Justin Ledogar, assistant professor in the East Tennessee State University College of Public Health's Department of Biomedical Health Sciences, has two papers in Nature's list of top 100 paleoanthropology papers.
"On February 7, 1925, Nature published a curious paper on a ‘missing link’ – the fossil of a form intermediate between apes and humans. The fossil, named Australopithecus africanus, confirmed Darwin’s suspicions that human origins lay in Africa, and opened the door to the study of human evolution in Africa. Ever since then, Nature – now augmented by other journals in the Nature Portfolio – has been the destination of choice for researchers publishing in this area." To mark the 100th anniversary, the journal selected a collection of 100 papers on palaeoanthropology in Africa selected from Nature, Nature Ecology and Evolution, and Nature Communications, in collaboration with Nature Africa.
Dr. Ledogar is first author on,"Mechanical evidence that Australopithecus sediba was limited in its ability to eat hard foods,"published in 2016.
Abstract:
Australopithecus sediba has been hypothesized to be a close relative of the genus Homo. Here we show that MH1, the type specimen of A. sediba, was not optimized to produce high molar bite force and appears to have been limited in its ability to consume foods that were mechanically challenging to eat. Dental microwear data have previously been interpreted as indicating that A. sediba consumed hard foods, so our findings illustrate that mechanical data are essential if one aims to reconstruct a relatively complete picture of feeding adaptations in extinct hominins. An implication of our study is that the key to understanding the origin of Homo lies in understanding how environmental changes disrupted gracile australopith niches. Resulting selection pressures led to changes in diet and dietary adaption that set the stage for the emergence of our genus.
He is a co-author of, "Drimolen cranium DNH 155 documents microevolution in an early hominin species," published in 2021.
Abstract:
Paranthropus robustus is a small-brained extinct hominin from South Africa characterized by derived, robust craniodental morphology. The most complete known skull of this species is DNH 7 from Drimolen Main Quarry, which differs from P. robustus specimens recovered elsewhere in ways attributed to sexual dimorphism. Here, we describe a new fossil specimen from Drimolen Main Quarry, dated from approximately 2.04–1.95 million years ago, that challenges this view. DNH 155 is a well-preserved adult male cranium that shares with DNH 7 a suite of primitive and derived features unlike those seen in adult P. robustus specimens from other chronologically younger deposits. This refutes existing hypotheses linking sexual dimorphism, ontogeny and social behaviour within this taxon, and clarifies hypotheses concerning hominin phylogeny. We document small-scale morphological changes in P. robustus associated with ecological change within a short time frame and restricted geography. This represents the most highly resolved evidence yet of microevolutionary change within an early hominin species.
Dr. Randy Wykoff, dean of the college, said, "In the 100 years since Australopithecus was first identified, our understanding of our early human ancestors has grown tremendously. Nature and its sister publications have become the premier location to publish ground-breaking reports on this topic. It is a reflection on the tremendous importance of Dr. Ledogar’s work that two articles been published in Nature, and they have been identified as among the most impactful articles in the field over the past century.”