COMPARATIVE MORPHOLOGY OF THE SCOLICES AND MICROTRICHES AMONG 5 SPECIES OF TETRABOTHRIUS (EUCESTODA, TETRABOTHRIIDAE)

The structure of the scolex, neck, and adjacent strobila of 5 species of Tetrabothrius was evaluated using low to high magnification scannin g electron microscopy. Species-specific patterns and morphotypes (spin iform, papilliform, and filiform) of microtriches were found on the sc olices and strobilar tegument of Tetrabothrius (Oriana) affinis, Tetra bathrius (Oriana)filiformis, and Tetrabothrius (Culmenamniculus) lacco cephalus; microtriches were absent in Tetrabothrius (Culmenamniculus) cylindraceus and Tetrabothrius (Tetrabothrius) sp. The presence, distr ibution, and form of microtriches may not be correlated with the subge neric divisions of Tetrabothrius or the host taxon. Unique patterns do not appear to be shared with other groups of cestodes, particularly o ther tetraphyllideans. We suggest that the spiniform, filiform, and pa pilliform types of microtriches may be symplesiomorphic for the Eucest oda.