Post by Admin on Oct 28, 2021 22:23:10 GMT
An international team of researchers, led by University of Winnipeg palaeoanthropologist Dr. Mirjana Roksandic, has announced the naming of a new species of human ancestor, Homo bodoensis. This species lived in Africa during the Middle Pleistocene, around half a million years ago, and was the direct ancestor of modern humans.
The Middle Pleistocene (now renamed Chibanian and dated to 774,000-129,000 years ago) is important because it saw the rise of our own species (Homo sapiens) in Africa, our closest relatives, and the Neanderthals (Homo neanderthalensis) 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 new name 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" according to Roksandic, lead author on the study.
Recently, DNA evidence has shown that some fossils in Europe called H. heidelbergensis were actually early Neanderthals, making the name redundant. For the same reason, the name needs to be abandoned when describing fossil humans from east Asia according to co-author, Xiu-Jie Wu (Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China).
Further muddling the narrative, African fossils dated to this period have been called at times both H. heidelbergensis and H. rhodesiensis. H. rhodesiensis is poorly defined and the name has never been widely accepted. This is partly due to its association with Cecil Rhodes and the horrendous crimes carried out during colonial rule in Africa -- an unacceptable honour in light of the important work being done toward decolonizing science.
The name "bodoensis" derives from a skull found in Bodo D'ar, Ethiopia, and the new species is understood to be a direct human ancestor. Under the new classification, H. bodoensis will describe most Middle Pleistocene humans from Africa and some from Southeast Europe, while many from the latter continent will be reclassified as Neanderthals,
The co-first author Predrag Radovic (Faculty of Philosophy, University of Belgrade, Serbia) says, "Terms need to be clear in science, to facilitate communication. They should not be treated as absolute when they contradict the fossil record."
The introduction of H. bodoensis is aimed at "cutting the Gordian knot and allowing us to communicate clearly about this important period in human evolution," according to one of the co-authors Christopher Bae (Department of Anthropology, University of Hawai'i at Manoa).
Roksandic agrees: "Naming a new species is a big deal, as the International Commission on Zoological Nomenclature allows name changes only under very strictly defined rules. We are confident that this one will stick around for a long time, a new taxon name will live only if other researchers use it."
Deciding whether a set of ancient human fossils belongs to one species or another is often a challenging problem open to heated debate. For instance, some researchers suggest that skeletal differences between modern humans and Neanderthals mean they were different species. However, other scientists argue that because there is recent abundant genetic evidence that modern humans and Neanderthals once interbred and had fertile, viable offspring, Neanderthals should not be considered a single species.
In the new study, researchers analyzed human fossils dating from about 774,000 to 129,000 years ago (once known as the Middle Pleistocene and now renamed the Chibanian). Previous work suggested modern humans arose during this time in Africa, while Neanderthals emerged in Eurasia. However, much about this key chapter in human evolution remains poorly understood — a problem paleoanthropologists call "the muddle in the middle."
Chibanian-era human fossils from Africa and Eurasia are often assigned to one of two species: Homo heidelbergensis or Homo rhodesiensis. However, both species often carried multiple, and often contradictory, definitions of the skeletal characteristics and other traits that described them.
Similarly, recent analyses of many fossils in East Asia now suggest they should no longer be called H. heidelbergensis, the researchers added. For instance, many facial and other features seen in Chibanian East Asian human fossils differ from those seen in European and African fossils of the same age.
In addition, Chibanian fossils from Africa are sometimes called both H. heidelbergensis and H. rhodesiensis. The scientists also noted that H. rhodesiensis was a poorly defined label that was never widely accepted in science, due in part to its association with controversial English imperialist Cecil Rhodes.
To help deal with all this confusion, the researchers now propose the existence of a new species, H. bodoensis, named after a 600,000-year-old skull found in Bodo D'ar, Ethiopia, in 1976. This new name would encompass many fossils previously identified as either H. heidelbergensis or H. rhodesiensis. The researchers suggest that H. bodoensis was the direct ancestor of H. sapiens, together forming a different branch of the human family tree than the one that gave rise to the Neanderthals and the mysterious Denisovans, which Siberian and Tibetan fossils suggested they lived about the same time as their Neanderthal cousins.
