Integrative taxonomic study of mononchid nematodes from riparian habitats in Bulgaria. I. Genera Mononchus Bastian, 1865 and Coomansus Jairajpuri & Khan, 1977 with the description of Mononchuspseudoaquaticus sp. nov. and a key to the species of Mononchus

The species diversity of the genera Mononchus Bastian, 1865 and Coomansus Jairajpuri & Khan, 1977 was assessed in a study of the mononchid nematodes from a wide range of riparian habitats in Bulgaria. Four species were identified based on morphological and morphometric data: Coomansusparvus (de Man, 1880), Mononchustruncatus Bastian, 1865, Mononchuspseudoaquaticus sp. nov., and Mononchus sp. The first three species were characterised both morphologically and molecularly (18S and 28S rRNA gene sequences) and the integration of these data and phylogenetic analyses provided support for their distinct species status. This paper provides detailed descriptions, morphometric data for multiple species populations, drawings and photomicrographs, and the first taxonomically verified sequences for C.parvus (n = 6), M.truncatus (sensu stricto) (n = 4) and M.pseudoaquaticus sp. nov. (n = 3). Comparative sequence and phylogenetic analyses suggested that the utility of the 18S rRNA gene for species delimitation is rather limited at least for some species complexes within the genus Mononchus. At the generic and suprageneric level, the 18S and 28S rDNA phylogenies both recovered the three genera represented by two or more species (Mononchus, Mylonchulus, and Parkellus) as monophyletic with strong support, the Mononchidae as paraphyletic, the Anatonchidae as monophyletic, and there was no support for a sister-group relationship between Mylonchulus and Mononchus. A key to the species of Mononchus is provided to facilitate the identification of the currently recognised 31 species.

A catalogue of the nematode slide collection from the late W.L. Nicholas held at National Research Collections Australia, CSIRO

A catalogue is presented of the nematode slide collection of W.L. Nicholas, which is deposited in the National Research Collections Australia at CSIRO. This is the most extensive slide collection of free-living marine and estuarine nematodes from Australia to date, and consists of 553 putative species, collected across a wide range of Australias eastern and northern regions over the course of nearly 40 years. The collection contains mostly marine and estuarine free-living nematodes collected on coarse substrate in littoral habitats. The most abundant genera were Desmodora, Theristus, and Onyx. Most taxa were found rarely, being recorded only once, and repeated sampling at several sandy beach sites revealed only a small proportion of the fauna on more than one occasion. A significant proportion of the taxa were also found to be widespread, occurring on more than one occasion at more than one location, with Theristus sp., Onyx sp., and Viscosia sp. occurring in the greatest number of localities. The catalogue adds an additional 90 species and 160 genera to the documented fauna of Australian free-living nematodes verifiable by specimens in permanent collections. It thus provides a better framework for studying nematode biodiversity and biogeography in the region.

A new needle nematode, Longidorus zanjanensis sp. nov. (Nematoda: Longidoridae) from north-western Iran

During a survey of soil nematodes in 2022, a new species of the genus Longidorus, described here as Longidorus zanjanensis sp. nov., was discovered in the rhizosphere of Astragalus sp. in Zanjan Province, Iran. The new needle nematode is described and illustrated based on morphological, morphometric, and molecular traits. Further, its females are characterized by having a long body ranging 5.6-7.7 mm long, lip region anteriorly flattened and almost continuous or slightly offset by a depression with body contour, ca 16.5-18.5 μm wide, amphidial fovea pouch-like without basal lobes, guiding ring at 35-41 μm distance from the anterior end, and an odontostyle and odontophore ranging 102-115 and 47-75 μm long, respectively. The pharyngeal bulb is 123-153 μm long, female reproductive system didelphic-amphidelphic containing sperm, vulva almost equatorial, located at 46.7-51.4% of body length, tail short, rounded to bluntly conoid, bearing two pairs of caudal pores and terminus widely rounded with distinct radial lines in hyaline region (39-50 μm long, c = 122.4-189.4, c' = 0.6-0.8). Males are common, making up to 60% of the adults, and are functional, with spicules 68.0-80.0 μm long, as well as having 8-14 ventromedian copulatory supplements. All four juvenile life developmental stages were present, with the tail of first-stage juvenile conoid shape, dorso-ventrally curved with rounded terminus. The polytomous codes delimiting the new species are: A4-B3-C3-D3-E1-F34-G12-H1-I2-J1-K6. Morphologically, the new species comes close to eight known species of the genus, namely L. apulus, L. armeniacae, L. crassus, L. kheirii, L. soosanae, L. proximus, L. pauli, and L. ferrisi. The morphological differences between the new species and the aforementioned species are discussed. Molecular phylogenetic analyses based on D2-D3 of large subunit (LSU) and internal transcribed spacer 1 (ITS1) rRNA sequences indicate that Longidorus zanjanensis sp. nov. is closely related to L. hyrcanus, L. soosanae, and L. elongatus.

How we study cryptic species and their biological implications: A case study from marine shelled gastropods

Methodological and biological considerations are intertwined when studying cryptic species. A potentially large component of modern biodiversity, the frequency of cryptic species among taxonomic groups is not well documented. The term "cryptic species" is imprecisely used in scientific literature, causing ambiguity when interpreting their evolutionary and ecological significance. This study reviews how cryptic species have been defined, discussing implications for taxonomy and biology, and explores these implications with a case study based on recently published literature on extant shelled marine gastropods. Reviewed gastropods were recorded by species. Records of cryptic gastropods were presented by authors with variable levels of confidence but were difficult to disentangle from inherent biases in the study effort. These complexities notwithstanding, most gastropod species discussed were not cryptic. To the degree that this review's sample represents extinct taxa, the results suggest that a high proportion of shelled marine gastropod species are identifiable for study in the fossil record. Much additional work is needed to provide a more adequate understanding of the relative frequency of cryptic species in shelled marine gastropods, which should start with more explicit definitions and targeted case studies.

Transcriptomics of Cruznema velatum (Nematoda: Rhabditidae) with a redescription of the species

Cruznema velatum isolated from soil in a chestnut orchard located at Guangdong province, China, is redescribed with morphology, molecular barcoding sequences, and transcriptome data. The morphological comparison for C. velatum and six other valid species is provided. Phylogeny analysis suggests genus Cruznema is monophyletic. The species is amphimix, can be cultured with Escherichia coli in 7-9 days from egg to egg-laying adult, and has a lifespan of 11 to 14 days at 20°C. The transcription data generated 45,366 unigenes; 29.9%, 31.3%, 24.8%, and 18.6% of unigenes were annotated in KOG, SwissProt, GO, and KEGG, respectively. Further gene function analysis demonstrated that C. velatum share the same riboflavin, lipoic acid, and vitamin B6 metabolic pathways with Caenorhabditis elegans and Pristionchus pacificus.

