Comparative Study of the Tegumental Surface of Several Species of Gorgoderina Looss, 1902 (Digenea: Gorgoderidae), as Revealed by Scanning Electron Microscopy

Abstract

Seven species representing Gorgoderidae Looss, 1899, previously have been examined by scanning electron microscopy. This study describes the papillary pattern on the body surface of 6 additional species—Gorgoderina attenuata, Gorgoderina bilobata, Gorgoderina diaster, Gorgoderina megalorchis, Gorgoderina parvicava, and Gorgoderina megacetabularis—from localities in the United States, Mexico, and Costa Rica. Four types of papillae (button, ciliated, rosette, and domed) were distinguished on the body surfaces of these trematodes and both the type and position of papillae varied among species. A consistent papillary pattern on the ventral forebody region and oral and ventral suckers is described. Three constant pairs of button papillae are around the stylet cavity. The pattern on the oral sucker consists of 10 papillae around the oral aperture. One of these pairs was doubled in G. bilobata and G. diaster; in addition, a variable number of papillae arranged in groups were usually present. Five pairs of button papillae were always present in a lateral position on the ventral surface of the forebody between both suckers. Six rosette papillae were observed on the ring of the ventral sucker, except in G. megacetabularis; 4 additional pairs of rosette papillae and 2 pairs of domed papillae were observed on the internal surface of this sucker. These papillae were not observed in G. bilobata and G. parvicava. Differences in the papillary pattern among species lie in the position of the different types of papillae.