It is well known that modern resting cysts with morphologies matching those of species of the fossil genus Spiniferites germinate into motile cells of the genus Gonyaulax. Different Spiniferites species have been connected to a single Gonyaulax species, raising the question of whether they are over-classified. Through germination experiments of cysts with the morphological features of four species of Spiniferites, viz. S. bentorii, S. hyperacanthus, S. ramosus and S. scabratus, we established cyst-theca relationships. Cysts with the morphology of S. bentorii gave rise to vegetative, motile cells of Gonyaulax nezaniae sp. nov., which is characterized by two stout antapical spines. Cysts with S. hyperacanthus and S. ramosus morphologies germinated into Gonyaulax whaseongensis and G. spinifera, respectively. Cysts with S. scabratus morphology lacked a ventral pore and were attributed to Gonyaulax cf. spinifera. Gene sequences for SSU, LSU and/or ITS-5.8S rRNA were obtained from these four species, and from cysts with the morphology of Spiniferites belerius, S. mirabilis, S. lazus, Spiniferites cf. bentorii and Tectatodinium pellitum. The maximum likelihood and Bayesian inference analyses based on LSU and SSU rRNA gene sequences revealed that cysts assignable to Spiniferites formed a polyphyletic group, intermingled with Tectatodinium, Bitectatodinium, Ataxiodinium and Impagidinium, whereas Gonyaulax species appeared as monophyletic. From our results we inferred the phylogenetic positions of S. bentorii, S. mirabilis, S. lazus, S. scabratus, Tectatodinium pellitum and Gonyaulax digitale for the first time, supporting the idea that Spiniferites species are not over-classified and each of them may correspond to different Gonyaulax species.
Bibliographical noteFunding Information:
The Regional Council of Brittany, the General Council of Finistère and the urban community of Concarneau-Cornouaille-Agglomèration are acknowledged for the funding of the Sigma 300 FE-SEM of the station of Marine Biology in Concarneau. Elisabeth Nèzan is thanked for isolating Gonyaulax digitale from Concarneau. This work was supported by the National Natural Science Foundation of China (42076085, 42030404), the National Key Research and Development Program of China (2019YFE0124700). Funding for collection of sediments in coastal waters of British Columbia (Canada) was provided by a Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery grant to VP. Sediment collection at Bahia de La Paz, Gulf of California was supported by CIBNOR projects PC013 and 20014. Collecting the sediments in the Croatian coastal water was funded by the Croatian Science Foundation under the project (IP-2014-09-3606), MARIPLAN.
© 2021 International Phycological Society.
- Gonyaulax nezaniae
- Gonyaulax spinifera
- Tectatodinium pellitum