Molecular and morphological characterization of Paurodontoides siddiqii n. sp. (Nematoda: Hexatylina, Sphaerulariidae) associated with bark samples of Pinus eldarica from western Iran

Abstract

A new species of Paurodontoides, P. siddiqii n. sp., is described and illustrated based on its morphological, morphometric, and molecular characters. The new species is characterized by a female 550–729 μm long, lip region continuous with body contour, stylet length 7.0–8.0 μm long or c. 1.0–1.2 times the lip region diameter, lateral fields with four smooth incisures, excretory pore at 85–125 μm from anterior end located at the base of the pharyngeal bulb or posterior to it, basal pharyngeal bulb with a short posterior extension projecting into the intestine, monodelphic–prodelphic reproductive system with prominent 19–22 μm long post-uterine sac, and elongate conoid tail with a filiform terminus. The new species is compared with two known species of the genus. It differs from the type species of the genus, P. linfordi, by having slightly shorter stylet, lateral field with smooth incisures, different position of the excretory pore, and absence of male. Compared to P. latus, the new species has a shorter body, shorter stylet, different position of the excretory pore, female tail shape and absence of male. The new species was also compared with close species of the genus Paurodontus because of lateral field marked with four lines, asymmetrical stylet knobs and absence of male. Molecular phylogenetic studies of the new species using partial sequences of 18S rDNA revealed that it forms a clade with a species of the genus Ficotylus. In phylogenetic analyses using partial sequences of the 28S rDNA D2-D3 domain, the new species formed a monophyletic group with a species of the genus Veleshkinema and Sphaerularia spp. (Sphaerulariinae).

Molecular and morphological characterization of Paurodontella composticola n. sp. (Nematoda: Hexatylina, Sphaerulariidae) from Iran

“…asymmetrical/ symmetrical stylet knobs, the presence/absence of a deep vertical amphidial aperture covered by an auriform cuticular flap, a chamber-like structure surrounding the esophageal bulb/or simple, a short/long basal esophageal bulb stem attaching/projecting into the intestine, an oviduct branching to form an uterine diverticulum or not, PUS present, rudimentary, or absent, and leptoderan bursa (Siddiqi, 2000;Handoo et al, 2010). Handoo et al (2010) documented a diagnostic key for identification of the species of the genus: the presence/or absence of PUS and a uterine diverticulum in the oviduct branching are the most important characters for species delimitation under this genus. Yaghoubi et al (2018) listed the morphological characters for species delimitation within Paurodontella and closely related genus Paurodontus.…”

“…is an amphimictic species characterized by the following characters: a large body length of 803 to 1,053 μ m (females) and 620,739 μ m (males), lateral fields marked by four incisures, stylet 8 to 9 μ m long, stylet with minute and asymmetrical basal knobs, a short stem-like extension projecting into lumen of intestine, excretory pore being located at the level of esophageal basal bulb region ca 116 to 144 μ m from anterior end in females, the absence of a uterine diverticulum branch, V = 87 to 91, the presence of a short PUS, sub-cylindrical tail, rare male with 24 to 25 μ m long spicules and leptoderan bursa. According to Handoo et al (2010), species of Paurodontella can be divided into those with/without a uterine diverticulum. Due to the presence of a relatively long body, short PUS, shape of posterior body and a non-branching oviduct to form uterine diverticulum, the new species P. composticola n. sp.…”

“…According to Handoo et al (2010), species of Paurodontella can be divided into those with/without a uterine diverticulum. Due to the presence of a relatively long body, short PUS, shape of posterior body and a non-branching oviduct to form uterine diverticulum, the new species P. composticola n. sp.…”

“…The genus Paurodontella (Husain and Khan, 1968) is a diverse and worldwide distributed Paurodontid taxon. To date, Paurodontella contains 14 nominal species (Handoo et al, 2010;Esmaeili et al, 2016b;Yaghoubi et al, 2018), including P. aberrans (Nandakumar and Khera, 1969;Sumenkova, 1975), P. apitica (Thorne, 1941;Husain and Khan, 1968), P. asymmetricus (Tikyani and Khera, 1968;Sumenkova, 1975), P. densa (Thorne, 1941;Husain and Khan, 1968), P. minuta (Husain and Khan, 1968), P. niger (Thorne, 1941;Husain and Khan, 1968), P. sohaili (Maqbool, 1982), P. auriculata (Anderson, 1985), P. balochistani-ca (Handoo et al, 2010), P. myceliophaga (Handoo et al, 2010), P. iranica (Golhasan et al, 2016), P. persica (Esmaeili et al, 2017a), P. parapitica (Esmaeili et al, 2016b), and P. gilanica (Yaghoubi et al, 2018). Among these, P. iranica, P. persica, P. gilanica and P. parapitica were described from Iran.…”

“…Biologically, in Paurodontidae, a fungus-feeding generation is well known and nothing is known about entomoparasitic forms, whereas in Sphaerulariidae, an entomoparasitic form is present. Some other nematologists (Chizhov, 2004;Andrássy, 2007;Handoo et al, 2010) followed Siddiqi's opinion considering Paurodontidae as a synonym of Sphaerulariidae. In this study, Siddiqi's (2000) scheme was followed.…”