Where does Homo antecessor fit?

Where does Homo antecessor fit?

Who am I? How do I fit into the grand scheme of things? These questions gnaw at someone going through an identity crisis.

 

Struggling with this type of uncertainty is unique to human experience. It’s unlikely that the hominids represented in the fossil record ever contemplated their identity-but humans sure have. Questions about who the hominids were and how they fit into the human evolutionary scheme consume paleoanthropologists (scientists who study the human fossil record). A fossilized hominid jawbone recovered from the Gran Dolina site in northern Spain has engendered a crisis of sorts, about the identity of Homo antecessor and its place in a widely held human evolutionary scenario.1

Between 1994 and 1996, paleoanthropologists recovered hominid fossils and stone artifacts from Gran Dolina that were dated between 780,000 and 857,000 years ago and assigned to a new species, Homo antecessor. Based on cranial and dental features, many evolutionary biologists consider this hominid to be part of the transitional sequence that led to modern humans. According to this view H. ergaster produced H. antecessor which, in turn, gave rise to H. heidelbergensis. This species then separately produced the lineage that led to Neanderthals and modern humans.2

The evolutionary identity of H. antecessor was based on analysis of immature jaw and facial features. To ensure its place in the human evolutionary pathway, paleoanthropologists needed access to the remains of adult individuals. This most recent H. antecessor find is just what paleoanthropologists had hoped for, an adult jawbone.

Analysis of this new jawbone, however, indicates that H. antecessor cannot be part of any evolutionary sequence that leads to modern humans. Rather it more closely resembles the erectine hominids found in Asia. In other words, from an evolutionary perspective H. antecessor is an insignificant side-branch, a dead end.

This recent discovery leaves a significant gap in the fossil record between H. ergaster and H. heidelbergensis and renders the putative human evolutionary pathway to modern humans sketchy at best. It also shows the speculative character of the various human evolutionary scenarios. It’s remarkable that the discovery of a single jawbone can overturn a widely held human evolutionary model. Yet, this frequently is the case.

Given the gaps in the hominid fossil record and the speculative nature of the various human evolutionary scenarios, H. antecessor’s identity seems more secure as a nonhuman primate, created by God with some limited intellectual and emotional abilities, but without any spiritual capacity.

References

  1. E Carbonell et al., “An Early Pleistocene Hominin Mandible from Atapuerca-TD6, Spain,” Proceedings of the National Academy of Sciences, USA 102 (2005): 5674-78.
  2. J. M. Bermudez de Castro et al., “A Hominid from the Lower Pleistocene of Atapuerca, Spain: Possible Ancestor to Neandertals and Modern Humans,” Science 276 (1997): 1392-95.

SIDEBAR

What is a hominid?

An Internet search or a dictionary definition yields that humans and hominids came from the same evolutionary line, but RTB’s creation model regards hominids as nonhuman primates. These creatures walked erect (bipedalism) and possessed limited intellectual and emotional abilities, but lacked spiritual capacity since they were not created in God’s image. What about Neanderthals? They were hominids. And Cro-Magnon and other so-called cavemen? Humans.