Anatrichosoma buccalis sp. n. (Nematoda: Trichosomoididae) from the Buccal Mucosa of the Common Opossum, Didelphis marsupialis L.

Abstract

The worm is described from the mucosa of the hard palate, gums, and tongue of the common opossum, Didelphis marsupialis, from Louisiana, Costa Rica, and Colombia. The new species differs from other described species of the genus by its marsupial host, the unique location in the host, and certain morphological characters. The pathology and certain observations on the biology of this species are discussed. This is the first report of this genus from a host indigenous to the Western Hemisphere. Anatrichosoma gerbillis Bernard comb. n. is proposed for Trichosomoides gerbillis Bernard, 1964. Nematodes of the genus Anatrichosoma were recovered from the buccal mucosa of the common opossum, Didelphis marsupialis, from southern Louisiana, Costa Rica, and Colombia. The host and unique location of these parasites together with certain morphological characters provide the basis for the description of a new species of the genus Anatrichosoma. Nematodes were fixed in glacial acetic acid, stored in a mixture of 95 parts 70% ethyl alcohol and 5 parts glycerin, and studied in glycerin mounts after evaporation of the alcohol. In the following description all measurements are in millimeters unless otherwise indicated. The range of measurements and their means of the paratypes follow in parentheses the values for the holotype and allotype. Drawings were made with the aid of a camera lucida. Anatrichosoma buccalis sp. n. (Figs. 1-7) Description: Trichuroidea Railliet, 1916, Trichosomoididae York and Maplestone, 1926, Anatrichosomatinae Smith and Chitwood, 1954, Anatrichosoma Smith and Chitwood, 1954. With the characters of the genus. Small, slender nematodes. Received for publication 17 March 1972. * Supported in part by the Tulane University International Center for Medical Research and Training grant AI-10050 from the NIAID, NIH, U. S. Public Health Service. t Department of Tropical Medicine and Medical Parasitology, Louisiana State University Medical Center, New Orleans, Louisiana 70112. t Department of Tropical Medicine and Parasitology, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana 70112. Body of female increasing in diameter from anterior to posterior. Body of male uniform in diameter throughout most of length, slightly tapered at anterior and posterior extremities, diameter less than one-third that of female, length same as female or slightly longer. Cuticle thick, transparent, with two broad lateral bacillary bands extending entire length of body. Head with two lateral amphids, cephalic papillae absent or inapparent. Lips absent, oral opening dorsoventrally elongate, small stylet present. Cephalic inflation present in female, absent in male. Cuticle of female greatly thickened from just posterior to cephalic inflation to near end of second stichocyte. Nerve ring just posterior to cephalic inflation in female. Preglandular esophagus elongate, muscular. Anterior stichocytes longer than wide, gradually becoming larger, more compacted, and wider toward posterior extremity of esophagus. Intestine terminating in a small muscular rectum. Anus terminal. Vulva at level of or just posterior to last stichocyte, lips salient. Cloaca of male terminal, without spicule or spicule sheath. Posterior extremity of male with 2 small lateral papillae. Egg bipolar, thick-walled, with well-developed larva when laid. Female (based on holotype and 41 paratypes): 25.1 (17.3 to 34.0, 25.5) long, 215 (110 to 280, 192) pu in maximum width. Anterior region of body (anterior extremity to esophagointestinal junction) 3.6 (2.8 to 4.9, 3.7) long, 140 (85 to 165, 137) p wide at last stichocyte, muscular portion of esophagus 230 (150 to 265, 235) IA long, nerve ring 63 (55 to 67, 62) uf from anterior extremity, stichocytes 92 (71 to 93, 84) in number. Posterior region of body 21.5 (14.5 to 29.6, 21.7) long. Ratio of anterior body region to total length 1:7.0 (1:5.8 to 1:8.3, 1:6.9). Eggs 61 (53 to 70, 62) i long, 37 (32 to 40, 35) u wide. Male (based on allotype and 10 paratypes): 28.3 (22.0 to 29.0, 27.6) long, 55 (45 to 55, 50) )u maximum width. Anterior region of body 5.1 (3.6 to 5.2, 4.6) long, 45 (45 to 54, 49) u wide at last stichocyte, muscular portion of esophagus 220 (210 to 280, 226) /u long, nerve ring 64 (60 to 67, 64) u from anterior extremity, stichocytes 81 (74 to 86,