Association between the parasitic larvae of the sea-anemone Peachia sp. with hydromedusae from temperate waters in the Southwestern Atlantic Ocean

PUENTE TAPIA, F. A.; GARESE, A.; DELPIANI, S. M.; ACUÑA, F. H.; GENZANO, G. N.

Marine Biodiversity

Springer

Año: 2021 vol. 51

1867-1616

Medusae have a great variety of biological interactions with different groups, including endo-ectoparasites such as sea anemone larvae. The purpose of the present study was described the seasonality of the association between the parasitic larval phase of the sea anemone Peachia sp. with the hydromedusa Liriope tetraphylla and Eucheilota ventricularis from Mar del Plata, Argentina. The interaction was observed in the austral warm period with temperatures ranging between 12 and 22.3 °C. Eucheilota ventricularis recorded the 57.89% of the total larvae, while L. tetraphylla the 41.10%. Prevalence in E. ventricularis was 1.92% while in L. tetraphylla was 0.44%. Intensity interval ranged between 1-2 sea anemones per host. Parasitized organisms in both host species were significantly larger than non-parasitized. A significant positive correlation was observed between the umbrellar diameter of both host species with the prevalence and intensity of infection. Peachia sp. was observed in different body host regions, varying in relation of the host specimen, but mainly adhering to the ex-umbrellar surface. The morphology of three phases of Peachia sp. are provided. The cnidom of sea anemone was composed of spirocysts, basitrichs, holotrichs I and II, and microbasic b-mastigophores, while the nucleotide frequencies identified (based on a fragment of the cytochrome c oxidase subunit 1 gen in the mitochondrial genome, CO1) were composed by A= 24.6%, T/U= 32.9%, C= 19.7%, and G= 22.9%.