An early Pliocene (5.1 Ma) fossil frog community from Langebaanweg, south-western Cape, South Africa

The 5.1 million year old fossil site of Langebaanweg (LBW) has provided a wealth of information on the evolution of west coast ecosystems along the southern west coast of South Africa and numerous taxa, including small and large mammals, and birds, make a first appearance in the fossil record at the site. Langebaanweg also contains a rich and diverse anuran fauna which derives from the two main fossil-bearing members at the site. This study identified six families, including Hyperoliidae, Brevicipitidae, Pxyicephalidae, Pipidae, Heleophrynidae and Bufonidae, and some 19 taxa have been differentiated. The majority of frog families identified from the LBW fossil material currently contain a high number of species endemic to the southwestern Cape or South Africa. LBW provides an insight into how current patterns of endemism and distribution may have evolved, and illustrates that the frog community in a region may change substantially over time. The progressive aridification of the west coast subsequent to 5.1 Ma has left very little trace of the rich and diverse frog community which existed during the early Pliocene, and diversity and endemnicity are low today. This challenges the generally held assumption that centres of origin may have a bearing on current-day frog distributions.

拥有510万年历史的兰格班韦格（Langebaanweg, LBW）化石遗址，为南非南部西海岸的沿海生态系统演化提供了海量研究资料；包括小型哺乳类、大型哺乳类与鸟类在内的众多分类群，均在此处的化石记录中首次出现。该遗址还产出了丰富多样的无尾类（anuran）动物群，其化石来自遗址内两处主要的含化石地层成员。本研究共鉴定出6个蛙类科，包括苇蛙科（Hyperoliidae）、短头蛙科（Brevicipitidae）、Pyxicephalidae（原文笔误为Pxyicephalidae）、爪蟾科（Pipidae）、垒堡蛙科（Heleophrynidae）以及蟾蜍科（Bufonidae），并区分出约19个分类群。从LBW化石材料中鉴定出的多数蛙类科，当前均包含大量西南开普地区或南非特有的物种。LBW遗址为揭示当前特有性与分布格局的演化历程提供了重要视角，同时证明某一区域的蛙类群落可随时间发生显著变化。510万年后，西海岸地区持续的干旱化几乎抹去了早上新世（early Pliocene）时期繁盛多样的蛙类群落痕迹，如今该区域的蛙类多样性与特有性均已大幅降低。这一发现对学界长期以来的主流假设提出了挑战——该假设认为类群起源中心会对现今蛙类的分布格局产生影响。