Two New Species of Free-living Marine Nematodes (Nematoda: Axonolaimidae and Tripyloididae) from the Coast of Antarctica

Abstract

Two new species of free-living marine nematodes, Odontophora odontophoroides sp. nov. and Parabathylaimus jare sp. nov., are described from the coastal sand of Langhovde, Lützow-Holm Bay, Dronning Maud Land, Antarctica. Odontophora odontophoroides sp. nov. is the only species in Odontophora Bütschli, 1874 that has bicuspidate odontia. Odontophora odontophoroides sp. nov. is similar to species in Odontophoroides Boucher and Helléouët, 1977 and Synodontium Cobb, 1920 in having bicuspidate odontia, but differs in having a didelphic reproductive system in females. Parabathylaimus jare sp. nov. differs from congeners in the unjointed inner labial and cephalic sensilla, the outer labial sensilla three-jointed in males and two-jointed in females, the position of the amphids, the shorter spicules, and the conical tail without long subterminal setae. Modified generic diagnoses and keys to species are included for Odontophora and Parabathylaimus De Coninck and Schuurmans Stekhoven, 1933. A new combination, Parabathylaimus arthropappus (Wieser andHopper, 1967) comb. nov., is established.

Three Free-Living Marine Nematodes from Sagami Bay, Japan, with a Description of Wiesoncholaimus jambio sp. nov. (Nematoda: Oncholaimidae)

“…A biological dredge onboard the research vessel Rinkai-Maru (Misaki Marine Biological Station, the University of Tokyo) was used to collect the specimens during the 12 th JAMBIO Coastal Organism Joint Survey. The methods used for sorting, fixation, and preparation for differential interference contrast microscopy were previously described by Shimada and Kakui (2019), and the methods used for taking photomicrographs and measurements were previously described by Shimada et al (2021). All examined specimens were deposited in the Invertebrate Collection of Hokkaido University Museum (ICHUM), Sapporo, Japan.…”

A new species of free-living marine nematode, Fotolaimus cavus sp. nov. (Nematoda, Oncholaimida, Oncholaimidae), isolated from a submarine anchialine cave in the Ryukyu Islands, southwestern Japan

“…We considered that these individuals belonged to the same species in the family Oncholaimidae. Three males and four females were permanently mounted in anhydrous glycerin (Shimada et al 2021), observed using a BX51 light microscope (Olympus, Japan) with differential interference contrast, and photographed with an PCM500 digital camera (AS ONE, Japan). One male and one female were dried using the hexamethyldisilazane method (Nation 1983), sputter-coated with gold to a thickness of 20 nm, and observed using an S-3000N scanning electron microscope (SEM; Hitachi, Japan).…”

“…oxyuris Ditlevsen, 1911, Oncholaimus cf. vesicarius (Wieser, 1959, Wiesoncholaimus jambio Shimada & Kakui, 2021, Adoncholaimus daikokuensis Shimada & Kajihara, 2014, and Adoncholaimus pseudofervidus Shimada & Kajihara, 2014, for phylogenetic analysis (Table 1). Total DNA was extracted using an ISOHAIR extraction kit (NIPPON GENE, Japan) following the protocols described by Tanaka et al (2012) and Iwahori (2014) with minor modifications.…”