Description and molecular characterization of Trachactinolaimus persicus sp. n. from Iran (Nematoda, Dorylaimida, Actinolaimidae), with new insights into the taxonomy and evolutionary relationships of the genus

A new species of the free-living nematode genus Trachactinolaimus, collected in natural habitats of northern Iran, is described, including morphological and molecular (28S-rDNA) data. Trachactinolaimus persicus sp. n. is characterized by its 1.95-2.44 mm long body, lip region weakly offset by depression and 18-20 μm wide, odontostyle 25-27 μm long, neck 540-636 μm long, pharyngeal expansion occupying one-half of the total neck length, bipartite uterus 2.6-3.9 body diameters long, vulva (V = 49-53) pore-like, tail long and filiform in both sexes (174-223 μm, c = 10.0-13.4, c' = 5.9-7.0 in females, 165-196 μm, c = 10.7-13.8, c' = 4.6-5.8 in males), spicules 68-75 μm long, and 12-14 almost contiguous ventromedian supplements with hiatus. Molecular data supports the monophyly of the genus and the hypothesis that Dorylaimidae are the sister group of actinolaims. The taxonomy of Trachactinolaimus is updated, including diagnosis, list of species, key to their identification, and a compendium of their main morphometrics. Dominiactinolaimus is regarded as its junior synonym.

Description of Acromoldavicus xerophilus n. sp. (Nematoda, Rhabditida, Elaphonematidae) from the southern Iberian Peninsula, including a key to species of the genus

A new species of the genus Acromoldavicus is described from coastal sand dunes and sandy soil in the southeast of the Iberian Peninsula. Acromoldavicus xerophilus n. sp. is characterized by its 557-700 μm body length, cuticle tessellated, lip region with three pairs of expanded lips bearing a large labial expansion, primary axils bearing guard processes with two different morphology, secondary axils lacking guard processes, stoma short and tubular with prostegostom bearing prominent rhabdia directed towards the stoma lumen, female reproductive system monodelphic-prodelphic, post-vulval sac 0.6-0.9 times body diameter, rectum very large, female tail short with biacute terminus and males unknown. The description, light micrographs, scanning electron microscope images, illustrations, and molecular analyses are provided. Molecular analyses (based on 18S and 28S rDNA) revealed its relationship with some species of the genera Cephalobus (18S tree), Nothacrobeles, Paracrobeles, and Spinocephalus (28S tree). Keys to species identification of this genus are also included.

Integrative taxonomy and phylogenetic relationships between representatives of genera within Merliniinae (Nematoda: Merliniidae), with new data on fourteen known and one unknown species

The application of integrative taxonomic approaches is useful to species delineation based on a combination of distinct types of characters, here morphological features and ribosomal DNA sequences. In this study, we surveyed ectoparasitic nematodes of the subfamily Merliniinae in cultivated and natural environments in Iran. Results of morphological and morphometrical studies, light and scanning electron microscopic observations, and molecular analyses allowed us the identification of fourteen known and one unknown species including representatives of the genera Amplimerlinius (five species), Geocenamus (one species), Merlinius (three species), Nagelus (two species), Paramerlinius (one species), Scutylenchus (two species), and Telomerlinius (one species). The unknown species, Scutylenchus sp., characterized by having 35-50 incisures at mid-body; lateral field with 6 longitudinal incisures; lip region slightly offset by a constriction, flattened at front end; bearing 5-7 annuli; cephalic framework not refractive; stylet robust, 18.3-27 μm long; post anal intestinal sac absent; tail elongate conical, dorsally convex, with 24 (19-28) annuli in ventral side, ending to a smooth terminus and males common; spicules 24.5-31 μm long. The phylogenetic analyses were carried out using molecular data from nuclear ribosomal DNA (rDNA) genes viz. D2-D3 expansion segments of the large ribosomal subunit (28S rRNA), partial small ribosomal subunit (18S rRNA), and internal transcribed spacer (ITS). The molecular variability of D2-D3 expansion segments of the 28S rRNA and partial 18S rRNA was low in this family in comparison to the ITS region, which could be a more helpful molecular marker in species and genus identification.

The enigmatic genus Loofilaimus (Nematoda, Dorylaimida, Loofilaimidae) revisited 25 years after, with remarkable new insights into its phylogeny

The evolutionary relationships of the nematode genus Loofilaimus are explored with an integrative approach, combining morphological and molecular (28S-rDNA) data. Never recorded since its original description in 1998, the finding of fresh specimens of its type and only species, L. phialistoma, allowed us to obtain SEM observations and sequencing, both for the first time, resulting in relevant aspects to elucidate its phylogeny. Morphologically, the genus is characterized by two autapomorphies affecting its lip region and pharynx. Molecular study revealed that it represents a very restricted evolutionary trend within Dorylaimida. The clade (Nygolaimina + (Loofilaimus + Dorylaimina)) is well supported. Loofilaimidae is accepted as a separate and valid family, which should also include Bertzuckermania.

