The Proboscis Hooks in Karkinorhynchidae and Gnathorhynchidae (Turbellaria, Kalyptorhynchia) as Basement Membrane or Intracellular Specializations

Abstract

Doe, D. A. (Department of Zoology, University of North Carolina, Chapel Hill, North Carolina 27514, USA.) The proboscis hooks in Karkinorhynchidae and Gnathorhynchidae (Turbellaria, Kalyptorhynchia) as basement membrane or intracellular specializations. Zool. Scr. 5 (3–4): 105–115, 1976.—The fine structure analysis of the proboscis hooks in the genus Cheliplana Beauchamp revealed that these structures are specializations within the basement lamina enclosing the proboscis. The fine structure analysis of the proboscis hooks in the genus Gnatho‐rhynchus Meixner revealed that these structures are intracellular specializations within a fold of epithelium located at the junction of the proboscis sheath and proboscis cone. The electron dense hook material is deposited primarily in microvilli along the outer cell surface of the cone epithelium. The fine structural analysis of the unarmed proboscis in the genus Proschizorhynchus Meixner agrees with the description for the armed schizorhynchs and these findings support the view that the Schizorhynchia is a monophyletic group. The fine structural analysis of the unarmed proboscis in Florianella bipolaris Rieger & Sterrer agrees with the description for Gnathorhynchus. A comparison of the proboscis and hooks in the two kalyptorhynch suborders suggests a more distant relationship between them. A discussion of the methods for the anchorage of intracellular, intercellular and extracellular hard structures is also included.

Hard Parts in the Female System of Syndesmis longicanalis (Platyhelminthes, Rhabdocoela, Umagillidae) Are Basement Membrane Derivatives

“…Hence Martens (1984) concluded that the basement membrane origin of the cirrus spines can be considered a synapomorphy for the Monocelididae (whereas hard parts of the copulatory organ in other Proseriata are of intracellular origin). The fact that teeth and hooks on the proboscis of the Schizorhynchia are basement membrane derivatives supports, according to Doe (1976), the view that the Schizorhynchia is a monophyletic taxon (implying that the intracellular formation of hooks in some of the Eukalyptorhynchia represents the plesiomorphic condition). The distribution of the two ways of formation of hard parts in the female systems of Platyhelminthes is yet to be investigated.…”

“…In Cheliplana sp. there are a number of hollow tubes within this middle layer (Doe 1976 , p. 106, figs. 2A,D).…”

“…(Rieger & Doe 1975), and Cheliplana sp. (Doe 1976)-on the one hand, and the stylet and spines of the cirrus of representatives of the proseriate family Monocelididae (Martens & Schockaert 1981;Martens 1984Martens , 1986 on the other hand.…”

Observations on the ultrastructure of the copulatory organ of Archilopsis unipunctata (Fabricius, 1826) (Proseriata, Monocelididae)

“…with the same appearence as the vasa deferentia and efferentiaunpublished data). Considering now the cirrus and its spines it has been revealed that hard structures in Turbellaria are either derivatives of the basement lamina, as the proboscis armature of Carchorodorhynchus and Diascorhynchus (Rieger & Doe 1975), or are intracellular condensations, as the proboscis hooks in Cheliplana and Gnathorhynchus (Doe 1976), the copulatory needles in Carenscoilia bidentata (Ehlers & Ehlers 1980) and the rods of the copulatory organ in Paratomella rubra (Mainitz 1977). A true cuticula, i.e.…”

Ultrastructure of the neodermal sclerites of Gyrocotyle urna Grube and Wagener, 1852 (Gyrocotylidea, Cestoda)

“…Furthermore, Bychowsky (1957) considered the distribution of the hard structures along whole body (like in Gyrocotyle) to be a primitive condition in conformity with monogenean evolution. However, no identical or equivalent sclerites have been found in turbellarians, digeneans, monogeneans and tapeworms (Lyons 1966;Doe 1976;Shaw 1981;Xylander 2001; see also Poddubnaya and Mackiewicz 2009 for the most recent literature review on digenean and cestode hard structures). Therefore, we support the earlier view of Xylander (2001) that the sclerites of Gyrocotyle with their typical shape, location within neodermal pockets and their laminated structure represent an autapomorphy of the Gyrocotylidea.…”