An interesting rare tylenchid species, Antarctenchus urmiensis n. sp. (Tylenchomorpha; Psilenchidae) from Urmia Lake islands, northwest Iran, with a discussion on the taxonomy of related genera

Abstract

A population of an amphidelphic tylenchid nematode was recovered from Urmia Lake islands in association with native shrubs of the region. It had a Tylenchidae-type cloacal bursa in male and looked morphologically similar to the genera under the family Psilenchidae sensu Siddiqi, representing a new species, described and illustrated in present study as Antarctenchus urmiensis n. sp. It is characterized by the slender body at anterior region, gradually narrowing toward posterior end. Four lines in lateral fields in extremities, increasing to six at mid-body. Deirids at secretoryexcretory pore (S-E pore) level and phasmids at 38-62% of the tail. Low-expanded cephalic region having a moderately sclerotized cephalic framework, continuous with body, and not flattened dorso-ventrally. Finely annulated cuticle. Amphidial apertures porelike. Short (13-15 µm long) stylet, its conus 35-42% of the total length and three small tear-drop like knobs. Pharynx with ellipsoid metacorpus and small valve, small saccate pharyngeal bulb offset from intestine. Reproductive system didelphic-amphidelphic, vulva with no membrane or epyptigma. Tail conical, not elongate or filiform, usually slightly ventrally bent, with a sharp or blunt tip and a small indentation at dorsal side close to tip. Males with similar anterior body region and tail to those of female, tylenchoid spicules and small cloacal bursa. In molecular phylogenetic analyses using partial small and large subunit ribosomal DNA (SSU and LSU rDNA D2-D3) sequences, the new species appeared as an independent lineage between the clades of Hoplolaimina sensu Siddiqi and the clades of Atetylenchus spp. + Psilenchus spp. in the SSU phylogeny. In LSU phylogeny, it placed in a clade including representatives of Atetylenchus, Psilenchus, Amplimerlinius, Pratylenchoides, Nagelus, and Geocenamus.The currently available phylogenies and taxonomic frameworks were re-evaluated for the placement of the didelphic Tylenchidaelike genera, the overall results showing the best resolution is achieved with the family concept of Psilenchidae under Dolichodoroidea.

Description of Boleodorus bushehrensis n. sp. (Rhabditida: Tylenchidae) from Southern Iran, and Observations on a Commonly Known Species

“…In the SSU- and LSU-based phylogenetic trees, representatives of Boleodorinae formed a clade (although with poor support in the SSU phylogeny) except for the genera Psilenchus De Man, 1921 and Atetylenchus (Boleodorinae sensu Geraert, 2008 , well suitable to be placed under Psilenchidae Paramonov, 1967 , see Amiri Bonab et al ., 2021 ). The other genera of the subfamily Boleodorinae sensu Geraert (2008) apparently have close phylogenetic affinities based on these two ribosomal markers.…”

“…The subfamily Boleodorinae Khan, 1964 belongs to the family Tylenchidae Örley, 1880 and includes eight valid genera ( Geraert, 2008 ; Yaghoubi et al ., 2016 ; Amiri Bonab et al ., 2021 ). Currently, Boleodorus Thorne, 1941 represents the largest genus of the subfamily and contains 33 species ( Munawar et al ., 2021 ), all of which were described using traditional, morphology-based methods.…”