Data from: A palaeoequatorial Ornithischian and new constraints on early dinosaur diversification

Current characterizations of early dinosaur evolution are incomplete:
existing palaeobiological and phylogenetic scenarios are based on a fossil
record dominated by saurischians and the implications of the early
ornithischian record are often overlooked. Moreover, the timings of deep
phylogenetic divergences within Dinosauria are poorly constrained owing to
the absence of a rigorous chronostratigraphical framework for key Late
Triassic–Early Jurassic localities. A new dinosaur from the earliest
Jurassic of the Venezuelan Andes is the first basal ornithischian
recovered from terrestrial deposits directly associated with a precise
radioisotopic date and the first-named dinosaur from northern South
America. It expands the early palaeogeographical range of Ornithischia to
palaeoequatorial regions, an area sometimes thought to be devoid of early
dinosaur taxa, and offers insights into early dinosaur growth rates, the
evolution of sociality and the rapid tempo of the global dinosaur
radiation following the end-Triassic mass extinction, helping to
underscore the importance of the ornithischian record in broad-scale
discussions of early dinosaur history.

当前针对恐龙早期演化的特征描述仍不完善：现有的古生物学与系统发育研究范式均基于以蜥臀目（saurischians）为主的化石记录，早期鸟臀目（ornithischian）化石记录所蕴含的科学启示常被忽视。此外，由于关键晚三叠世-早侏罗世化石点缺乏严格的年代地层学框架，恐龙总目（Dinosauria）内部深层系统发育分化的时间节点约束极为有限。产自委内瑞拉安第斯山脉早侏罗世最早期地层的新型恐龙，是首个从与精确放射性同位素定年直接关联的陆相沉积中发掘的基干鸟臀目类群，同时也是南美洲北部地区被正式定名的第一种恐龙。该物种将鸟臀目的早期古地理分布范围拓展至古赤道区域——这一区域此前常被认为鲜有早期恐龙分类群存在——并为研究早期恐龙的生长速率、社会性演化，以及三叠纪末大灭绝（end-Triassic mass extinction）后全球恐龙辐射演化的快速节奏提供了新视角，同时也凸显了鸟臀目化石记录在早期恐龙宏观演化讨论中的重要性。