Thecadinium is a morphologically heterogenous marine benthic genus. Its polyphyly has been discussed. After redefinition of the sensu stricto genus, sensu lato taxa now need reclassification. Heterotrophic, morphologically closely related species were studied in detail. Molecular phylogenetic data for three of the four known species (T. ornatum, T. acanthium, T. ovatum) and new morphological data were obtained, leading to an emended thecal plate pattern, including the presence of an apical pore complex and an additional hypothecal plate. The results confirm the close relationship of the species and justify the description of Carinadinium gen. nov., characterized by the tabulation APC 3/4′ 1/0a 6″ 6c 5s 5‴ 2′‴, an epithecal plate of special morphology, an apical flange, a ventral pore, antapical appendages, a descending cingulum and lateral cell flattening. The genus can be separated into two sub-clades, one with a third precingular ‘dimple’-plate, four apical and no anterior intercalary plates and the other with a ‘multi-pimple’-plate as third precingular or its homolog plate, three apical and one anterior intercalary plate. Carinadinium is phylogenetically related to the planktonic genera Protoceratium, Pentaplacodinium, and Ceratocorys (family Protoceratiaceae), and clearly belongs into the order Gonyaulacales, but with uncertain family affiliation.

Thecadinium是一种形态异质的海洋底栖动物。已经讨论了它的多系。在重新定义后狭义属意义上拉托类群现在需要重新分类。对异养的、形态上密切相关的物种进行了详细研究。获得了四种已知物种中的三种（T. ornatum、T. acanthium、T. ovatum）的分子系统发育数据和新的形态学数据，导致了修正的膜板模式，包括顶孔复合物的存在和额外的假设盘子。结果证实了物种的密切关系并证明了Carinadinium的描述将军 11月，以表格APC 3/4′ 1/0a 6″ 6c 5s 5‴ 2′‴为特征，特殊形态的上皮板，顶端法兰，腹孔，顶端附属物，降扣带和侧细胞扁平. 该属可分为两个亚分支，一个具有第三个前缘“酒窝”板、四个顶端且没有前嵌板，另一个具有“多疙瘩”板作为第三个前缘板或其同源板，三个心尖和一个前嵌板。Carinadinium在系统发育上与浮游属Protoceratium、Pentaplacodinium和Ceratocorys（Protoceratiaceae 科）有关，显然属于 Gonyaulacales，但家族隶属关系不确定。