(Haemoproteidae, Haemosporida) infects gulls ( spp.) in South Africa, with redescription of .

spp. are dipteran-borne protozoa that infect erythrocytes and reticulo-endothelial cells of birds. These parasites are not usually transmitted between birds belonging to different orders. The suborder Lari (order Charadriiformes) comprises ~170 avian species, the majority of which are aquatic, including gulls, terns, auklets, murres and skuas, among others. In spite of the diversity of this avian group, there is limited known diversity of haemosporidian parasites, with only 4 recorded morphospecies thus far. We examined the blood smears of 21 kelp gulls () captured at a breeding colony in South Africa, as well as -positive archival blood smears of 15 kelp gulls and 1 Hartlaub's gull () sampled while under care at seabird rehabilitation facilities in South Africa. sp. infection was detected in 19% of wild-caught kelp gulls. All parasites from the gulls were morphologically identified as , a species previously recorded in Lari birds at the Galapagos Islands (Ecuador), Rocas Atoll (Brazil) and Poland. Gene sequencing uncovered a new cytochrome lineage, LARDOM01, which was closely related to the previously reported lineage CREFUR01. Additionally, we evaluated a hapantotype blood smear of , which had been described infecting a brown skua () in South Africa. We provide a redescription of and discuss the morphological characters distinguishing it from . Further research is necessary to improve our knowledge about the host and geographic distribution, health effects and phylogeny of and .