New species of avian schistosomes from Argentina: from Gondwanaland to gulls

LORENTI ELIANA; DIAZ, JULIA I.; CREMONTE, FLORENCIA; GILARDONI, CARMEN; BRANT, SARA

Otro; 2018 ASP Meeting; 2018

In the blood fluke family Schistosomatidae, the diversity and natural history of the marine speciesare less well-known than the fresh water species. Most of the diversity of marine schistosomes hasbeen reported from gastropod intermediate hosts, the focus on this host in part because of their rolein transmitting species that cause cercarial dermatitis (swimmer?s itch). As part of a larger effortto discover and describe the schistosome diversity in Argentina, avian hosts spend some time inmarine habitats were examined. Two species gulls were examined, the kelp gull (Larus dominicanus)and the brown-hooded gull (Chroicocephalus maculipennis). The former species is found throughoutthe southern hemisphere, populations largely sedentary in fresh and marine waters, and the latterspecies is a South American endemic, populations spending most time in freshwater habitats andintertidal marshes, but also in marine coast. Two different species of schistosomes were recovered,one from each of the two species of gull hosts. These schistosomes were different both geneticallyand morphologically. Schistosomes from L. dominicanus from Patagonia marine coast has neitheroral nor ventral suckers and the male has a short gynaecophoric canal without transversal bands.Conversely, schistosomes from C. maculipennis from Buenos Aires province, a northern inland site,also has neither oral nor ventral suckers, but the gynaecophoric canal of the male is longer and beginsfurther down from the anterior end than that of the former species. The molecular phylogeneticresults showed two distinct clades. The first clade is a species that has been found previous inArgentina from both Larus and the marine gastropod, Siphonaria lessonii, as well as is aligned with aspecimen from penguins from South Africa. The second clade is unique and did not group with anydefined species or clade, other than members of the large freshwater clade of long, thin adult wormsthat use a diversity of freshwater, and some marine, gastropods. Not surprisingly, the diversity anddistribution of these schistosomes is correlated with the vagility and distribution of their bird hosts.Such that worms from hosts distributed in the southern hemisphere are more closely related toeach other than species from northern hemisphere. However, how these current distributions mightrelate to the gastropod evolutionary history and presence in the supercontienent, Gondwanalandmost importantly, yet awaits more sampling. These two species add to the list of about 10 avianschistosome species from Argentina alone, with 5 avian schistsome species put within a molecularphylogenetic context.