Recent research has focused new attention on the earliest fossil samples of Homo erectus, more than 1.8 million years ago. One candidate found in 1974 is a #hominin hip bone from Koobi Fora, KNM-ER 3228. #paleoanthropology

A new paper by @ashleyshammond @Mavumavu91 and coworkers focuses on a fossil from the same time frame at Koobi Fora, KNM-ER 2598. The thick bar, or torus, across the back of this occipital bone is a feature mostly known from other H. erectus fossils. https://doi.org/10.1038/s41467-021-22208-x

Revisiting the site where this occipital was found, they identified more hominin fossils including a piece of hip bone, KNM-ER 77072. It's not clear whether this may be the same individual, but the authors suggest it also is consistent with H. erectus.

When it was found in 1974 and later in the 1980s, most scientists focused on the humanlike size of KNM-ER 3228, and some similarities with OH 28 and Arago 44, both much later fossils attributed at the time to H. erectus. https://doi.org/10.1002/ajpa.1330630404

The bone was an important one in my own thinking at the turn of the millennium, as a sign that H. erectus represented a new body size niche for Homo compared to Australopithecus. That's a piece of thinking that has changed a lot in 20 years. https://doi.org/10.1093/oxfordjournals.molbev.a026233

Arago 44 is almost certainly not H. erectus. It may be an early Neandertal or another (H. heidelbergensis?) species. OH 28 could possibly be H. erectus, but if so may be a most recent occurrence of the species in Africa. I suspect it's something else.

Other early hip bones attributed to H. erectus don't look a lot like KNM-ER 3228. Two of these, KNM-WT 15000 and KNM-ER 1808, are associated with skeletal material that pegs them as H. erectus. One possibility is that KNM-ER 3228 is actually something else.

The new research by @ashleyshammond and coworkers provides a nice short review of this anatomical diversity, and reminds us of the possibility that more than one species of Homo may be represented by these hip bones. https://doi.org/10.1038/s41467-021-22208-x