Data from: Assessing niche conservatism using a multi-proxy approach: dietary ecology of extinct and extant spotted hyenas

A central premise of bioclimatic envelope modeling is the assumption of niche conservatism. Whereas such assumptions are testable in modern populations, it is unclear if niche conservatism holds over deeper time spans and over very large geographic ranges. Hyaenids occupied a diversity of ecological niches over time and space, and until the end-Pleistocene they occurred in Europe and most of Asia, with Asian populations of Crocuta suggested as being genetically distinct from their closest living extant relatives. Further, little is known regarding if and how the dietary ecology of extinct populations of Crocuta differed from their extant African counterparts. Here, we use a multi-proxy approach to assess an assumption of conserved dietary ecology in late Pleistocene and extant Chinese spotted hyenas via finite element analysis, dental microwear texture analysis, and a novel dental macrowear method here proposed. Results from finite element simulations of the masticatory apparatus of Chinese and African Crocuta demonstrate lower skull stiffness and higher stress in the orbital region of the former when biting with carnassial teeth, suggesting that Chinese Crocuta could not process prey with the same degree of efficiency as extant C. crocuta. Dental microwear textural data further support this interpretation as Chinese Crocuta have intermediate and indistinguishable complexity values (indicative of hard object feeding) between the extant African lion (Panthera leo) and extant hyenas (C. crocuta, Hyaena hyaena, and Parahyaena brunnea) – being most similar to the omnivorous P. brunnea. The use of dental macrowear to infer dietary behavior may also be possible in extinct taxa as evinced by dietary correlations between extant African feliforms and dental macrowear assignments. Collectively, this multi-proxy analysis suggests that Chinese Crocuta may have exhibited dietary behavior distinct from living C. crocuta, and assumptions of niche conservatism may mask significant dietary variation in species broadly distributed in time and space.

生物气候信封模型（bioclimatic envelope modeling）的核心前提是生态位保守性（niche conservatism）假设。尽管这类假设可在现代种群中得到验证，但目前尚不清楚生态位保守性是否适用于更久远的时间跨度以及超大型地理分布范围。鬣狗科（Hyaenidae）类群在不同时间与空间维度占据了多样的生态位，直至更新世末期，它们曾分布于欧洲与亚洲大部分区域，有研究表明斑鬣狗属（Crocuta）的亚洲种群与其现存近亲在遗传上存在差异。此外，目前学界对已灭绝的斑鬣狗种群的饮食生态是否与现存非洲同类存在差异，以及差异的具体形式，仍知之甚少。本研究采用多代理（multi-proxy）研究方法，通过有限元分析（finite element analysis）、牙齿微磨损纹理分析（dental microwear texture analysis）以及本文提出的一种新型牙齿宏观磨损方法，对更新世晚期与现存中国斑鬣狗的保守饮食生态假设进行评估。对中国与非洲斑鬣狗咀嚼装置的有限元模拟结果显示，当用裂齿咬合时，中国斑鬣狗的颅骨刚度更低，眼眶区域应力更高，这表明中国斑鬣狗无法像现存斑鬣狗（Crocuta crocuta）那般高效地处理猎物。牙齿微磨损纹理数据进一步佐证了这一结论：中国斑鬣狗的纹理复杂度值处于现存非洲狮（Panthera leo）与现存鬣狗类群（现存斑鬣狗C. crocuta、条纹鬣狗Hyaena hyaena以及棕鬣狗Parahyaena brunnea）之间，且无显著差异——这类特征通常指示硬食行为，其复杂度与杂食性的棕鬣狗最为相似。通过牙齿宏观磨损特征推断饮食行为的方法，在已灭绝类群中同样具备可行性，这一点已在现存非洲食肉形类（feliforms）的饮食与其牙齿宏观磨损特征的相关性研究中得到证实。综合来看，这项多代理分析表明，中国斑鬣狗的饮食行为或与现存斑鬣狗存在显著差异，而生态位保守性假设可能掩盖了在时间与空间上广泛分布的物种所存在的显著饮食变异。