Mujal Eudald, Fortuny Josep, Bolet Arnau, Oms Oriol, López José Ángel
Departament de Geologia, Universitat Autònoma de Barcelona, Bellaterra, Spain.
Centre de Recherches en Paléobiodiversité et Paléoenvironnements, Muséum National d'Histoire Naturelle, Bâtiment de Paléonologie, Paris, France.
PLoS One. 2017 Apr 19;12(4):e0174693. doi: 10.1371/journal.pone.0174693. eCollection 2017.
The vertebrate recovery after the end-Permian mass extinction can be approached through the ichnological record, which is much more abundant than body fossils. The late Olenekian (Early Triassic) tetrapod ichnoassemblage of the Catalan Pyrenean Basin is the most complete and diverse of this age from Western Tethys. This extensional basin, composed of several depocenters, was formed in the latest phases of the Variscan orogeny (Pangea breakup) and was infilled by braided and meandering fluvial systems of the red-beds Buntsandstein facies. Abundant and diverse tetrapod ichnites are recorded in these facies, including Prorotodactylus mesaxonichnus isp. nov. (tracks possibly produced by euparkeriids), cf. Rotodactylus, at least two large chirotheriid morphotypes (archosauriform trackmakers), Rhynchosauroides cf. schochardti, two other undetermined Rhynchosauroides forms, an undetermined Morphotype A (archosauromorph trackmakers) and two types of Characichnos isp. (swimming traces, here associated to archosauromorph trackmakers). The Pyrenean ichnoassemblage suggests a relatively homogeneous ichnofaunal composition through the late Early Triassic of Central Pangea, characterized by the presence of Prorotodactylus and Rotodactylus. Small archosauromorph tracks dominate and present a wide distribution through the different fluviatile facies of the Triassic Pyrenean Basin, with large archosaurian footprints being present in a lesser degree. Archosauromorphs radiated and diversified through the Triassic vertebrate recovery, which ultimately lead to the archosaur and dinosaur dominance of the Mesozoic.
二叠纪末大灭绝之后的脊椎动物复苏情况，可以通过遗迹化石记录来研究，遗迹化石比实体化石丰富得多。加泰罗尼亚比利牛斯山脉盆地的晚奥伦尼克期（早三叠世）四足动物遗迹组合，是西特提斯地区该时期最完整、最多样化的。这个伸展盆地由几个沉积中心组成，形成于华力西造山运动（泛大陆解体）的最后阶段，被红层束带砂岩相的辫状河和曲流河系统所充填。在这些相中记录了丰富多样的四足动物足迹化石，包括新种中轴前足迹原前指足迹（可能由派克鳄类留下的足迹）、似轮足迹、至少两种大型坚蜥类形态类型（主龙形类足迹制造者）、似肖氏喙龙类、另外两种未确定的似喙龙类形态、一种未确定的形态类型A（主龙形类足迹制造者）以及两种类型的卡氏鱼迹（游泳痕迹，这里与主龙形类足迹制造者有关）。比利牛斯山脉的遗迹组合表明，在泛大陆中部早三叠世晚期，遗迹动物群的组成相对均匀，其特征是存在前指足迹和轮足迹。小型主龙形类足迹占主导地位，在三叠纪比利牛斯山脉盆地的不同河流相中有广泛分布，大型主龙类足迹的出现程度较低。在三叠纪脊椎动物复苏过程中，主龙形类辐射演化并多样化，最终导致中生代主龙和恐龙占据主导地位。