Characterization of Hoplolaimus seinhorsti and Hoplolaimus pararobustus (Tylenchina: Hoplolaimidae) from banana, with phylogeny and species delineation in the genus Hoplolaimus

The morphological and molecular characterisations of two lance nematode species isolated from the rhizosphere of banana, Hoplolaimus seinhorsti and H. pararobustus, are provided based on an integrative study that includes light and scanning electron microscopy, phylogenetic analysis and two tree-based molecular species delimitation methods (GMYC and bPTP). Nineteen new sequences were obtained, including 5 partial 18S rRNA, 6 D2-D3 of 28S rRNA, 1 ITS rRNA and 7 COI mtDNA (the first COI sequences of H. seinhorsti and H. pararobustus), and an updated morphological character comparison of 37 Hoplolaimus species is presented. The tree-based molecular species-delimitation approaches employed gave markedly differing results, and also showed remarkable discrepancies among the investigated genes, although the bPTP output was found to agree well with established morphological species delimitations. Both species-delimitation approaches did, however, provide the same output for the COI mtDNA sequences, and the COI mtDNA gene sequence was also found to correspond better to established morphological species. It is therefore recommended by this paper as representing the most suitable barcode marker for Hoplolaimus species identification. This integrative study also resulted in the corrective reassignment of 17 gene sequences that were previously unidentified or incorrectly classified, as well as concluding that H. pararobustus consists of two cryptic species.

Morphological and molecular characterisation of a new cryptic species of Criconemoides informis group, C. neoinformis n. sp., and C. persicus n. sp., with notes on C. avicenniae

Criconemoides neoinformis n. sp., a cryptic species of C. informis group, and C. persicus n. sp. were recovered from the rhizosphere of pear and grass, in Zanjan and West Azerbaijan provinces, northwestern Iran, respectively. Criconemoides neoinformis n. sp. is characterised by 522-585 μm long females, having four separated pseudolips, anteriorly flattened lip region comprised of two annuli, 57-63 retrorse body annuli with smooth to slightly crenate margins, without anastomoses, 86.9-90.4 μm long stylet, having 6-10 annuli from vulva to posterior end and tail conical rounded with two, three or multilobed terminus and presence of males. Criconemoides persicus n. sp. could be characterised by flatly rounded lip region, having fused rectangular pseudolips, 515-615 μm body length, stylet 60-65 μm, body annuli 120-132 with smooth to slightly crenate margins, without anastomoses, 9-12 annuli from vulva to posterior end and tail conical rounded with two trilobed terminus. In inferred phylogenies, these two new species clustered with known Criconemoides species in 18S, 28S, ITS and COI trees. These species are clearly separated molecularly by all the studied markers. The use of molecular markers, mainly D2-D3 expansion segments of 28S rRNA, ITS region and COI, are very promising in the case of cryptic species found in this group of nematodes. We provided molecular markers (two sequences per marker) for these new species with morphological/morphometrical data using an integrative taxonomy approach for the unequivocal identification of these species.

Reliability and Utility of Standard Gene Sequence Barcodes for the Identification and Differentiation of Cyst Nematodes of the Genus Heterodera

Difficulties inherent in the morphological identification of cyst nematodes of the genus Heterodera Schmidt, 1871, an important lineage of plant parasites, has led to broad adoption of molecular methods for diagnosing and differentiating species. The pool of publicly available sequence data has grown significantly over the past few decades, and over half of all known species of Heterodera have been characterized using one or more molecular markers commonly employed in DNA barcoding (18S, internal transcribed spacer [ITS], 28S, coxI). But how reliable are these data and how useful are these four markers for differentiating species? We downloaded all 18S, ITS, 28S, and coxI gene sequences available on the National Center for Biotechnology Information (NCBI) database, GenBank, for all species of Heterodera for which data were available. Using a combination of sequence comparison and tree-based phylogenetic methods, we evaluated this dataset for erroneous or otherwise problematic sequences and examined the utility of each molecular marker for the delineation of species. Although we find the rate of obviously erroneous sequences to be low, all four molecular markers failed to differentiate between at least one species pair. Our results suggest that while a combination of multiple markers is best for species identification, the coxI marker shows the most utility for species differentiation and should be favored over 18S, ITS, and 28S, where resources are limited. Presently, less than half the valid species of Heterodera have a sequence of coxI available, and only a third have more than one sequence of this marker.

Description of Rotylenchus zhongshanensis sp. nov. (Tylenchomorpha: Hoplolaimidae) and discovery of its endosymbiont Cardinium

A new bisexual species of Rotylenchus is described and illustrated based on morphological, morphometric and molecular characterizations. Rotylenchus zhongshanensis sp. nov. is characterized by having a conoid lip region complying with the basic pattern for Hoplolaimidae, but with pharyngeal glands slightly overlapping intestine dorsally and cuticle thickened abnormally in female tail terminus. Females have robust stylet (30.1-33.8 μm). The pharyngeal gland has short dorsal (11.2-16.8 μm) overlap on the intestine. The vulva is located at 48.0-56.5% of body length, and phasmids are pore-like, 4-6 annuli posterior to the anus. For males, phasmids are pore-like, 11-17 annuli posterior to cloaca. The spicules are ventrally arcuate (21.0-28.5 μm) with gubernaculum in 5-8 μm length. The rRNA and mitochondrial COI genes were successfully sequenced from the assembled whole-genome sequences of the new species, and were used for reconstructing the phylogenetic relationships of the new species. A new strain of cyto-endosymbiont Cardinium was also discovered from the genome sequences of R. zhongshanensis sp. nov. The 16S rRNA phylogeny analyses revealed that this new bacterial strain is closed to that from cyst and root-lesion nematodes.

A New Interactive Web-Based Polytomous Key for Species Identification of Pin Nematodes of the Genus Paratylenchus Micoletzky, 1922 (Nematoda: Paratylenchinae) with the Use of Ribosomal and Mitochondrial Genes

Pin nematodes of the genus Paratylenchus comprise 140 species. This group of nematodes is characterized by a quite homogeneous morphology and cosmopolitan distribution and is prevalent in cultivated and natural soil ecosystems. The present study describes the first interactive and illustrated web-assisted polytomous identification key for the genus Paratylenchus. The updated Paratylenchus species polytomous key was based on a wide list of 24 diagnostic characters generated for the 140 species comprising this genus. Here we developed a web-assisted method to achieve an easy and accurate Paratylenchus species characterization that will greatly improve the identification of these plant-parasitic nematodes for many diagnostic laboratories and researchers. However, this identification needs to be completed with the use of molecular markers available for the species due to the existence of species complexes studied in former researches. This idea is pointed in the polytomous key in the specific species complexes up-to-know. In some cases, the presence in the soil as survival stage of few individuals in the fourth-stage juvenile (J4) required the use of molecular markers for species identification. We suggest the use of at least a fragment of mitochondrial COI gene for species identification or the combination of nuclear D2-D3 regions of the 28S rRNA and the COI to complement each marker. However, for some species complexes, the use of the D2-D3 regions alone has not enough resolution to separate the putative species inside the species complex. Web-based polytomous key was constructed using the free software Xper3, for computers and mobile devices (smartphones, tablets, and pocket PCS).

First report of Xiphinema ifacolum Luc, 1961 (Dorylaimida: Longidoridae) from Nigeria

A population of a species of dagger nematode (Xiphinema) belonging to the non-americanum group was recovered from the fields of kola nut (Cola sp.) in southern Nigeria. The morphological and morphometric data obtained from this population were consistent with the characteristics of the species Xiphinema ifacolum. In addition, molecular identification based on D2-D3 expansion segments of 28S rRNA and partial mitochondrial COI gene regions confirmed its identity. According to our knowledge, this is the first report of the species from Nigeria, and the second report from Africa, after the original description from Foulaya, Guinea.

