|
Thorny-headed Worms - Phylum: Acanthocephala
|
|
"I love parasites, I can't get enough of them." - Gary Larson, American writer, cartoonist and actor. (b. 1950).
|
The phyllum: Acanthocephala or Thorny-headed Worms, also known as Spiny-headed Worms or Scratch Worms, contain three classes of parasitic worms which according to recent studies are to be regarded as highly modified members of the Phylum: Rotifera. That being so the two phylla can then be joined to become the new phylum: Syndermata. For now they are treated here separately.
|
There are some 1,420 described species in the phyllum. It was the Italian Francesco Redi, considered by many to be the 'father of parasitology'; who provided the earliest known description of a species of the phylum. The name Acanthocephala was first proposed by Joseph Kolreuter in 1771 and later confirmed by Karl Rudolphi, a Swedish helminthologist in 1809.
|
Image 1. Electron Microscope image of Thorny-headed Worm head.
|
|
|
The oldest known examples of Acanthocephala were eggs found in Brazil in fossilised dung or coprolite (possibly from a crocodilyform) that date back some 70-80 million years. It is however quite possible that this group of organisms evolved earlier.
|
iNaturalist currently recognises three Classes in the phylum and despite there being 1,400+ species, sightings of the animals are uncommon. Some are small, only a few milimeters in length but, there are a few that can grow to as much as 65 centimeters long.
|
|
Records of sightings of Thorny-headed Worms in Australia are not all that numerous. The very nature of their habits demands specific expertise just looking for them. That is not to say though that they will for ever remain elusive in the Northern Rivers, although it is probably more likely that they will eventually be discovered in a marine or freshwater environment as Acanthocephalans begin their life as a parasite inside small invertebrates such as crustaceans or insects.
|
Until such time as positively identified photos of Acanthocephala are received they are not further dealt with here.
Gary Larson (see the quote at the top of the page) is the creator of "The Far Side" cartoons and as such he seems to be an unlikely contender to have an organism named after him but that is exactly what happened in 1989 when the evolutionary parasitologist, Dale Clayton, from the University of Utah, named a chewing louse in honour of Gary Larson. For more on that story, CLICK HERE.
References and links:
> Image 1. Amin, O. A, Heckmann, R. A & Ha, N. V. (2014) Acanthocephalans from fishes and amphibians in Vietnam, with descriptions of five new species. Parasite, 21, 53 doi:10.1051/parasite/2014052 licensed under the Creative Commons Attribution 4.0 International license downloaded for use here on 09/08/2022.
> Image 2. Anonymous image from the collection of the Biological-Medical Library of the University of Padova (Padua), Italy. https://phaidra.cab.unipd.it/o:351975
> Cardia, D.F.F., Bertini, R.J., Camossi, L.G., Letizio, L.A., (2019). 'First record of Acanthocephala parasites eggs in coprolites preliminary assigned to Crocodyliformes from the Adamantina Formation (Bauru Group, Upper Cretaceous), São Paulo, Brazil.' Anais da Academia Brasileira de Ciências. 91 (Suppl. 2)
> Perrot-Minnot, M.J., Cozzarolo, C.S., Amin, O., Barčák, D., Bauer, A., Marijic .V.F., García-Varela, M., S., Hernández-Orts, J.S., Yen Le, T.T., Nachev, M., Orosová, M, Rigaud T, Šariri, S., Wattier, R., Reyda, F., Sures, B., (2023). 'Hooking the scientific community on thorny-headed worms: interesting and exciting facts, knowledge gaps and perspectives for research directions on Acanthocephala.' Parasite. 2023;30:23. doi: 10.1051/parasite/2023026
> Shimek, R., (2006). 'Nano-Animals, Part I: Rotifers.' Reefkeeping.com. Accessed 28-07-2022.
> Zimmer, C., (2000). 'Parasite Rex.' Free Press, New York, United States.
https://en.wikipedia.org/wiki/Coprolite
https://en.wikipedia.org/wiki/Crocodyliformes
https://en.wikipedia.org/wiki/Francesco_Redi
https://en.wikipedia.org/wiki/Karl_Rudolphi
https://en.wikipedia.org/wiki/Joseph_Gottlieb_K%C3%B6lreuter
https://inaturalist.ala.org.au/taxa/151826-Acanthocephala
https://bie.ala.org.au/species/NZOR-6-53977#overview
https://attheu.utah.edu/facultystaff/the-far-side-of-science/
Header image:
An original public domain photomicrographic image released by Dr. Neil Campbell, Univ. of Aberdeen, Scotland.
An original public domain photomicrographic image released by Dr. Neil Campbell, Univ. of Aberdeen, Scotland.