¶ … taxonomic status of Mystery Skull #1 is most likely Neanderthal. The reasons for assigning the skull to this taxon are readily stated. Mystery Skull #1 looks morphologically similar to a modern human in many ways. The orbital sockets and zygomatic protrusions are similarly spaced, and the dentition is remarkably similar to that of a modern human. However there is a noticeably more pronounced brow ridge on the skull which is not reminiscent of Homo sapiens contemporary or archaic. Instead we should look at the overall shape of the skull, and we discover that it has a much flatter longer crown with less of a forehead, typical of Neanderthal skulls, rather than the higher dome of Homo sapiens. In addition to this longer and lower brain case, Mystery Skull #1 also exhibits a marked bulge at the very back, which is again typical of Neanderthals. Another tell-tale sign is the mid-facial area of the skull -- in Neandertals, this area protrudes (possibly an evolutionary adaptation to protect against cold), where it does not in Homo sapiens or Homo erectus.

Mystery Skull #1 exhibits an Index of Supra-orbital height of 60, an Index of Nuchal Area Height of 29, and an Index of Condylar Position of 78. These numbers are readily analogous to the measurements of our Neanderthal sample, in which the three indices are 67, 35, and 89. This makes Mystery Skull #1 smaller than our Neandertal sample -- perhaps a female or a juvenile -- but it is the ratios of each of these indices to each other that indicate our taxon. In particular the relatively low index of Nuchal Area compared to the other two indices helps us to rule out that this is just a Homo sapiens who just played too much football without a helmet -- only Neandertals exhibit this low ratio of Nuchal Height compared to the other two indices.

The taxonomic status of Mystery Skull #2 is Australopithecus Africanus. The reasons for assigning the skull to this taxon are fairly straightforward. The teeth on Mystery Skull #2 exhibit features which indicate an evolutionary...

Yet overall the shape of the skull is reminiscent of a chimpanzee, except there is a noticeable larger brain capacity. This is likely to suggest Australopithecus Africanus, which had a similar body size to the modern chimpanzee but with a larger brain and more human-like teeth. The extremely broad zygomatics, extending out far past the orbital sockets, indicate something far more ape-like than a modern human in certain ways -- yet the teeth are remarkably human for such an ape-like skull. We should also note the exceptionally pronounced brow ridge on the skull, which indicates it is farther back in the human evolutionary tree -- but in this case the brow ridge is again not quite as pronounced as that of a chimpanzee, especially because the slightly larger brain capacity here shows us a domed forehead and a larger brain moreso than a chimp skull would.
Mystery Skull #2 exhibits an Index of Supra-orbital height of 71, an Index of Nuchal Area Height of 38, and an Index of Condylar Position of 46. These numbers are readily analogous to the measurements of our Australopithecus Africanus sample, in which the three indices are 70, 35, and 44. In this case, no other hominin species exhibits the same basic pattern of a very high supra-orbital height index compared with the other two indices (which are much closer in value to each other, although the condylar position is the higher value). For this reason the indices indicate Africanus but also help to rule out other candidates.

The taxonomic status of the Newly Found Skull is Homo Erectus.

Various features of this skull help to indicate our taxon. The exceptionally large molars on this skull are a good indicator, as are the thick heavy brow-ridge and the low long shape of the skull. In the case of the dentition it is important to note that Homo Erectus has larger molars…