The extant morphospecies of the Trilobatus sacculifer plexus (T. sacculifer, T. quadrilobatus, T. immaturus and T. trilobus) have widespread biogeographical distributions and long stratigraphical ranges, and are thus routinely utilized in palaeoceanographical studies. The descendant morphospecies Globigerinoidesella fistulosa is comparatively short-ranging (Pliocene–Pleistocene) and an important biostratigraphical marker. However, taxonomic concepts of these morphospecies are inconsistently applied between workers, leading to loss of information and incomparable datasets. We present a taxonomic appraisal of each morphospecies, including detailed taxonomic histories and refinement of their morphological concepts, using a combined population-based and typological approach. Morphometric data and scanning electron microscopy are used to illustrate morphological intergradation in the Trilobatus sacculifer plexus. The distinctive morphology of Globigerinoidesella fistulosa is shown to develop from T. sacculifer (as previously documented), but also from the other morphospecies in the plexus, providing the first fossil evidence demonstrating that the four morphospecies of the T. sacculifer plexus are the same species. Our new analyses support culturing and molecular genetic evidence from extant specimens that suggests the four T. sacculifer plexus morphospecies are the same biological species. However, we advocate using the four morphospecies concepts (T. sacculifer, T. quadrilobatus, T. immaturus and T. trilobus) and G. fistulosa, here refined, to increase their palaeoecological and biostratigraphical value.

所述的现存形态种Trilobatus sacculifer丛（Ť。sacculifer，Ť。quadrilobatus，Ť。immaturus和Ť。trilobus）具有广泛的生物地理分布和长地层范围内，并且因此在常规研究palaeoceanographical利用。后代形态种Gglobigerinoidesella fistulosa相对较短（上新世-更新世），是重要的生物地层标志。但是，这些形态学的分类概念在工作人员之间不一致地应用，从而导致信息丢失和数据集不可比。我们使用基于人口和方法的组合方法，对每种形态学进行分类学评估，包括详细的分类学历史和其形态学概念的完善。形态计量学数据和扫描电子显微镜用于说明三角叶lo神经丛中的形态学转变。的独特的形态Globigerinoidesella fistulosa被示出从开发Ť。葡萄球菌（如前所述），但也来自丛中的其他形态学，提供了第一个化石证据，证明了T的四个形态学。葡萄球菌属是同一物种。我们的新分析结果支持培养，并从现存标本显示四个分子遗传学证据牛逼。葡萄球菌属的形态种类是相同的生物种类。然而，我们主张使用四个形态种概念（Ť。sacculifer，Ť。quadrilobatus，Ť。immaturus和Ť。trilobus）和G ^。fistulosa，这里提炼，以提高他们的古生态和biostratigraphical值。