An 800,000-year-old skeleton of an ancestor species to modern humans belonged to a female and not a male as previously assumed, new research has shown.
The gender change for the skeleton, previously known as the Boy of Gran Dolina, came after researchers used modern techniques to analyse dental tissues, finding it belonged to a girl aged between nine and 11 years.
The skeleton is an example of Homo antecessor – believed to be the final common ancestor shared by Homo sapiens and Neanderthals before the two species split.
The remains were found at the Spanish archeological site Grand Dolina in the 1960s, and it was later determined they died after being killed and eaten by a rival tribe.
Scientists had no idea what the actual gender was until this study, with the concept of it being a boy coming from a children’s book about the dig site written by José Maria Bermúdez de Castro in 2002 called El Chico De La Gran Dolina.
‘At this time it was not known what sex this fossil belonged to, so a male name was chosen, but it could have been a female one,’ said study author Cecilla Garcia.
An 800,000-year-old skeleton of an ancestor species to modern humans belonged to a female and not a male as previously assumed, new research has shown. Artist impression
DETERMINING GENDER THROUGH DENTISTRY
Estimating the sex of the ‘Girl of Gran Doline’ was done by the Dental Anthropology Group at the Centro Nacional de Investigación de la Evolución Humana (CENIEH).
It was accomplished by studying the proportions of the dental tissues in the canines of these ancient human fossils.
The enamel and dentin dimensions in these dental pieces are sexually dimorphic traits.
In other words, they enable male and female individuals within a population to be distinguished.
For this reason, these parameters have previously been employed to estimate sex in forensic samples, where they reach an accuracy rate of up to 92.3%.
The new study, by Garcia and colleagues at the Dental Anthropology Group at the Centro Nacional de Investigación de la Evolución Humana (CENIEH), is the first to estimate the sex of two of the most complete fossils found at the dig site.
Using modern techniques, they examined the remains of individual H1, from which the species Homo antecessor was defined, and the individual H3, previously assumed to be a girl due to the children’s book on the dig site.
The results revealed that the two individuals’ canines show differences comparable to those observed between modern men and women.
‘This has allowed it to be established that H1 was probably a male, while the fossil H3 was probably a female,’ Carcia explained.
The human remains found at Gran Dolina have been analysed by many researchers, although up to now it had not been possible to assess gender differences.
This is because the majority of the individuals were immature, meaning that they had not reached adolescence, which complicates estimating their sex.
On top of this, there is the difficulty entailed by having only small skeleton fragments available, rather than a complete set of bones, they added.
‘To date, we only knew the sex of one tooth fragment, from which enamel proteins were obtained, added co-author José María Bermúdez de Castro.
The gender change for the skeleton, previously known as the Boy of Gran Dolina, came after researchers used modern techniques to analyse dental tissues
‘This study conducted by our Group now opens up a new and highly reliable way to estimate sex through a non-destructive method.’
Estimating the sex was accomplished by studying the proportions of the dental tissues in the canines – the enamel and dentin dimension.
This is because the dimensions of these are sexually dimorphic traits, meaning they are different between males and females of a species.
For this reason, this technique has been used in the past to estimate the sex in forensic samples – with accuracy of 92.3 per cent and in fossil samples.
Teeth offer the additional advantage that their formation is complete at an early stage, and therefore they allow sex to be estimated even in immature individuals.
The team said this was an especially useful point in the field of paleoanthropology.
For the first time they were able to confirm that the remains of the individual H3 from Gran Dolina belonged to a girl aged between 9 and 11.
The skeleton, found at Gran Dolina, in a cave (pictured), is an example of Homo antecessor – believed to be the final common ancestor shared by Homo sapiens and Neanderthals
The remains were found at the Spanish archeological site Grand Dolina in the 1960s, and it was later determined they died after being killed and eaten by a rival tribe
‘This individual is represented by a partial face and a fragment of the frontal bone, although typically this appears in photographs together with a mandible found in 2003 which, curiously, is considered very likely to be of female sex’, explains García.
The Girl of Gran Dolina probably had a stature and body proportions similar to those of a modern girl of her age, although it may be that she developed earlier.
Even though not much is yet known about how her life more than 800,000 years ago might have been, we do know something about how her story ended.
The remains found at Gran Dolina, including those of the girl, show clear evidence of cannibalism, probably the result of a confrontation between rival groups.
The findings have been published in the Journal of Anthropological Sciences.
WHO WERE THE HOMO ANTECESSORS?
A lifelike model of a Homo antecessor female is posed scooping out the brains of decapitated head
Homo antecessor is one of the earliest known varieties of human discovered in Europe, dating as far back as one million years ago.
Believed to have weighed around 14 stone, Homo antecessor was said to have been between 5.5 and 6ft tall.
Their brain sizes were roughly between 1,000 and 1,150 cm³, which is smaller than the average 1,350 cm³ brains of modern humans.
The species is believed to have been right-handed, making it different from other apes, and may have used a symbolic language, according to archaeologists who found remains in Burgos, Spain in 1994.
How Homo antecessor may be related to other Homo species in Europe has a subject of fierce debate.
Many anthropologists believe there was an evolutionary link between Homo ergaster and Homo heidelbergensis.
Archaeologist Richard Klein claims Homo antecessor was a separate species completely, that evolved from Homo ergaster.
However, others claim Homo antecessor is actually the same species as Homo heidelbergensis, who lived in Europe between 600,000 and 250,000 years ago in the Pleistocene era.
In 2010 stone tools were found at the same site in Happisburgh, Norfolk, believed to have been used by Homo antecessor.
Scientists believe that these early human species would breed with one another on a regular basis.
Dr Matthias Meyer, a palaeogeneticist at the Max Planck Institute for Evolutionary Anthropology, in Leipzig, Germany said: ‘The evolutionary history of archaic humans in the Middle Pleistocene was quite complex.
‘It could be that both the ancestors of the Sima people and Denisovans interbred with another archaic group like Homo antecessor or Homo erectus.
‘Or it is possible that the mitochondrial DNA we know from late Neanderthals came in from another group that left Africa.’