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Multiple tarantula deaths for a wholesale breeder were reported in 2018. The breeder noticed white discharge in the oral cavities of the tarantulas. Upon inspection, it was discovered that the white discharge was a large group of nematodes intertwined inside the tarantula's oral cavity. We examined the nematodes and propose a new species, Tarantobelus jeffdanielsi n. sp., in the currently monotypic genus Tarantobelus based on a combination of morphological and morphometrical data and unique nuclear rDNA 28S and 18S sequences. Based on phylogenetic analyses, the previously described Tarantobelus arachnicida was relocated, along with T. jeffdanielsi, into the family Panagrolaimidae. We also provide evidence of the ability of T. jeffdanielsi to parasitize Galleria mellonella larvae and the tarantula Grammostola pulchra. The life span and fecundity of the new species were also assessed, resulting in an 11.2-d average life span, and a total fertility rate of 158 nematodes/adult. [ABSTRACT FROM AUTHOR]

Phasmarhabditis hermaphrodita is reported for the first time in North America from cadavers of the invasive slug species Deroceras reticulatum, D. laeve and Lehmannia valentiana collected from three different locations in California, USA. Four isolates were identified using combined morphology, morphometries and molecular sequence data for complete internal transcribed spacer (ITS-1, 5.8S, ITS-2), D2-D3 expansion segments of the large subunit (LSU or 28S) and nearly complete small subunit (SSU or 18S) ribosomal DNA. Extremely low sequence variations in the COI gene of the mitochondria were observed among US isolates as well as between US isolates and the two UK sequences. The occurrence of P. hermaphrodita in North America has regulatory implications for potential biological control strategies against non-native gastropod species that are pests in ornamental and agricultural cultivation on this continent. The D2-D3 sequence of the LSU rDNA is new for the species. [ABSTRACT FROM AUTHOR]

Hemiplectus muscorum, the type and single representative of its genus, is redescribed on the basis of abundant new material collected in the UK, Canada and the USA using both light and scanning electron microscopy. The phylogenetic relationships of the species are inferred from morphological as well as molecular data. Maximum parsimony, neighbour joining and maximum likelihood analyses of small subunit (SSU) rRNA sequences support a position nested among the Plectidae. This conflicts with our morphological assumptions of character polarity, as it implies that the absence of a valvate bulb in Hemiplectus is a reversal rather than a plesiomorphy. The excretory system of Hemiplectus is described more precisely. Its structure is highly reminiscent of the system in Plectus but differs in the presence of an anterior and posterior pair of pseudocoelomocytes flanking the renette cell. A pair of lateral somatic setae is identified as possible homologues of the 'deirids' in Plectus and Rhabditida. Measurements and descriptions are given of all four juvenile stages. [ABSTRACT FROM AUTHOR]

The morphology and morphometry of nematodes of six species of the family Ceramonematidae is described using light and scanning electron microscopy. In this paper, we describe two new species and redescribe two known species of Ceramonema and one new species each of Pselionema and Pterygonema. Ceramonema altogolfi sp. n. is characterised by the 0.8-1.3 mm long body, 187-247 body annules, weakly developed zygapophyses, presence of intracuticular vacuoles, sexual dimorphism in amphid shape, presence of vaginal sclerotisation, complex gubernaculum and relatively uniform anal and cloacal annules, whilst C. inguinispina sp. n. has a 0.8-1.1 mm long body, 135-191 body annules, weakly developed zygapophyses, presence of intracuticular vacuoles, sexual dimorphism in amphid shape, absence of vaginal sclerotisation, thorn-shaped precloacal projection, plate-like gubernaculum and double cloacal annule. Pselionema psednum sp. n. is distinguished by 1.4-1.7 mm long body, 251-292 body annules, weakly developed zygapophyses, absence of intracuticular vacuoles, sexual dimorphism in amphid shape and Pterygonema mexicanum sp. n. is characterised by having amphids lacking a central thorn-like projection and pharynx with a distinct posterior glandular bulb. Populations of Ceramonema rectum and Ceramonema cf. yunfengi are also described. The male cloacal region of the species examined appears to be a rich potential source of taxonomic characters that have as yet received insufficient attention for this family. [ABSTRACT FROM AUTHOR]

Hirschmanniella santarosae sp. n. is described from the largest vernal pool in the Santa Rosa Plateau Ecological Reserve, Murrieta, California, USA. The cryptic new species is morphologically very close to H. pomponiensis and H. gracilis as it can be distinguished from the former only by a more anterior excretory pore position and by more flattened as well as laterally expanded stylet knobs, whilst it differs from the latter in the greater distance from phasmid to tail tip and in the bursal alae ending near the phasmids rather than near the tail tip. Analysis of the rDNA small subunit (SSU) and D2D3 expansion segments of the large subunit (LSU) shows that H. santarosae sp. n. is genetically distinct, having respective sequence homology of 98.89% and 95.9% with H. pomponiensis for these loci. Congruence in SSU and D2D3 gene trees as well as unambiguous character autapomorphies further support the new species status of H. santarosae sp. n. and sibling relationship with H. pomponiensis. Although many more isolates and species will need to be studied before informative biogeographic analyses can be performed, the presently available sequence data suggest that some Hirschmanniella lineages have diversified independently on either side of the Atlantic. [ABSTRACT FROM AUTHOR]

