Found this specimen of about 3 cm long and 5 mm width along a freshwater brook in the province of Limburg, The Netherlands. I have seen millions of freshwater invertebrates from our country and I consider myself a specialist on annelids (leeches, oligo- and polychaetes) but I don't thing it is either of them. The only thing I can think of is some sort of (free living?) tapeworm. As it is collected with a pondnet, it is not sure if this is truly aquatic. It is flattened and gradually becoming smaller towards the end or head? Is it decapitated? Does anybody has an idea? many thanks
edit: I can't see an oral/anal opening, chaetae are absent.
Ton that is a neat find, and out of my wheelhouse. I have passed it along to a colleague to see if he has any answers.
Somehow my last answer disappeared. Short version is you need to stain and/or clear this specimen for more anatomical details. Only microscopic oncospheres/ coracidia are free living stages of cestodes Rarely adult or metacestodes will be expelled to exterior. Also look into expelled pentastomids.
Ton, this is not my field of expertise, but as you see no openings, could it be a string of eggs?
Recently, I have seen photos of the cestode Schistocephalus solidus, parasite of sticklebacks, which look remarkably similar. However, these are of course not free-living and not normally present outside the hosts. It seems worthwhile to look into this and similar species.
Through mediation of Ate-Alma Cohen from Naturalis (Leiden) I have got an answer from Tomáš Scholz (Institute of parasitology (Czech Rep.) and as I'm not an expert on this subject I only did understand the first word :-) : "Yes, it is the diphyllobothriidean cestode Schistocephalus solidus. It is difficult to say whether it is metacestode (i.e. larva called plerocercoid) from the body cavity of three-spined stickleback (Gasterosteus acuelatus) or from the definive host, a fish-eating bird. In fact, plerocercoids grow long time and are almost completely developed excepot for production of eggs, which is confined to the intestine of the bird definitive host.".
- Badges
- Science method
- Similar topics
- Biological Science
- Ecology