Haliplectus is a coastal marine nematode present at inter tidal zones, salt marshes and sand dunes. At Saaftinghe Land, a salt marsh in the south-west of the Netherlands, numbers of 25 million per square meter have been found.
The narrow sclerotized buccal cavity with distinct cheilorhabdions and a small denticle at the base followed by a narrow pharynx tube suggests a bacterial feeding behaviour. The pharynx has a small oval-shaped anterior bulb, a tubular istmus and a large rounded muscular basal bulb with a distinct valvular apparatus. For species identification the number and position of supplements (or papillae), present just in front of the cloaca, is important.