Genus Oxydirus
Thorne, 1939
Photo Gallery- Costa Rica

Belondiridae.  Neck tapering uniformly to the narrow rounded lip region which is not set off in any manner.  Tails of both sexes filiform.  Supplements consisting of an adanal pair and a numerous ventromedian ones.  Submedian papillae present.  Spear length about equal to lip regon width in both known species, the aperture occupying less than one-half of its length.  Esophagus enlarged near middle by gradual expansion the basal portion  surrounded by a sheath of broad spiral nuscles.  Ovaries one or two. Male prerectum extending anterior to supplement series.  Lateral cords usually about one-sixth as wide as body, the lateral pores apparently in two lines.

Type species: Oxydirus oxycephaloides (DeMan, 1921)

Diagnosis:  Belondiridae with the above general description.  The long slender tails of both sexes immediately distinguish it from all other Belondiridae except Swangeria from which it is differentiated by the structure of the pharynx and the form of the esophagus.

(Description- Thorne, 1939).

Specimens from Costa Rica
    Oxydirus sp. (1)