Department of Anthropology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
Bureau of Land Management, Utah State Office, Salt Lake City, UT, USA.
Sci Adv. 2019 Feb 27;5(2):eaau1200. doi: 10.1126/sciadv.aau1200. eCollection 2019 Feb.
Stable isotope analysis of the first fossilized remains from Belize offers valuable insights into the conditions within which this individual lived and its ability to adapt to the increasing aridity of the Last Glacial Maximum (LGM). Cathodoluminescence (CL) microscopy was used to identify chemical alteration of the tooth during fossilization. Results demonstrate that the inner orthodentin resists diagenesis, yielding potentially unaltered values. Using an intensive "vacuum milling" technique, the inner orthodentin produced an accelerator mass spectrometry (AMS) date of 26,975 ± 120 calibrated years before the present. The stable carbon and oxygen isotope analysis of this layer shows that the tooth recorded two wet seasons separated by one longer dry season and that this sloth was able to adapt its diet to the marked seasonality of the LGM. This study offers new insights into obtaining reliable isotope data from fossilized remains and suggests that this individual adapted to climate shifts, contributing to the conversation surrounding megafauna extinction.
对伯利兹首例有化石记录的遗骸进行稳定同位素分析，为了解个体生活的条件及其适应末次冰盛期（LGM）日益干旱的能力提供了有价值的见解。利用阴极发光（CL）显微镜来鉴定化石过程中牙齿的化学变化。结果表明，内牙本质抵抗成岩作用，产生潜在未改变的值。使用密集的“真空研磨”技术，内牙本质产生加速器质谱（AMS）日期为 26975±120 年前校准。该层的稳定碳和氧同位素分析表明，牙齿记录了两个雨季，其间有一个较长的旱季，这种树懒能够根据 LGM 的明显季节性调整其饮食。这项研究为从化石遗骸中获得可靠的同位素数据提供了新的见解，并表明个体适应了气候变化，为有关巨型动物灭绝的讨论做出了贡献。
