Abstract
Syphacia (Syphacia) sulawesiensis n. sp. and S. (S.) muris (Yamaguti 1935) were recorded from Rattus xanthurus (Gray 1867) in North Sulawesi, Indonesia. Syphacia sulawesiensis is readily distinguished from other members of the subgenus Syphacia and from those for which a subgeneric position has yet to be settled in that it has large vesicular lateral alae, an excretory pore positioned well to the rear, a short tail and apices of caudal papillae posterior to the midtail level in the male, and closely-set excretory pore and vulva in the female. This is the second species of the genus Syphacia Seurat 1916 found to be parasitic in Rattus Fischer 1803. The females of S. muris from R. xanthurus have a much larger body than those reported previously from other murid species.