Description of Geocenamus vietnamensis sp. n. (Nematoda: Merliniidae) from Vietnam

Abstract

A new species of the genus Geocenamus was isolated from soil and root samples from the rhizosphere of Casuarina equisetifolia (Casuarinaceae) in Quang Nam province, Vietnam. This species is characterized by a round-to-hexagonal labial disc, the presence of a labial region, which is continuous or slightly offset from the body with six sectors, lateral sectors of first labial annulus being smaller than the submedian sectors, the presence of six to seven labial annules; the absence of deirids; stylet length 24 to 28 μ m long, body length 776 to 979 μ m long; lateral field with six to eight lateral lines, without areolation at mid-body and with areolation in outer bands at the tail region and a pointed tail terminus. Geocenamus vietnamensis n. sp. most closely resembles G. boghiae in having a non-sclerotized head framework and lacking a bursa in the males. It can be clearly distinguished from all other species of the genus Geocenamus by these characteristics. The combination of morphology, morphometric features, and phylogenetic trees, based on D2-D3 of 28S and ITS rDNA sequences, showed that this new species can be clearly separated from all other sequenced species. This record is the first for Geocenamus in Vietnam.

Integrative taxonomy, distribution, and host associations of Geocenamus brevidens and Quinisulcius capitatus from southern Alberta, Canada

“…Sequenced genetic markers from the nematodes examined in the present study (after discarding primer sequences and ambiguously aligned regions), along with several stunt nematode sequences obtained from the GenBank database, were used in the phylogenetic reconstruction. Outgroup taxa for each dataset were selected based on previously published studies ( Handoo et al, 2014 ; Maria et al, 2020 ; Nguyen et al, 2019 ). Multiple-sequence alignments of the newly obtained and published sequences were made using the FFT-NS-2 algorithm of MAFFT V.7.450 ( Katoh et al, 2019 ).…”

A new stunt nematode, Geocenamus chengi n. sp. (Nematoda: Merliniinae) in the rhizosphere of tea (Camellia sinensis) from Zhejiang Province, China

“…The DNA sequences were compared with those of the other merlinids and related nematodes available at the GenBank sequence database using the BLAST homology search program. Outgroup taxa for the data set were chosen according to previously published data ( Handoo et al., 2014 ; Nguyen et al, 2019 ). Multiple alignments of the different sequences were made using the Q-INS-i algorithm of MAFFT v. 7.205 ( Katoh and Standley, 2013 ).…”

Diversity of plant-parasitic nematodes on medicinal plants in melinh station for biodiversity, Vinh Phuc Province, Vietnam

“…For morphological examination, nematodes were observed through a Olympus BX-51 light microscope equipped with a drawing tube and digital camera. To confirm morphological identification, ITS and 28S gene regions of nematodes were amplified and sequenced (Nguyen et al, 2019a); specific primers were used for Meloidogyne spp. (Randig et al, 2002).…”