 48 sequences are new for this study. The data were analysed by Bayesian inference. Monophyly of the genus is corroborated by the resulting tree, with Heterodrilus ersei (a taxon representing a small group of species with aberrant male genitalia) proposed to be outside all other sampled species. Although earlier regarded as a member of the subfamily Rhyacodrilinae, both molecular and morphological data seem to support that Heterodrilus is closely related to Phallodrilinae. However, the results are not conclusive as to whether the genus is the sister group of, or a group nested inside, or separate from this latter subfamily. The studied sample of species suggests at least two major clades in Heterodrilus with different geographical distributions, in one of the clades, most species are from the Indo-West Pacific Ocean, while in the other, the majority are from the Western Atlantic Ocean. Morphological characters traditionally used in Heterodrilus taxonomy are optimized on the phylogenetic tree, revealing a high degree of homoplasy. [ABSTRACT FROM AUTHOR]

A survey on freshwater oligochaetes was conducted between October 2011 and June 2013 in selected wetlands of the Dakshina Kannada, Udupi, and Shimoga districts of Karnataka, India. In this study, 260 wetlands were sampled and examined for the presence of microdriles. Sixteen species of aquatic oligochaetes were recorded. Of these, 10 species belonged to the family Naididae (monophyletic) and 6 species to the family Pristinidae. The species' distribution patterns in different water bodies and habitat specificity (if any) in the study area are presented. [ABSTRACT FROM AUTHOR]

Within Oligochaeta, Chaetogaster limnaei is unusual in exhibiting a parasitic relationship with freshwater pulmonate snails. Taxonomic confusion has been caused by differences in what have been considered 2 subspecies of this worm: Chaetogaster limnaei limnaei is an ectosymbiont and is present inside the mantle cavity of the snail, whereas Chaetogaster limnaei vaghini is parasitic and lives in the kidney of the snail. This study explored the distribution of these annelids in central New York and used mitochondrial DNA sequence data from the COI locus to examine the relationship, evolution, and species status of the ectosymbiotic and parasitic forms of C. limnaei. Snails (Physa gyrina) were collected from 6 streams and lakes in central New York, with additional specimens collected from a lake in Massachusetts for comparison. One hundred and forty snails were examined, and at least 1 form of Chaetogaster was present in 88 specimens, a prevalence of 62.9%. COI sequence data from New York and Massachusetts did not reveal separate ectosymbiotic and parasitic lineages. Instead, all parasitic forms were part of a mixed clade that included both ectosymbiotic and parasitic forms. This mixed clade was nested within clades of ectosymbiotic forms only, suggesting that a plastic lineage of C. limnaei, able to be both ectosymbionts and parasites, evolved from ectoparasitic ancestors. [ABSTRACT FROM AUTHOR]

Given their ubiquitous nature, it is surprising that more oligochaete annelid worms (Annelida: Clitellata) have not adopted an endoparasitic lifestyle. Exceptions, however, are the understudied members of the genus Dero (Allodero) that parasitize the ureters of tree frogs and toads. This study experimentally explores the life cycle and host specificity of Allodero hylae, the worm's use of chemical cues in host searching, and its seasonal prevalence and abundance over a year-long collection period on the Florida Southern College campus. A total of 2,005 A. hylae was collected from the ureter, urinary bladder, or expressed urine of wild Osteopilus septentrionalis; a significant positive correlation was found between host snout-vent length and parasite intensity for female but not male hosts. Monthly prevalence of A. hylae reached a peak of 58% in April, but never dropped below 20% in any month; mean abundance peaked March-May, whereas few worms were recovered in December and January. Confirming a parasitic lifestyle, wild-collected hosts with intense infections, typically >40 worms, showed obvious dilatation of the ureter wall, and some young-of-the-year O. septentrionalis exposed to A. hylae in the laboratory were killed by the apparent rupture of the host's ureter. The worm has a direct life cycle: worms expelled in the host's urine are capable of locating and re-infecting other hosts within aquatic microhabitats such as bromeliad tanks, and worms can survive for weeks in a free-living environment, even undergoing a morphological change. Further, chemotaxis assays found a positive response to a tree frog attractant for worms recently removed from hosts. Overall, this study provides the first multifaceted investigation on the life history and ecology of any Allodero spp., which offers new insights into an understudied endoparasitic oligochaete. [ABSTRACT FROM AUTHOR]

