Diplolaimelloides woaabi sp. n. (Nematoda: Monhysteridae): A Novel Species of Free-Living Nematode from the Great Salt Lake, Utah

A new species of free-living nematode inhabiting microbialites in Great Salt Lake, Utah, USA is described both molecularly by 18S-sequencing and morphologically with scanning electron microscopy and differential interference contrast (DIC) microscopy. Diplolaimelloides woaabi sp. nov. (family Monhysteridae, order Monhysterida) is characterized by a combination of the following characters: ocelli present; a relatively small body size (<1.5 mm); short anterior sensory setae; cryptospiral amphidial fovea; a funnel-shaped anterior buccal cavity and reduced secondary cavity; fused lips; long double spicules and conspicuous male bursa displaying four pairs of post-cloacal papillae arranged in a (2 + 2) pattern, a single mid-ventral pre-cloacal papilla, two pairs of papillae posterior to the bursa, and an additional offset mid-tail papillae pair; and a pair of sub-apical extensions on spicules. An updated key to all species of Diplolaimelloides Meyl, 1954 is given. This species is notable for its adaptation to hypersaline microbialites, positioning it as both an extremophile and a potential bioindicator of ecological change in Great Salt Lake.