Five new and five known species of the genus Tylencholaimus de Man, 1876 (Nematoda: Dorylaimida: Tylencholaimoidea) from Western Ghats of India

Five new and five known species of the genus Tylencholaimus de Man, 1876 are described from the Western Ghats of India. Tylencholaimus macroamphidius sp. nov. has a 0.61–0.85 mm long body, angular lips, large amphid, 8.0–9.0 μm long odontostyle, odontophore with asymmetrical basal knobs, pharyngeal bulb expanding gradually, female genital system mono-prodelphic, and a rounded to conoid tail. Tylencholaimus shamimi sp. nov. has a 0.57–0.71 mm long body, 6.0–7.0 μm long odontostyle, odontophore with basal thickening, pharyngeal bulb expanding gradually, female genital system amphidelphic and a convex-conoid tail. Tylencholaimus southindicus sp. nov. has a 0.44–0.55 mm long body, lip region with distinct labial disc, 4.5–5.5 μm long odontostyle, odontophore with minute basal knobs, pharyngeal expansion abrupt, female genital system mono-prodelphic, and a rounded-conoid to rounded tail. Tylencholaimus striatus sp. nov. has a 0.30–0.34 mm long body with distinctly striated cuticle, 5.0–5.5 μm long odontostyle, odontophore with minute basal knobs, pharyngeal bulb expanding abruptly, female genital system mono-prodelphic, and a conoid tail with bluntly rounded terminus. Tylencholaimus tamiliensis sp. nov. has 0.51–0.58 mm long body, 5.5–6.0 μm long odontostyle, odontophore with minute basal knobs, pharyngeal bulb expanding gradually, female genital system mono-prodelphic and tail rounded to conoid with sunken terminus. Five known species of the genus Tylencholaimus viz. T. mirabilis, T. teres, T. micronanus, T. ibericus and T. cosmos also recorded from the region and redescribed/illustrated.

A new genus and species of the family Microlaimidae (Nematoda: Chromadorea) from intertidal sand of the Jeju Island, South Korea

As a part of the study of marine nematofauna of a sandy intertidal zone of Jeju Island (South Korea), a number of species have been proven as new for science. Here a new species representing a new genus of the family Microlaimidae (Chromadorea), Jejulaimus sinyangensis gen. n., sp. n. is described. The new monotypic genus is characterized by head set off abruptly from the body; anterior sensilla pattern 6+10, where six outer labial setiform sensilla together with four longer cephalic setiform sensilla are integrated in a common crown; pharyngostoma armed with a dorsal tooth and surrounded by convex muscular pharyngeal tissue, forming an anterior pharyngeal bulb which is distinctly set off from the rest of the pharynx; terminal pharyngeal bulb oval; ventral pore and ampulla of the excretory-secretory gland situated just posterior to the nerve ring; an only anterior testis present. The new genus bears some resemblance to the genera Bolbolaimus, Pseudomicrolaimus and Spirobolbolaimus in having an anterior pharyngeal bulb and in the position of the ventral pore of the excretory/secretory gland, but differs from them by anterior sensilla pattern 6+10, absence of subventral teeth in buccal cavity, and monorchic condition of male reproductive system.

Description of Ditylenchus acantholimonis n. sp. (Rhabditida: Anguinidae) from Iran, a morphological and molecular phylogenetic study

Summary Ditylenchus acantholimonis n. sp. is described based on morphological, morphometric and molecular characters. It was isolated from the rhizosphere soil of Acantholimon sp. in Golestan province, Iran, and is mainly characterised by having four lines in the lateral field, a pyriform to bottle-shaped offset pharyngeal bulb, post-vulval uterine sac 36.6-56.1% of the vulva to anus distance long, and a subcylindrical to conical tail with widely rounded tip. It is further characterised by short to medium-sized females, 480-617 μm long, with a fine stylet having small rounded knobs, V = 80.8-83.6, c = 11.0-13.8, c′ = 3.3-4.6, and males with 16.0-17.0 μm long spicules. The new species was morphologically compared with six species having four lines in their lateral field, rounded tail tip and comparable morphometric data namely: D. dipsacoideus, D. emus, D. exilis, D. paraparvus, D. sturhani, and D. solani. It was also compared with two species, D. ferepolitor and D. angustus, forming a maximally supported clade in the 18S tree. The phylogenetic analyses using the maximal number of Anguinidae and several Sphaerularioidea genera based upon partial 18S and 28S rDNA D2-D3 sequences revealed that Ditylenchus is polyphyletic. In the 18S tree, the new species formed a clade with D. ferepolitor (KJ636374) and D. angustus (AJ966483); in the 28S tree it formed a poorly supported clade with D. phyllobios (KT192618) and Ditylenchus sp. (MG865719).