A new needle nematode, Longidorus maginicus n. sp. (Nematoda: Longidoridae) from southern Spain

During nematode surveys in natural vegetation in Sierra Mágina, Jaén province, southern Spain, a Longidorus species closely resembling Longidorus carpetanensis was found, but application of integrative taxonomic approaches clearly demonstrated that it is a new species described herein as Longidorus maginicus n. sp. The new species is amphimictic, characterized by a moderately long body (4.2-5.2 mm); lip region anteriorly flattened, slightly separated from the rest of body by a depression, 9.0-11.0 μm wide and 3.5-6.0 μm high; amphidial fovea not lobed; relatively short odontostyle (61.0-70.5 μm); guiding ring located 23.5-27.0 μm from anterior end; vulva located at 42.0%-51.3% of body length; female tail 39.0-61.0 μm long, conoid, dorsally convex with rounded terminus (c' = 1.3-2.1), with two or three pairs of caudal pores; and males common (1:2 ratio males:females), with moderately long spicules (39.0-48.5 μm) and 1 + 6-9 ventromedian supplements and three juvenile developmental stages. According to the polytomous key, codes for the new species are (codes in parentheses are exceptions): A2-B1-C2-D2-E1-F2(3)-G2-H5(4)-I2-J1-K6. The results of molecular analysis of D2-D3 28S, internal transcribed spacer region, partial 18S rDNA, and cytochrome oxidase c subunit 1 (coxI) gene sequences further characterized the new species status, and separated it from L. carpetanensis and other related species.

Ecological and morphological differentiation among COI haplotype groups in the plant parasitic nematode species Mesocriconema xenoplax

DNA barcoding with the mitochondrial COI gene reveals distinct haplotype subgroups within the monophyletic and parthenogenetic nematode species, Mesocriconema xenoplax. Biological attributes of these haplotype groups (HG) have not been explored. An analysis of M. xenoplax from 40 North American sites representing both native plant communities and agroecosystems was conducted to identify possible subgroup associations with ecological, physiological, or geographic factors. A dataset of 132 M. xenoplax specimens was used to generate sequences of a 712 bp region of the cytochrome oxidase subunit I gene. Maximum-likelihood and Bayesian phylogenies recognized seven COI HG (≥99/0.99 posterior probability/bootstrap value). Species delimitation metrics largely supported the genetic integrity of the HG. Discriminant function analysis of HG morphological traits identified stylet length, total body length, and stylet knob width as the strongest distinguishing features among the seven groups, with stylet length as the strongest single distinguishing morphological feature. Multivariate analysis identified land cover, ecoregion, and maximum temperature as predictors of 53.6% of the total variation (P = 0.001). Within land cover, HG categorized under “herbaceous,” “woody wetlands,” and “deciduous forest” were distinct in DAPC and RDA analyses and were significantly different (analysis of molecular variance P = 0.001). These results provide empirical evidence for molecular, morphological, and ecological differentiation associated with HG within the monophyletic clade that represents the species Mesocriconema xenoplax.

Phylogeny of Drosophila saltans group (Diptera: Drosophilidae) based on morphological and molecular evidence

Drosophila saltans group belongs to the subgenus Sophophora (family Drosophilidae), and it is subdivided into five subgroups, with 23 species. The species in this group are widely distributed in the Americas, primarily in the Neotropics. In the literature, the phylogenetic reconstruction of this group has been performed with various markers, but many inconsistencies remain. Here, we present a phylogenetic reconstruction of the saltans group with a greater number of species, 16 species, which is the most complete to date for the saltans group and includes all subgroups, in a combined analysis with morphological and molecular markers. We incorporated 48 morphological characters of male terminalia, the highest number used to date, and molecular markers based on mitochondrial genes COI and COII. Based on the results, which have recovered the five subgroups as distinct lineages, we propose a new hypothesis regarding the phylogenetic relationships among the subgroups of the saltans group. The relationships of the species within the sturtevanti and elliptica subgroups were well supported. The saltans subgroup showed several polytomies, but the relationship between the sibling species D. austrosaltans and D. saltans and their close relation with D. nigrosaltans were well supported in the molecular and total evidence analyses. The morphological analysis additionally supported the formation of the clade D. nigrosaltans—D. pseudosaltans. The observed polytomies may represent synchronous radiations or have resulted from speciation rates that have been too fast relative to the pace of substitution accumulation.

Description of Laimaphelenchus piceae sp. n., a new evidence of cryptic speciation, and L. sinensis Gu et al., 2020 (Rhabditida: Aphelenchoididae), a record from Shanxi province, north China

This contribution deals with the record and description of one new species and record of one known species of the genus Laimaphelenchus from Shanxi province, north China. The type population of L. piceae sp. n. is characterised by having females 642-807 μm long, the cephalic region with six labial sectors divided by ribs, stylet 12-14 μm long, lateral field with four incisures, postvulval uterine sac (PUS) 114-161 μm long, vulva with a well-developed anterior flap, tail with a single stalk at tip, bearing four pedunculate tubercles, each tubercle including 5-7 finger-like protrusions; males spicules 18-24 μm long and three pairs of caudal papillae present. The new species looks closely similar to L. persicus, representing its cryptic species, being separated by differences in some morphological indices and partial large subunit (LSU) rDNA sequences. Its morphological differences from other relevant species were discussed. L. sinensis was also recorded from Shanxi province for the first time. The phylogenetic relationships of the recovered populations were reconstructed using sequences of the near full length small subunit (SSU) and D2-D3 segments of LSU rDNA, and the relationships of both species were discussed.

Phylum Nematoda: trends in species descriptions, the documentation of diversity, systematics, and the species concept

This paper summarizes the trends in nematode species description and systematics emerging from a comparison of the latest comprehensive classification and census of Phylum Nematoda (Hodda 2022a, b) with earlier classifications (listed in Hodda 2007).   It also offers some general observations on trends in nematode systematics emerging from the review of the voluminous literature used to produce the classification.   The trends in nematodes can be compared with developments in the systematics of other organisms to shed light on many of the general issues confronting systematists now and into the future.  

Morphological, Morphometrical and Molecular Characterization of Oscheius siddiqii Tabassum and Shahina, 2010 (Rhabditida, Rhabditidae) from India with Its Taxonomic Consequences for the Subgenus Oscheius Andrássy, 1976

An insect parasitic nematode belonging to the genus Oscheius was recovered from the agricultural soils from the Hapur district in western Uttar Pradesh, India. Morphological studies on this species exhibited its high resemblance with two Pakistani species: Oscheius siddiqii and O. niazii. No molecular data are available for these taxa but, morphologically, both species do not differ significantly from our strains and each other. Hence, these nematodes can be considered conspecific, and the correct name for this taxon is O. siddiqii, the first described species. The phylogenetic analyses of the ITS-, 18S-, and the 28S rDNA sequences showed that O. siddiqii is a sister taxon to the group formed by Oscheius microvilli, O. myriophilus, O. safricanus, and several unidentified Oscheius species. Additionally, our analyses show that based on molecular and morphological data, the species Oscheius rugaoensis and O. microvilli cannot be distinguished from O. chongmingensis and O. myriophilus, respectively, and are thus considered junior synonyms of these taxa. Furthermore, the available data are not sufficient to evaluate the status of Oscheius basothovii and O. safricanus, which are, in consequence, considered species inquirendae. These findings highlight the necessity of the proper morphological and molecular characterisation of the described Oscheius species.

