title: A new Gambierdiscus species (Dinophyceae) from Rarotonga, Cook Islands: Gambierdiscus cheloniae sp. nov.
abstract: Ciguatera fish poisoning (CFP) has been reported for many years in Rarotonga, Cook Islands, and has had the world's highest reported incidence of this illness for the last 20 years. Following intensive sampling to understand the distribution of the causative organisms of CFP, an undescribed Gambierdiscus species was isolated from the Rarotongan lagoon. Gambierdiscus cheloniae sp. nov. has the common Gambierdiscus Kofoidian plate formula (except for a variability in the number of precingular plates in aberrant cells): Po, 3', 6″ (7″), 6C?, 6 or 7S, 5'″, 1p and 2″″. The 2' plate is hatchet shaped and the dorsal end of 1p is pointed and the relatively narrow 1p plate. Morphologically G. cheloniae is similar to the genetically closely related species G. pacificus, G. toxicus and G. belizeanus, although smaller (depth and length) than G. toxicus. The apical pore plate varies from those of G. belizeanus and G. pacificus, which are shorter and narrower, and from G. toxicus, which is larger. G. cheloniae also differs from G. pacificus in the shape of the 2' plate. The description of this new species is supported by phylogenetic analyses using three different gene regions. G. cheloniae produced the putative maitotoxin-3 analogue, MTX-3, but neither maitotoxin or monitored ciguatoxin. Extracts of G. cheloniae were shown to be highly toxic to mice by intraperitoneal (i.p.) injection, although they were less toxic by gavage. It is possible that this species produces toxins other than putative MTX-3.
authors.affiliation: Cawthron Institute, 98 Halifax Street East, Private Bag 2, Nelson 7042, New Zealand. Electronic address: kirsty.smith@cawthron.org.nz.
authors.forename: Kirsty F
authors.initials: KF
authors.lastname: Smith
authors.affiliation: Cawthron Institute, 98 Halifax Street East, Private Bag 2, Nelson 7042, New Zealand.
authors.forename: Lesley
authors.initials: L
authors.lastname: Rhodes
authors.affiliation: Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, PO Box 123, Broadway, New South Wales 2007, Australia.
authors.forename: Arjun
authors.initials: A
authors.lastname: Verma
authors.affiliation: Sydney Institute of Marine Sciences, Chowder Bay Rd, Mosman 2088, New South Wales Australia.
authors.forename: Belinda G
authors.initials: BG
authors.lastname: Curley
authors.affiliation: Cawthron Institute, 98 Halifax Street East, Private Bag 2, Nelson 7042, New Zealand.
authors.forename: D Tim
authors.initials: DT
authors.lastname: Harwood
authors.affiliation: Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, PO Box 123, Broadway, New South Wales 2007, Australia.
authors.forename: Gurjeet S
authors.initials: GS
authors.lastname: Kohli
authors.affiliation: Ministry of Marine Resources, Private Bag, Avarua, Rarotonga, Cook Islands.
authors.forename: Dorothy
authors.initials: D
authors.lastname: Solomona
authors.affiliation: Climate Change Cook Islands, Office of the Prime Minister, Private Bag, Avarua, Rarotonga, Cook Islands.
authors.forename: Teina
authors.initials: T
authors.lastname: Rongo
authors.affiliation: AgResearch, Ruakura Research Centre, 10 Bisley Road, Private Bag 3240, Hamilton 3214, New Zealand.
authors.forename: Rex
authors.initials: R
authors.lastname: Munday
authors.affiliation: Plant Functional Biology and Climate Change Cluster, University of Technology Sydney, PO Box 123, Broadway, New South Wales 2007, Australia; Sydney Institute of Marine Sciences, Chowder Bay Rd, Mosman 2088, New South Wales Australia.
authors.forename: Shauna A
authors.initials: SA
authors.lastname: Murray
mesh_terms: D000818:Animals; D036841:Ciguatera Poisoning / Q000139:chemically induced; D004141:Dinoflagellida / Q000145:classification* / Q000166:cytology / Q000235:genetics; D017125:Genes, Protozoan / Q000235:genetics; D062312:Islands; D008387:Marine Toxins / Q000378:metabolism / Q000633:toxicity; D051379:Mice; D010802:Phylogeny; D011114:Polynesia; D013045:Species Specificity
chemical_list: D008387:Marine Toxins
keywords: Ciguatoxin; Cook Islands; Epiphytic dinoflagellates; Gambierdiscus; LSU rDNA; Maitotoxin; Phylogeny; SSU rDNA