Date Published:
7 January 2010 |
The teeth of a 30,000-year-old child are shedding new light on the evolution of modern humans
The teeth of a 30,000-year-old child are shedding new light on the
evolution of modern humans, according to research from the University
of Bristol (England, UK) published this week in PNAS.
The teeth are part of the remarkably complete remains of a child found in the
Abrigo do Lagar Velho, Portugal and excavated in 1998-9 under the leadership
of Professor João Zilhão of the University of Bristol. Classified as a modern
human with Neanderthal ancestry, the child raises controversial questions about
how extensively Neanderthals and modern human groups of African descent interbred
when they came into contact in Europe.
‘Early modern humans’, whose anatomy is basically similar to that of the human race today, emerged over 50,000 years ago and it has long been the common perception that little has changed in human biology since then.
When considering the biology of late archaic humans such as the Neanderthals, it is thus common to compare them with living humans and largely ignore the biology of the early modern humans who were close in time to the Neanderthals.
With this in mind, an international team, including Professor Zilhão, reanalysed the dentition of the Lagar Velho child (all of its deciduous – milk – teeth and almost all of its permanent teeth) to see how they compared to the teeth of Neanderthals, later Pleistocene (12,000-year-old) humans and modern humans.
Employing a technique called micro-tomography which uses x-rays to create cross-sections of 3D-objects, the researchers investigated the relative stages of formation of the developing teeth and the proportions of crown enamel, dentin and pulp in the teeth.
They found that, for a given stage of development of the cheek teeth, the front teeth were relatively delayed in their degree of formation. Moreover, the front teeth had a greater volume of dentin and pulp but proportionally less enamel than the teeth of recent humans.
The teeth of the Lagar Velho child thus fit the pattern evident in the preceding Neanderthals, and contrast with the teeth of later Pleistocene (12,000-year-old) humans and living modern humans.
Professor Zilhão said:
“ This new analysis of the Lagar Velho child joins a growing body of
information from other early modern human fossils found across Europe (in
Mladec in the Czech Republic, Pestera cu Oase and Pestera Muierii in Romania,
and Les Rois in France) that shows these ‘early modern humans’ were ‘modern’
without being ‘fully modern’. Human anatomical evolution continued after
they lived 30,000 to 40,000 years ago.”
The team was led by Priscilla Bayle (Muséum National d’Histoire Naturelle, France) and Roberto Macchiarelli (Université de Poitiers, France) and included Erik Trinkaus (Professor of Anthropology at Washington University, St.-Louis, Cidália Duarte (Câmara Municipal do Porto, Portugal), and Arnaud Mazurier (CRI-Biopôle-Poitiers, France).
Paper: Dental maturational sequence and dental
tissue proportions in the early Upper Paleolithic child from Abrigo do Lagar
Velho, Portugal by Priscilla Bayle, Roberto Macchiarelli, Erik Trinkaus,
Cidália Duarte, Arnaud Mazurier, and João Zilhão.
News
is included on the IvyRose website to inform visitors about current health issues,
but not to endorse any particular view or activity. Any views expressed in the
article above are not necessarily those of IvyRose Ltd.. Material in this news
item was released by Bristol University on 07 January 2010 and may have been
edited (e.g. in style, length, and/or for ease of understanding by our international
readers) for inclusion here. For further information, please visit their website.
|