Morphological and molecular characterization of Labronema montanum sp. n. (Dorylaimida, Dorylaimidae) from Spain

A new species of the genus Labronema, collected in a natural mountain habitat of the southern Iberian Peninsula, in Spain, is studied, including its morphological and morphometric characterization, SEM observations, and D2-D3 28S-rRNA sequences. Labronema montanum sp. n. is distinguishable by its 1.56 to 2.08 mm long body, with lip region being offset by constriction and 19 to 24 µm broad, odontostyle 21 to 29 µm long, neck 417 to 551 µm long, pharyngeal expansion 205 to 272 µm long, the presence of three cardiac lobes at the pharyngo-intestinal junction, a long and tripartite uterus, longitudinal vulva (V = 57-60), a short and rounded caudal region (19–35 µm, c = 56-86, c = 0.5-0.8), spicules 65 to 76 µm long, and 20 to 25 nearly contiguous ventromedian supplements with hiatus.

A low-cost technique to manufacture a container to process meiofauna for scanning electron microscopy

An easy and low-cost method to elaborate a container to dehydrate nematodes and other meiofauna in order to process them for scanning electron microscopy (SEM) is presented. Illustrations of its elaboration, step by step, are included. In addition, a brief methodology to process meiofauna, especially nematodes and kinorhynchs, and illustrations are provided. With this methodology it is possible to easily introduce the specimens, to lock them in a closed chamber allowing the infiltration of fluids and gases (ethanol, acetone, carbon dioxide) but avoiding losing the specimens. After using this meiofauna basket for SEM the results are efficient. Examples of nematode and kinorhynch SEM pictures obtained using this methodology are also included.

<i>Bathyodontus mirus</i> (Andrássy, 1956), primera cita de un representante del suborden Bathyodontina (Nematoda, Mononchida) en la fauna ibérica

Se estudia la especie Bathyodontus mirus (Andrássy, 1956) Hopper y Cairns, 1956, recolectada en dunas de arena en el suroeste peninsular. Se presentan una descripción, medidas e ilustraciones (fotografías con microscopía óptica). Los ejemplares ibéricos se comparan brevemente con otras poblaciones conocidas de la misma especie. Y se ofrece un compendio de las especies del género Bathyodontus, incluida una clave para su identification. Se trata de la primera cita de un miembro del suborden Bathyodontina en el ámbito Ibero-balear y en la región Mediterránea.

Nematodes of the Order Rhabditida from Andalucía Oriental, Spain. The Genera Protorhabditis (Osche, 1952) Dougherty, 1953 and DiploscapterCobb, 1913, with Description of P. spiculocrestata sp. n. and a Species Protorhabditis Key

A new species of the genus Protorhabditis is described from natural areas in the SE Iberian Peninsula. Protorhabditis spiculocrestata sp. n. is distinguished by its body length 387-707 mum in females and 375-546 mum in males, lip very low and flattened, stoma 14-22 mum long, female tail conical-elongate (48-100 mum, c = 6.4-8.3, c' = 4.8-7.5), phasmid near anus, male tail conical (20-27 mum, c = 18.3-22.3, c' = 1.4-1.5), bursa peloderan closed anteriorly and bears eight papillae (1+2+1+1+3), spicules 23-26 mum long, and gubernaculum 10-16 mum long. Diploscapter coronatus is also presented. Description, measurements and illustrations, including SEM photographs, are provided. A key to species of Protorhabditis is also given as well a compendium of their measurements.

Description and SEM Observations of Stegelletina coprophila sp.n. (Nematoda: Rhabditida) from Caves of Andalucía Oriental, Spain

A new species of the genus Stegelletina is described from caves of Andalucía Oriental (SE Iberian Peninsula). Stegelletina coprophila sp. n. is characterized by its body 386 to 536 mum long in females and 391 and 521 mum in males, lateral field with three incisures, lips bearing four tines, labial probolae 4 to 6 mum long and bifurcate, pharyngeal corpus 1.5 to 2.9 times isthmus length, spermatheca 18 to 43 mum long, postvulvar sac 0.5 to 1.6 times the corresponding body diameter long, female tail conical (24-34 mum, c = 14.2-17.2, c' = 1.7-2.3), male tail conical (26-35 mum, c = 12.1-17.1, c' = 1.4-1.8), spicules 20 to 25 mum long, and gubernaculum 10 to 13 mum long. Descriptions, measurements and illustrations, including SEM photographs, are provided for the species.

Nematodes of the order rhabditida from andalucía oriental, Spain. The genera nothacrobeles allen &noffsinger, 1971 and zeldia thorne, 1937

A new species of the genus Nothacrobeles is described from natural areas (a salt lake) in the Southeast Iberian Peninsula. Nothacrobeles lanceolatus sp. n. is characterized by its body length, two rows of cuticular punctations per annulus, labial probolae bifurcate with divergent prongs, pharyngeal corpus 2.4 to 3.5 times isthmus length, spermatheca length, postuterine sac 0.5 to 1.1 times the corresponding body diameter ratio, female tail conical and bearing a spindle-shaped or conical mucro with acute terminus, phasmid at 8 to 17 microm posterior to the anus, male tail conical with acute mucro, spicules length, and gubernaculum length. In addition, Nothacrobeles cf. lunensis and Zeldia punctata are studied. Cervidellus capricornis is transferred to genus Nothacrobeles. A key to species of Nothacrobeles is also provided.