The Middle Pleistocene (now renamed Chibanian and dated to 774,000-129,000 years ago) is important because it saw the rise of our own species (Homo sapiens) in Africa, our closest relatives, and the Neanderthals (Homo neanderthalensis) 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 new name 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" according to Roksandic, lead author on the study.
Recently, DNA evidence has shown that some fossils in Europe called H. heidelbergensis were actually early Neanderthals, making the name redundant. For the same reason, the name needs to be abandoned when describing fossil humans from east Asia according to co-author, Xiu-Jie Wu (Institute of Vertebrate Paleontology and Paleoanthropology, Beijing, China).
Further muddling the narrative, African fossils dated to this period have been called at times both H. heidelbergensis and H. rhodesiensis. H. rhodesiensis is poorly defined and the name has never been widely accepted. This is partly due to its association with Cecil Rhodes and the horrendous crimes carried out during colonial rule in Africa -- an unacceptable honour in light of the important work being done toward decolonizing science.
The name "bodoensis" derives from a skull found in Bodo D'ar, Ethiopia, and the new species is understood to be a direct human ancestor. Under the new classification, H. bodoensis will describe most Middle Pleistocene humans from Africa and some from Southeast Europe, while many from the latter continent will be reclassified as Neanderthals,
The co-first author Predrag Radovic (Faculty of Philosophy, University of Belgrade, Serbia) says, "Terms need to be clear in science, to facilitate communication. They should not be treated as absolute when they contradict the fossil record."
The introduction of H. bodoensis is aimed at "cutting the Gordian knot and allowing us to communicate clearly about this important period in human evolution," according to one of the co-authors Christopher Bae (Department of Anthropology, University of Hawai'i at Manoa).
Roksandic agrees: "Naming a new species is a big deal, as the International Commission on Zoological Nomenclature allows name changes only under very strictly defined rules. We are confident that this one will stick around for a long time, a new taxon name will live only if other researchers use it."
Deciding whether a set of ancient human fossils belongs to one species or another is often a challenging problem open to heated debate. For instance, some researchers suggest that skeletal differences between modern humans and Neanderthals mean they were different species. However, other scientists argue that because there is recent abundant genetic evidence that modern humans and Neanderthals once interbred and had fertile, viable offspring, Neanderthals should not be considered a single species.
In the new study, researchers analyzed human fossils dating from about 774,000 to 129,000 years ago (once known as the Middle Pleistocene and now renamed the Chibanian). Previous work suggested modern humans arose during this time in Africa, while Neanderthals emerged in Eurasia. However, much about this key chapter in human evolution remains poorly understood — a problem paleoanthropologists call "the muddle in the middle."
Chibanian-era human fossils from Africa and Eurasia are often assigned to one of two species: Homo heidelbergensis or Homo rhodesiensis. However, both species often carried multiple, and often contradictory, definitions of the skeletal characteristics and other traits that described them.
Similarly, recent analyses of many fossils in East Asia now suggest they should no longer be called H. heidelbergensis, the researchers added. For instance, many facial and other features seen in Chibanian East Asian human fossils differ from those seen in European and African fossils of the same age.
In addition, Chibanian fossils from Africa are sometimes called both H. heidelbergensis and H. rhodesiensis. The scientists also noted that H. rhodesiensis was a poorly defined label that was never widely accepted in science, due in part to its association with controversial English imperialist Cecil Rhodes.
To help deal with all this confusion, the researchers now propose the existence of a new species, H. bodoensis, named after a 600,000-year-old skull found in Bodo D'ar, Ethiopia, in 1976. This new name would encompass many fossils previously identified as either H. heidelbergensis or H. rhodesiensis. The researchers suggest that H. bodoensis was the direct ancestor of H. sapiens, together forming a different branch of the human family tree than the one that gave rise to the Neanderthals and the mysterious Denisovans, which Siberian and Tibetan fossils suggested they lived about the same time as their Neanderthal cousins.