美国纽约城市大学孟津课题组揭示了哺乳动物不同颌关节的趋同进化。相关论文发表在2025年9月24日出版的《自然》杂志上。
在这里，该课题组报告了两种具有新颖形状的哺乳动物的次颌关节，为哺乳动物颌的进化提供了见解。第一种是Polistodon8，一种中侏罗世食草动物三齿龙，体型相对较大，生活方式可能是穴居的，独特地进化出了牙颌关节。第二具化石是早侏罗世的摩根齿兽，它的牙齿-鳞状关节缺乏球泡状髁，这支持了哺乳动物的牙齿髁是由牙齿侧脊的扩张形成的假说。这些不同的关节反映了在高级犬齿动物中反复的进化实验，其中次级颌关节是独立出现的，而承重的牙鳞关节是哺乳动物的一种突触形态。尽管身体小型化可能推动了这一转变，但他们的研究结果表明，其他因素也参与其中，如颌细胞重组、摄食生态和咀嚼行为。这些类群的生态形态多样性表明，表型可塑性和环境诱导的形态变化可能塑造了下颌关节的进化，强调了生态压力和发育灵活性如何指导哺乳动物祖先颌骨结构的多样化。
研究人员表示，单牙骨的下颌及其在牙状髁和鳞状盂之间的继发性颅下颌关节的进化被认为是脊椎动物的关键创新，并定义了哺乳动物的特征。
附：英文原文
Title: Convergent evolution of diverse jaw joints in mammaliamorphs
Author: Mao, Fangyuan, Jiang, Shan, Liu, Jun, Ren, Jicheng, Ye, Yong, Liu, Yu, Shen, Xin, Wang, Tao, Wang, Guofu, Wang, Ping, Chen, Juan, Meng, Jin
Issue&Volume: 2025-09-24
Abstract: The evolution of a single-dentary-boned lower jaw and its secondary craniomandibular articulation between the dentary condyle and the squamosal glenoid has been regarded as a pivotal vertebrate innovation and defining mammalian trait1,2,3,4,5,6,7. Here we report two mammaliamorphs with novel shapes of secondary jaw joint, offering insight into the evolution of the mammalian jaw. The first, Polistodon8, a Middle Jurassic herbivorous tritylodontid with a relatively large body size and a lifestyle that is likely to have been fossorial, uniquely evolved a dentary–jugal articulation. The second, an Early Jurassic morganucodontan, exhibits a dentary–squamosal joint that lacks a bulbous condyle, supporting the hypothesis that the mammalian dentary condyle was formed by expansion of the lateral ridge of the dentary9. These diverse joints reflect repeated evolutionary experimentation in advanced cynodonts, in which secondary jaw joints arose independently7,10, and in which the load-bearing dentary–squamosal joint is a synapomorphy of mammaliaforms. Although body miniaturization might have driven this transformation11, our findings indicate that other factors were involved, such as jaw-muscle reorganization, feeding ecology and masticatory behaviour7,12,13,14,15,16,17. The ecomorphological diversity of these taxa suggest that phenotypic plasticity and environmentally induced morphological changes18,19,20 could have shaped jaw-joint evolution, emphasizing how ecological pressures and developmental flexibility guided the diversification of jaw structures in mammalian ancestors.
DOI: 10.1038/s41586-025-09572-0