New Albian to Cenomanian (Cretaceous) dinoflagellate cyst taxa of ovoidinioid affinities from East Greenland, the Barents Sea and England

Palyno-biostratigraphical studies of upper Albian-Lower Cenomanian successions from East Greenland, the south-western Barents Sea and south-eastern England have revealed new dinoflagellate cyst taxa of clear or questioned ovoidinioid affinities. This paper describes the new genus <i>Sindridinium</i>, four new species – <i>Ovoidinium epelidosphaeroides</i> sp. nov., <i>Epelidosphaeridia manifesta</i> sp. nov., <i>Sindridinium borealis</i> gen. et sp. nov. and <i>Sindridinium anaanae</i> gen. et sp. nov. – and proposes a new combination, <i>Sindridinium? </i> <i>torulosa</i> comb. nov. (formerly <i>Canningia torulosa</i>). The genus <i>Epelidosphaeridia</i> is emended based on features seen in <i>E.</i> <i>manifesta</i> sp. nov., which demonstrate peridiniacean affinities and support inclusion in the Ovoidinioideae. Morphological gradations between <i>Epelidosphaeridia spinosa, E. manifesta</i> sp. nov. <i>and Ovoidinium epelidosphaeroides</i> sp. nov., suggest close phylogenetic relationships, also postulated between <i>Sindridinium? torulosa</i> comb. nov., <i>S. borealis</i> gen. et sp. nov. and <i>S. anaanae</i> gen. et sp. nov. The stratigraphic ranges of the taxa described are calibrated to known dinoflagellate markers and mid-Cretaceous ammonites.

针对东格陵兰、巴伦支海西南部及英格兰东南部的阿尔布阶上部-森诺曼阶下部地层序列开展的孢粉生物地层学（palyno-biostratigraphical）研究，发现了一批具有明确或疑似卵形藻类（ovoidinioid）亲缘关系的沟鞭藻囊孢（dinoflagellate cyst）新类群。本文记述了新属*Sindridinium*，以及4个新种：卵形藻属*Ovoidinium*的新种（sp. nov.）*Ovoidinium epelidosphaeroides*、*Epelidosphaeridia*属的新种（sp. nov.）*Epelidosphaeridia manifesta*，以及新属*Sindridinium*下的2个新属新种（gen. et sp. nov.）*Sindridinium borealis*与*Sindridinium anaanae*；同时提出1个新组合（comb. nov.）：*Sindridinium? torulosa*（原名为*Canningia torulosa*）。研究基于*E. manifesta* sp. nov.所呈现的形态特征，对*Epelidosphaeridia*属进行了修订，该类群显示出多甲藻科（Peridiniaceae）亲缘关系，支持其归入卵形藻亚科（Ovoidinioideae）。*Epelidosphaeridia spinosa*、*E. manifesta* sp. nov.与*Ovoidinium epelidosphaeroides* sp. nov.之间存在的形态渐变现象，表明三者间存在紧密的系统发育关系；*Sindridinium? torulosa* comb. nov.、*S. borealis* gen. et sp. nov.及*S. anaanae* gen. et sp. nov.之间也被推测存在类似的亲缘关系。本次记述的各类群的地层延限范围，均校准于已知沟鞭藻地层标志及白垩纪中期菊石组合。