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Homo bodoensis Discovery Muddles Human Evolutionary Models

As I write this article, we are entering the winter months in Southern California. I know, I know. For anyone who has ever lived in the Midwest, winter in Southern California is an oxymoron. 

As the joke goes:
Q: How is the weather in Southern California like pizza?
A: Even when it’s bad, it is still pretty good. 

We get most of our annual rain in the winter months. And because the temperatures are cool in the morning and there is a lot of moisture in the air, it is not unusual to walk out the front door and be greeted by car windshields covered with condensation. 

Like most people, the first thing I do is turn on the defroster when I get in my car on those cold, damp winter mornings. Once my windshield begins to clear, I usually turn off the defroster because I don’t like the hot air blowing on me. Unfortunately, my impatience is rarely rewarded. My windshield often fogs up again before I drive to the end of the block because I don’t let the car’s interior warm up sufficiently to keep the moisture from recondensing on my windows. 

On these winter mornings, I end up spending the first few miles of my morning trip turning my defroster on and off as my car’s windshield repeatedly clears up and fogs over. 

Anthropological Fog
My morning drive on cold, damp winter mornings serves as an apt metaphor for the ensuing aftermath that usually takes place in physical anthropology when new hominin fossils—including one we’ll discuss in a moment—are discovered. 

While consensus exists among paleoanthropologists about the biology of hominin fossils, very little agreement exists about the evolutionary relationships among these creatures. It is not uncommon for paleoanthropologists to advance several different “evolutionary trees” to describe the hominin fossil record. There is often disagreement about how different hominin fossils should even be classified. (I go into some of the reasons for this confusion in Who Was Adam?

Paleoanthropologists hope that each new fossil find will help bring clarity. And, at first blush, newly characterized fossil finds seemingly do clear up some of this confusion. Yet, it soon becomes evident that this newly achieved clarity is destined to be obscured as researchers weigh the full implications of the discovery.

A recent (2021) research team’s proposal powerfully illustrates this recurring problem that confronts paleoanthropologists. The researchers argue that Homo heidelbergensis and Homo rhodesiensis should be abandoned as species and replaced by a new hominin species they call Homo bodoensis.1

Homo bodoensis
In the fall of 2021, a team from the University of Winnipeg headed by Mirjana Roksandic published a perspectives piece in the journal Evolutionary Anthropology in which they contend that H. heidelbergensis (and H. rhodesiensis) never existed and should be abandoned altogether as part of hominin classification. The team asserts that H. heidelbergensis has long been a “catchall category,” a placeholder used to assign fossils from the Middle Pleistocene (around 750,000 to 125,000 years ago) that don’t fit anywhere else. In fact, they point out that fossil remains assigned to H. heidelbergensis often have incompatible features.

Based on a reanalysis of the Bodo cranium, which was discovered in 1976 in Bodo D’ar, a site in the Awash River valley in Ethiopia and that dates to around 600,000 years in age, they make three points. First, they argue for the creation of a new species designation, Homo bodoensis. They insist that H. rhodesiensis specimens (recovered exclusively in Africa) should be reassigned to H. bodoensis. So, too, should fossil specimens in Africa assigned to H. heidelbergensis. According to the research team, the geographical range of H. bodoensis included all of Africa and extended into the Levant (countries bordering on the eastern Mediterranean Sea).

Figure: The Bodo Cranium
Credit: Wikipedia

Second, the University of Winnipeg scientists argue that the H. heidelbergensis specimens recovered in Europe should be reclassified as early Neanderthals. It should be noted that this part of their proposal has been previously advanced by other paleoanthropologists.2

Finally, the researchers maintain that H. heidelbergensis specimens recovered in Asia don’t fit with either Neanderthals or H. bodoensis and, consequently, belong to a distinct species and separate evolutionary lineage. From an evolutionary standpoint, the researchers place H. bodoensis species in the branch that led exclusively to modern humans.  

Fog, Not Clarity
It should be noted that some evolutionary anthropologists have expressed skepticism about this proposal. For example, Christopher Stringer at the Natural History Museum in London asserts that it is unnecessary to designate a new hominin species. In fact, he favors retaining H. rhodesiensis as a species and recategorizing African H. heidelbergensis specimens as members of H. rhodesiensis. Stringer also doesn’t support abandoning H. heidelbergensis. Instead, he thinks that this category should be reserved for specimens in Europe, retaining H. heidelbergensis as the evolutionary ancestor to Neanderthals and Denisovans. Lastly, Stringer is skeptical that the Bodo skull (the holotype in Roksandic’s scheme) is ancestral to modern humans.3

John Hawk, a paleoanthropologist from the University of Wisconsin, is also hesitant about Roksandic’s proposal. Reflecting a lumper’s approach (that which favors combining all similar species into the same genus and species) to the hominin fossil record, Hawk thinks that it is best to simply regard all the hominin specimens as belonging to a single evolving species comprised of distinct interbreeding populations.

Still, Roksandic’s team makes a compelling case. And other paleoanthropologists agree that H. heidelbergensis didn’t exist. If the team’s proposal is accepted, it may, indeed, bring some clarity to the hominin fossil record, particularly for the so-called “muddle in the middle.” But it also creates uncertainty. 

Since the 1970s, a significant fraction of paleoanthropologists has regarded H. heidelbergensis as the transitional intermediate linking Homo erectus to modern humans and Neanderthals. Some anthropologists believe that the “Heidelberg Man” is the common ancestor that gave rise to the two separate lineages leading to modern humans and Neanderthals/ Denisovans, respectively. 

