Cyst-Theca Relationship and Phylogenetic Position of Impagidinium caspienense Incubated from Caspian Sea Surface Sediments: Relation to Gonyaulax baltica and Evidence for Heterospory within Gonyaulacoid Dinoflagellates
|Author(s)||Mertens Kenneth1, Takano Yoshihito2, Gu Haifeng3, Bagheri Siamak4, Pospelova Vera5, Pienkowski Anna J.6, 7, Leroy Suzanne A. G.8, Matsuoka Kazumi2|
|Affiliation(s)||1 : IFREMER, LER BO, Stn Biol Marine, Pl Croix,BP40537, F-29185 Concarneau, France.
2 : Inst East China Sea Res ECSER, 1-14 Bunkyo Machi, Nagasaki 8528521, Japan.
3 : SOA, Inst Oceanog 3, Xiamen 361005, Peoples R China.
4 : AREEO, Inland Waters Aquaculture Res Ctr, Iranian Fisheries Sci Inst, Anzali 66, Iran.
5 : Univ Victoria, Sch Earth & Ocean Sci, OEASB A405,POB 1700 STN CSC, Victoria, BC V8W 2Y2, Canada.
6 : MacEwan Univ, Dept Phys Sci, Edmonton, AB T5J 4S2, Canada.
7 : Bangor Univ, Sch Ocean Sci, Menai Bridge LL59 5AB, Anglesey, Wales.
8 : Brunel Univ London, Inst Environm, Uxbridge UB8 3PH, Middx, England.
|Source||Journal Of Eukaryotic Microbiology (1066-5234) (Wiley), 2017-11 , Vol. 64 , N. 6 , P. 829-842|
|WOS© Times Cited||24|
|Keyword(s)||Ataxiodinium choane, Baltic Sea, Impagidinium pallidum, Pyxidinopsis psilata, salinity, Spiniferites belerius, Spiniferites ramosus|
We investigate the cyst-theca relationship of Impagidinium caspienense. Through an incubation experiment, we succeeded in examining the motile stage. Additional molecular analysis of single-cyst PCR (LSU and SSU rDNA) reveal that the cyst is related to the species Gonyaulax baltica Ellegaard et al. (2002). The ability of this species to belong to two types of cyst-based genera (spiniferate and impagidinioid) suggests that environmental (particularly salinity) and not genetic factors explain the formation of both morphotypes by Gonyaulax baltica, which provides evidence for heterospory in this species. The affiliation to Gonyaulax baltica demonstrates that Impagidinium caspienense is not endemic to the Caspian Sea. The phylogenetic position of several other gonyaulacoid species is also documented: Impagidinium pallidum, Ataxiodinium choane, Pyxidinopsis psilata, Spiniferites belerius, and Spiniferites ramosus. The LSU and SSU rDNA based phylogenies suggest that the genera Impagidinium and Spiniferites are not monophyletic, and that Pyxidinopsis psilata and Ataxiodinium choane are close to Gonyaulax verior and Gonyaulax polygramma, respectively. In addition, this study accentuates the importance of cyst morphology in the classification of the Gonyaulacales.