Trypanoxyuris (Trypanoxyuris) minutus (Nematoda: Oxyuridae) in the two howler monkeys species (Cebidae) from Mexico

Trypanoxyuris (Trypanoxyuris) minutus Schneider, 1866 is morphometrically characterized, based on 4 males and 35 females found in fecal samples of the 2 Mexican species of howler monkeys: Alouatta palliata mexicana Merriam, 1902 (Los Tuxtlas, Veracruz) and Alouatta pigra Lawrence, 1933 (Palenque, Chiapas). This work shows micrographs of the parasite morphology in light and electron microscopy. Its identification was based on the presence of a quadrangular cephalic plate, which makes the species different from the other 7 species in the subgenus Trypanoxyuris. We noticed that there were 3 equidistant longitudinal ridges on the eggs surface which form, in apical view, a triangular contour with rounded corners.