Yet, as a consequence of the proposal from the University of Winnipeg team, the ancestral species that gave rise to the lineage that culminates in modern humans and the one that culminates in Neanderthals and the Denisovans is now unknown. Perhaps this species would have been a late-appearing member of H. erectus. Or perhaps it was Homo antecessor. Or perhaps it is a hominin species yet to be discovered. In other words, more fog.

Their proposal also orphans a collection of Asian hominin specimens that were previously grouped together as H. heidelbergensis. At this juncture, it is unclear what will happen with these unassigned fossils.

It is nothing short of shocking to think that the reanalysis of fossil specimens based on a single skull can call into question the existence of one of the key transitional intermediates in many human evolutionary scenarios. This provocative proposal calls attention to the speculative nature and uncertainty of even the best models in human evolution and the chaotic nature of the discipline.  

While the chaos that characterizes hominin natural history is not sufficient reason to reject human evolution, it does provide justification for those (like me) who express skepticism about the capacity of evolutionary models to offer a robust explanation for humanity’s origin. 

RTB Human Origins Model
Instead of regarding the hominins as evolutionary intermediates leading to the emergence of modern humans, RTB’s creation model offers a different approach. Our model views these creatures as animals created by God. Accordingly, these extraordinary creatures walked erect and possessed some level of intelligence. These abilities allowed them to cobble together tools and even adopt a level of “culture.” However, our model maintains that the hominins were not spiritual beings made in God’s image. We reserve this status exclusively for modern humans.

Our model predicts biological similarities will exist among the hominins and modern humans to varying degrees. It also predicts biological differences. But, because the hominins were not created in God’s image, they would be expected to be distinct from modern humans in their cognitive capacity, behavior, “technology,” and “culture.”

RTB’s human origins model readily accommodates the discovery of H. bodoensis and the reclassification of H. heidlebergensis and H. rhodesiensis fossil specimens. All three of these (possibly hypothetical) hominins reasonably could be understood as creatures made by God that—although remarkable in their own right—lacked the image of God.

While the RTB model does not make any predictions toward this end, the chaos and uncertainty surrounding hominin natural history and presumed evolutionary relationships among these species help justify the RTB model. This confusion may well be an indicator that the evolutionary paradigm is not the best way to interpret the hominin fossil record. In science, new discoveries should add clarity and support, if a theory is sound. If, on the other hand, new discoveries raise questions and foster chaos, it is a sure sign that the theory is invalid or woefully incomplete, signaling the need for a new approach.

Impact on Other Christian Human Origins Models
Not only does the proposal from the University of Winnipeg scientists have implications for the RTB human origins model, but it also has ramifications for other Christian human origins models. For example, this proposal has bearing on a model recently advanced by apologist William Lane Craig.

Based on his analysis of key passages from the Old and New Testaments, Craig takes the view that Adam and Eve must have been real historical individuals. He asserts that the biblical data is insufficient to determine when Adam and Eve lived and that this question is better suited for science. In pursuing an answer, Craig adopts an evolutionary approach to humanity’s origin. Based on his analysis of the scientific literature, he places Adam and Eve as members of H. heidelbergensis, living somewhere between 750,000 to 1 million years ago.5

The University of Winnipeg team’s reassessment of the hominin fossil record wreaks havoc on Craig’s proposal, because H. heidelbergensis may well be nonexistent. The primary basis for Craig’s view is that Neanderthals (which represent a distinct evolutionary lineage from modern humans) should be regarded as descendants of Adam and Eve and, therefore, members of the human family. This inclusion forces Craig to place Adam and Eve in the group that gave rise to the two evolutionary lineages. 

Yet, if the Roksandic team’s proposal is correct, then the group that includes Adam and Eve is unknown in Craig’s scheme. If the group that gave rise to the two lines (that culminated in modern humans and Neanderthals) happens to be a late-appearing H. erectus, then Craig would be forced to conclude that Adam and Eve belonged to this group of hominins. Yet, he excludes them as part of the group of hominins that bear God’s image based on his assessment of their biology and behavioral capacity. And, if he were to include them, does that mean that he needs to include early-appearing H. erectus? If so, this maneuver would require Adam and Eve to live 1.8 million years ago. If Craig doesn’t include early-appearing H. erectus, then we are left with the uncomfortable scenario in which some members of a species are image bearers (late-appearing H. erectus) and others are not (early-appearing H. erectus). 

Here’s the bottom line: Even though human evolution has broad support among most life scientists, the number of hominin species and their putative evolutionary relationships remain obscured and uncertain. This lack of clarity justifies skepticism on the part of Christians who embrace some form of creationism. It also frustrates Christian scholars who adopt some form of theistic evolution, paving the way for greater support for approaches like the RTB creation model for humanity’s origin.

Resources

Endnotes

  1. Mirjana Roksandic et al., “Resolving the ‘Muddle in the Middle’: The Case for Homo bodoensis sp. nov.,” Evolutionary Anthropology (October 28, 2021), doi:10.1002/evan.21929.
  2. For example, see J. L. Arsuaga et al., “Neandertal Roots: Cranial and Chronological Evidence from Sima de los Huesos,” Science 344, no. 6190 (June 20, 2014): 1358–1363, doi:10.1126/science.1253958; Michael Balter, “RIP for a Key Homo Species?” Science 345, no. 6193 (July 11, 2014): 129, doi:10.1126/science.345.6193.129.
  3. Michael Marshall, “New Human Species Has Been Named Homo bodoensis—But It May Not Stick,” New Scientist, October 28, 2021.
  4. Kate Baggaley, “Is It Time to Change the Way We Talk about Human Evolution?Popular Science, October 28, 2021. 
  5. William Lane Craig, In Quest of the Historical Adam: A Biblical and Scientific Exploration (Grand Rapids, MI: Eerdmans, 2021). 

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