Department of Biological Sciences, George Washington University, Washington, DC, USA.
Department of Geoscience, University of Wisconsin-Madison, Madison, WI, USA.
Proc Biol Sci. 2024 Oct;291(2033):20241041. doi: 10.1098/rspb.2024.1041. Epub 2024 Oct 30.
The severe greenhouse climate and seasonality of the early to mid-Late Triassic are thought to have limited terrestrial diversity at lower latitudes, but direct adaptations to these harsh conditions remain limited in vertebrates at the palaeoequator. Here, we present gen. et sp. nov., an early amphibian with specialized adaptations for seasonal estivation from the upper Jelm Formation of the Late Triassic of Wyoming, USA. are found in an association of vertebrate estivation burrows across a locally dense horizon, offering insights into the evolution and ecology of vertebrates amid the challenging conditions of low-latitude Late Triassic ecosystems. Estivation chambers were excavated within point bar deposits of an ephemeral river system, recording the cyclical signature of Triassic megamonsoons and documenting a vertebrate response to annual climate extremes across tens to hundreds of seasons. Phylogenetic analysis recovers within a group of temnospondyls characterized by fossorial adaptation, underscoring the widespread adoption of burrowing and estivation in total group Lissamphibia. hints at the pivotal role seasonal dynamics played in shaping amphibian evolution.
早期到晚三叠世,严酷的温室气候和季节性被认为限制了低纬度地区的陆地生物多样性,但在古赤道地区的脊椎动物中,对这些恶劣条件的直接适应仍然有限。在这里,我们提出了一个新属种,一种来自美国怀俄明州晚三叠世杰尔姆组上部的具有季节性夏眠专门适应的早期两栖动物。它们是在一个沿局部密集层分布的脊椎动物夏眠洞穴组合中发现的,为在低纬度晚三叠世生态系统的挑战性条件下脊椎动物的进化和生态提供了见解。夏眠室是在一个短暂河流系统的点坝沉积物中挖掘出来的,记录了三叠纪大季风的周期性特征,并记录了脊椎动物对数十到数百个季节的年度气候极端的反应。系统发育分析将归入一个以穴居适应为特征的无尾两栖类群中,强调了在总群有尾两栖类中广泛采用的穴居和夏眠。的发现暗示了季节性动态在塑造两栖动物进化方面发挥的关键作用。