Molecular and morphological characterisation of the metacestode Anthobothrium sp. infecting Loligo vulgaris from Tunisian coasts.

Cestode larvae of Anthobothrium sp. were collected from the caecum and stomach of the common squid Loligo vulgaris Lamarck, 1798 (Cephalopoda: Loliginidae) in Tunisian waters (Bay of Bizerte and Gulf of Tunis), with the highest prevalence recorded in the Gulf of Tunis (52.94%). These specimens were morphologically characterised and compared to previously described Anthobothrium larvae from other hosts. Molecular analysis using 28S ribosomal DNA (rDNA), combined with phylogenetic reconstruction (maximum likelihood and pairwise distances), revealed that the sequences cluster with adult specimens from several elasmobranch species. These definitive hosts include Carcharhinus obscurus and Carcharhinus limbatus, which are common in Tunisian waters, thereby providing new insights into the potential life cycle of this parasite. Loligo vulgaris represents a new host record for Anthobothrium sp. larvae and appears to be its preferred cephalopod host in the Mediterranean. Finally, a comprehensive checklist of metacestodes recorded in L. vulgaris is provided.