Abursanema, Yaghoubi, Ali, Pourjam, Ebrahim, Pedram, Majid, Siddiqi, Mohammad Rafiq & Atighi, Mohammad Reza, 2014

Yaghoubi, Ali, Pourjam, Ebrahim, Pedram, Majid, Siddiqi, Mohammad Rafiq & Atighi, Mohammad Reza, 2014, Description of Abursanema iranicum n. gen., n. sp. (Nematoda: Hexatylina, Sphaerularioidea) from Iran and its phylogenetic relationships, Zootaxa 3826 (2), pp. 301-314 : 304-305

Genus Abursanema n. gen.

Description. Body straight or slightly ventrally arcuate after fixation, less than 1mm long. Cuticle thin, outer cuticle smooth, inner cuticle finely annulated. Lateral field narrow, with two incisures. Head low, flattened, framework six-sectored, lateral sectors narrower than submedian ones. Amphidial apertures not clearly observed. Stylet short, without basal knobs, dorsal arm of the shaft slightly longer than the ventral one. Orifice of dorsal pharyngeal gland located close to stylet base, at ca 1–2 µm distance. Corpus cylindroid, metacorpus spindleshaped, lacking cuticular thickening or valve, isthmus short, terminal bulb large, pyriform, with three pharyngeal glands and a stem-like extension projecting into the lumen of intestine. Excretory pore opening from near base of isthmus to opposite basal bulb. Vulva at 66–75% of total body length, more than two body widths distance from anus in type species. Ovary single, prodelphic, outstretched anteriorly, usually reflexed twice at proximal end, cells in single row, spermatheca rounded to ellipsoid, filled with spheroid sperm, postvulval uterine sac less than corresponding body width in length. Tail conoid with narrow terminus, similar in both sexes. Spicules simple, slightly arcuate, 18–23 Μm long in type species. Gubernaculum arcuate. Bursa absent. Entomoparasitic infective females not found.

Diagnosis and relationships. In the above-mentioned morphological and biological characters, Abursanema n. gen. belongs to the superfamily Sphaerularioidea and family Paurodontidae . The new genus is distinguished from all other valid genera in the family Paurodontidae by the absence of a bursa.

It can also be distinguished from Paurodontus by having a stylet without basal knobs (vs stylet with rounded and symmetrical knobs), and by having two incisures in lateral field (vs four or six).

The new genus differs from Misticius by the absence of stylet knobs (vs stylet with prominent symmetrical basal knobs), having two incisures in lateral field (vs absence of lateral field), and by having the excretory pore opening near base of isthmus to opposite basal bulb (vs near the stylet base).

When compared with Neomisticius , the new genus differs by the absence of stylet knobs (vs stylet with prominent symmetrical basal knobs), excretory pore opening opposite terminal bulb (vs near the base of stylet) and by having a longer tail (vs a short, subcylindrical one with a small projection at its tip).

It differs from Paurodontella by the absence of stylet knobs (vs stylet with basal knobs) and the presence of short postvulval uterine sac (vs absence).

Abursanema n. gen. is close to Paurodontoides , but differs by the absence of stylet knobs (vs stylet with asymmetrical basal knobs) and by having a head with six sectors (vs eight).

From Luella , the new genus differs by having two incisures in the lateral field (vs absence), and structure of the base of the terminal bulb (vs bulb offset and stem-like, basal extension absent).

The genus Bealius has a stylet with knobs, a stem-like basal pharyngeal bulb extension projecting into the intestine dorsally, no lateral field or postvulval uterine sac, dissimilar tail shape in female and male, and spicules with a bifurcate tip in comparison with the new genus.

Based on molecular data, the new genus has sequences similar to those of Sphaerularia Dufour, 1837 . However, it differs from the free-living phase by absence of a bursa in male and by having a stem-like basal extension in pharyngeal bulb projecting into the intestine (vs basal pharyngeal bulb abutting or slightly overlapping the intestine).

Based on male characters (especially lacking of bursa), the new genus is similar to Gymnotylenchus Siddiqi, 1961 , but is clearly different in having a stylet without basal knobs, extension of the basal pharyngeal bulb into the intestine (vs pharyngeal glands forming an elongate diverticulum extending over intestine dorsally or subdorsally), junction of pharynx and intestine posterior to nerve ring (vs anterior to nerve ring), two incisures in lateral field vs six, and structure of the spicules (tylenchoid vs prominently cephalated) and presence of a gubernaculum (vs absence).

Type habitat and locality: Recovered from bark samples of dead Populus alba L. collected in village of Sorkh Abad, Hamedan province, western Iran, during April 2013.

Type material: Holotype male, 7 paratype males and 17 females deposited in the Nematode Collection of the Faculty of Agriculture, Tarbiat Modares University, Tehran, Iran. Three male and three female paratypes deposited in each of the following collections: CABI Europe-UK, Egham, Surrey, UK; USDA Nematode Collection, Beltsville, MD, USA; Department of Nematology, Agricultural University, Wageningen, the Netherlands.