Morphological and Molecular Characterization of Labrys filiformis n. sp. (Rhabditida: Tylenchidae) from Iran

Abstract

Labrys filiformis n. sp., the second species of the rare genus Labrys, was recovered from natural forests of Gilan province and is described based upon morphological and molecular characters. The new species is characterized by its smooth cuticle under light microscopy, lateral field with two incisures forming a single plain band, lip region continuous with body contour, dorso-ventrally flattened and forming four poorly prominent lobes, having a dorso-ventrally narrower protuberant labial plate laterally extended to the amphidial margins, oral area (oral plate) dorso-ventrally elongated and embedded in the labial plate with six small labial sensilla surrounding the slightly prominent oral aperture, amphidial apertures as longitudinally lemniscatic slits bordered by the labial plate extensions which are overlapped at the middle length of amphids, stylet delicate, 6 to 7 µm long, elongate weakly developed fusiform median bulb with weak valve, wide excretory pore with long and heavily sclerotized duct, offset spermatheca filled with small spheroid sperm cells, 106 to 127 µm long elongate-conoid tail with filiform distal region and finely rounded tip. Molecular phylogenetic analyses were performed using a near-full length fragment of the 18S rDNA and the D2-D3 expansion segments of the 28S rDNA using Bayesian inference and maximum likelihood methods. In the inferred phylogenetic tree with 18S rDNA, the new species has a close affinity with several isolates of the type species, Labrys chinensis. The reconstructed phylogenetic tree using partial 28S rDNA, revealed the new species is nested inside the putative monophyletic group of several populations of L. chinensis.

An integrative study of Sakia sisanganensis n. sp. (Rhabditida: Tylenchidae) from Sisangan forest, Iran, and new morphological observations for the genus

“…Troccoli and Geraert (1995) reported a population of S. indica from Papua province of Indonesia which has a median bulb with a developed valve, elongate cylindrical pharyngeal bulb and a filiform tail, which is narrower at the distal end. It seems that the Papuan population has remarkable differences compared with the type population of S. indica , specifically the Papuan population has a distinct Labrys ‐type cephalic region and the labial disk (Konani, Panahandeh, Pourjam, Álvarez‐Ortega, & Pedram, 2018; Panahandeh, Abolafia, et al, 2018b; Qing & Bert, 2018) (see Figure a in Troccoli & Geraert, 1995). Therefore, only the original data of S. indica were used in our morphological comparisons.…”

“…Following our continuing study of tylenchid nematodes in cultivated and natural habitats of northern Iran (the history in Panahandeh, Pourjam, et al, 2018a; Panahandeh, Abolafia, et al, 2018b), one population of the genus Sakia was recovered from decaying bark and wood samples from undisturbed Sisangan forest in northern Iran. The species is herein described as S. sisanganensis n. sp.…”

Morphological and molecular data of two species of the rare genera Thada Thorne, 1941 and Tenunemellus Siddiqi, 1986 (Nematoda: Tylenchidae) from Iran

“…The taxonomic studies on the members of the family Tylenchidae reported from Iran are well documented and discussed in Karegar (2018). Some other species of the genera Miculenchus Andrássy, 1959 (Panahandeh et al ., 2019a), Coslenchus Siddiqi, 1978 (Hosseinvand et al, 2019), Labrys Qing & Bert, 2018 (Panahandeh et al ., 2018, 2019b), Sakia Khan, 1964b (Panahandeh et al ., 2019c), Basiria Siddiqi, 1959 (Eisvand et al ., 2019) and Malenchus Andrássy, 1959 (Jalalinasab et al ., 2019) have since been reported or described from Iran through morphological and molecular studies. The present study aims to describe the newly recovered species, named Thada populus n.…”

Cephalenchus driekieae n. sp. (Nematoda: Tylenchidae) from South Africa, a new member of the genus with a long pharyngeal overlap

“…Its members are commonly found in vast ecological niches viz . soil, algae, fungi, and plant material ( Panahandeh et al, 2018 ). Currently, approximately 44 genera and 412 species are known in this family ( Qing and Bert, 2019 ).…”

“…Traditionally, most tylenchids were identified based solely on morphological characters ( Geraert, 2008 ), which led to taxonomic confusions within the family ( Qing and Bert, 2019 ). However, in recent years, DNA-based techniques have been extensively used for taxonomic studies of tylenchids ( Bert et al, 2010 ; Pereira and Baldwin, 2016 ; Pereira et al, 2017 ; Pedram et al, 2018 ; Panahandeh et al, 2018, 2019 ; Qing and Bert, 2019 ).…”