The morphological characters of Acanthostomum spiniceps, A. abscondihim and Orientocreadium lazeri studied using light
microscope, and were supported by the scanning electron micrographs which showed that the tegument of A. spiniceps is
covered by triangular spines till the anterior half of the body, while the rest is free of spines. The oral sucker spines are broad with pointed end and partially or totally ensheathed with a pitted tegument, while the mouth opening surrounded by a row of dome-shaped papillae. The tegumental spines of A. absconditum are of two types; the first is scally, indented, closely packed and arise in the anterior part of the first third of the body, followed by elongate indented spines. The oral sucker spines are elongated and narrower than those of A. spiniceps and ensheathed with the tegument till the second third of its length. In O. lazeri the tegument is covered by claw-like spines with blunt tips and arranged in transverse rows
and diminished posteriorly. The oral sucker carries sensory papillae while the ventral sucker is provided with small spines in addition to sensory papillae.