加拿大卡尔加里大学Darla K. Zelenitsky团队研究了一种新的蒙古暴龙与真暴龙的进化。相关论文于2025年6月11日发表于《自然》杂志上。

真暴龙类（Eutyrannosaurians）是一类大型掠食性恐龙，在晚白垩世末期曾主导亚洲和北美的陆地动物群。这些顶级掠食者起源于白垩纪中期体型较小的暴龙超科恐龙，但由于化石材料的匮乏，人们对这些早期类群知之甚少。研究组报道了在蒙古上白垩统下部地层中发现的一种新的暴龙超科恐龙——康和蒙古龙（Khankhuuluu mongoliensis gen. et sp. nov.），该发现为理解真暴龙类的起源和演化提供了新的视角。

系统发育分析显示，康和蒙古龙位于真暴龙类之外最接近的位置，并将体型巨大、吻部深壮的暴龙族（Tyrannosaurini）与体型较小、吻部浅平、形态纤细的分支龙族（Alioramini）解析为高度衍生的真暴龙类姊妹支系。康和蒙古龙和较晚分化的分支龙族均独立地拥有与幼年真暴龙类相似的特征，即浅平的颅骨和纤细的体型，这强化了异时发育（heterochrony）在真暴龙类演化中的关键作用。尽管真暴龙类主要受到过型形成（peramorphosis，即加速生长）的影响，但研究组表明，分支龙族是一个衍生的（derived）支系，它通过幼态持续（paedomorphosis）保留了未成熟的特征，而非如广泛接受的那样是一个更基干（basal）的类群。

该研究结果表明，亚洲的暴龙超科恐龙（类似康和蒙古龙）曾扩散至北美，并在晚白垩世中期演化出真暴龙类。此后，真暴龙类在北美多样化并一直局限于该地；直到晚白垩世末期，才通过单次扩散事件重返亚洲，并在那里演化出分支龙族和暴龙族。分支龙族与暴龙族之间显著的形态差异，很可能是由各自不同的异时发育趋势演化所致——前者为幼态持续，后者为过型形成——这使得它们能够在亚洲共存并占据不同的生态位。

附：英文原文

Title: A new Mongolian tyrannosauroid and the evolution of Eutyrannosauria

Author: Voris, Jared T., Zelenitsky, Darla K., Kobayashi, Yoshitsugu, Modesto, Sean P., Therrien, Franois, Tsutsumi, Hiroki, Chinzorig, Tsogtbaatar, Tsogtbaatar, Khishigjav

Issue&Volume: 2025-06-11

Abstract: Eutyrannosaurians were large predatory dinosaurs that dominated Asian and North American terrestrial faunas in latest Cretaceous times. These apex predators arose from smaller-bodied tyrannosauroids during the ‘middle’ Cretaceous that are poorly known owing to the paucity of fossil material1,2,3. Here we report on a new tyrannosauroid, Khankhuuluu mongoliensis gen. et sp. nov., from lower Upper Cretaceous deposits of Mongolia that provides a new perspective on eutyrannosaurian origins and evolution. Phylogenetic analyses recover Khankhuuluu immediately outside Eutyrannosauria and recover the massive, deep-snouted Tyrannosaurini and the smaller, gracile, shallow-snouted Alioramini as highly derived eutyrannosaurian sister clades. Khankhuuluu and the late-diverging Alioramini independently share features related to a shallow skull and gracile build with juvenile eutyrannosaurians, reinforcing the key role heterochrony had in eutyrannosaurian evolution. Although eutyrannosaurians were mainly influenced by peramorphosis or accelerated growth4,5,6,7,8,9,10, Alioramini is revealed as a derived lineage that retained immature features through paedomorphosis and is not a more basal lineage as widely accepted11,12,13,14,15,16,17,18,19. Our results reveal that Asian tyrannosauroids (similar to Khankhuuluu) dispersed to North America, giving rise to Eutyrannosauria in the mid-Late Cretaceous. Eutyrannosauria diversified and remained exclusively in North America until a single dispersal to Asia in the latest Cretaceous that established Alioramini and Tyrannosaurini. Stark morphological differences between Alioramini and Tyrannosaurini probably evolved due to divergent heterochronic trends—paedomorphosis versus peramorphosis, respectively—allowing them to coexist in Asia and occupy different ecological niches.

DOI: 10.1038/s41586-025-08964-6

Source: https://www.nature.com/articles/s41586-025-08964-6