Bat fossil endocasts have been little studied in the literature (nine published works, only one in the XXI^th century), and macromorphology of the brain of extant bats has only been characterized at the family-level. We describe here in detail the endocranial casts of four fossil hipposiderid species based on μCT-scans data and propose a revised nomenclature of the hipposiderid brain structures that leave their imprint on endocranial casts. Exhaustive comparisons of the external morphology of our fossil cranial endocast sample allow us to discuss the distribution of both qualitative and quantitative features in this family for different epochs. A conservatism of the brain is considered to be the rule during bats evolution. Indeed, we found that encephalization did not increase since the Eocene in hipposiderid bats (contrary to other mammals) and that macromorphology of the brain is close between Paleogene, Miocene, and extant hipposiderid species. However, subtler but promising fine anatomical characters might allow distinguishing genera and species. Eventually, expanding the fossil sample and/or adding extant species could shake the paradigm of temporal homogeneity and bring new light on the morpho-anatomical evolutionary history of Hipposideridae.

蝙蝠化石endocasts在文献（9级发表的作品，很少被研究只有一个在二十^日世纪），而现存蝙蝠大脑的宏观形态仅在家庭层面上得以表征。我们在此基于μCT扫描数据详细描述了四种化石河马纲动物的颅内铸件，并提出了一种修改过的河马纲脑结构命名法，使它们在颅内铸件上留下了印记。我们对化石颅内铸样品的外部形态进行详尽的比较，使我们能够讨论该家族在不同时期的定性和定量特征的分布。蝙蝠进化过程中，大脑的保守性被认为是规则。的确，我们发现自从新世代的河马类蝙蝠（与其他哺乳动物相反）以来，脑组织化并未增加，并且大脑的宏观形态在古近代，中新世和现存的河马类物种之间是紧密的。但是，微妙但很有前途的精细解剖特征可能会区分属和种。最终，扩大化石样本和/或增加现存物种可能会动摇时间同质性的范式，并为河马科的形态解剖进化史带来新的启示。