Helobdella longicollis

External morphology

Body narrow—particularly in the pregenital region— somewhat stout, lacking papillae or tubercles, and without a nuchal gland or nuchal plate. Gonopores separated by an annulus; male gonopore at XII a2. Anus at XXVI/XXVII. Somites I and II represented by a single annulus, sometimes subdivided; III and IV uniannulate; V bi- or triannulate; VI through XXIV triannulate; XXV biannulate; XXVI and XXVII uniannulate. Color uniform, slightly yellowish, without striations or maculae.

Internal morphology

Salivary glands compact, located in somite XIII. Crop provided with a pair of postceca in somite XIX, following a descending course as far as XX/XXI, and four pairs of mere cecal digitations in the anterior somites (XV through XVIII). Six pairs of testes. Vasa deferentia with an extensive descending course, transitioning abruptly into the spermatic duct at the recurrent limb, which extends as far as XVI/XVII or XVIII/XIX. The procurrent (or ascending) limb consists of the spermatic ducts and long ejaculatory ducts that empty into the atrial cornua. Ovaries located in somites XV and XVI, or XVI and XVII.

Habitat & range

Habitat

Freshwater

Region

South America

Recorded from

Paraguay, Argentina

Junior synonyms

Acritobdella longicollis