Archaic Hominins That Were Contemporaneous With Modern Humans

There were at least eight named non-H. sapiens archaic hominin species that existed in time periods overlapping those of  modern humans, H. sapiens, who evolved around 300,000 years ago. All were in the "Old World". There is no credible evidence that archaic hominin ever made it to the Americas, Australia, New Zealand, or most of the other islands of Oceania beyond island southeast Asia.

One was H. erectus that went extinct around 100,000 years ago after more than two million years roaming the Old World, first in Africa and later in Asia. There were also two hobbit-like species in island Southeast Asia, three East Eurasian sister clades to modern humans, the small but not hobbit-like H. naledi in Southern Africa, and Neanderthals in West Eurasia, although some of these species may actually be regional variants of the same species. 

All of these archaic hominin species had gone extinct (with the possible extended duration of a small isolated relict population or two, perhaps H. floresiensis) by about 29,000 years ago, leaving modern humans as the sole survivors (although some modern humans have Neanderthal ancestry (up to about 2%) from admixture events starting around 100,000 years ago, and some modern humans have both Neanderthal and also up to about 6% Denisovan ancestry, although absolute percentages are harder to estimate than percentages relative to other individuals with the same kind of introgression) from admixture events around the time that modern humans reached Southeast Asia. Incidentally, the introgression went both ways, with Neanderthals having up to 6% modern human introgressed ancestry, possibly due to events as much as 250,000 years ago. These sister clades capable of producing hybrid offspring may have been regionally specialized into climate niches.

Notably the remains of the Red Deer Cave People of China from 14,000 years ago (a few thousand years before the start of the Holocene era) are genetically modern humans and are not archaic hominins despite some of their seemingly archaic features. See also here.

I am also inclined to think that they may yet be a small relict population of small archaic hominins in a remote Indonesian jungle on the island of Sumatra and perhaps Flores as well, where these cryptids, called Orang Pendek, locally, have been attested but not definitively confirmed to still exist. I discuss this further at this post.

Homo floresiensis (discovered in 2003) are commonly known as "hobbits" and have been found on the island of Flores. Their phylogeny is disputed, but I find the theory that they are an asian branch of H. habilis to be most convincing. H. luzonesis (discovered in 2007) is similar and contemporaneous, but found further east in the Philippines and is supported by a less complete archaeological record. Both of these diminutive species are found in association with late Pleistocene tools and "oriental fauna".

Personally, being more of a lumper than a splitter, I'm inclined to see H. floresiensis and H. luzonesis as sub-species variations of the same species ("race" within that species to use some outdated terminology), and likewise to see H. longi, H. juluensis, and Denisovans as sub-species variations of the Denisovan species. The Hualongdong archaic hominin fossils, might be another hybrid individual or could be a hybrid individual, perhaps a Neanderthal-Denisovan hybrid individual (something that has precedent in a Denisovan cave DNA sample). 

Academic anthropologists, in contrast, tend to be splitters, in part, because it is cool and career advancing to discover and name your own archaic species, in part because the data is so fragmentary that grouping different fragmentary remains in a clade presumes relationships between the remains that aren't solidly proven, and in part, because it is easy to underestimate how much morphological diversity is possible within a single species if populations of it exposed to different environmental conditions.

H. longi a.ka. "dragon man" dates to an earlier time period (still contemporaneous with modern humans in Africa) in China and Manchuria, was discovered in 1933, and has been hypothesized to be a sister clade to Neanderthals, Denisovans, and modern humans, and a descendant of the pre-modern human hominin species H. antecessor due in part to basal archaic features in the skull. 

H. juluensis (literally "big heads") is contemporaneous H. longi, and beyond that time frame into the time frame of H. floresiensis and was discovered from 1976-1979 in China and Tibet. The authors assign this specimen along with Xiahe and Penghu fossils, to the Denisovan species (a sister clade to Neanderthals and modern humans) based upon comparisons of their fossil teeth and rough geometric proximity. H. juluensis is found in association with early Paleolithic tools and remains of Palearctic fauna. But they have larger brain cases than H. longi. A previous suggestions of the link between H. longi and the Denisovan species are discussed here and here at this blog. At least one Denisovan tooth has been found in Laos dated to 131,000 years ago.

The article also discusses the Hualongdong archaic hominin fossils that "date to the late Middle Pleistocene (~300,000 years BP) and display a mosaic of characteristics that cannot be easily fitted into any one lineage," although they are closer to H. longi and H. juluensis. This individual could be a hybrid between these two subspecies, with H. erectus, or with a Neanderthal who was far east of his usual range.

Prior to 2021, H. longi and H. juluensis tended to be classified as H. erectus (remains of which start to appear at a much greater time depth in Asia) or as archaic modern humans.

The Narmada and Maba partial skulls, especially the latter, are suggestively associated with Neanderthals by the article.

These Asian archaic species also overlap in time with the Southern African archaic hominin clade H. naledi which is a sister clade to the modern human ancestors and to the common ancestor of modern humans, Neanderthals, and Denisovans, but is not actually among our ancestors. As I explained at the link, this species "is basically a story from The Silmarillion of hominin evolution. It is entertaining, especially for hard core human evolution fans, but it doesn't really advance the plot."

A small number of papers reported genetic evidence in modern Africans of admixture with an archaic hominin "ghost species" in Africa, but subsequent papers have explained this "ghost species" signal as a methodological artifact that merely arises from population structure in early modern human Africans (see also here). But there may have been relict archaic hominins that did not admix with modern humans in Africa that were also contemporaneous with modern humans, at least, early on.

The question of whether behaviorally modern humans started showing advanced behavior around 70,000-50,000 years ago (at the dawn of the Upper Paleolithic era and close in time to the Out of Africa event for modern humans), was associated with an evolutionary leap in their brains is an open and unresolved question. See also here (addressing the question of what made modern humans genetically distinct from archaic hominins).

A greater degree of Late Quaternary hominin morphological variability is present in eastern Asia than previously assumed. Indeed, a number of distinct populations are present, some that now have new specific names: Homo floresiensis; H. luzonensis; H. longi; H. juluensis. With this piece, we describe the various groupings based on the current hominin fossil record of eastern Asia.

Christopher J. Bae & Xiujie Wu, "Making sense of eastern Asian Late Quaternary hominin variability" 15 Nature Communications 9479 (November 2, 2024) (opoen access) (hat tip to neo).