Remarkable Cryptic Diversity of Paratylenchus spp. (Nematoda: Tylenchulidae) in Spain

In previous studies, fifteen species of Paratylenchus, commonly known as pin nematodes, have been reported in Spain. These plant-parasitic nematodes are ectoparasites with a wide host range and global distribution. In this research, 27 populations from twelve Paratylenchus species from 18 municipalities in Spain were studied using morphological, morphometrical and molecular data. This integrative taxonomic approach allowed the identification of twelve species, four of them were considered new undescribed species and eight were already known described. The new species described here are P. caravaquenus sp. nov., P. indalus sp. nov., P. pedrami sp. nov. and P. zurgenerus sp. nov. As for the already known described species, five were considered as first reports for the country, specifically P.enigmaticus, P. hamatus, P. holdemani, P. israelensis, and P. veruculatus, while P. baldaccii, P. goodeyi and P. tenuicaudatus had already been recorded in Spain. This study provides detail morphological and molecular data, including the D2-D3 expansion segments of 28S rRNA, ITS rRNA, and partial mitochondrial COI regions for the identification of different Paratylenchus species found in Spain. These results confirm the extraordinary cryptic diversity in Spain and with examples of morphostatic speciation within the genus Paratylenchus.

Integrative Taxonomy and Molecular Phylogeny of the Plant-Parasitic Nematode Genus Paratylenchus (Nematoda: Paratylenchinae): Linking Species with Molecular Barcodes

Pin nematodes of the genus Paratylenchus are obligate ectoparasites of a wide variety of plants that are distributed worldwide. In this study, individual morphologically vouchered nematode specimens of fourteen Paratylenchus species, including P. aculentus, P. elachistus, P. goodeyi, P. holdemani, P. idalimus, P. microdorus, P. nanus, P. neoamblycephalus, P. straeleni and P. veruculatus, are unequivocally linked to the D2-D3 of 28S, ITS, 18S rRNA and COI gene sequences. Combined with scanning electron microscopy and a molecular analysis of an additional nine known and thirteen unknown species originating from diverse geographic regions, a total of 92 D2-D3 of 28S, 41 ITS, 57 18S rRNA and 111 COI new gene sequences are presented. Paratylenchus elachistus, P. holdemani and P. neoamblycephalus are recorded for the first time in Belgium and P. idalimus for the first time in Europe. Paratylenchus is an excellent example of an incredibly diverse yet morphologically minimalistic plant-parasitic genus, and this study provides an integrated analysis of all available data, including coalescence-based molecular species delimitation, resulting in an updated Paratylenchus phylogeny and the corrective reassignment of 18 D2-D3 of 28S, 3 ITS, 3 18S rRNA and 25 COI gene sequences that were previously unidentified or incorrectly classified.

Species Diversity of Pin Nematodes (Paratylenchus spp.) from Potato Growing Regions of Southern Alberta, Canada

Pin nematodes (Paratylenchus spp.) are polyphagous parasitic species with a wide host range and geographical distribution; their diversity is unknown in the potato growing region of Alberta, Canada. The present study aims to provide morphological and molecular characterization of three pin nematode species, namely P. neoprojectus, P. tateae, and a new species, Paratylenchus enigmaticus sp. nov. All of them were recovered from the potato growing region of southern Alberta. The nematodes were isolated using the sieving and flotation-centrifugation method, and their morphology was assessed by light microscopy. Molecular characterization was performed using partial 18S, D2–D3 expansion domains of the 28S and ITS ribosomal genes. This study is the first report of molecular characterization of P. tateae and P. neoprojectus, being new records from southern Alberta, and two Spanish populations of P. tateae comprising the first report of this species in Europe. The phylogenetic analysis of the 18S, D2–D3 expansion domains of the 28S and ITS ribosomal DNA regions underscores the importance of using molecular data for accurate species identification and clarifies the status of P. nanus type B and P. sheri. Moreover, our findings will be useful to determine the impact of pin nematodes on potato production in future field research.

Description of Hemicycliophora cardamomi sp. n. (Nematoda: Hemicycliophoridae) associated with Amomum longiligulare T.L. Wu and a web-based key for the identification of Hemicycliophora spp

During a survey of plant diseases in the Central Highlands of Vietnam, a new plant-parasitic nematode, Hemicycliophora cardamomi sp. n., was discovered in the growing areas of Amomum longiligulare, a valuable medicinal plant with high economical value. The new species is characterized by a cuticular sheath loosely fitting body; a labial region continuous to the body contour bearing 3 annuli; a lateral field frequently marked by a discontinuous single line with indistinct additional short lines in some parts along the body; a modified vulval lip with an anterior lip c. 4 annuli long; and a post-vulval body tapering to a pointed tail tip with an abrupt constriction at the last third of the post-vulval body. Morphology and molecular characterizations of D2-D3 expansion segment of 28S rRNA, ITS, and COI mtDNA gene regions clearly distinguish the new species from all other 133 known species. This study also provides a newly developed web-based key for the identification of Hemicycliophora spp. in order to accelerate the identification process, to minimize the increasing error load associated with larger datasets, and to avoid any dependence on a single starting entry. This key includes both an existing Bray-Curtis similarity measure and a newly developed similarity formula.

Taxonomical considerations and molecular phylogeny of the closely related genera Bitylenchus, Sauertylenchus and Tylenchorhynchus (Nematoda: Telotylenchinae), with one new and four known species from Iran

During several nematological surveys in cultivated and natural habitats in Khuzestan and Zanjan provinces of Iran, a new species, Bitylenchus parvulus n. sp., two new records for Iran - namely, Tylenchorhynchus agri and Tylenchorhynchus graciliformis - and a population of Bitylenchus parvus and one of Sauertylenchus maximus were recovered and characterized based upon morphological and molecular approaches. The new species is characterized by lip region with five to seven annuli, stylet 17.7 (17.0-18.5) μm long, sub-cylindrical tail narrowing abruptly near terminus giving a bluntly digitate shape to the tail tip, cuticle near anterior part of vulva wrinkled and post-rectal sac occupies whole of tail cavity. The phylogenetic analyses were carried out using molecular data from D2-D3 expansion segments of large ribosomal subunit (28S rRNA) for all studied species and the partial small ribosomal subunit (18S rRNA) for the new species. The representatives of Bitylenchus and Sauertylenchus formed distinct clades from Tylenchorhynchus members, supporting the hypothesis in which Bitylenchus and Sauertylenchus could be considered as valid genera, but rejecting the 'large-genus' concept for Tylenchorhynchus. Also, Sauertylenchus ibericus was proposed as a junior synonym of S. maximus based on the results from morphological and phylogenetic analysis. Furthermore, an identification key for all known species included in the three genera Bitylenchus, Tylenchorhynchus and Sauertylenchus is presented herein. The number of transverse annuli on the lip region and presence/absence of post-rectal sac were considered as the main diagnostic characters for classifying the species into seven groups, and other morphological and morphometric characters were subsequently used for distinguishing species in each group.

