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Islandinium minutum subsp. barbatum subsp. nov. (Dinoflagellata), a New Organic‐Walled Dinoflagellate Cyst from the Western Arctic: Morphology, Phylogenetic Position Based on SSU rDNA and LSU rDNA , and Distribution
Author(s) -
Potvin Éric,
Kim SoYoung,
Yang Eun Jin,
Head Martin J.,
Kim Hyuncheol,
Nam SeungIl,
Yim Joung Han,
Kang SungHo
Publication year - 2018
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/jeu.12518
Subject(s) - biology , dinoflagellate , phylogenetic tree , arctic , morphology (biology) , phylogenetics , evolutionary biology , botany , zoology , genetics , ecology , gene
A study of modern sediment from the Western Arctic has revealed the presence of a distinctive brown‐colored cyst with a spherical central body bearing unbranched processes that are usually solid with a small basal pericoel. Distinctive barbs project from some processes, and process tips are usually minutely expanded into conjoined barbs. The archeopyle is apical and saphopylic. This cyst corresponds to Islandinium ? cezare morphotype 2 of Head et al. (2001, J. Quat. Sci ., 16:621). Phylogenetic analyses based on the small and large subunit rRNA genes infer close relationship with Islandinium minutum , the type of which is that of the genus. Re‐examination of specimens of I. minutum reveals the presence of minute barbs on its processes, but differences with Islandinium ? cezare morphotype 2 remain based on size, process distribution, and barb development. Furthermore, the internal transcribed spacer shows I. minutum to be distinct from this morphotype. On the basis of these small but discrete differences, we propose the new subspecies Islandinium minutum subsp. barbatum subsp. nov. Molecular sequencing of other cysts encountered, namely Echinidinium karaense , an unidentified flattened cyst, and “ Polykrikos quadratus ”, places them in the Monovela clade, the latter showing greater morphological variability than previously thought.