北卡罗莱纳州自然科学博物馆James G. Napoli团队的一项最新研究报道了矮暴龙和暴龙在白垩纪末期共存。相关论文于2025年10月30日发表在《自然》杂志上。

研究人员描述了来自地狱溪组的一具保存非常完好的、近乎成熟的暴龙骨架（NCSM 40000），它与N. lancensis的全型标本具有相同的自异形。该研究组将比较解剖学、纵向生长模型、个体发育特征不变性观察和一个新的系统发育数据相结合，验证了Nanotyrannthem的有效性，最终证明了该分类单元与Tyrannosaurthem区分开来，位于Tyrannosauridae之外，并且出乎意料地包含两个物种-N。长臂猿和长臂猿；他们的研究结果促使人们重新评估几十个现有的基于目前站不住脚的个体发生轨迹的假设。最后，研究组在北美的马斯特里赫特地区记录了至少两个共生的、生态形态学上不同的属，这表明在白垩纪末期灭绝的100万年里，α暴龙的多样性蓬勃发展。

据了解，雷克斯暴龙是研究最全面的已灭绝脊椎动物之一，也是恐龙古生物学的一个模型系统。作为最后幸存的非鸟类恐龙之一，霸王龙是评估白垩纪末期大灭绝（地球上最大的生物灾难之一）之前陆地生物多样性、生态系统结构和生物地理交换的重要数据。暴龙的古生物学研究，包括个体发育生态位划分、摄食、运动生物力学和生活史，利用了包含多个假设生长阶段的不断扩大的骨骼样本，然而暴龙的次类群仍然存在争议。一个关键的悬而未决的问题涉及到未成熟暴龙的标本，这些标本被认为代表了不同的矮暴龙分类群。

附：英文原文

Title: Nanotyrannus and Tyrannosaurus coexisted at the close of the Cretaceous

Author: Zanno, Lindsay E., Napoli, James G.

Issue&Volume: 2025-10-30

Abstract: Tyrannosaurus rex ranks among the most comprehensively studied extinct vertebrates1 and a model system for dinosaur paleobiology1. As one of the last surviving non-avian dinosaurs, Tyrannosaurus is a crucial datum for assessing terrestrial biodiversity, ecosystem structure, and biogeographic exchange immediately preceding the end-Cretaceous mass extinction —one of Earth’s greatest biological catastrophes. Paleobiological studies of Tyrannosaurus, including ontogenetic niche partitioning2-4, feeding, locomotor biomechanics,5,6and life history7-9 have drawn upon an expanding skeletal sample comprising multiple hypothesized growth stages—and yet the Tyrannosaurus hypodigm remains controversial10-13. A key outstanding question relates to specimens considered to exemplify immature Tyrannosaurus1,14-19, which have been argued to represent the distinct taxon Nanotyrannus11,13,20,21. Here, we describe an exceptionally well-preserved, near somatically mature tyrannosaur skeleton (NCSM 40000) from the Hell Creek Formation that shares autapomorphies with the holotype specimen of N. lancensis. We couple comparative anatomy, longitudinal growth models, observations on ontogenetic character invariance, and a novel phylogenetic dataset to test the validity of Nanotyrannus, demonstrating conclusively that this taxon is distinguishable from Tyrannosaurus, sits outside Tyrannosauridae, and unexpectedly contains two species—N. lancensis and N. lethaeus, sp. nov. Our results prompt a re-evaluation of dozens of existing hypotheses based on currently indefensible ontogenetic trajectories. Finally, we document at least two co-occurring, ecomorphologically distinct genera in the Maastrichtian of North America, demonstrating that tyrannosauroid alpha diversity was thriving within one million years of the end-Cretaceous extinction.

DOI: 10.1038/s41586-025-09801-6

Source: https://www.nature.com/articles/s41586-025-09801-6