An illustrated comparison of a Neanderthal (left) and a modern human (right).
(Photo credit: Alice Walczer Baldinazzo.
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An international study of infant remains from 50,000-75,000 years ago has provided new evidence about the developmental trajectory of our evolutionary ‘cousins’, Neanderthals.
University of Queensland skeletal histologist Dr Justyna Miszkiewicz led analysis of ancient baby teeth and bones, revealing the growth of Neanderthals was remarkably similar to modern humans.
“The remains were unearthed in Sesselfelsgrotte, Germany in the 1960s and 1970s and lay in a museum until around 20 years ago when it was confirmed they were Neanderthal,” Dr Miszkiewicz said.
“Neanderthals were a separate species to Homo sapiens but co-existed alongside humans for around 5,000 years.
“We believe the bones came from a potentially unborn baby, while the molar teeth may have come from 2 different children – but they are all exceptionally rare.”
Researchers used non-invasive micro-computed tomography (micro-CT) to document the internal structure of the fragile specimens.
“Using this ‘virtual microanatomy’ technology we’ve been able to identify patterns in the bone tissue that are typical of a rapidly growing foetal skeleton,” Dr Miszkiewicz said.
“Some of the long bones, like the femur and humerus, showed regions of increased compactness and structural organisation that indicate more advanced growth than a typical modern human baby.
“But overall, the developmental trajectory still appears broadly similar to us modern humans during the early stage of life.”
Co-lead Dr Ricardo Miguel Godinho from the University of Algarve said the molars were ‘milk’ teeth, commonly lost before being replaced by adult teeth.
“The micro-CT scans revealed unusual mineralisation defects deep within the dentine [calcified tissue beneath the tooth enamel],” Dr Godinho said.
“These regions are consistent with interglobular dentine, a defect that forms when tooth mineralisation is interrupted.
“We can’t say for sure, but lesions like this could point to systemic disturbances such as vitamin D deficiency, calcium deficiency or impaired calcium absorption.”
The researchers said because these dental features likely formed between the third trimester of pregnancy and the child’s second year, they may record physiological or metabolic stress very early in life.
Top-bottom, left-right: Three-dimensional reconstruction of a Neanderthal child’s tooth and arm bone. A virtual microanatomy tooth slice shows mineralisation defects, while the bone slices show microanatomical organisation.
(Photo credit: Justyna Miszkiewicz.)
Dr Miszkiewicz said the study was an important insight into a species which once co-existed with humans.
“These tiny remnants provide an incredible glimpse into our human evolutionary history,” she said.
“It’s important to understand where we came from, and the ways in which we’re similar.”
The researchers said further high-resolution and multi-method studies would help refine interpretations of early Neanderthal growth and the origin of the dental defects.
Read the research in Royal Society Open Science.
Collaboration and acknowledgements
The research paper is part of the SHARP project, led by Dr Alvise Barbieri from the University of Algarve and funded by National Geographic.
Dr Miszkiewicz is an ARC Future Fellow in the archaeology team at UQ’s School of Social Science .
