Heterodiplostomum cf. lanceolatum Dubois, 1936

Aguiar, Aline, Morais, Drausio Honorio, Firmino Silva, Lidiane A., Anjos, Luciano Alves Dos, Foster, Ottilie Carolina & Silva, Reinaldo José Da, 2021, Biodiversity of anuran endoparasites from a transitional area between the Atlantic Forest and Cerrado biomes in Brazil: new records and remarks, Zootaxa 4948 (1), pp. 1-41 : 18

Heterodiplostomum cf. lanceolatum Dubois, 1936

Hosts (prevalence; range): L. podicipinus (4/225; 2–4) and P. platensis (1/38; 2).

Site of infection: cavity and hindlimb muscles

Stage: metacercaria encysted

Type host and type locality: Erythrolamprus sp. (= Coluber sp.) ( Colubridae ), Brazil.

Comments: the genus Heterodiplostomum comprises only two species: Heterodiplostomum lanceolatum and Heterodiplostomum helicopsis Mañé-Garzón & Alonso. Both metacercariae are morphologically similar to their respective adults with exception to the maturity of sexual organs and the absence of eggs ( Queiroz et al. 2020). These proterodiplostomids have a flat forebody and a cylindrical hindbody which harbor the reproductive organs at the end of this region ( Dubois 1936 and Queiroz et al. 2020). Moreover, we observed characteristics such as caeca finishing before copulatory burse, vitellaria extending posteriorly before holdfast organ, a very small oral sucker and a globular pharynx which is larger than oral sucker (see Dubois 1936 and Queiroz et al. 2020); these combination of features led us to identify our specimens as Heterodiplostomum cf. lanceolatum . However, we recognize the importance of molecular tools to confirm the species, especially immature parasites which share many morphological features. Amphibians usually act as an intermediate host in the cycle of this parasite which uses snakes as definitive hosts. Pseudis platensis is a new host for this metacercaria and other anuran hosts in South America are L. podicipinus ( Queiroz et al. 2020) and L. chaquensis ( Hamann et al. 2006) .