Hooks: 5-9; anterior teeth: 6-10; posterior teeth: 12-20.
Maximum adult body length: 13 mm; tail: 22-30 %.
Body slender, needle-like and firm, opaque; transversal musculature absent; head fairly narrow; hooks serrated both in juveniles and in adults. Fin bridge absent. Anterior fins of medium length, reaching to posterior end of ventral ganglion, partially rayed, angular; posterior fins long, partially rayed, angular. Collarette absent or very small; gut diverticula absent. Small eyes, with T-shaped pigment spot. Seminal vesicles with knob and trunk; position of seminal vesicles: between fins, nearly touching both posterior fins and tail fin when mature. Ovaries long, reaching anterior end of ventral ganglion or neck region; ova small. Adhesive papillae and adhesive organs absent. Apical glands absent.
Distribution: epipelagic; Atlantic between 40°N and 40°S.
Remarks: seminal vesicles with elaborate knob with two papillae.