Morphology of Denisovan molars: problems of taxon identification in the context of genetic data

Abstract

Attempts to analyse fragmentary specimens of Denisovan remains in conjunction with archaeological and genetic data may be a useful experience in the search for taxonomically valuable traits. The paper presents the results of a dental analysis of 3 permanent molars and 1 deciduous tooth of the upper and lower jaws of different individuals, representing different stages of the Denisovan (Homo altaensis or Homo s. denisovan) existence in the territory of modern Altai during the Pleistocene. The chronological age of the finds is marked by a wide interval from about 300–200 kyBP to 84–55 kyBP. The materials were obtained during excavations in Denisova Cave (Northwestern Altai). The presence of both exceptional megadontia and obvious hominin features in the odontoglyphics of Denisovans allows us to discuss this feature as the most characteristic. The crowns of the teeth show certain proportions, with a relative reduction of the hypocone, but the dimensions of this tubercle are consistently larger than in other hominins (with the exception of Homo heidelbergensis and Neanderthals, who often show the same variations, but with different proportions and less crown size). Often, the chewing surface shows features characteristic of anatomically modern humans and Neanderthals, but at the same time the teeth are marked by the presence of unique combinations characteristic of hominoids, not hominins. The tooth of a representative of a later wave of migration shows a greater number of unique combinations than the tooth of a representative of an early wave of migrants to Altai. It is possible that the later populations of Denisovans showed a founder effect during selection, crystallizing, among other things, rare phenotypes, for example, unique combinations of chewing surface relief.

Keywords

• altai
• pleistocene hominins
• denisovans
• homo altaensis
• homo s. denisovan
• odontology
• paleogenetics