Hominin round-up

Neanderthal ‘high-carb’ diet and self-medication

There is no doubt that the reconstruction of DNA from Neanderthal and Denisovan fossils is the most important forensic breakthrough as regards hominin evolution and relationships, but another approach has is starting to shed light on past lifestyles. Most workers have regarded Neanderthals as being predominantly meat-eaters from the evidence for their big-game hunting feats. In an attempt to get close to their actual diet some researchers have begun to exploit the lack of dental hygiene among fossil hominins: many teeth bear plaque or dental calculus (hardy, K. and 16 others 2012. Neanderthal medics? Evidence for food, cooking, and medicinal plants entrapped in dental calculus. Naturwissenschaften, v. 99, p. 617-626). Karen Hardy of the Universitat Autònoma de Barcelona and British, Spanish and Australian colleagues used gas chromatography and mass spectrometry and analysis of trapped microfossils in Neanderthal teeth to explore their everyday lives.

The results show signs of wood smoke: a good indicator of cooking and perhaps smoke preservation. Bitumen traces help confirm its use in hafting tools. But the most interesting feature is the consistent identification of cooked carbohydrate residues, enzyme activity on which would have produced the sugars strongly implicated in the formation of substantial plaque deposits. The data suggest that nuts, grass seeds, and possibly even green vegetables were a major part of the Neanderthal diet, A fascinating outcome is the discovery of molecules of the compounds that confer bitterness on a number of herbs with known medicinal properties, such as yarrow and chamomile. That does not prove that Neanderthals were accomplished herbalists, for many primates seek out such plants when feeling ill and even domestic cats will be seen eating grass if they have digestive problems or worms. Yet practical knowledge of herbal remedies cannot be ruled out. This novel, hi-tech approach to life-style analysis will surely blossom for most fossilized hominin dentition bears plenty of plaque. We await with interest the first signs of regular use of tooth-cleaning with woody fibres.

Neanderthals and Aurignacians survived massive volcanic disaster

About 39 thousand years ago the famous volcanic field of the Campi Flegrei west of Naples underwent a massive explosive eruption that created a huge ash plume whose deposition blanketed most of southeastern and eastern Europe with the Campanian Ignimbrite. The ashfall and the probable disruption of climate and ecosystems over a number of years would have greatly stressed both Neanderthal and modern human (Aurignacian) populations of the area. There are a few sites in the Ukraine and Russia where tools occur below, within and above the ash deposit, but little to suggest the extent to which both populations were affected. However, tangible ash deposits are not the only evidence for volcanic events in human history: fine ash would have permeated everything during the eruption. A host of European geologists and archaeologists have sought microscopic evidence of the Campanian Ignimbrite in sediments within caves that were occupied at this time (Lowe, J. and 41 others 2012. Volcanic ash layers illuminate the resilience of Neanderthals and early modern humans to natural hazards. Proceedings of the National Academy of Sciences doi/10.1073/pnas.1204579109): ignimbrite events are signified in cave deposits by ash dominated by minute glassy shards, whose shape is distinctive. The study was able to show that although the effects of the 39 ka eruption must have been devastating for local humans, both groups pulled through. The fact that Neanderthals survived the eruption and attendant prolonged climatic cooling suggests indirectly that their eventual demise was probably not a result of ecological disaster and more likely to have reflected their incapacity to compete successfully with the Aurignacian and later fully-modern human cultures.

Quite a crowd

Who was the earliest human? Initially this accolade went to Homo habilis, first found by Louis Leakey at Olduvai Gorge, Tanzania in 2 Ma old sediments. Similar fossils turned up at Koobi Fora on the shores of Lake Turkana (formerly Lake Rudolr) in Kenya also thanks to the Leakey dynasty. Yet as more remains of that antiquity were found differences among them began to emerge, which some ascribed to different species and others to effects of sexual dimorphism among H. habilis. The majority view emerged of two distinct species H. habilis and ergaster but the possibility of a third cohabiting member of the early East African human family was clung to in the shape of the single-fossil ‘H. rudolfensis’ . There the issue stood for more than two decades. Then, in the manner of London Transport, fossils of three individual humans were unearthed at Koobi Fora by the determined Leakey family (Leakey, M.G. et al. 2012. New fossils from Koobi Fora in northern Kenya confirm taxonomic diversity in early Homo. Nature, v. 488, p. 201-204). They seem to have confirmed three separate cohabiting species of human in Kenya in the period between 1.8 and 2.0 Ma: habils, rudolfensis and erectus/ergaster. Now, this is quite odd as the threefold morphological distinction ought to reflect three lifestyles sufficiently different to support the species over several hundred thousand years. Hopefully, there are teeth and dental plaque…