Horologinella属最初的定义包含小个体的和具特有的滴漏器形的微体化石.归到该属的不同类型可分成形态构造不同的两类:具板式和非板式类型,进一步证实了在Horologinella属的分类上颇混乱的情形.在本组合中,具板式类型极少见,与这类孢粉类型有关的形态学、地层分布及古环境特征的资料非常少见.文中描述了中西伯利亚北部阿纳巴尔湾早白垩世的H. anabarensis Pestchevitskaya的许多保存良好的标本,利用这些保存良好的标本可以研究Horologinella类型的详细板式形态.前、后腰区和顶区的反映板式及第一块顶板片的对应位置和反映纵沟的构造,说明Horologinella具板式的类型与膝沟藻目的沟鞭藻囊孢,尤其是与瑞提膝沟藻亚目的分子有很密切的关系.古生物学和孢粉学的资料显示H.anabarensis和有利于微体浮游植物组合发育的浅海环境有关.

Following the original definition the genus Horologinella includes the microfossils of small size and specifichour-glass shape. Various types assigned to this genus can be divided into two groups of sufficiently different morphology:tabulated and nontabulated forms, that confirms rather confusion situation withing the taxonomy of genus Horologinella.Tabulated Horologinella forms have been extremely rare observed in palynological assemblages and a little information isavailable concerning the morphology, stratigraphic range and palaeoenvironmental characteristic of these palynomorphs. Agood preservation of numerous specimens of species H. anabarensis Pestchevitskaya 2001, described from Lower Cretaceoussediments of Anabar Bay section (North of Middle Siberia), allows to investigate the morphology of tabulated Horologinellaforms in details. The paratabulation pattern of precingular, postcingular and apical series as well as configuration of first apicalhomologue and parasulcal structure suggest that tabulated forms of Horologinella have close affinities to gonyaulacaleandinoflagellate cysts, especially to members of suborder Rhaetogonyaulacaceae. Paleontological and palynological data evi-dence that H. anabarensis is associated with shallow marine environments favorable for the development of rather richmicrophytoplankton assemblage.

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The report is pre-sented under financial support of Organizing Committee ofX IPC and Russian Fund of Fundamental Researches，00-05-65405, 01-05-06186，