Genus Belonolaimus
Steiner, 1949

Diagnosis:  Dolichodorinae.  Body elongate-cylindroid, straight when relaxed.  Lateral field a single incisure when viewed in cross section.  Lip region with 8 or 10 annules, set off by constriction in known species.  However, on certain undescribed forms the lip region is not set off.  From a face view the lip region is observed to be quadrangular, with four rounded lips formed by deep indentations on the dorsal, ventral, and lateral sectors.  Labial disc circular.  Amphids out near head contour, deep in the lateral clefts.  One conspicuous papilla observed on each sublateral lip.  Spear 100 u long or more, with well-developed knobs.  Basal part of esophagus extending in lobes back over anterior end of intestine.  Junction of esophagus and intestine an obscure muscular valve.  Hemizonid anterior to excretory pore.  Ovaries two, outstretched.  Testis single, outstretched.  Bursa enveloping tail.
(Description- Thorne, 1961)

Definition:   Belonolaiminae.  Head offset, annulated, 4-lobed.  Spear very long.  Procorpus with long coiled lumen.  Dorsal oesophageal gland opening close to spear base.  Ovate median bulb clearly set off, wth large crescentic valve plates.  Isthmus short, expanding to a spathulate glandular lobe overlapping the intestine.  Lateral field absent save for a median line.  Female tail cyindrical, about 3 body-widths long with rounded tip; phasmids about 1/2 tail-length; gonads paired, opposed, outstretched; spermathecae present.  Male tail long, surrounded by voluminous bursa; phasmids 1/3 tail-length.  Spicules arcuate with ventral flanges.  Gubernaculum with titillae.
(Description- Goodey, 1963)

Belonolaiminae. SEM face view shows a well marked, rounded labial disc, and first lip annulus divided into six sectors, lateral sectors almost completely regressed, seen only as small interruptions of the first one or two labial annuli. Labial region marked by deep longitudinal grooves. Stylet very long, 60-150 um long, its cone 70-80% of total stylet length. Corpus as in Morulaimus. Oesophageal glands overlapping beginning of intestine. Female tail cylindroid with a broadly rounded terminus. Lateral field with four lines or less.
(Description- Fortuner and Luc, 1987)

Type Species:  Belonolaimus gracilis Steiner, 1949

Species list: