Paraorientatractis semiannulata n. g., n. sp. (Cosmocercoidea: Atractidae) from the Large Intestine of the SideNecked Turtle, Podocnemis unifilis Troschel, 1848 (Testudines: Pelomedusidae) in Brazil
Vol. 92(3): 359-364
Lynda M Gibbons/+, LF Khalil, CJ Marinkelle*
International Institute of Parasitology, CAB INTERNATIONAL, 395A Hatfield Road, St Albans, Herts AL4 0XU, UK *Universidad de los Andes, Apartado Aéreo 4976, Bogota, Colombia
Specimens collected from the large intestine of the sidenecked turtle Podocnemis unifilis Troschel, 1848 in the region of Cuminá and Trombetas rivers near Pará, 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.
Key words: Nematoda Atractidae Paraorientatractis n. g. Paraorientatractis semiannulata n. sp. Podocnemis Brazil
The genus Podocnemis Wagler, 1830 accomodates turtles referred to as the hiddennecked turtles or sidenecked turtles found in South American rivers. The genus belongs to the order Testudines and the family Pelomedusidae. A survey undertaken by one of us (CJM) in the region of the Cuminá and Trombetas rivers near Pará, Brazil resulted in the collection of large numbers of an atractid nematode from the large intestine of Podocnemis unifilis. Nine species of nematodes have so far been reported from Podocnemis spp. (Table). A comparison of the specimens described herein with the species listed revealed that they had distinct differences which separated them from these species and consequently a new genus and new species are proposed to accomodate them.
ACKNOWLEDGEMENTS
To Dr A Petter of the Museum National d'Histoire Naturelle, Paris for making available type specimens of Orientatractis levanhoai for examination and Mr Richard Tranfield of the International Institute of Parasitology for his assistance with the preparation of the scanning electron micrographs.
+Corresponding author. Fax: +44-1727-86.8721
Received 4 December 1996
Accepted 19 February 1997
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