Molecular characterization of free-living nematodes from Kermadec Trench (Nematoda: Aegialoalaimidae, Xyalidae) with description of emAegialoalaimus/em emtereticauda/em n. sp.

The Kermadec Trench is the world's fifth deepest trench and extends from approximately 26 to 36°S near the northeastern tip of New Zealand's North Island. Here, we describe a new species of Aegialoalaimus, a nematode genus with unusual buccal cavity and pharynx morphology, from a site at 9540 metres water depth in Kermadec Trench, and provide the first SSU and D2-D3 of LSU sequences for Aegialoalaimus, Manganonema, Metasphaerolaimus constrictus and Daptonema amphorum. Aegialoalaimus tereticauda n. sp. is characterised by body length 755-864 µm, cephalic sensilla papilliform ( 1 µm long), excretory pore located slightly anterior to posterior bulb in males and slightly anterior to nerve ring in females, arcuate spicules 18-22 µm long, gubernaculum present, precloacal supplements absent, and cylindrical tail 58-64 µm long with rounded tip. Relationships between Aegialoalaimus and Chromadorean orders could not be elucidated based on our SSU analysis; no link could be found with the Plectida, where the Aegialoalaimidae is currently placed, or with the Isolamiida or Cylindrolaimus (Areaolaimida), which share a similar and unusual buccal and pharynx morphology. Our SSU phylogenetic analysis confirms the placement of Manganonema within the Xyalidae, although relationships with other xyalid genera remain unclear. The Sphaerolaimidae formed a clade together with the Monhysteridae, which contradicts the current classification where the Sphaerolaimidae and Xyalidae are classified together into the superfamily Sphaerolaimoidea and the Monhysteridae into the Monhysteroidea. Although limited research has been conducted on the nematode diversity in Kermadec Trench to date, the available data show that half of all invertebrate species known from the trench are nematodes, which highlights the importance of conducting further taxonomic research on this group in hadal environments.

emEubostrichopsis/em emjohnpearsei/em n. gen., n. sp., the first stilbonematid nematode (Nematoda, Desmodoridae) from the US West Coast.

A new genus of the marine Stilbonematinae (Nematoda, Desmodoridae) is described from the Pacific coast of the United States of America. The worms inhabit the sulfidic sediment among the roots of the surfgrass Phyllospadix sp. in the rocky intertidal. The ectosymbiotic coat is of a new type for Stilbonematinae. It consists of rod-shaped bacteria pointed at both poles densely attached with one pole to the host cuticle. This is the first report of this symbiotic nematode subfamily from the US West Coast.

A Helminth Survey of Northern Bobwhite Quail (Colinus virginianus) and Passerines in the Rolling Plains Ecoregion of Texas.

The Northern bobwhite quail (Colinus virginianus) is a popular game bird that has been experiencing a well-documented decline throughout Texas since the 1960s. While much of this decline has been attributed to habitat loss and fragmentation, recent studies have identified other factors that may also contribute to decreasing quail populations. Parasites, in particular, have become increasingly recognized as possible stressors of quail, and some species, particularly the eyeworm (Oxyspirura petrowi) and cecal worm (Aulonocephalus pennula) are highly prevalent in Texas quails. Eyeworm infection has also been documented in some passerines, suggesting helminth infection may be shared between bird species. However, the lack of comprehensive helminth surveys has rendered the extent of shared infection between quail and passerines in the ecoregion unclear. Thus, helminth surveys were conducted on bobwhite, scaled quail (Callipepla squamata), Northern mockingbirds (Mimus polyglottos), curve-billed thrashers (Toxistoma curvirostre), and Northern cardinals (Cardinalis cardinalis) to contribute data to existing parasitological gaps for birds in the Rolling Plains ecoregion of Texas. Birds were trapped across 3 counties in the Texas Rolling Plains from March to October 2019. Necropsies were conducted on 54 individuals (36 quail and 18 passerines), and extracted helminths were microscopically identified. Nematode, cestode, and acanthocephalan helminths representing at least 10 helminth species were found. Specifically, A. pennula and O. petrowi had the highest prevalence, and O. petrowi was documented in all of the study species. This research adds to the body of knowledge regarding parasitic infections in quail and passerines of the Rolling Plains ecoregion and highlights the potential consequences of shared infection of eyeworms among these bird species.

