阿根廷布宜诺斯艾利斯大学Claudia A. Marsicano等研究人员合作发现，巨型干群四足动物是冈瓦纳晚古生代冰河时期的顶级掠食者。相关论文于2024年7月3日在线发表于国际学术期刊《自然》。

研究人员描述了一种新的巨型干群四足动物——Gaiasia jennyae，其化石来自纳米比亚早二叠世（大约2.8亿年前）高古纬度（约南纬55度）的沉积层，这一发现对上述假设提出了挑战。Gaiasia的标本包括多个大型的半联骨骼，其特征为弱骨化的头骨、松散连接的口盖、宽大的菱形副蝶骨、向后突出的枕骨、以及放大的、交错咬合的齿骨和冠状齿。系统发育分析将Gaiasia定位在四足动物干群中，作为来自欧亚美利加的石炭纪Colosteidae的姊妹类群。

Gaiasia比之前描述的所有具指干群四足动物都大，提供了大陆四足动物在石炭纪–二叠纪去冰期最后阶段已在冈瓦纳冷温带地区建立起来的证据。这表明大陆四足动物在石炭纪–二叠纪过渡期的分布更加全球化，意味着之前关于全球四足动物动物群更替和扩散的假设需要重新考虑。

据了解，当前关于早期四足动物演化的假设认为，它们与石炭纪古赤道的大型产煤湿地有着密切的生态和地理联系，并在晚石炭纪（大约3.07亿年前）被现代羊膜动物和滑体动物的亲缘类群迅速取代。这些假设主要基于几乎完全限于古赤道盘古大陆（劳亚古陆）的四足动物化石记录。

附：英文原文

Title: Giant stem tetrapod was apex predator in Gondwanan late Palaeozoic ice age

Author: Marsicano, Claudia A., Pardo, Jason D., Smith, Roger M. H., Mancuso, Adriana C., Gaetano, Leandro C., Mocke, Helke

Issue&Volume: 2024-07-03

Abstract: Current hypotheses of early tetrapod evolution posit close ecological and biogeographic ties to the extensive coal-producing wetlands of the Carboniferous palaeoequator with rapid replacement of archaic tetrapod groups by relatives of modern amniotes and lissamphibians in the late Carboniferous (about 307million years ago). These hypotheses draw on a tetrapod fossil record that is almost entirely restricted to palaeoequatorial Pangea (Laurussia)1,2. Here we describe a new giant stem tetrapod, Gaiasia jennyae, from high-palaeolatitude (about 55°S) early Permian-aged (about 280million years ago) deposits in Namibia that challenges this scenario. Gaiasia is represented by several large, semi-articulated skeletons characterized by a weakly ossified skull with a loosely articulated palate dominated by a broad diamond-shaped parasphenoid, a posteriorly projecting occiput, and enlarged, interlocking dentary and coronoid fangs. Phylogenetic analysis resolves Gaiasia within the tetrapod stem group as the sister taxon of the Carboniferous Colosteidae from Euramerica. Gaiasia is larger than all previously described digited stem tetrapods and provides evidence that continental tetrapods were well established in the cold-temperate latitudes of Gondwana during the final phases of the Carboniferous–Permian deglaciation. This points to a more global distribution of continental tetrapods during the Carboniferous–Permian transition and indicates that previous hypotheses of global tetrapod faunal turnover and dispersal at this time2,3 must be reconsidered.

DOI: 10.1038/s41586-024-07572-0

Source: https://www.nature.com/articles/s41586-024-07572-0