Molecular characterization of the worm Diomedenema diomedeae from the air sacs of grey-headed albatrosses on Marion Island

Abstract

Albatrosses are the world’s most endangered family of seabirds, and Marion Island and Prince Edward Island are Subantarctic nesting sites of global importance for seabird conservation, including five species of albatrosses. In March-April 2016 a number of grey-headed albatross (Thalassarche chrysostoma. chicks was found dead along the southern coast of Marion Island (46°57?S 37°42?E.. Affected chicks were weak, prostrated, apathetic, had drooping wings, and eventually died while sitting on the nest. Five carcasses were necropsied, and samples were obtained for pathological and parasitological analysis. Four chicks appear to have died from starvation in association with tick infestation and predator harassment, and one died due to air-sac helminthiasis, with extensive haemorrhage in the air sacs and multifocal pyogranulomatous air-sacculitis. The air sac parasites were identified as Diomedenema diomedeae, a nematode worm of the family Desmidocercidae, superfamily Aproctoidea. D. diomedeae had been described in 1952 from the body cavity of a grey-headed albatross that had washed ashore in South Australia, and was never recorded since its original description. We produced sequences for the nuclear 18S rRNA gene and the mitochondrial cytochrome c oxidase subunit I gene, which are the first DNA sequences for a species of the superfamily Aproctoidea. Phylogenetic analyses of the gene sequences corroborate that the superfamily Aproctoidea belongs to the suborder Spirurina, as had been previously speculated on the basis of morphology. Furthermore, the phylogenetic analyses suggest that Aproctoidea is closely related to Diplotiraenoidea, a superfamily of worms that infect the air sacs and subcutaneous tissues of a variety of bird species. These results demonstrate how research at remote sites such as the Prince Edward Islands can provide valuable insight into the evolution and genetics of parasites that are otherwise poorly represented in the literature. - Abstract as displayed in the - Abstract booklet. There was no presentation.