Morphology and molecular systematic of marine gregarines (Apicomplexa) from Southwestern Atlantic spionid polychaetes

RUECKERT, S.; GLASINOVICH, N.; DIEZ, M.E.; CREMONTE, F.; VÁZQUEZ, N.

JOURNAL OF INVERTEBRATE PATHOLOGY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 2018 vol. 159 p. 49 - 60

0022-2011

Gregarines are a common group of parasites that infect the intestines of marine invertebrates, and particularlypolychaetes. Here, we describe for the first time four gregarine species that inhabit the intestines of three spionidspecies: Dipolydora cf. flava, Spio quadrisetosa and Boccardia proboscidea from the Patagonian coast, Argentina,using light and scanning electron microscopy and molecular phylogenetic analyses of small subunit (SSU) rDNAsequences. Even though the spionid species thrive in the same environments, our results showed a high hostspecificity of the gregarine species. Selenidium cf. axiferens and Polyrhabdina aff. polydorae were both identifiedfrom the intestine of D. cf. flava. The new species, Polyrhabdina madrynense sp. n. and Selenidium patagonica sp. n.,were described from the intestines of S. quadrisetosa and the invasive species B. proboscidea, respectively. Allspecimens of D. cf. flava and S. quadrisetosa were infected by gregarines (P = 100%), recording the highest meanintensity values of infection (MI = 80; 60 respectively), in contrast to B. proboscidea (P = 60%; MI = 38). Weassociated this finding with the recent invasion of this host. It is expected that in the future, an increase of itspopulation density might favour a rising intensity of this gregarine infection.