Search

The ring nematode genus Xenocriconemella De Grisse and Loof, 1965 comprises only one nominal species, Xenocriconemella macrodora (Taylor, 1936) De Grisse and Loof, 1965. The initial objective of the present study was to investigate the morphological-morphometric and molecular diversity of 28 X. macrodora populations in the Iberian Peninsula associated with tree forests (mainly Quercus spp.). However, a detailed integrative taxonomic analysis (morphological-morphometric and molecular data) from each population and analysis of this data using principal component analysis (PCA) for morphometric data (including these 28 populations and other 25 X. macrodora populations around the world) and molecular and phylogenetic species delimitation methods revealed that X. macrodora forms a species complex. This species complex is composed by species that are morphometricly and morphologically similar, but clearly different at the molecular level. Three new species are described applying integrative taxonomy, namely as Xenocriconemella iberica sp. nov., Xenocriconemella paraiberica sp. nov. and Xenocriconemella pradense sp. nov. However, the molecular diversity of this species in USA and Italy confirmed that additional species are likely present in this species complex, and the diversity of this group may be higher than expected. The study of X. macrodora topotypes can clarify the position of this species using molecular markers under an integrative approach.

Ring nematodes are obligate ectoparasites on crops and natural herbaceous and woody plants, and some species are of economic importance and cause damage to roots of several crops. Recent integrative taxonomical analyses recognized the existence of two cryptic species within the Criconema annuliferum morphotype in Spain. In this study, we corroborated that morphometric, morphological and a multi-locus analysis (including the ribosomal markers D2-D3 expansion segments of 28S rRNA, ITS rRNA, 18S RNA, and the mitochondrial DNA cytochrome oxidase I gene) identified a new lineage clearly separated from C. annuliferum, C. paraannuliferum and C. plesioannuliferum. The new lineage was described herein as Criconema pseudoannuliferum sp. nov., confirming that C. annuliferum species complex species complex comprises a hyper-cryptic species complex. This research analysed soil samples from the rhizosphere of maritime pine (Pinus pinaster Ait.) forests in Bermeja-Crestellina Mountain, located at the western part of Málaga province, southern Spain. The integrative taxonomical analyses revealed the occurrence of a new cryptic species identified using females, males and juveniles with detailed morphology, morphometry and molecular markers, described herein as Criconema pseudoannuliferum sp. nov. All molecular markers (D2-D3, ITS, 18S and COI) were obtained from the same individual that was also used for morphological and morphometric analyses. This research demonstrated the hidden diversity within the C. annuliferum species complex species complex can reach to four lineages under ribosomal and mitochondrial gene markers for one morphospecies group, which includes four species, viz. C. annuliferum, C. paraannuliferum, C. plesioannuliferum, and C. pseudoannuliferum sp. nov. Criconema pseudoannuliferum sp. nov. was detected in moderate soil density in two maritime pine forests (5 and 25 nematodes/500 cm3 of soil) suggesting that does not cause damage to maritime pine.

Ring nematodes are obligate ectoparasites on cultivated and wild herbaceous and woody plants, inhabiting many types of soil, but particularly sandy soils. This study explored the morphometrical and molecular diversity of ring nematodes resembling Criconema annuliferum in 222 soil samples from fruit crops in Spain, including almond, apricot, peach and plum, as well as populations from cultivated and wild olives, and common yew. Ring nematodes of the genus Criconema were detected in 12 samples from under Prunus spp. (5.5%), showing a low to moderate nematode soil densities in several localities from southeastern and northeastern Spain. The soil population densities of Criconema associated with Prunus spp. ranged from 1 nematode/500 cm3 of soil in apricot at Sástago (Zaragoza province) to 7950 and 42,491 nematodes/500 cm3 of soil in peach at Ricla and Calasparra (Murcia province), respectively. The integrative taxonomical analyses reveal the presence of two cryptic species identified using females, males (when available), and juveniles with detailed morphology, morphometry, and molecular markers (D2-D3, ITS, 18S, and COI), described herein as Criconema paraannuliferum sp. nov. and Criconema plesioannuliferum sp. nov. All molecular markers from each species were obtained from the same individuals, and these individuals were also used for morphological and morphometric analyses. Criconema paraannuliferum sp. nov. was found in a high soil density in two peach fields (7950 and 42,491 nematodes/500 cm3 of soil) showing the possibility of being pathogenic in some circumstances.

Parasitic nematodes of millipedes from Nigeria are molecularly characterized for the first time. During nematode surveys on live giant African millipedes from several localities in Nigeria, 4 species of rhigonematids were identified by application of integrative taxonomical approaches (morpho-anatomy and molecular markers), including Brumptaemilius sp., Gilsonema gabonensis, Obainia pachnephorus, and Rhigonema disparovis. The results of morphometric and molecular analyses of D2-D3 28S, ITS, partial 18S rRNA, and cytochrome oxidase c subunit 1 (COI) gene sequences further characterized the rhigonematid species, and clearly separated them from other related species. Phylogenetic relationships based on 28S and 18S rRNA genes suggest that genera within Ransomnematoidea (Ransomnema, Heth, Carnoya, Brumptaemilius, Cattiena, Insulanema, Gilsonema) and Rhigonematoidea (Rhigonema, Obainia, Xystrognathus, Trachyglossoides, Ichthyocephaloides) clustered rather closer than could be expected in view of their morphological differences. Phylogenetic relationships based on ITS and COI are congruent with those of other ribosomal genes; however, they are not conclusive due to the scarcity of available sequences of these genes for these genera in NCBI.

