Morphological and molecular characterization of n. sp. (Nematoda: Actinolaimidae) from Korea, with an updated compendium of the genus.

A new species of the genus isolated from the bark of a dead red pine tree was characterized using morphometric data and molecular DNA barcodes. n. sp. was characterized by its medium sized body 2.50 to 2.98 mm long; lip region truncate, angular and offset by a depression; odontostyle 23.5 to 27.0 μm long; basal shield of pharynx present; vulval opening wide and longitudinal, positioned slightly anteriorly (V = 42.5-47.7); several advulval papillae; female tail long and filiform (324.0-435.0 μm long, c' = 10.1-14.2); a clearly visible copulatory hump; spicules 60.0 to 70.5 μm long; 12 to 15 (mostly 12-14) large contiguous ventromedian supplements, and male tail conoid to broadly rounded. The new species was morphologically compared with , and . The phylogenetic relationships among species were reconstructed using 18S- and 28S-rRNA gene sequences. The phylogenies showed well-supported sister relations of n. sp. with and . In addition, the ITS-rRNA gene sequences of n. sp. were supplied, representing the first characterization of the gene for the genus.