Further data on Iranian marine nematode diversity, with description of three new Desmodoridae Filipjev, 1922 (Nematoda: Desmodorida) species from the Persian Gulf

Summary The Desmodoridae is a diverse and widespread family of free-living nematodes. Here, we provide the first record of the group in the Persian Gulf and describe three new species: Metachromadoroides sinuspersici sp. n., Zalonema iranicum sp. n. and Z. supplementorum sp. n. Metachromadoroides sinuspersici sp. n. is characterised by finely annulated cuticle, short and stout cephalic sensilla, amphidial fovea on cuticular thickening, pharyngeal bulb well developed and partitioned into three sections, absence of precloacal supplements, and presence of 6-8 pairs of rounded postcloacal papillae. Zalonema iranicum sp. n. is characterised by papilliform subcephalic sensilla (best observed with SEM), convex cephalic capsule, large multispiral amphidial fovea with 4-5 turns in both males and females, buccal cavity with one ventrosublateral and two dorsal teeth and posterior body of males with lateral alae extending from the last third of the body to the cloacal aperture and ventral alae extending 1395-2250 μm anterior to the cloacal aperture, and no precloacal supplements. Zalonema supplementorum sp. n. is characterised by four subcephalic sensilla 1-2 μm long, multispiral amphidial fovea with three turns in both males and females, buccal cavity with one dorsal and two ventrosublateral teeth, males with lateral alae present on each side of body from posterior half of body to cloacal aperture, ventral alae extending 942-1257 μm anterior to cloacal aperture, strongly cuticularised spicules 41-43 μm long, and 12-16 precloacal supplements. Near full length SSU and partial D2-D3 LSU sequences are provided for M. sinuspersici sp. n. and Z. iranicum sp. n., and the COI sequence is provided for Z. iranicum. The SSU phylogeny suggests a close relationship between M. sinuspersici sp. n. and Metachromadora and Metachromadoroides species and the monophyly of Zalonema (after currently available data). The LSU phylogeny suggests an affinity between Metachromadoroides and Zalonema with Spirinia and Acanthopharynx, respectively.

Distribution of trichodorid species in mainland China with description of Trichodorus hangzhouensis sp. nov. (Nematoda, Triplonchida)

Seven trichodorid species including a new one (Trichodorus hangzhouensissp. nov., T. nanjingensis, T. pakistanensis, T. cedarus, Paratrichodorus porosus, Nanidorus renifer and N. minor) were recovered from the rhizosphere of different hosts in 13 provinces of China. Each of the recovered species was characterized based on morphology and molecular data using rRNA gene sequences. Trichodorus hangzhouensissp. nov. is characterized by its males having medium-sized onchiostyle (46–49 µm) and three ventromedian cervical papillae (CP) anterior to the secretory-excretory (S-E) pore, CP1 located opposite the anterior part of isthmus, S-E pore opposite the isthmus or anterior end of pharyngeal bulb, spicules slightly ventrally curved, relatively small, 33.2 (32.0–34.5) µm long, wider slightly marked capitulum, lamina partially striated without bristles at striation; and females having rounded triangular sclerotized vaginal pieces with tips directed towards vulva, 1.5–2.0 µm sized, at about 1 µm apart, vulva pore-like in ventral view. Phylogenetic analysis based on D2-D3 28S rRNA gene sequences differentiated the new species among Trichodorus species from Europe, Asia and USA which formed a large clade. A review of the distribution of Trichodorus, Nanidorus and Paratrichodorus species revealed that T. cedarus, T. nanjingensis, T. pakistanensis and P. porosus are the most widespread species recorded from different provinces of China. This is the first extensive study of trichodorid species occurring in China.

