Ultrastructure of Karyakartia egyptensis Abdou, Dronen and Blend 2006 (Digenea: Lepocreadiidae) from the Red Sea fish, Terapon jarbua.

The tegumental surface of Karyakartia egyptensis Abdou, Dronen and Blend 2006, infecting the Red Sea fish, Terapon jarbua, is described using scanning and transmission electron microscope. Scanning electron microscopy showed that the mouth is surrounded by a single row of 14 digitform tegumental extensions that are seen protruding from the oral sucker. The tegumental surface is covered with posteriorly-directed, multidigitated, scale-like spines that arise from the tegumental enfoldings. Multidigitated spines with 11 to 22 digits are densely distributed on the first and second thirds of the body. Spines with 5 digits are less densely distributed on the tegumental surface of the ventral sucker. Uniciliated knob like sensory papillae and smooth tegumental ridges are observed on the tegument. These are particularly dense on the tegumental surface of the suckers. Transmission electron microscopy revealed that the distal cytoplasm contains tegumental spines at different developmental stages. Three types of membrane-bounded vesicles containing electron dense material: disc-shape opaque vesicles, ovoid electron opaque vesicles and electron lucent vesicles were described.