研究人员报告了一个不寻常的长颈鹿化石，獬豸盘角鹿（Discokeryx xiezhi），来自早中新世，它有一个不寻常的盘状头部结构和已知哺乳动物中最复杂的头颈关节。其独特的形态和有限元分析表明，它适应于激烈的头部撞击行为。牙釉质同位素数据表明，獬豸盘角鹿占据了一个不同于其他食草动物的生态位，与现代长颈鹿特有的高位觅食生态位相当。该研究表明，长颈鹿比其他反刍动物表现出更高的头部结构多样性，生活在特定的生态位可能促进了各种种内战斗行为，导致不同长颈鹿品系的极端头颈形态。
据悉，自达尔文时代以来，长颈鹿的长颈一直被认为是适应性进化的一个典型例子。
附：英文原文
Title: Sexual selection promotes giraffoid head-neck evolution and ecological adaptation
Author: Shi-Qi Wang, Jie Ye, Jin Meng, Chunxiao Li, Loc Costeur, Bastien Mennecart, Chi Zhang, Ji Zhang, Manuela Aiglstorfer, Yang Wang, Yan Wu, Wen-Yu Wu, Tao Deng
Issue&Volume: 2022-06-03
Abstract: The long neck of the giraffe has been held as a classic example of adaptive evolution since Darwin’s time. Here we report on an unusual fossil giraffoid, Discokeryx xiezhi, from the early Miocene, which has an unusual disk-shaped headgear and the most complicated head-neck joints in known mammals. The distinctive morphology and our finite element analyses indicate an adaptation for fierce head-butting behavior. Tooth enamel isotope data suggest that D. xiezhi occupied a niche different from that of other herbivores, comparable to the characteristic high-level browsing niche of modern giraffes. The study shows that giraffoids exhibit a higher headgear diversity than other ruminants and that living in specific ecological niches may have fostered various intraspecific combat behaviors that resulted in extreme head-neck morphologies in different giraffoid lineages.
DOI: abl8316
Source: https://www.science.org/doi/10.1126/science.abl8316