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A new dinoflagellate cyst genus and species are described here as Hiddenocysta gen. nov. and Hiddenocysta matsuokae sp. nov. from Holocene sediments in a core from the west coast of Vancouver Island (British Columbia, Canada). The genus Hiddenocysta encompasses spherical to ovoid skolochorate cysts, characterized by a gonyaulacoid plate pattern and a 2P precingular archeopyle. The species H. matsuokae is characterized by a granular wall and slender trifurcate processes with heavily perforated process bases. Two end members are described here based on process morphology and number of processes (formas 1 and 2). Cyst wall chemistry is analyzed using micro-Fourier transform infrared (FTIR) spectroscopy and reveals a unique dinosporin composition consistent with a gonyaulacoid autotrophic feeding strategy. [ABSTRACT FROM AUTHOR]

Highlights • Halodinium verrucatum sp. nov. is described, Hexasterias problematica is emended. • LSU and SSU rDNA is obtained for Halodinium verrucatum and Hexasterias problematica. • Molecular phylogeny and DAPI-staining demonstrate these are ciliate resting cysts. • micro-FTIR of resting cysts and tintinid loricae supports this affiliation. • The distribution and ecology of both palynomorphs is discussed. Abstract Species in the genera Hexasterias and Halodinium have been recorded over the last decades as acritarchs in palynological and/or plankton studies. In paleoenvironmental studies, these resting stages are often interpreted as indicators of freshwater input. The biological affinity of these genera has never been definitely established. Here, a new species, Halodinium verrucatum sp. nov., is described and molecular evidence (single specimen SSU and LSU rDNA sequencing) reveals that both this new species and Hexasterias problematica , collected from sediment samples in the Skagerrak and Baltic Sea, are resting stages of prorodontid ciliates. Additionally, infrared spectroscopic analysis (micro-FTIR) of Hexasterias problematica and Halodinium spp. specimens indicates a carbohydrate-based composition of the cyst wall with evidence for nitrogen-containing functional groups. A similar composition is recorded for tintinnid loricae, which further supports the placement of Hexasterias and Halodinium as ciliate cysts, and the composition is consistent with the heterotrophic nature of ciliates. The morphologically similar species Radiosperma corbiferum has a comparable composition, suggesting a similar ciliate affinity and indicating the utility of micro-FTIR in understanding acritarch affinity. Hexasterias problematica typically occurs in coastal waters from temperate to arctic regions. Halodinium verrucatum sp. nov. is observed in temperate estuarine sediments in the northern hemisphere. [ABSTRACT FROM AUTHOR]

The genus Spiniferites currently encompasses 142 dinoflagellate cyst species. Some Spiniferites species are difficult to identify because of an incomplete or doubtful description, and/or substandard iconography. This study re-describes and re-illustrates the Spiniferites holotypes first described by Reid in 1974. It also discusses topotype material from surface sediments recovered from British estuaries, and attempts to provide further constraints on the classification of species in this genus using the geochemical characterization of their cyst walls. Reid described four new Spiniferites species: Spiniferites belerius, Spiniferites delicatus, Spiniferites elongatus and Spiniferites lazus. New photomicrographs are presented here for the holotypes of Spiniferites delicatus and Spiniferites elongatus, and additional morphological observations based on newly processed topotype material are given. The geochemical characterization of the Spiniferites cyst walls showed overall consistency with a carbohydrate-based dinosporin. However, variability in the dinosporins suggests that, in this genus, the cyst wall composition may be species-specific. Analysis of the characteristic spectral regions for unclassified Spiniferites species showed that, in some cases, it may be possible to constrain the likely species affinity using the cyst wall chemistry. However, in most cases, the morphologically unspeciated cysts did not show sufficient similarity to an identified species' cyst wall chemistry to be more conclusive. This could either reflect an intermediate species that cannot be clearly characterized using morphology or dinosporin composition, or it represents a completely different species. In either case, both the morphological and geochemical evaluations highlight the difficulties in classifying species of this genus unequivocally. [ABSTRACT FROM AUTHOR]