For a variety of reasons, Madagascar's rich and highly distinctive faunal assemblage has long attracted attention. Recurring questions with the associated studies have concerned when and how the ancestors of the various clades reached the island. For the land-bound animals, the common view is that they arrived after the Cretaceous on ‘rafts' that washed in from Africa. However, this centuries-old discussion has been periodically spiked with proposals for land-bridges, with a recent one arguing for three separate causeways or stepping-stone chains connecting Africa and Madagascar in the early, middle, and late Cenozoic (66–60 Ma, 36–30 Ma, and 12–5 Ma). Here, the general idea of former causeways spanning the Mozambique Channel is evaluated based on an extensive survey of the related geological and geophysical literature, a large portion of which dates from the last half-decade. The analysis, which makes use of a newly-developed topological schema, indicates that only a small number of the supposed dry-land sub-paths were actually subaerial during each of the postulated colonization windows. Notably, during the Early Oligocene, a 220–250 km² pinnacle in the Sakalaves Seamount group formed a volcanic ‘high-island’. The other offshore sectors that were exposed would have been atoll crowns: Juan de Nova Island throughout the Cenozoic and the northern Sakalaves in the Late Miocene. However, it would have been challenging for most land animals to exist on those low-elevation carbonate platforms for any length of time. Therefore, the notion of Africa and Madagascar being linked in the Cenozoic by terrestrial walkways can be regarded as falsified. Over-water dispersal best explains how 26 of Madagascar's 27 land-vertebrate clades colonized the landmass. The exception, a group of small, soil-dwelling snakes, is likely a relict lineage whose ancestors were present on the island prior to Madagascar's geographical isolation that resulted from the tectonic block's breakup with India-Seychelles c. 85 Ma.

由于种种原因，马达加斯加丰富且极具特色的动物群落长期以来一直备受关注。相关研究中反复出现的问题涉及各种进化枝的祖先何时以及如何到达该岛。对于陆生动物来说，普遍的看法是，它们是在白垩纪之后乘坐从非洲冲来的“木筏”抵达的。然而，这个具有数百年历史的讨论不时出现关于陆桥的提议，最近的一个争论是在新生代早期、中期和晚期（66-60 Ma 、36-30 毫安和 12-5 毫安）。在这里，基于对相关地质和地球物理文献的广泛调查，评估了跨越莫桑比克海峡的前堤道的总体概念，其中很大一部分可以追溯到过去五年。使用新开发的拓扑模式的分析表明，在每个假设的殖民窗口期间，只有少数假设的旱地子路径实际上是地下的。值得注意的是，在渐新世早期，220-250 kmSakalaves^{海山群的2座顶峰}形成了一个火山“高岛”。暴露的其他近海区域将是环礁：新生代的胡安德诺瓦岛和晚中新世的北部萨卡拉韦斯岛。然而，对于大多数陆地动物来说，在这些低海拔地区生存是一个挑战任何时间长度的碳酸盐平台。因此，非洲和马达加斯加在新生代由陆地走道连接的概念可以被认为是错误的。水上扩散最好地解释了马达加斯加 27 种陆地脊椎动物进化枝中的 26 种是如何在陆地上定居的。例外情况是，一群居住在土壤中的小型蛇类，很可能是一个孑遗血统，其祖先在马达加斯加地理隔离之前就已经存在于岛上，这是由于构造块与印度-塞舌尔c的分裂造成的。85 毫安。