Morphology of obligate ectosymbionts reveals Paralaxus gen. nov.: A new circumtropical genus of marine stilbonematine nematodes

Stilbonematinae are a subfamily of conspicuous marine nematodes, distinguished by a coat of sulphur-oxidizing bacterial ectosymbionts on their cuticle. As most nematodes, the worm hosts have a relatively simple anatomy and few taxonomically informative characters, and this has resulted in numerous taxonomic reassignments and synonymizations. Recent studies using a combination of morphological and molecular traits have helped to improve the taxonomy of Stilbonematinae but also raised questions on the validity of several genera. Here, we describe a new circumtropically distributed genus Paralaxus (Stilbonematinae) with three species: Paralaxus cocos sp. nov., P. bermudensis sp. nov. and P. columbae sp. nov. We used single worm metagenomes to generate host 18S rRNA and cytochrome c oxidase I (COI) as well as symbiont 16S rRNA gene sequences. Intriguingly, COI alignments and primer matching analyses suggest that the COI is not suitable for PCR-based barcoding approaches in Stilbonematinae as the genera have a highly diverse base composition and no conserved primer sites. The phylogenetic analyses of all three gene sets, however, confirm the morphological assignments and support the erection of the new genus Paralaxus as well as corroborate the status of the other stilbonematine genera. Paralaxus most closely resembles the stilbonematine genus Laxus in overlapping sets of diagnostic features but can be distinguished from Laxus by the morphology of the genus-specific symbiont coat. Our re-analyses of key parameters of the symbiont coat morphology as character for all Stilbonematinae genera show that with amended descriptions, including the coat, highly reliable genus assignments can be obtained.

The hidden diversity of the potato cyst nematode Globodera pallida in the south of Peru

Our knowledge of the diversity of potato cyst nematodes in their native areas still remains patchy and should be improved. A previous study based on 42 Peruvian Globodera pallida populations revealed a clear south to north phylogeographic pattern, with five well-supported clades and maximum diversity observed in the south of Peru. In order to investigate this phylogeographic pattern more closely, we genotyped a larger collection of Peruvian populations using both cathepsin L gene sequence data and a new set of 13 microsatellite loci. Using different genetic analyses (STRUCTURE, DAPC), we consistently obtained the same results that led to similar conclusions: the presence of a larger genetic diversity than previously known suggesting the presence of cryptic species in the south of Peru. These investigations also allowed us to clarify the geographic borders of the previously described G. pallida genetic clades and to update our knowledge of the genetic structure of this species in its native area, with the presence of additional clades. A distance-based redundancy analysis (dbRDA) was also carried to understand whether there was a correlation between the population genetic differentiation and environmental conditions. This analysis showed that genetic distances observed between G. pallida populations are explained firstly by geographic distances, but also by climatic and soil conditions. This work could lead to a revision of the taxonomy that may have strong implications for risk assessment and management, especially on a quarantine species.

Plant-parasitic nematodes associated with sugarcane in Kilimanjaro, Tanzania

Morphological and molecular analyses of plant-parasitic nematodes (PPN) from 12 sugarcane plantation sites of Tanganyika Planting Company (TPC) Limited in Kilimanjaro region of Tanzania revealed the presence of six PPN genera, i.e. Helicotylenchus, Hemicycliophora, Pratylenchus, Rotylenchulus, Scutellonema, and Tylenchorhynchus. The genera with the highest densities and present in virtually all samples were Pratylenchus and Rotylenchulus, and the most important species appeared to be R. parvus, P. zeae, T. crassicaudatus, and T. ventrosignatus. A total sequences of 11 partial ITS, 15 D2-D3 of 28S, and 6 partial 18S of rRNA gene, and 7 partial COI gene of mtDNA of these species were obtained in this study. Morphology and molecular data comparisons between the Tanzanian R. parvus and the South African R. parvus indicated that R. parvus is a cryptic species complex. Based on the results of morphological and molecular analyses of T. crassicaudatus and T. agri from China, Haiti, Indonesia, Iran, Niger and the USA, T. agri syn. n. is proposed as a junior synonym of T. crassicaudatus.

Mitochondrial COI gene is valid to delimitate Tylenchidae (Nematoda: Tylenchomorpha) species

Tylenchidae is a widely distributed soil-inhabiting nematode family. Regardless their abundance, molecular phylogeny based on rRNA genes is problematic, and the delimitation of taxa in this group remains poorly documented and highly uncertain. Mitochondrial Cytochrome Oxidase I (COI) gene is an important barcoding gene that has been widely used species identifications and phylogenetic analyses. However, currently COI data are only available for one species in Tylenchidae. In present study, we newly obtained 27 COI sequences from 12 species and 26 sequences from rRNA genes. The results suggest that the COI gene is valid to delimitate Tylenchidae species but fails to resolve phylogenetic relationships.

Phylogeography of the highly invasive sugar beet nematode, Heterodera schachtii (Schmidt, 1871), based on microsatellites

Plant-parasitic nematodes (PPNs) threaten crop production worldwide. Yet few studies have examined their intraspecific genetic diversity or patterns of invasion, critical data for managing the spread of these cryptic pests. The sugar beet nematode Heterodera schachtii, a global invader that parasitizes over 200 plant species, represents a model for addressing important questions about the invasion genetics of PPNs. Here, a phylogeographic study using 15 microsatellite markers was conducted on 231 H. schachtii individuals sampled from four continents, and invasion history was reconstructed through an approximate Bayesian computation approach, with emphasis on the origin of newly discovered populations in Korea. Multiple analyses confirmed the existence of cryptic lineages within this species, with the Korean populations comprising one group (group 1) and the populations from Europe, Australia, North America, and western Asia comprising another (group 2). No multilocus genotypes were shared between the two groups, and large genetic distance was inferred between them. Population subdivision was also revealed among the populations of group 2 in both population comparison and STRUCTURE analyses, mostly due to different divergent times between invasive and source populations. The Korean populations showed substantial genetic homogeneity and likely originated from a single invasion event. However, none of the other studied populations were implicated as the source. Further studies with additional populations are needed to better describe the distribution of the potential source population for the East Asian lineage.

Description of Rotylenchus rhomboides n. sp. and a Belgian population of Rotylenchus buxophilus (Tylenchomorpha: Hoplolaimidae)

During a survey in the Botanical garden of Ghent University, a new species Rotylenchus rhomboides n. sp. and a population of Rotylenchus buxophilus were found. Rotylenchus rhomboides n. sp. is characterized by the presence of a rhomboid-like widening of the mid-ridge of lateral field at the level of vulva, a feature previously unknown within the genus. The population of the new species, composed only by females, has a rounded labial region with 4 to 5 annuli, robust stylet (31–37 μm long), short dorsal esophageal gland (9–19 μm) overlap of the intestine, vulva located slightly posterior to mid-body, and hemispherical or rounded tail shape with large phasmids located 3 to 5 annuli anterior to the level of anus. The hierarchical cluster analysis based on morphological features indicated that the new species closely resembles R. corsicus, R. gracilidens, and R. rugatocuticulatus. The DNA analyses of the D2-D3 of 28S rDNA, ITS rDNA, and COI mtDNA sequences of Rotylenchus rhomboides n. sp. show a close relationship with R. buxophilus, R. goodeyi, R. laurentinus, R. pumilus, and R. incultus, all of which can also be differentiated from the new species by morphological features. The combination of morphological, morphometric, and molecular characteristics confirmed the new species and the first report of R. buxophilus on yam (Dioscorea tokoro) in Belgium.

