Tsikoane suppl. material

The upper Stormberg Group of Lesotho has an abundant and diverse ichnological record that dates to the Early Jurassic. Herein, we re-evaluate a known ichnosite in the lowermost Clarens Formation (Karoo Supergroup) at Tsikoane in northern Lesotho. The site was reported to preserve tridactyl tracks as natural casts in the ceiling of overhangs and true track impressions on a fallen sandstone block. At least three track-bearing palaeosurfaces, associated with horizontally laminated sandstones and desiccated green mudstones, can be traced over a distance of 250 m. Associated with one of the track-bearing palaeosurfaces, discrete, U-shaped, cross-sectional structures are interpreted as a series of natural casts, surface tracks, true tracks and undertracks. Although the Tsikoane tracks were historically assigned to a single ichnogenus, later synonymized with Grallator, our findings show a higher diversity of tridactyl ichnites, with tracks that have Kayentapus-like and Eubrontes-like features in addition to previously recognized Grallator-like features. These new findings, within their high-resolution sedimentological context, improve the understanding of theropod palaeodiversity and palaeoecology in southern Africa during a crucial period in dinosaur history marked by increases in both abundance and diversity.

莱索托上斯托姆贝格群（upper Stormberg Group）保存有丰富多样的遗迹化石记录，其地质年代可追溯至早侏罗世。本文重新评估了位于莱索托北部齐科阿内（Tsikoane）的卡鲁超群（Karoo Supergroup）克莱伦斯组（Clarens Formation）最下部一处已知遗迹点。据此前报道，该遗迹点在崖壁悬顶的顶板岩层中保存有以天然铸型形式产出的三趾足迹，同时在一块坠落的砂岩块体上保留有实体足迹印痕。至少三处产足迹的古地表，与水平层理砂岩及脱水绿色泥岩伴生，可在250米的延展范围内被追索识别。在其中一处产足迹的古地表伴生的离散U形横截面构造，被解释为一系列天然铸型、表面足迹、实体足迹与下覆足迹（undertracks）。尽管齐科阿内的足迹在历史上被归为单一遗迹属，后被归入与格雷拉迹（Grallator）同物异名的类群，但本研究发现三趾遗迹化石的多样性更高：除此前已识别的格雷拉迹（Grallator）类特征外，还存在类似凯娜塔普迹（Kayentapus）与真蜥脚迹（Eubrontes）的形态特征。这些依托高分辨率沉积学背景的新发现，增进了我们对恐龙历史关键时期——即恐龙丰度与多样性均显著增长的阶段——南非南部地区兽脚类恐龙的古生物多样性与古生态的认知。