Additional data on Iranian trichodorids (Triplonchida: Trichodoridae) and proposal for a new synonymy

Abstract

Molecular data on several species of trichodorids occurring in Iran are provided. Live specimens of two species, Trichodorus arasbaranensis and T. gilanensis, were collected from their type localities. One population of T. orientalis was collected from Arasbaran forests in Eastern Azarbayjan province. The species Paratrichodorus porosus, occurring in Gilan province, and one European isolate of P. pachydermus were also included in phylogenetic analysis. An Iranian population of T. minzi, representing only the second population found of this rare species, was recovered from soil samples collected from grasslands of north-western Iran and is in morphological congruence with the original description of the species. Besides morphological study, molecular phylogenetic study was performed on newly reported species using partial 28S rDNA data, and the phylogenetic relations of all sequenced species as inferred from Bayesian analysis are discussed. According to the phylogenetic tree, two newly described species, T. golestanensis and T. iranicus, formed a clade and further studies revealed they have the same morphology and molecular sequences of 28S rDNA D2-D3. Accordingly, T. golestanensis is regarded as a junior synonym of T. iranicus according to the Principle of Priority.

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

“…Regional endemicity has been observed for Trichodorus and Paratrichodorus species. Subbotin et al (2019) stated that Californian populations of Trichodorus may be endemic originating in the same region, and hypothesized that this is an apparent centre of speciation, in addition to the Iberian Peninsula ( Decraemer et al 2013 ) and Irano-Anatolian region ( Pedram et al 2015 , 2017 , Asghari et al 2018 ). The distribution of trichodorids throughout Asia (except for Iran) is not well documented but in the distribution data of EPPO 2014 , trichodorids are either present or widespread in Afghanistan, Bahrain, China, India, Indonesia, Japan, Korea, Turkey, and Uzbekistan.…”

“…Previously, morphological identification alone rendered difficulties due to the mixed species complexes, phenotypic variation (such as shape of some sclerotized structures, e.g., stylet, male spicules, vagina with its sclerotized pieces), overlapping diagnostic characters and uniformity in general appearance; however, DNA-based strategies have made it possible to overcome the limitations of the morphological approach only and provided useful insights into trichodorid taxonomy ( Subbotin et al 2019 ). In recent years several nematologists have successfully applied rRNA genes sequence (18S, 28S, and ITS) analyses for studying the phylogenetic relationships of trichodorid species ( Duarte et al 2010 , Zhao et al 2013 , Pedram et al 2015 , 2017 , Decraemer et al 2019 ). The importance of sequence-based studies for species identification and the lack of molecular data of known species from China has led us to compile a detailed report of trichodorids occurring in the country.…”

“…Regional endemicity has been observed for Trichodorus and Paratrichodorus species Subbotin et al (2019). stated that Californian populations of Trichodorus may be endemic originating in the same region, and hypothesized that this is an apparent centre of speciation, in addition to the Iberian Peninsula (Decraemer et al 2013) and Irano-Anatolian region(Pedram et al 2015,…”

Molecular characterisation of some stubby root nematodes (Nematoda: Trichodoridae) from the USA and other countries

“…Recently, other apparent centres of speciation and diversification of Trichodoridae were found in the Iberian Peninsula and Irano-Anatolian region. At present, Spain contains the highest number of Trichodorus species per country (15 species) (Decraemer et al, 2013) followed by Iran with nine Trichodorus species recorded (Pedram et al, 2015;Asghari et al, 2018). However, we have to take into account that the recently differentiated species (e.g., from Iran, Spain) are based on a combined molecular and morphological approach.…”

“…The newly obtained sequences of the D2-D3 of 28S rRNA gene were aligned using ClustalX 1.83 (Thompson et al, 1997) with corresponding published gene sequences (Kumari & Subbotin, 2012;Zhao et al, 2013;Heydari et al, 2014;Pedram et al, 2014Pedram et al, , 2015Pedram et al, , 2017Asghari et al, 2018;Decraemer et al, 2018;Huang et al, 2018 and others). Outgroup taxa for each dataset were chosen based on previously published data (Kumari & Subbotin, 2012;Decraemer et al, 2018).…”