Introduction: An important goal for understanding how animals have evolved is to reconstruct the ancestral features and evolution of the nervous system. Many inferences about nervous system evolution are weak because of sparse taxonomic sampling and deep phylogenetic distances among species compared. Increasing sampling within clades can strengthen inferences by revealing which features are conserved and which are variable within them. Among the Annelida, the segmented worms, the Clitellata are typically considered as having a largely conserved neural architecture, though this view is based on limited sampling. Results: To gain better understanding of nervous system evolution within Clitellata, we used immunohistochemistry and confocal laser scanning microscopy to describe the nervous system architecture of 12 species of the basally branching family Naididae. Although we found considerable similarity in the nervous system architecture of naidids and that of other clitellate groups, our study identified a number of features that are variable within this family, including some that are variable even among relatively closely related species. Variable features include the position of the brain, the number of ciliary sense organs, the presence of septate ventral nerve cord ganglia, the distribution of serotonergic cells in the brain and ventral ganglia, and the number of peripheral segmental nerves. Conclusions: Our analysis of patterns of serotonin immunoreactive perikarya in the central nervous system indicates that segmental units are not structurally homogeneous, and preliminary homology assessments suggest that whole sets of serotonin immunoreactive cells have been gained and lost across the Clitellata. We also found that the relative position of neuroectodermal and mesodermal segmental components is surprisingly evolutionarily labile; in turn, this revealed that scoring segmental nerves by their position relative to segmental ganglia rather than to segmental septa clarifies their homologies across Annelida. We conclude that fine taxonomic sampling in comparative studies aimed at elucidating the evolution of morphological diversity is fundamental for proper assessment of trait variability. [ABSTRACT FROM AUTHOR]

Although strategies that increase the survival of a predator attack have been widely observed, the strategy of altering reproductive effort under predation threats has not been well documented. A switch to sexual reproduction or an increased asexual reproductive rate may be inducible antipredator strategies in animals that are capable of both asexual and sexual reproduction. The results of laboratory experiments with two oligochaete species, Stylaria lacustris (L.) and Nais christinae Kasprzak, indicated that an increased asexual reproductive rate, a less typical strategy in response to alarm cues from conspecifics, is employed by the Naididae worms. The oligochaetes of both species exposed to conspecific cues also used the additional strategy of increased length at fission and consequently the increased length of parental worms and descendants after fission. The increase in body length appears to be beneficial in the case of sublethal predation by invertebrates. The similar life history changes observed in these two oligochaete species may be a universal adaptation against diverse predators that are abundant in the littoral zone. [ABSTRACT FROM AUTHOR]

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This study investigated the structure of the Oligochaeta and Chironomidae assemblages associated with monospecific stands of two submerged macrophyte species: Egeria najas and Hydrilla verticillata. Samplings were carried out in Leopoldo Backwater and Paraná river, in August 2008. To assess the structure of Oligochaeta and Chironomidae assemblage in each macrophyte we calculated: species density, richness, diversity, and evenness. A detrended correspondence analysis (DCA) was used to summarize Oligochaeta and Chironomidae assemblages composition. The highest values of species density and richness for the two groups were recorded in H. verticillata. Although there were no significant differences in density, richness and Shannon diversity, the assemblage composition of these groups was significantly different between plant species. These results suggest that despite being a recent colonizer in the upper Paraná river habitats, the non-native species H. verticillata seems to provide favorable conditions for the establishment of native assemblages of Chironomidae and Oligochaeta. Moreover, differences in the species composition of Oligochaeta and Chironomidae arose from peculiar characteristics of each plant, as attached microorganisms and organic matter, so that other factors, rather than plant architecture can also influence the assemblage of these groups.

One new species of Naidinae (Oligochaeta, Naididae), Nais badia sp. n. and one new record species from China, Tubifex montanus Kowalewski, 1919 (Tubificinae) are found in southern Tibet. The new species is distinguished from congeners by its large area of reddish brown pigment in the anterior segments I-VIII, serrate hairs, pectinate needles with 1-2 intermediate teeth, ventral chaetae partly with 1-2 fine intermediate teeth and wave-like movements. The new material of the species Tubifex montanus differs slightly from the previous descriptions by its vas deferens entering atrium subapically, wide ental end of penial sheath and smooth hair chaetae. [ABSTRACT FROM AUTHOR]

