Mosaic dental morphology in a terminal Pleistocene hominin from Dushan Cave in southern China.

Recent studies reveal high degrees of morphological diversity in Late Pleistocene humans from East Asia. This variability was interpreted as complex demographic patterns with several migrations and possible survival of archaic groups. However, lack of well-described, reliably classified and accurately dated sites has seriously limited understanding of human evolution in terminal Pleistocene. Here we report a 15,000 years-old H. sapiens (Dushan 1) in South China with unusual mosaic features, such as large dental dimensions, cingulum-like structures at the dentine level in the posterior dentition and expression of a "crown buccal vertical groove complex", all of which are uncommon in modern humans and more typically found in Middle Pleistocene archaic humans. They could represent the late survival of one of the earliest modern humans to settle in an isolated region of southern China and, hence, the retention of primitive-like traits. They could also represent a particularity of this group and, hence, reflect a high degree of regional variation. Alternatively, these features may be the result of introgression from some late-surviving archaic population in the region. Our study demonstrates the extreme variability of terminal Pleistocene populations in China and the possibility of a complex demographic story in the region.

Invading Europe: did climate or geography trigger early Eocene primate dispersals?

The Palaeocene-Eocene transition is characterized by a significant turnover of mammalian taxa in the fossil record of the northern continents, and primates are among the groups that make their first appearance at this time. One of the many questions that remain to be answered with regard to the earliest evolution of primates is the reason for their sudden and virtually simultaneous appearance in the fossil records of Asia, Europe and North America. The most obvious environmental correlate of the Palaeocene-Eocene transition is a sharp but relatively short-lived warming event leading up to the Palaeocene-Eocene thermal maximum (PETM) and evidenced in the stratigraphic record by a negative delta(13)C excursion. It remains unclear, however, whether or how this warming event may have influenced Palaeocene-Eocene faunal turnovers. This paper explores the hypothesis that environmental changes associated with the PETM facilitated an invasion of Western Europe by primates by comparing the ecological structure of local mammalian fauna immediately before and following the Palaeocene-Eocene transition. The results suggest that changes to the ecological profile of local mammalian fauna were relatively small and did not favour an invasion by primates, although a major uncertainty remains with respect to the availability of arboreal niches. At present it seems more likely that the invasion of western Europe by primates was due to the breakdown of one or more dispersal barriers close to the end of the Palaeocene.