A solution containing dimethyl sulphoxide, disodium EDTA, and saturated NaCl (abbreviated here as DESS) was tested for various applications in the preservation of nematodes for combined morphological and molecular analyses. The solution can be used to preserve individual nematodes, nematode extracts, or entire soil/sediment samples. Preserved material can be easily stored for months at room temperature, shipped by mail, or carried in luggage. Morphological features are usually well preserved; specimen quality being comparable to formalin-based fixatives and much better than ethanol fixation. Specimens can be transferred to glycerin with little or no modification of traditional protocols. Unlike formalin-preserved material, routine PCR can be performed on individual specimens after any of these procedures with success rates and amplification sizes comparable to PCR of fresh specimens. At this point we have no data on long-term preservation quality. Nevertheless, DESS solution clearly enhances and simplifies a wide range of nematological studies due to its combined suitability for morphological and molecular analyses, as well as its less hazardous chemical properties. [ABSTRACT FROM AUTHOR]

Abstract: Phylogenetic reconstructions of relations within the phylum Nematoda are inherently difficult but have been advanced with the introduction of large-scale molecular-based techniques. However, the most recent revisions were heavily biased towards terrestrial and parasitic species and greater representation of clades containing marine species (e.g. Araeolaimida, Chromadorida, Desmodorida, Desmoscolecida, Enoplida, and Monhysterida) is needed for accurate coverage of known taxonomic diversity. We now add small subunit ribosomal DNA (SSU rDNA) sequences for 100 previously un-sequenced species of nematodes, including 46 marine taxa. SSU rDNA sequences for >200 taxa have been analysed based on Bayesian inference and LogDet-transformed distances. The resulting phylogenies provide support for (i) the re-classification of the Secernentea as the order Rhabditida that derived from a common ancestor of chromadorean orders Araeolaimida, Chromadorida, Desmodorida, Desmoscolecida, and Monhysterida and (ii) the position of Bunonema close to the Diplogasteroidea in the Rhabditina. Other, previously controversial relationships can now be resolved more clearly: (a) Alaimus, Campydora, and Trischistoma belong in the Enoplida, (b) Isolaimium is placed basally to a big clade containing the Axonolaimidae, Plectidae, and Rhabditida, (c) Xyzzors belongs in the Desmodoridae, (d) Comesomatidae and Cyartonema belongs in the Monhysterida, (e) Globodera belongs in the Hoplolaimidae and (f) Paratylenchus dianeae belongs in the Criconematoidea. However, the SSU gene did not provide significant support for the class Chromadoria or clear evidence for the relationship between the three classes, Enoplia, Dorylaimia, and Chromadoria. Furthermore, across the whole phylum, the phylogenetically informative characters of the SSU gene are not informative in a parsimony analysis, highlighting the short-comings of the parsimony method for large-scale phylogenetic modelling. [Copyright &y& Elsevier]

Abstract: Nematodes of the suborder Cephalobina include an ecologically and morphologically diverse array of species that range from soil-dwelling microbivores to parasites of vertebrates and invertebrates. Despite a long history of study, certain of these microbivores (Cephaloboidea) present some of the most intractable problems in nematode systematics; the lack of an evolutionary framework for these taxa has prevented the identification of natural groups and inhibited understanding of soil biodiversity and nematode ecology. Phylogenetic analyses of ribosomal (LSU) sequence data from 53 taxa revealed strong support for monophyly of taxa representing the Cephaloboidea, but do not support the monophyly of most genera within this superfamily. Historically these genera have primarily been recognized based on variation in labial morphology, but molecular phylogenies show the same general labial (probolae) morphotype often results from recurrent similarity, a result consistent with the phenotypic plasticity of probolae previously observed for some species in ecological time. Phylogenetic analyses of LSU rDNA also recovered strong support for some other groups of cephalobs, including taxa representing most (but not all) Panagrolaimoidea. In addition to revealing homoplasy of probolae, molecular trees also imply other unexpected patterns of character evolution or polarity, including recurrent similarity of offset spermatheca presence, and representation of complex probolae as the ancestral condition within Cephaloboidea. For Cephalobidae, molecular trees do not support traditional genera as natural groups, but it remains untested if deconstructing probolae morphotypes or other structural features into finer component characters may reveal homologies that help delimit evolutionary lineages. [Copyright &y& Elsevier]