Macquaridrilus mcmurtrieaen. sp. is described from Campbell Island. This resembles the only other species in the genus,Macquaridrilus bennettaeJamieson, 1968, in most aspects, but shows significant differences in the anatomy of its genitalia. In particular, the spermathecal pores are dorsal rather than lateral, the spermathecae lack diverticulae, the ejaculatory duct is more stout and muscular, the vas deferens is shorter relative to other organs and the anterior prostate is compact rather than elongate. The presence of a cuticular sperm canal appears to be an apomorphy for the genus. The new species was collected from streams and tarns across the island. http://zoobank.org/urn:lsid:zoobank.org:pub:652AF61D-CFB2-4D07-94C8-59E6FB549D5F http://zoobank.org/urn:lsid:zoobank.org:act:984F2456-768D-48A1-87AD-4453768BAB8A [ABSTRACT FROM AUTHOR]

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The genetic and morphological variation within Rhyacodrilus falciformis Bretscher, 1901 ( Clitellata: Naididae) in Europe was explored using an integrative approach, with three unlinked genetic markers [the mitochondrial cytochrome c oxidase subunit I ( COI), the nuclear histone 3 ( H3) and internal transcribed spacer region ( ITS)] combined with morphology, to investigate whether this taxon constitutes a single or several species. Using Automatic Barcode Gap Discovery on the COI data set, the specimens were divided into seven clusters, used as hypothetical species that were further tested with the other data sources. Single-gene trees were estimated for all three markers, using coalescence analysis and they were in many parts incongruent with each other. Only one of the clusters was supported by all trees; it was also morphologically differentiated from the other clusters by the shape of its modified penial chaetae. This group consists of two specimens from the Crotot Cave in south-eastern France, and morphologically they fit a previously described but invalid variety, ' pigueti', which is here described as a new species, Rhyacodrilus pigueti Achurra & Martinsson sp. n. The study highlights the fact that a single data source (e.g. COI barcodes) seldom provides a sufficient basis for taxonomic decisions such as species delimitation. [ABSTRACT FROM AUTHOR]

Ilha Grande National Park is an important conservation unit localized in the Southern part of the upper Paraná river floodplain (Brazil) that includes diverse aquatic environments. Oligochaeta (Annelida) is a large group of invertebrates, with several small specimens inhabiting almost every possible niche at most freshwater ecosystem. The goal of the present study was to examine the spatial variation of Oligochaeta community in five floodplain lakes from the Ilha Grande National Park and relate the distribution with abiotic variables. Samples were taken at five sampling stations using a modified Petersen grab. Thirteen species of Oligochaeta belonging to two families Naididae and Tubificidae were recorded. Different patterns of richness and abiotic factors were identified among the lakes located in the island and at the margin of Paraná river. The different patterns of granulometric texture affected directly the distribution of the Oligochaeta assemblage of theses environments. The results of this study permit to infer that the Oligochaeta assemblage, in preserved areas, present a higher richness in relation to long term studies with more frequent samplings. We concluded that Ilha Grande National Park contributes for the preservation of benthic invertebrates.

Taxonomic keys of 24 naidid and nine tubificid species, from 65 sampling localities situated in different regions of Colombia, were elaborated. 22 naidids and all tubificids represent first reports forColombia. Some ecological data like altitude distribution, sediment preference and trophic requirements are presented.Se elaboraron claves taxonómicas de 24 especies de naididos y nueve de tubifícidos, encontrados en 65 localidades de muestreo situadas en diferentes regiones de Colombia. 22 especies de naididos y todos los tubifícidos representan nuevos hallazgos para el país. Se presentan algunos datos ecológicos de las diferentes especies como distribución altitudinal, preferencia de sustrato y requerimientos tróficos.

Copyright of Acta Scientiarum: Biological Sciences is the property of Universidade Estadual de Maringa 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.)

Copyright of Biota Neotropica is the property of Biota Neotropica 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.)

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

Oligochaete worms were collected from 4 sites at Al-Swaib marshes, southern Iraq, during October 2010 to March 2011. A total of one aeolosomatid species (Aeolosoma leidyi Cragin, 1887) and 11 naidid species (Pristina sima (Marcus, 1944), Pristina osborni (Walton, 1906), Dero (Aulophorus) furcatus (Müller, 1773), Dero (Dero) digitata (Müller, 1773), Dero (Dero) nivea Aiyer, 1929, Slavina appendiculata d'Udekem, 1855, Nais pardalis Piguet, 1906, Nais variabilis Piguet, 1906, Nais communis Piguet, 1906, Allonais gwaliorensis (Stephenson, 1920), Allonais pectinata(Stephenson, 1910) were recorded for the first time from Iraq. The results indicate that there is high number of species of oligochaetes in the Iraqi limnic environment, in which these species are finding the favorable conditions for live. [ABSTRACT FROM AUTHOR]