A new dagger nematode, Xiphinema poasense n. sp. (Nematoda: Longidoridae), from Costa Rica

A new dagger nematode,Xiphinema poasensen. sp., is described and illustrated from three populations extracted from soil associated with a combined plantation ofEucalyptussp.,Cupressussp. andPennisetumsp. and wild plants from a tropical pre-montane forest in Costa Rica. The new dagger nematode is characterised by a moderate body size 2612 (2416-3042) μm long, a rounded lip region 15.0 (13.5-16.5) μm broad, separated from the body contour by a shallow depression, amphidial fovea large, stirrup-shaped, a very long odontostyle (175 (164-188) μm), stylet guiding ring located 167 (136-181) μm from anterior end, vulva situated anterior to mid-body (36-40%), anterior genital branch complete but strongly reduced, without uterine differentiation, female tail short, hemispherical to convex-conoid with a c′ ratio = 0.7 (0.6-0.8) and bearing two pairs of caudal pores, and male absent. Integrative diagnosis was completed with molecular data using D2-D3 expansion segments of 28S rRNA, ITS1 region, partial 18S-rRNA and the partial mitochondrial gene cytochrome c oxidase subunit 1 (coxI). The phylogenetic relationships based on D2-D3 segments of this species with otherXiphinemaspp. of theX.non-americanumgroup indicated thatX. poasensen. sp. clustered with other species with a reduced anterior genital branch from the morphospecies Group 2,viz.,X. costaricenseandX. krugi. However, the phylogeny ofcoxIand partial 18S rRNA gene revealed that the new species did not cluster withXiphinemaspecies having the anterior genital branch absent or reduced (i.e., morphospecies Groups 1 and 2, respectively).

Soil nematodes in alpine meadows of the Tatra National Park (Slovak Republic)

The assemblages of soil nematodes were studied at five alpine meadow sites, 1763-2200 m. a. s. I., in the Tatra National Park in the Slovak Republic. A total of 110 species were distinguished, 19 species were recorded in the Slovak Republic for the first time. The interesting new records are the occurrence of Sphaeronema alni at the elevation of 2003 m a . s. I. and the populations of Coomansus menzeli at four sites. The total numbers of species at individual sites varied from 45 to 72. The most abundant nematode genera were Aglenchus, Plectus. Acrobeloides, Paratylenchus, Eudorylaimus, Helicotylechus, and Aphelenchoides. The total mean abundance ranged from 704 to 2054 × 103ind.m-2 and the total mean biomass from 442 to 1531 mg.m-2. The lowest values of the Maturity Indices (ΣMI, Ml) were found at the highest elevation. The significantly highest values of the Plant Parasite Index were at the lowest elevation. The mean values of the of the Enrichment Index varied from 16.3 to 38.4, the mean values of the Structure Index from 64.1 to 85.4. The Structure metabolic footprints were significantly greater at the lowest elevation than at the highest elevation. Cluster Analysis and Principal Component Analysis performed on species presence and absence, genera abundance and genera metabolic footprints showed nematode assemblages at sites of high­er elevations different from those at sites of lower elevations.

Species Delimitation and Description of Mesocriconema nebraskense n. sp. (Nematoda: Criconematidae), a Morphologically Cryptic, Parthenogenetic Species from North American Grasslands

Nematode surveys of North American grasslands conducted from 2010 to 2015 frequently recovered a species of criconematid nematode morphologically resembling Mesocriconema curvatum. These specimens were recovered from remnant native prairies in the central tallgrass ecoregion of North America, and not from surrounding agroecosystems. Historical records indicate that M. curvatum is a cosmopolitan species feeding on a wide range of agronomic and native plants. DNA barcoding indicates North American grasslands contain at least 10 phylogenetically distinct lineages of Mesocriconema that resemble, but are not, M. curvatum. Analysis of the two most common lineages reveals two distinctly different population structures. The variation in population structure suggests unique evolutionary histories associated with their diversification. These two major lineages share a sympatric distribution and their slight morphological differences contrast with a high level of genetic separation. Based on their genetic divergence, fixed diagnostic nucleotides, population structure, species delimitation metrics, and a sympatric distribution, we believe that one of these distinct lineages warrants formal nomenclatural recognition. Herein, we provide formal recognition for Mesocriconema nebraskense n. sp. and discuss its relationship to other Mesocriconema lineages discovered in native North American grasslands.

Molecular and morphological characterisation of Ditylenchus persicus n. sp. (Nematoda: Anguinidae) from Kermanshah province, western Iran

A new species of the genusDitylenchus,D.persicusn. sp., was collected around the roots of grapevine and is described and illustrated herein based on morphological and molecular studies. The new species is characterised by a body length of 783 (635-928) μm and 689 (670-715)μm in female and male, respectively, delicate stylet 6.2 (5.0-7.0)μm long, six lines in the lateral field, median bulb of pharynx well developed, muscular with crescentic valve, basal pharyngeal bulb pyriform with 10 (8-13)μm long stem extending into intestine, post-vulval uterine sac relatively short, 16 (14-18)μm long, female and male tail elongate-conoid with finely rounded terminus, and bursa covering 65-80% of male tail length. Morphologically,D.persicusn. sp. appears closer to five known species of the genus, namely:D.arachis,D.caudatus,D.clarus,D.myceliophagusandD. nanus. The results of phylogenetic analyses based on sequences of D2-D3 expansion region of 28S rRNA, ITS and partial 18S rRNA genes confirmed the close molecular relationship betweenD.persicusn. sp. and otherDitylenchusspecies such asD. myceliophagus,D. africanus,D. arachis,D. destructorandD. halictus.

Morphological and molecular characterisation of Longidorus juglans sp. nov. and a sister species L. fangi Xu & Cheng, 1991 (Nematoda: Longidoridae) from China

Longidorus juglanssp. nov. is a new needle nematode detected from the rhizosphere of a walnut tree in Shanxi Province, P.R. China. It was distinguished by female body length of 3.9-5.2 mm; lip region 14-18 μm wide, rounded and continuous, amphidial fovea pocket-shaped without distinct basal lobes; moderately long odontostyle (125-140 μm); guide ring at mid-odontostyle and situated 69-78 μm from anterior end; short and blunt conoid tail (30-41 μm long, c = 118-147, c′ = 0.6-0.9), bearing 2-3 caudal pores on each side. The male ofL. juglanssp. nov. is 5.1 mm long, with 13 ventro-median supplements, a short and blunt conoid tail bearing 3-4 caudal pores on each side, and spicules 73 μm long. Three developmental juvenile stages were recognised. This new species is very similar to another Chinese speciesL. fangiin general morphology, but can be distinguished by the number of juvenile stages and DNA sequences of SSU, ITS1, ITS2 and D2-D3 of LSU rDNA. Morphological and molecular characterisation was provided forL. fangirepresenting two new geographical records. The phylogenetic relationships among these species were analysed using data from SSU, D2-D3 of LSU, ITS1 and ITS2 rDNA, which revealed thatL. juglanssp. nov. andL. fangiwere clustered together withL. diadecturus,L. litchiiandL. jonesiwhose guide ring is located at mid-odontostyle level.