Nematode samplings in various areas and crops of Greece were carried out and the recovered nematode species were characterized using morphological and molecular data. Seven species of plant-parasitic nematodes were recovered, three of which are reported for the first time in Greece, including Hemicycliophora poranga, Helicotylenchus dihystera and Tylenchorhynchus zeae. Four other recovered species had already been reported in Greece, including Bitylenchus hispaniensis, Helicotylenchus microlobus, Nanidorus minor and Scutellonema brachyurus. D2-D3 segments of 28S rRNA gene for all of these nematode species are provided.

Heterodera zeae Koshy, Swarup & Sethi, 1971 (corn cyst nematode) is an important disease of corn in several areas of the world, including India, Nepal, Pakistan, Egypt, USA, Greece and Portugal (Subbotin et al., 2010). It is a sedentary semi-endoparasite feeding on corn roots and other Poaceae plants and has been associated with significant yield losses in corn (Subbotin et al., 2010). During autumn 2022 a plant-parasitic nematode survey performed in corn at central-western area of Spain (Talavera de la Reina, Toledo), revealed a commercial field with stunted plants. Nematodes were extracted from soil by centrifugal-flotation method (Coolen, 1979). Corn roots inspection detected infections by immature and mature cysts, and soil revealed also mature live cysts and second-stage juveniles (J2s) with a population density of 1010 eggs and J2s/500 cm3 soil (including eggs from cysts). J2s and cysts were processed to pure glycerine using De Grisse's (1969) method. DNA was isolated from single live fresh J2s specimens for amplifying and sequencing of cytochrome c oxidase subunit II (COII) mitochondrial region using the primer pair species-specific H.Gly-COIIF_inFOR/P116F-1R (Riepsamen et al., 2011); D2 and D3 expansion domains of the 28S rRNA were amplified using the D2A/D3B primers (De Ley et al. 1999); internal transcribed spacer (ITS) region using primers TW81/AB28 (Subbotin et al., 2001); and cytochrome c oxidase subunit 1 (COI) gene was amplified using the primers JB3/JB5 (Bowles et al., 1992). Brown cysts were lemon-shaped with a protruding vulval cone with fenestra ambifenestrate, bullae prominent below underbridge and characteristically arranged in finger-like bullae (Fig. 1). J2 with slightly offset lip region (3-5 annuli), stylet strong with rounded stylet knobs, lateral field with four lines, and tail short and tapering conically. Measurements of cysts (n=10) included body length 559 (432-688) µm, body width 450 (340-522) µm, fenestral length 40 (36-43) µm, semif

Paratylenchus species are obligate ectoparasitic nematodes on cultivated and wild herbaceous and woody plants occupying numerous soil categories. Several species may cause damage to several crops (viz. P. dianthus, P. enigmaticus, P. microdorus, P. hamatus and P. epacris on carnation, lettuce, rose and walnut, respectively). This investigation proves and emphasizes the relevance of applying integrative taxonomy for the accurate detection of Paratylenchus species in mountainous wild environments in the Malaga province, Southern Spain. This research analyzed 45 soil samples of maritimus pine and one of green heather in southern Spain and identified fourteen Paratylenchus species, two of them are described herein as new species (P. paraaonli sp. nov., P. plesiostraeleni sp. nov.), six of them were first reports for Spain (P. canchicus, P. nainianus, P. neonanus, P. salubris, Paratylenchus sp. 2 SAS, and P. wuae), and six species (P. caravaquenus, P. microdorus, P. nanus, P. neoamblycephalus, P. sheri, and P. variabilis) have been already reported in Spain. Accordingly, these data increase the biodiversity of pin nematodes in Spain comprising a total of 47 species (33.1% out of 142 total species of this genus). Phylogenetic analyses based on ribosomal and mitochondrial markers (D2-D3, ITS, and partial COI) resulted in a consistent position for the newly described Paratylenchus species in this study (P. plesiostraeleni sp. nov., P. paraaonli sp. nov.). Paratylenchus plesiostraeleni sp. nov. grouped in a separated subclade as unequivocal species from the P. straeleni-complex species (including P. straeleni and P. parastraeleni), and P. paraaonli sp. nov. clustered with P. vitecus, but clearly separate from this species. This study indicates that Paratylenchus species diversity in natural environments may be higher than expected, and this study may help in accurate identifications.

