Specimens collected from the large intestine of the sidenecked turtle
Podocnemis unifilis Troschel, 1848 in the region of Cumina and Trombetas
rivers near Para, Brazil are assigned to a new genus and new species of the
nematode superfamily Cosmocercoidea and family Atractidae and named
Paraorientatractis semiannulata. The new genus is separated from the
nearest genus Orientatractis by the funnelshaped mouth opening, the
presence of 4 distinct lips, 4 papillae in the internal cycle, one on each
lip margin, 2 lateral amphids with large amphidial pores and absence of
submedian papillae. It is also separated from Orientatractis and
Proatractis by the presence of striated lateral alae which curve dorsally
extending from mid oesophagus to mid tail, the difference in size of the
vulvar opening and the presence of large transverse ridges or semiannules
on the dorsal surface. The new species can be separated from the species of
the genera Orientatractis and Proatractis by the characters that
distinguish the genera and the arrangement of the caudal papillae on the
male. A host/parasite list for Podocnemis spp. is included.