Morphological and molecular characterisation of Scutellonema species from yam (Dioscorea spp.) and a key to the species of the genus

The yam nematode, Scutellonema bradys, is a major threat to yam (Dioscorea spp.) production across yam-growing regions. In West Africa, this species cohabits with many morphologically similar congeners and, consequently, its accurate diagnosis is essential for control and for monitoring its movement. In the present study, 46 Scutellonema populations collected from yam rhizosphere and yam tubers in different agro-ecological zones in Ghana and Nigeria were characterised by their morphological features and by sequencing of the D2-D3 region of the 28S rDNA gene and the mitochondrial COI genes. Molecular phylogeny, molecular species delimitation and morphology revealed S. bradys, S. cavenessi, S. clathricaudatum and three undescribed species from yam rhizosphere. Only S. bradys was identified from yam tuber tissue, however. For barcoding and identifying Scutellonema spp., the most suitable marker used was the COI gene. Additionally, 99 new Scutellonema sequences were generated using populations obtained also from banana, carrot, maize and tomato, including the first for S. paralabiatum and S. clathricaudatum, enabling the development of a dichotomous key for identification of Scutellonema spp. The implications of these results are discussed.

Aphelenchoides salixae n. sp. (Nematoda: Aphelenchoididae) isolated from Salix alba in western Iran

Aphelenchoides salixaen. sp. was isolated from wood and bark samples of a dead willow in Kermanshah Province, western Iran. The nematodes were collected directly from wood samples and were successfully reared onBotrytis cinerea. The new species has a body length of 567 (507-620) μm (females) and 382 or 400 μm (males). The cuticle is weakly annulated with four lateral lines. Lip region offset. The stylet is 9.5 (9-10) μm long with small basal swellings. The excretory pore is locatedcaone body diam. posterior to the metacorpus valve. The spicules are short with the dorsal limb 14 or 15 μm long (n = 2), apex and rostrum rounded and only slight offset. The female tail is cylindrical with a broadly rounded terminus. The male tail is conical, bearing six (2 + 2 + 2) caudal papillae with a hamate mucron at terminus. The new species belongs to the Group 1 category ofAphelenchoidesspecies and is close to seven known species, namely:A. capsuloplanus,A. confusus,A. limberi,A. obtusicaudatus,A. obtusus,A. orientalisandA. rotundicaudatus. Molecular analyses of the partial 18S, D2-D3 expansion segments of the 28S rRNA genes and internal transcribed spacer (ITS) supported it as a new species and that the new species is closest toA.besseyi,A. fujianensisandA. ritzemabosiin dendrograms inferred using 18S and 28S D2-D3 genes.

Remarkable Diversity and Prevalence of Dagger Nematodes of the Genus Xiphinema Cobb, 1913 (Nematoda: Longidoridae) in Olives Revealed by Integrative Approaches

The genus Xiphinema includes a remarkable group of invertebrates of the phylum Nematoda comprising ectoparasitic animals of many wild and cultivated plants. Damage is caused by direct feeding on root cells and by vectoring nepoviruses that cause diseases on several crops. Precise identification of Xiphinema species is critical for launching appropriate control measures. We make available the first detailed information on the diversity and distribution of Xiphinema species infesting wild and cultivated olive in a wide-region in southern Spain that included 211 locations from which 453 sampling sites were analyzed. The present study identified thirty-two Xiphinema spp. in the rhizosphere of olive trees, ten species belonging to Xiphinema americanum-group, whereas twenty-two were attributed to Xiphinema non-americanum-group. These results increase our current knowledge on the biodiversity of Xiphinema species identified in olives and include the description of four new species (Xiphinema andalusiense sp. nov., Xiphinema celtiense sp. nov., Xiphinema iznajarense sp. nov., and Xiphinema mengibarense sp. nov.), and two new records for cultivate olives (X. cadavalense and X. conurum). We also found evidence of remarkable prevalence of Xiphinema spp. in olive trees, viz. 85.0% (385 out of 453 sampling sites), and they were widely distributed in both wild and cultivated olives, with 26 and 17 Xiphinema spp., respectively. Diversity indexes (Richness, Hill´s diversity, Hill´s reciprocal of D and Hill´s evenness) were significantly affected by olive type. We also developed a comparative morphological and morphometrical study together with molecular data from three nuclear ribosomal RNA genes (D2-D3 expansion segments of 28S, ITS1, and partial 18S). Molecular characterization and phylogenetic analyses allowed the delimitation and discrimination of four new species of the genus described herein and three known species. Phylogenetic analyses of Xiphinema spp. resulted in a general consensus of these species groups. This study is the most complete phylogenetic analysis for Xiphinema non-americanum-group species to date.

Unravelling the Biodiversity and Molecular Phylogeny of Needle Nematodes of the Genus Longidorus (Nematoda: Longidoridae) in Olive and a Description of Six New Species

The genus Longidorus includes a remarkable group of invertebrate animals of the phylum Nematoda comprising polyphagous root-ectoparasites of numerous plants including several agricultural crops and trees. Damage is caused by direct feeding on root cells as well as by transmitting nepoviruses that cause disease on those crops. Thus, correct identification of Longidorus species is essential to establish appropriate control measures. We provide the first detailed information on the diversity and distribution of Longidorus species infesting wild and cultivated olive soils in a wide-region in southern Spain that included 159 locations from which 449 sampling sites were analyzed. The present study doubles the known biodiversity of Longidorus species identified in olives by including six new species (Longidorus indalus sp. nov., Longidorus macrodorus sp. nov., Longidorus onubensis sp. nov., Longidorus silvestris sp. nov., Longidorus vallensis sp. nov., and Longidorus wicuolea sp. nov.), two new records for wild and cultivate olives (L. alvegus and L. vineacola), and two additional new records for wild olive (L. intermedius and L. lusitanicus). We also found evidence of some geographic species associations to western (viz. L. alvegus, L. intermedius, L. lusitanicus, L. onubensis sp. nov., L. vineacola, L. vinearum, L. wicuolea sp. nov.) and eastern distributions (viz. L. indalus sp. nov.), while only L. magnus was detected in both areas. We developed a comparative study by considering morphological and morphometrical features together with molecular data from nuclear ribosomal RNA genes (D2-D3 expansion segments of 28S, ITS1, and partial 18S). Results of molecular and phylogenetic analyses confirmed the morphological hypotheses and allowed the delimitation and discrimination of six new species of the genus described herein and four known species. Phylogenetic analyses of Longidorus spp. based on three molecular markers resulted in a general consensus of these species groups, since lineages were maintained for the majority of species. This study represents the most complete phylogenetic analysis for Longidorus species to date.

Morphological and molecular characterisation of one new and several known species of the reniform nematode, Rotylenchulus Linford & Oliveira, 1940 (Hoplolaimidae: Rotylenchulinae), and a phylogeny of the genus

The reniform nematodes of the genusRotylenchulusare semi-endoparasites of numerous herbaceous and woody plant roots and are mainly distributed in tropical and subtropical regions. In this study, we provide morphological and molecular characterisation of six out of ten presently known valid species ofRotylenchulus:R. clavicaudatus,R. leptus,R. macrodoratus,R. macrosoma,R. reniformisandR. saccharifrom South Africa, USA, Italy and Spain.Rotylenchulus parvuswas only studied morphologically. A new species,R. macrosomoidessp. n., isolated from soil and roots of sugarcane in South Africa, is described. The phylogeny ofRotylenchulus, as inferred from the analyses of D2-D3 of 28S rRNA, ITS rRNA,coxImtDNA andhsp90gene sequences, is presented. The study revealed thatR. reniformisandR. macrosomahave a sister relationship, but that relationships between otherRotylenchulusspecies remain unresolved. The phylogenetic analysis also confirmed the hypothesis that this genus originated from the Afrotropical zoogeographical region. Our study revealed thatR. reniformisandR. macrosomoidessp. n. have two distinct rRNA gene types andR. macrosomahave three rRNA gene types in their genomes. PCR with species-specific primers was developed for rapid diagnostics ofR. reniformis.

