Homo bodoensis lived in Africa during the early Middle Pleistocene, around 500,000 years ago, and was the direct ancestor of the Homo sapiens lineage; however, this species was not the most recent common ancestor of Eurasian (Neanderthals and Denisovans) and African (Homo sapiens) hominins.
Homo bodoensis had a pan-African distribution with the peripheral range extending into the eastern Mediterranean (Southeast Europe and the Levant) from which it could have contributed to the repopulation of European (and possibly Central and East Asian) demographic sinks after the glaciations. Image credit: Ettore Mazza.
The Middle Pleistocene (774,000-129,000 years ago) is important because it saw the rise of Homo sapiens in Africa and Neanderthals in Europe.
However, human evolution during this age is poorly understood, a problem which paleoanthropologists call the ‘muddle in the middle.’
The announcement of Homo bodoensis hopes to bring some clarity to this puzzling, but important chapter in human evolution.
“The study of human evolution in the Middle and Late Pleistocene has experienced significant advances in recent decades,” said lead author Dr. Mirjana Roksandic, a paleoanthropologist in the Department of Anthropology at the University of Winnipeg and the University of Tübingen, and her colleagues.
“We now know that the origin of Homo sapiens was African (possibly pan-African) and extends further back into the late Middle Pleistocene than previously thought.”
“It is also clear that this taxon was dispersing out of Africa prior to 60,000 years ago, likely in multiple smaller waves, with a major dispersal post-60,000 years ago .”
“Further, over the past two decades species assigned to the genus Homo (e.g., Homo floresiensis, Homo naledi, and Homo luzonensis) that were contemporary with the Homo sapiens lineage but are considered to have played little to no role in the latter’s evolution, attest to the complexity of the later Pleistocene human evolutionary record.”
“The Middle Pleistocene is no longer dismissed as the proverbial ‘muddle in the middle,’ but is increasingly recognized as a key time frame that witnessed the appearance, on a global scale, of two critical traits of later human morphology: greater encephalization and smaller teeth, and likely the differentiation of geographic groups.”
Homo bodoensis is an early Middle Pleistocene ancestor of Homo sapiens. Image credit: Ettore Mazza.
Homo bodoensis is based on a reassessment of existing fossils from Africa and Eurasia from this time period.
Traditionally, these fossils have been variably assigned to either Homo heidelbergensis or Homo rhodesiensis, both of which carried multiple, often contradictory definitions.
“Talking about human evolution during this time period became impossible due to the lack of proper terminology that acknowledges human geographic variation,” Dr. Roksandic said.
Previously, paleoanthropologists found that some fossils of Homo heidelbergensis actually belonged to early Neanderthals, making the name redundant. For the same reason, the name needs to be abandoned when describing fossil humans from east Asia.
Further muddling the narrative, African fossils dated to this period have been called at times both Homo heidelbergensis and Homo rhodesiensis. The latter species is poorly defined and the name has never been widely accepted.
The name bodoensis refers to the site of Bodo D’ar in Ethiopia where the fossil specimen Bodo 1 was discovered.
“Bodo 1 is a partial cranium of an adult (presumably male) individual, preserving the face and the anterior braincase, found in autumn 1976 by Alemayehu Asfaw, Paul Whitehead and other members of the Rift Valley Research Mission in Ethiopia headed by Jon Kalb,” the researchers said.
Homo bodoensis holotype partial cranium Bodo 1 (Middle Awash, Ethiopia): frontal (a), left lateral (b), superior (c), and inferior (d) views. Scale bar – 5 cm. Image credit: Jeffrey H. Schwartz / Roksandic et al., doi: 10.1002/evan.21929.
Under the new classification, Homo bodoensis will describe most Middle Pleistocene humans from Africa and some from Southeast Europe, while many from Europe (e.g. Sima de los Huesos) will be reclassified as Neanderthals.
“Homo bodoensis separated from the Eurasian groups before the split of the Eurasian forms into Neanderthals, Denisovans, and possibly other groups,” the scientists said.
“While essentially an African species, Homo bodoensis may have played a role in the evolutionary history of the Levant and Europe.”
“In particular, Middle Pleistocene specimens from the two regions (mostly concentrated in the eastern Mediterranean), which do not demonstrate any Neanderthal traits, such as Mala Balanica (Serbia) and some specimens from the Levant such as Hazorea and Nadaouiyeh Aïn Askar could be considered as Homo bodoensis.”
“The species was potentially present in Europe during the Middle Pleistocene (as evidenced by the Ceprano specimen) and may have contributed to a mixed morphology seen in Arago, Petralona, and possibly other fossils in Western Europe.”
The team’s paper was published this week in the journal Evolutionary Anthropology.
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Mirjana Roksandic et al. Resolving the ‘muddle in the middle:’ The case for Homo bodoensis sp. nov. Evolutionary Anthropology, published online October 28, 2021; doi: 10.1002/evan.21929