A new land planarian species of the genus Othelosoma (Platyhelminthes: Tricladida: Terricola: Rhynchodemidae) from the eastern highlands of Zimbabwe

Abstract

A new species of rhynchodemid flatworm, Othelosoma nyanga, is described from Rhodes Nyanga National Park in the eastern highlands of Zimbabwe. Live flatworms are yellow, with a faint dark central line dorsally and appear cylindrical in photographs. They were found under dead wood stumps in grassland. Preserved worms are cylindrical, and up to 22 mm long and 2.5 mm wide. A dorsal anterior retractor muscle causes the head to be strongly retracted in preserved specimens. Ventrally, there is a narrow, ciliated creeping sole. There is well-developed parenchymal longitudinal musculature. Ovaries are anterior. The two ovovitelline ducts fuse posterior to the gonopore and form two further ducts. One short duct runs anteriorly and opens into the common antrum, above the gonopore. The other runs posteriorly, with a short connection to a large bursa, and continues posteriorly before entering the rear of the common antrum. The penis is exceptionally long and extends into a posterior extension of the antrum.