Líffræðifélag Íslands - biologia.is
Líffræðiráðstefnan 2023

Piridium sociabile - the inconspicuous commonplace parasite

Höfundar / Authors: Ásthildur Erlingsdóttir (1), Mark Freeman (2), Nóa Sólrún Guðjónsdóttir (1) and Árni Kristmundsson (1)

Starfsvettvangur / Affiliations: 1. Tilraunastöð Háskóla Íslands í meinafræði að Keldum, 2. Ross University School of Medicine

Kynnir / Presenter: Ásthildur Erlingsdóttir

Piridium sociabile (P. soc) is an evolutionary unique marine parasite, found in the foot of the common whelk (Buccinum undatum). P. soc. was described by Ruth Patten (1936) and originally thought to be an apicomplexan parasite, but has recently been demonstrated to be an ancestor of all Apicomplexa and most closely related to the photosynthetic free-living chromerids, which are associated with coral reefs. Little has been done to gain further insight into the biology of P. soc. prior to this project. The aim of the project was to determine the geographical distribution of P. soc. around Iceland and detect other potential host species.
575 common whelks were collected around Iceland along with 258 individuals of 25 mollusc species. Samples were dissected and analyzed using a stereoscope, microscope and histology.
The results showed a great abundance and high prevailance of P. soc. around Iceland along with a surprising number of other host species, which are parasitized by P. soc. related organisms. This indicates that P. sociabile is a prevalent parasite of the common whelk and has a relatively wide distribution. Also, as an ancient or ancestral parasitic form, it has likely parasitized common ancestors of gastropod species and co-evolved with these hosts during speciation events.