Orobdella Oka, 1895

Nakano, Takafumi, 2011, Redescription of Orobdella ijimai (Hirudinida: Arhynchobdellida: Gastrostomobdellidae), and two new species of Orobdella from the Ryukyu Archipelago, Japan, Zootaxa 2998, pp. 1-15 : 3

Genus Orobdella Oka, 1895

Emended diagnosis. Annulation of mid-body somite variable (complete quadr-, sex-, or octannulate). Post-anal annulus absent. Pharynx terminating in XIV or XVI. Gastropore at the nephridioporal annulus of XIII or in the annular furrow between nephridioporal annulus and neural annulus of XIII., or absent. Gastroporal duct single, joining with crop in XIV, or not joining with crop. Nephridiopores variable, 17–20 pairs. Male gonopore in the last annular furrow of XI, at the last annulus of XI, or at the penultimate annulus of XI. Female gonopore at the nephridioporal annulus of XIII or in the annular furrow between nephridioporal annulus and neural annulus of XIII. Gonopores separated by one full somite. Testisacs multiple per somite. Male median reproductive system in XI, being weakly muscularized atrium with atrial cornua (erpobdelloid) or without atrial cornua, without penis sheath or penis. Ovisacs globular, in XIII. Oviducts short, converging into common oviduct. Female median reproductive system essentially lacking (micromorphic).

Remarks. The genus Orobdella differs from the type genus, Gastrostomobdella , in the following characteristics: post-anal annulus absent (present in Gastrostomobdella ); Gastropore at XIII (XV); Gastroporal duct lies on female organ (behind female organ); ovisacs globular (elongated).

Type species. Orobdella whitmani Oka, 1895 .