Incomplete Fragmentation of Giant Tegument Nuclei in Acanthellae of Acanthocephalus tenuirostris (Palaeacanthocephala, Echinorhynchida)

The giant nuclei of the tegument of Acanthocephalus tenuirostris show incomplete fragmentation at the late acanthella stage. This process is preceded by the transformation of the nuclei and their acquisition of a tree shape. Thin connections between the fragments of the tegument nuclei are preserved in both cystacanth and adult acanthocephalans. It is assumed that such an organization of the nuclear apparatus ensures the vital activity of the tegument, the volume of which increases repeatedly during the subsequent growth of the acanthocephalan.