Contracaecum larvae: morphological and morphometric retrospective analysis, biogeography and zoonotic risk in the amazon.

In Brazil there are several records of parasitic nematodes of fish with zoonotic potential, especially those belonging to the family Anisakidae. This study considers the morphology, morphometry and prevalence of Contracaecum in Astronotus ocellatus , fish consumed in the Amazon and sold as ornamental and it also performs a retrospective analysis of the diversity of fish with larvae of Contracaecum, in studies carried out in Brazil over a period of 90 years. 40 specimens of A. ocellatus were necropsied, and the nematodes were collected and fixed in 93 parts 70% ethyl alcohol, 5 parts formaldehyde, and 2 parts glacial acetic acid (AFA) for morphological analysis under light microscopy and scanning electron microscopy. Of the 40 fish collected during this work, 27 were parasitized by Contracaecum larvae with a total intensity of 150 larvae. Retrospective analysis of intermediate host diversity for Contracaecum larvae resulted in 16 orders, 49 families, 96 genera, 140 species and a hybrid morphotype. In the retrospective study, half of the fish were from freshwater, with the order Perciformes being the most representative, with 16 families, 30 genera and 37 species. In Brazil, the occurrence of larvae of Contracaecum in fish was reported in 15 of the 26 states, with Rio de Janeiro presenting the most information regarding fish harboring Contracaecum larvae.

Contracaecum larvae: morphological and morphometric retrospective analysis, biogeography and zoonotic risk in the amazon / Larva de Contracaecum: análise retrospectiva morfológica e morfométrica, biogeografia e risco zoonótico na amazônia

Abstract In Brazil there are several records of parasitic nematodes of fish with zoonotic potential, especially those belonging to the family Anisakidae. This study considers the morphology, morphometry and prevalence of Contracaecum in Astronotus ocellatus , fish consumed in the Amazon and sold as ornamental and it also performs a retrospective analysis of the diversity of fish with larvae of Contracaecum, in studies carried out in Brazil over a period of 90 years. 40 specimens of A. ocellatus were necropsied, and the nematodes were collected and fixed in 93 parts 70% ethyl alcohol, 5 parts formaldehyde, and 2 parts glacial acetic acid (AFA) for morphological analysis under light microscopy and scanning electron microscopy. Of the 40 fish collected during this work, 27 were parasitized by Contracaecum larvae with a total intensity of 150 larvae. Retrospective analysis of intermediate host diversity for Contracaecum larvae resulted in 16 orders, 49 families, 96 genera, 140 species and a hybrid morphotype. In the retrospective study, half of the fish were from freshwater, with the order Perciformes being the most representative, with 16 families, 30 genera and 37 species. In Brazil, the occurrence of larvae of Contracaecum in fish was reported in 15 of the 26 states, with Rio de Janeiro presenting the most information regarding fish harboring Contracaecum larvae.

Resumo No Brasil existem vários registros de nematóides parasitos de peixes com potencial zoonótico, especialmente aqueles pertencentes à família Anisakidae. Este estudo considera a morfologia, morfometria e prevalência de Contracaecum em Astronotus ocellatus, peixe consumido na Amazônia e vendido como ornamental, e também realiza uma análise retrospectiva da ictiofauna parasitada com larvas de Contracaecum, em estudos realizados no Brasil, durante um período de 90 anos. 40 espécimes de A. ocellatus foram necropsiados, e os nematóides foram coletados e fixados em 93 partes de álcool etílico 70%, 5 partes de formaldeído e 2 partes de ácido acético glacial (AFA) para análise morfológica em microscopia de luz e microscopia eletrônica de varredura. Dos 40 peixes coletados durante este trabalho, 27 estavam parasitados por Contracaecum, com intensidade total de 150 larvas. Análises retrospectivas da diversidade de hospedeiros intermediários para larvas de Contracaecum resultaram em 16 ordens, 49 famílias, 96 gêneros,140 espécies e um morfotipo híbrido. No estudo retrospectivo, metade dos peixes eram de água doce, sendo a ordem Perciformes a mais representativa, com 16 famílias, 30 gêneros e 37 espécies. No Brasil, a ocorrência de larvas de Contracaecum em peixes foi relatada em 15 dos 26 estados, com o Rio de Janeiro apresentando mais informações sobre peixes portadores de larvas de Contracaecum.