This study aimed to evaluate the prevalence and distribution of Paratylenchus species in the main areas of Prunus spp. production in Spain, their ecological constraints, and new molecular tools for the specific identification of major species. Pin nematodes are recognized as plant-parasitic nematodes with a wide host range and global distribution. Therefore, understanding the environmental and agronomic factors involved in their distribution is critical to design environmental and sustainable management strategies to reduce plant damage. A total of 219 sampling sites were surveyed and 12 Paratylenchus species were identified based on an integrative taxonomic approach (P. baldaccii, P. enigmaticus, P. goodeyi, P. hamatus, P. holdemani, P. indalus, P. israelensis, P. pedrami, P. tateae, P. tenuicaudatus, P. veruculatus, and P. zurgenerus). The most common pin nematode was P. hamatus, followed by P. tenuicaudatus. Nematode abundance was influenced by climatic characteristics, soil chemical properties, and agronomic management practices. Nine explanatory variables were selected as the most strongly associated with Paratylenchus distribution. Specifically, P. tenuicaudatus was significantly correlated with soil chemical characteristics, such as pH and carbon, sulfur, and sodium content, whereas P. goodeyi was closely related to fields with <10 years of almond cultivation. Species-specific PCRs were developed for P. hamatus and P. tenuicaudatus and their validity was evaluated studying the molecular variability of these species and against other Paratylenchus species.

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).

Longidorid nematodes comprise more than 500 species, and Longidorus and Xiphinema are the most diversified, prevalent, and cosmopolitan genera within plant-parasitic nematodes. The genus Longidorus comprise a group of species, some of which are vectors of plant viruses. New sampling for needle nematodes was carried out in a grapevine area in Thessaloniki, northern Greece, and one nematode species of Longidorus (L. leptocephalus) was recovered. Nematodes were extracted from soil samples by modified sieving and a decanting method. Extracted specimens were processed using glycerol, mounted on permanent slides, and subsequently identified morphologically. Nematode DNA was extracted from individual, live specimens, and PCR (Polymerase Chain Reaction) assays were performed for D2-D3 expansion segments of 28S rRNA, ITS1 rRNA, and partial mitochondrial COI regions. Morphology and morphometric data obtained from this population were consistent with the original description and reported populations of L. leptocephalus. To our knowledge, this is the first report of L. leptocephalus in Greece and the second in the Mediterranean Basin after the record of the species from Slovenia, extending the geographical distribution of this species in Europe.

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.

An emerging research line in conservation ecology addresses how environmental change drivers may cause the biotic homogenization of ecological communities by shifts in species diversity and community composition. While the drivers have been explored in unmanaged ecosystems and managed agricultural systems, this issue has received limited attention in regards to a key soil bioindicator organisms, soil nematodes.In this study, we evaluated the effect of land-use change and intensification on the diversity of plant-feeding nematodes (PFN) thought taxonomic and functional measures of alpha and beta diversity. We selected olive tree farms in southern Spain as the study system, given the wide distribution of wild forms in unmanaged systems and cultivated forms in agricultural systems, thus providing the opportunity to assess the effects of land use intensity.Notably, our study revealed that the conversion from natural to agricultural systems and even moderate increases in land-use intensity caused a significant biotic homogenization by enhancing the functional similarities of PFN communities. Our study emphasizes the key role of body size in structuring nematode communities in response to land-use type and intensity.Synthesis and applications. The importance of soil nematodes in soil processes is well known. We show that land use intensification reduces soil nematode diversity. Our study has important implications for the development of management strategies that foster soil biodiversity conservation such as no or minimal tillage and logging, vegetative covers and the maintenance of natural habitat.

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.

Sampling for needle nematodes was carried out in a grapevine area in Thessaloniki, North Greece and two nematode species of Longidorus (L. pauli and L. pisi) were collected. Nematodes were extracted from 500 cm3 of soil by modified sieving and decanting method, processed to glycerol and mounted on permanent slides, and subsequently identified morphologically and molecularly. Nematode DNA was extracted from single individuals and PCR assays were conducted to amplify D2-D3 expansion segments of 28S rRNA, ITS1 rRNA, and partial mitochondrial coxI regions. Morphology and morphometry data obtained from these populations were consistent with L. pauli and L. pisi identifications. To our knowledge, this is the first report of L. pauli for Greece, and the second world report after the original description from Idleb, Syria, extending the geographical distribution of this species in the Mediterranean Basin.

Specimens of a thin longidorid species collected in Peñalba (Huesca), north-west Spain, were previously described as Paralongidorus iberis. However, we conclude, through scanning electron microscopy and molecular studies on a population from about 15 km from the type locality and on paratype specimens, that this species was originally placed in the wrong genus. Both populations have pore-like amphidial apertures, not slit-like as in Paralongidorus, and the species is therefore transferred to Longidorus. Longidorus iberis n. comb. is regarded as a valid species and is clearly different from closely related species such as L. tabernensis, L. iliturgiensis, L. alvegus and L. indalus in morphometrics and molecular markers. Molecular data are reported for the first time, including the D2-D3 expansion segments of 28S rRNA, ITS1 rRNA, partial 18S rRNA and partial mitochondrial coxI regions. These molecular markers were used for inferring the phylogenetic relationships with other species within Longidorus and Paralongidorus, all clearly separating L. iberis n. comb. from other related taxa and placing the species in the Longidorus clade, rather than with Paralongidorus.