Life Cycle of Cloacitrema philippinum sp. n. (Trematoda: Digenea: Philophthalmidae)

Abstract

In a survey of larval trematodes infecting Cerithium ornata Adams, a snail from the mangrove swamps and fishponds in Navotas, Rizal, Philippines, two species of cercariae were found. One belonged to Acanthoparyphium paracharadrii Velasquez, 1964. The other, a megalurous cercaria, was found experimentally to be the larva of a new philophthalmid described as Cloacitrema philippinum sp. n. About 3% of 3,375 snails examined harbored the early developmental stages in their digestive glands. Encysted metacercariae, collected from the silt in finger bowls containing naturally infected snails, were fed to laboratory-raised chicks and ducklings. Experimental adults were recovered 12 to 15 days later from the cloaca of the hosts. Of the six species in the genus Cloacitrema Yamaguti, 1935, five have been described from the cloaca of birds. Cloacitrema ovatum Yamaguti, 1935, the type species, is from Bucephala clangula clangula (L.) in Japan. Cloacitrema michiganensis McIntosh, 1938, is from Actitis macularia (L.) and Himantopus mexicanus (Miiller) from Douglas and Munro lakes, Michigan, and Coral Gables (Tamiami Trail), Florida; also from Catoptrophorus semipalmatus inornatus (Brewster) and Larus californicus Lawrence, Playa del Rey, Los Angeles County, California, USA. Cloacitrema oswaldoi Travassos, 1940, is from Nyctianassa violacea (L.) in Brazil; and three species are from the USSR: C. deltoida Mamaev, 1959, from Tringa incana (Gmelin) in Siberia; C. marilae Cimbaluk and Leonov, 1963, from the cloaca and rectum of Aythya marila (L.) in Kamchatka; and C. pharyngeata Belopolskaia, 1963, from the body cavity of Tringa glareola (L.) and Limosa lapponica (L.)? in Nizhnii Amur. The only life cycle reported for a species of Cloacitrema is a preliminary one for C. michiganensis by Robinson (1952) who found early stages in Cerithidea californica Haldeman. MATERIALS AND METHODS From February 1965 to February 1967, 3,375 Cerithium ornata Adams were collected from estuarine mud flats and mangrove swamps near Received for publication 30 August 1968. * Supported in part by Research Grant AI-0660301, 02, 03 (656-M) NIH, U. S. Public Health Service, c/o Dr. I. E. Wallen, Head, Office of Oceanography and Limnology, Smithsonian Institution, National Museum; and a grant-in-aid from the Office of Research Coordination, University of the Philippines. fishponds at Navotas, Rizal, Philippines. Snails were kept in large finger bowls with a small amount of brackish water. The water was changed daily and the emerged cercariae were collected by means of pipettes. Both living and stained specimens were studied. Neutral red (0.5% aqueous solution) was used to stain living specimens. The early developmental stages were recovered from cracked, naturally infected snails. Rediae, cercariae, and metacercariae were fixed in hot 3% formalin, stored in 70% glycerine-alcohol, and later stained in precipitated Grenacher's borax carmine. The flame cell pattern was studied in cercariae that were allowed to encyst and then artificially excysted with fine needles 20 to 30 min later. Metacercariae, collected from the silt in finger bowls containing infected snails, were fed to laboratory-raised chicks and ducklings. Experimental adults and immature specimens recovered 12 to 15 days later from the cloaca of the experimental hosts were fixed in AFA and later stained in precipitated Grenacher's borax carmine. All measurements are in microns. Ten rediae were fixed without pressure, and 10 each of cercariae and metacercariae and 5 gravid adults were fixed under cover slips. Averages are in parentheses.