Homo heidelbergensis (aka: Heidelberg Man) was just an archaic Neanderthal and was NOT a common ancient ancestor for H. sapiens and Neanderthals even though some people still seem to think so.
The OOA (Out of Africa) theory holds the view that Heidelberg Man is an ancestor of modern humans and Neanderthals, however. That theory claims this hominin species was present in Africa, Europe, and Asia 600-200 kya. Their skulls have features of both Homo erectus and Homo sapiens and their brain size is almost as large as H. sapiens. Yet, keep in mind that Neanderthals had slightly larger brains than modern humans do. This species was first discovered in 1907 near Heidelberg, Germany.
Further, mainstream theory (OOA) says that Neanderthals, Denisovans, and H. sapiens all descended from Heidelberg Man who appeared in Africa around 700 kya where it is known as Homo rhodesiensis. Fossils have been found in Ethiopia, Namibia, and South Africa and the theory holds that somewhere between 400-300 kya a group of this species migrated into Europe and western Asia by unknown routes and that they evolved into the Neanderthals in Europe. Another group migrated out of Africa and into Asia and they evolved into the mysterious Denisovans. Those who remained in Africa (H. rhodesiensis) evolved into anatomically modern humans sometime between 300-200 kya according to conventional OOA theory. They then migrated in a second wave into Europe and Asia between 125-60 kya. And so that is basically what the OOA says but is it so?
Some paleoanthropologists and others believe H. heidelbergensis is nothing more than a variant of H. erectus! Others hold the view that it was an archaic Neanderthal but not a common ancestor of Neanderthals and archaic modern humans, H. sapiens. So, again, the waters are muddied and everything is uncertain and foggy!! That is, unless you consider the following FACTS!
Fossil remains found at the Dmanisi site in Russian Georgia show that H. erectus was living in that area 1.8 mya. The cold and extreme climate in Europe prevented hominins from colonizing Europe until about 1.4 mya. The oldest fossils of hominins in Europe are found in southern Spain. Those found at Atapuerca in Spain date to around 1.2 mya. Geneticists have discovered that 1.2-1.0 mya there was a sudden collapse in the population numbers of human ancestors on the planet so harsh climate was not the only thing that contributed to the late settlement of Europe by ancient human ancestors. This was a near mass extinction event for ancient human ancestors (AHA)! It must have been a global catastrophe! It’s believed that humans on the planet could have been reduced to a number as low as 18.500 individuals! This was first discovered by geneticist Lynn Jorde at the University of Utah. There are many super volcanoes on the Earth and most likely this whatever this event was it had to be on the scale of the Mt Toba eruption 75,000 years ago or bigger.
A uniquely European species of hominin is H. antecessor who MAY be a common ancestor for Neanderthals and H. sapiens. Homo antecessor lived between 1.2 mya and 800 kya. It had a mix of archaic and modern features. The OOA theory holds the view that this species may have been one of the first to migrate out of Africa and into Eurasia, however, there is much debate over whether this species is a separate species or not. The fossil remains of H. antecessor are mostly from children and as we all know children’s bodies CHANGE as they grow up! They may, in fact, be the fossil remains of young H. erectus and NOT a new species of AHA at all. However, they could be the fossil remains of H. heidelbergensis instead!
The OOA holds the view that Heidelberg Man evolved from H. erectus 600 kya which was living in Africa, Europe, and Asia. The African version of Heidelberg Man, according to the OOA, is called Homo rhodesiensis. I think it highly likely that these two species are one in the same species, H. heidelbergensis and there are only slight morphological variations in the fossil remains of the two.
Some have postulated that H. antecessor may be a good candidate for being the last common ancestor for Neanderthals and modern humans. OOA holds the view that a group of H. erectus evolved into H. antecessor in Africa who then migrated into Europe. They then evolved into Heidelberg Man in Europe and those remaining in Africa evolved as H. rhodesiensis and eventually into H. sapiens. This is known as the “Homo antecessor Migration Model.” In my opinion this is a weak hypothesis! The finds at Dmanisi contradict this model. Dmanisi fossils show clearly that the first hominins to enter Europe were CLEARLY H. erectus! Further, it seems that the ONLY place H. antecessor lived was in northern Spain!! Antecessor fossils are found at two sites in Spain and they are both located in the Sierra de Atapuerca mountains in northern Spain. NO remains of H. antecessor have been found in Africa!!! In my mind H. antecessor is of the H. erectus species of ancient human ancestor and not a separate species at all, however, it may be that this AHA is a hybrid mix!
In a project headed by the Max Planck Institute led by Matthais Meyer a molecular biologist MtDNA was extracted from hominin fossil remains at the Sima de los Huesos site in Spain. The fact that they were able to extract viable DNA from fossil remains almost 1/2 myr is by itself astounding! The results of the DNA analysis proved them to be the remains of Neanderthals. Thus, a split from a common ancestor by Neanderthals and H. sapiens had to be pushed back to between 550-765 kya because Heidelberg Man didn’t exist until sometime after 660 kya! What became rather clear was that H. heidelbergensis was an archaic NEANDERTHAL.
The second study involved scientists from Indiana University. Their study was based on comparative morphology of European fossil remains. They focused on fossil teeth and dental bones. They found that NONE of the fossil remains connected to modern humans! They also concluded that ALL European fossil remains of hominins connect to the Neanderthals!! They concluded that H. sapiens and Neanderthals split (diverged) sometime around 1 million years ago (mya)!!
We do know that there was interbreeding between Neanderthals and H. sapiens and I think it was likely more frequent than perhaps the academics might like to admit. Also, morphological changes in H. erectus are really only cosmetic between 1.8 mya and 900 kya and one thing that is highly significant is around 800 kya the hominin brain increased in size VERY RAPIDLY! And there were also several adaptations in hominin anatomy at this same time. To date we are uncertain as to what caused this.
So H. heidelbergensis was an archaic Neanderthal and was NOT a common ancestor for Neanderthals and modern humans, H. sapiens. However, there may well be a common ancestor for both and the search continues to identify it.