New and known species of Nothotylenchus Thorne, 1941 (Nematoda: Anguinidae) from Iran with an updated list of species

During a survey conducted during 2013–2017, five known and two new species of Nothotylenchus Thorne, 1941 were collected from the southern provinces of Iran. N. brzeskii n. sp. is characterised by a body length of 774–922 µm, lateral fields with four incisures, delicate, short stylet (7–8 µm) with small rounded knobs, pyriform, offset or slightly overlapping basal pharyngeal bulb, posterior vulva position (V = 83.4–84.4), short PUS (5–10 µm), spicules 20.5–23 µm long, and thick tail with rounded to dull terminus. N. siddiqi n. sp. is characterised by a body length of 573–645 µm, six to nine incisures in lateral fields, delicate, short stylet (6.5–7.5 µm) with rounded knobs, pyriform or slightly elongate and offset basal pharyngeal bulb, V = 79.3–81.0, PUS = 26.5–40 µm, short spicules = 14.5–16.5 µm, and tail with rounded terminus. Morphometric data of the studied species are presented and intraspecific variation of their morphometrics and morphological characters is discussed. The list of world Nothotylenchus species is updated, and a dichotomous identification key and an updated tabular compendium for 41 valid species are provided.

Description of Ditylenchus paraparvus n. sp. from Iran with an updated list of Ditylenchus Filipjev, 1936 (Nematoda: Anguinidae)

During a survey, 12 known and one new species of Ditylenchus Filipjev, 1936 were collected from southern provinces of Iran during 2013–2017. Ditylenchus paraparvus n. sp. is characterised by a short body length (441–543 µm), lateral field with four lines, delicate and short stylet (6–7.5 µm) with small rounded or posteriorly sloping knobs, pyriform and offset basal pharyngeal bulb, V = 67.7–76.4, short post-vulval uterine sac less than one vulval body width long, small spicules (12.5–15 µm) and almost cylindrical tail (71–90 µm) with rounded end. Morphometric data of studied species are presented and intraspecific variation of their morphometrics and morphological characters is discussed. The list of the world Ditylenchus species is updated, and a dichotomous identification key and an updated tabular compendium for 63 valid species is provided.

Meplitumen aluna gen. nov., sp. nov. an interesting eutardigrade (Hypsibiidae, Itaquasconinae) from the Sierra Nevada de Santa Marta, Colombia

A new genus of Itaquasconinae, Meplitumengen. nov., and a new species, Meplitumenalunasp. nov., are described. The new genus has characters present in other genera of Itaquasconinae but in a unique combination. The spiral thickening of the bucco-pharyngeal tube is also present anteriorly to the insertion point of the stylet supports, excluding only the short portion where the apophyses for the insertion of the stylet muscles (AISM) are present. This character is similar to Astatumen Pilato, 1997 but Meplitumengen. nov. differs from this genus as stylet furcae are shaped differently and as stylet supports and placoids are present. The presence of a spiral thickening in a portion of the buccal tube anterior to the stylet supports distinguishes the new genus from Mesocrista Pilato, 1987, Platicrista Pilato, 1987 and Itaquascon de Barros, 1939. Meplitumengen. nov. also differs from Mesocrista, in having the caudal processes of the AISM pointing laterally (instead of postero-laterally), and the apices of the caudal processes of the stylet furcae unswollen. From Itaquascon the new genus also differs by having more robust stylet supports, pharyngeal bulb with placoids, stylet furcae differently shaped. Meplitumengen. nov. also differs from Platicrista in having caudal processes of the AISM more robust and not flexible, and more slender stylet supports. The new species, Meplitumenalunasp. nov., has a cuticle with a very faint roughness at the caudal extremity of the body, and eyes probably absent. The pharyngeal bulb is long, with two long, narrow, rod-shaped macroplacoids; a microplacoid and septulum are absent. The claws are well developed with main branches provided with accessory points, and at the base of the claws, a structure interpretable as a very thin lunule is present. Other cuticular thickenings on the legs are absent.