TENTACULAR ARMATURE OF THE TRYPANORHYNCH CESTODE SYNBOTHRIUM-FILICOLLE (LINTON, 1890) (=PTEROBOTHRIUM-HETERACANTHUM DIESING, 1850) AND ITS TAXONOMIC SIGNIFICANCE

The armature of Synbothrium filicolle (Linton, 1890) is shown, based u pon examination of Linton's specimens, by light and scanning electron microscopy. This species, a junior synonym of Pterobothrium heteracant hum Diesing 1850, represents the species upon which the genus Pterobot hrium Diesing, 1850 was created, but details of the external surface o f the tentacular armature have never been established with certainty. A longitudinal band of spiniform microhooks on the external tentacular surface clearly distinguishes this species from the otherwise similar Pterobothrium acanthotruncatum Escalante and Carvajal, 1984. The band merges with a triangular group of uncinate hooks in the basal armatur e not previously described. The 2 Brazilian species, P. crassicolle Di esing, 1850 and P. heteracanthum, used in the creation of the genus, b oth possess an external band of hooks. Three different modifications o f the armature of the external surface have been described for species of Pterobothriurm. These include a discrete band of microhooks, small groups of microhooks contiguous with the intercalary rows, and the ab sence of a band of microhooks.