Homo Heidelbergensis

In 1907, a jawbone was found near Heidelberg, Germany, in the sands deposited by the Neckar River, the species was named Homo heidelbergensis. Popularly known as the ‘Mauer jaw’, it was well-preserved, lacking a bony chin, but with teeth like those of modern humans. Primitive features in the specimen and suggested that Homo heidelbergensis could be distinguished from Asian and African representatives of Homo erectus. The Mauer jaw is often grouped with mandibles and partial craniums from Arago Cave in France and Petralona in Greece. If we include the Sima de los Huesos in Spain, additional skulls and numerous postcranial bones can be added to the species hypodigm. The Petralona and Arago specimens also share anatomical similarities with crania from various locations, including Broken Hill (Kabwe) in Zambia, Elandsfontein in South Africa, and Bodo from the Middle Awash of Ethiopia. This suggests that Homo heidelbergensis may have inhabited both Africa and Europe. The species is considered potentially related not only to Neanderthals but also to modern humans. Anatomically, Homo heidelbergensis had a bigger brain compared to Homo erectus, averaging around 1,230 cubic centimeters. The skull relatively is taller than in Homo erectus. The front of the head is wider, the sides are high and arched like in modern humans, and the back is more rounded. The part at the back of the skull is longer than in Homo erectus. The jaw joint is similar to that of Homo sapiens, along with certain parts of the ear bone. The bony ridge above the eyes in is still quite large. The front part of the head is flatter, like in Homo erectus. The overall shape is less round compared to modern humans. The face is connected to the skull in a way that emphasizes the projection of the face. The nose opening is more vertical, and the canal in the front of the upper jaw is placed more forward than in Homo erectus. The point where the two halves of the jaw meet is receding, and there's a developed internal area for the teeth. European jaws of Homo heidelbergensis also look similar to Neanderthals. Some individuals from Sima de los Huesos were tall and robust, with limb bones and a pelvis suggesting possible differences in size between males and females, similar to what we see in recent populations. The classification of Homo heidelbergensis in the human family tree is a debated topic. The Mauer mandible, dating back 609,000 years, is among the oldest Middle Pleistocene fossils in Europe, aligning with findings in Bodo, Africa. Some scientists suggest replacing "Homo heidelbergensis" with "Homo bodoensis." Supporters say it clarifies Middle Pleistocene hominin classification, especially from Africa and the eastern Mediterranean. Opponents argue against changing long-standing names, expressing concerns about confusion and potential political motivations. The evolution and classification of these middle Pleistocene hominins is debated. One view groups populations into evolving grades within Homo sapiens, indicating a single lineage with brain and skull advancements. Alternatively, some propose cladogenesis within Homo, arguing for a unique morphology in living humans that separates them from most fossil hominins. They believe only those sharing specific features should be considered Homo sapiens. Some researchers propose two lineages. The European branch, including Neanderthals, traces back to the Middle Pleistocene through fossils like Petralona, Arago, Sima de los Huesos, and Mauer. This perspective suggests repeated speciation events. Another lineage, rooted in Africa, includes specimens like Broken Hill, Elandsfontein, and Bodo, referred to as Homo rhodesiensis. Some late members display a mix of archaic and modern features.