Molecular characterisation of two known species of Paratylenchus Micoletzky, 1922 from Iran with notes on the validity of Paratylenchus audriellus Brown, 1959

During a survey on pin nematodes in western Iran, two populations of Paratylenchus audriellus and Paratylenchus tenuicaudatus were collected and subsequently analysed morphologically and molecularly. Paratylenchus audriellus is characterised by the long stylet (48-61 μm) and the typical female tail with a characteristic claw-like process with sharply pointed terminus. To our knowledge, the Iranian population of P. tenuicaudatus is the first record from Iran. The molecular characterisation of P. audriellus nematodes using the D2-D3 of 28S rRNA and the partial 18S rRNA gene sequences revealed that this species is clearly separated from P. straeleni and should be considered as a valid taxon.

On the identity of Aporcelinus granuliferus (Cobb, 1893) Andrássy, 2009 and its taxonomic consequences

The intricate taxonomical history of Aporcelinus granuliferus, the most often recorded species of its genus, is reviewed and discussed. A new concept, based on its original description, is proposed for it as type material is apparently lost although available data provide enough information to complete and update its diagnosis: 1.20-1.70 mm long body, lip region 15-16 μm broad, odontostyle 17-21 μm long, neck 309-403 μm long, pharyngeal expansion 155-214 μm long, dorsal cell mass present at pharyngo-intestinal junction, uterus simple and up to one body diam. long, V = 47-55, female tail conical with acute tip and occasionally somewhat recurved dorsad (46-55 μm; c = 24-37; c′ = 1.4-1.9), and male absent. The population studied by Thorne & Swanger (1936) is certainly not conspecific with Cobb’s original one due to significant differences in lip region breadth and odontostyle length, and belongs to a non-described species, herein characterised and named as A. brasiliensis sp. n.: 1.5-1.6 mm long body, lip region offset by constriction and 24-27 μm wide, odontostyle 25-28 μm long, neck 345-370 μm long, V = 48, tail conical (46-55 μm; c = 29-32; c′ = 1.3-1.4) with very finely rounded or acute tip and barely recurved dorsad, spicules 54-72 μm long and nine irregularly spaced ventromedian supplements with no hiatus. The three females deposited with USDANC are not identical either to those studied by Cobb or by Thorne & Swanger, and also belong to a non-described species, herein characterised as named as A. neogranuliferus sp. n.: 1.25-1.31 mm long body, lip region offset by constriction and 17.5-18.0 μm broad, odontostyle 18 μm at its ventral side, neck 312-337 μm long, pharyngeal expansion 136-168 μm long, dorsal cell mass present at level of pharyngo-intestinal junction, uterus simple and 41-48 μm long or 0.6 times corresponding body diam., V = 49-53, female tail conical (28-35 μm; c = 36-46; c′ = 0.8-1.0) with finely rounded terminus and no hyaline region. Both Dorylaimus reynecki and D. yucatanensis, hitherto considered to be identical to A. granuliferus, are valid species, being transferred to Aporcelinus as A. reynecki comb. n. and A. yucatanensis comb. n. The available information on D. micrurus and D. menzeli lacks sufficient relevant detail to characterise these species, which are therefore regarded as species inquirendae within Aporcelinus and are transferred as A. micrurus comb. n. and A. menzeli comb. n. The true identity of other records of A. granuliferus is analysed and discussed in the light of the new concept of the taxon.

Molecular phylogenetic analysis and comparative morphology resolve two new species of olive-tree soil related dagger nematodes of the genus Xiphinema (Dorylaimida : Longidoridae) from Spain

The genus Xiphinema constitutes a large group of ~275 species of polyphagous, plant-ectoparasitic nematodes that are distributed almost worldwide. Some species affect agricultural crops by feeding directly on root cells as well as by transmitting nepoviruses. Despite their agricultural importance, species discrimination in Xiphinema is difficult, leading to potential misidentification. Integrative taxonomy, based on the combination of molecular analyses and morphology, constitutes a new insight into Xiphinema species identification. In this study we describe two new species of Xiphinema from the Iberian Peninsula (X. macrodora, sp. nov. and X. oleae, sp. nov.) associated with cultivated and wild olive trees. Both species have specific rRNA sequences. Morphologically, Xiphinema macrodora, sp. nov. is characterised by a very long body (7.2–8.7 mm), a very long odontostyle and odontophore (190–206 and 105–120 µm, respectively), and a well developed pseudo-Z-organ, comprising 8 to 12 sclerotised bodies. Xiphinema oleae, sp. nov. is characterised by an odontostyle and an odontophore 136–149 and 65–80 µm long, respectively, and a well developed Z-organ with refractive inclusions (3–5), variable in shape. Additionally, X. macrodora, sp. nov. has the longest body size, and the longest odontostyle and odontophore of any Xiphinema, whereas X. oleae, sp. nov. is the first species with a well developed Z-organ from the Iberian Peninsula. http://zoobank.org/urn:lsid:zoobank.org:pub:E4CE8711-22EF-40E4-9D39-6FE962F25225

Characterisation of a topotype and other populations of Hemicriconemoides strictathecatus Esser, 1960 (Nematoda: Criconematidae) from Florida with description of H. phoenicis sp. n. from the USA

The results of morphological and molecular analyses of a Florida topotype and other populations of Hemicriconemoides strictathecatus showed that this sheathoid nematode consists of two morphotypes, both with an average stylet length of more than 70 μm, but having different tail termini, bluntly pointed or rounded. These findings confirmed the morphological similarity of H. strictathecatus with H. mangiferae, which was considered a junior synonym of this species as previously proposed by Decraemer & Geraert (1992, 1996). Populations of a sheathoid nematode with a stylet length ranging from 62.5 to 72.0 μm from Taiwan, China, South Africa and Venezuela and identified in previous studies as H. strictathecatus were found to be morphologically and molecularly different from this species and are now considered as representatives of H. litchi. Another sheathoid nematode population from Florida, considered to be H. mangiferae by McSorley et al. (1980), was also found to be morphologically and molecularly congruous with H. litchi. During nematological surveys in Florida, a new sheathoid nematode was detected on date palms imported from California into Florida and is described herein as H. phoenicis sp. n. This new species is related morphologically to the H. strictathecatus morphotype with pointed tail terminus. Both have a stylet longer than 70 μm. The new species is phylogenetically related to H. strictathecatus and H. litchi. It differs morphologically from other Hemicriconemoides species by the cuticular ornamentation of the annuli, which are marked by coarse longitudinal ridges, grooves and thick margins. Morphological and molecular characterisations of H. cocophillus from Mozambique and Florida, USA are also elucidated in this study. New phylogenies of the genus Hemicriconemoides as inferred from the analyses of the ITS rRNA, D2-D3 of 28S rRNA and partial coxI gene sequences are provided.