Latronema whataitai sp n. (Nematoda: Selachinematidae) from intertidal sediments of New Zealand, with notes on relationships within the family based on preliminary 18S and D2-D3 phylogenetic analyses

摘要

Latronema whataitai sp. n. is described from intertidal sediments of Hataitai Beach, North Island of New Zealand, and its placement within the Selachinematidae investigated using 18S and D2-D3 molecular sequences. Latronema whataitai sp. n. is characterised by relatively slender body (a = 22-25), outer labial setae and cephalic setae of similar length, anterior buccal cavity with three sets of seven teeth with larger central tooth positioned above the other six, circular amphid with faint outline, males with 12-13 precloacal supplements and spicules with pointed projection near distal end, and tail 2.0-2.6 anal body diam. long. The cuticle ultrastructure of the genus is investigated for the first time using scanning electron microscopy. Molecular phylogenies of near full length small subunit and D2-D3 expansion segments of the large subunit rRNA genes do not provide support for the division of Selachinematidae into the subfamilies Selachinematinae and Choniolaiminae, and do not support a close relationship between Latronema and Richtersia despite some morphological similarities. These preliminary results are based on a small number of molecular sequences, and therefore the current morphology-based classification remains the most tractable system for the Selachinematidae until more comprehensive analyses are conducted.