Early Homo Erectus In Spain And Where It Fits In The Larger Narrative

Overview

Anthropologists have found partial Homo erectus remains in Spain from 1.1-1.4 million years ago, adding to 1.97 million year old Homo erectus remains in Grăunceanu, Romania, and 1.77-1.85 million year old Homo erectus remains in Dmanisi, Georgia. 

Homo erectus first appears in Africa. Outside of Africa, Homo erectus remains are most often found in Indonesia and China, dating from around 108,000 years ago in Southeast Asia, back to about 70,000 years after this species evolved in Africa. 

Homo erectus went extinct in most of the world around 1,000,000 years ago, but persisted longer in Southeast Asia and possibly in East Asia, and relict populations of Homo erectus probably admixed with Denisovans at some point when both species existed. A major population bottleneck described below, probably took place in Homo erectus starting around 930,000 years ago, but it didn't result in the complete extinction of the species. Homo erectus was probably extinct by the time that modern humans first ventured beyond South Asia (not long after the Toba eruption ca. 75,000 years ago). It is plausible that the Toba eruption, followed by first contact with modern humans, may have led to the final extinction of Homo erectus, to the final extinction of H. floresiensis and H. luzonensis, and also to the extinction of Denisovans over most of their range (with the last relict Denisovans in Tibet probably going extinct in connection with their contacts with modern humans in this remote place).

We know that Homo erectus evolved in Africa rather than Eurasia, because that is where the species that Homo erectus evolved from, mostly likely H. habilis, but possibly some other African archaic hominin, was located at the time, and not just because the oldest Homo erectus remains are found there.

The oldest identified H. erectus specimen is a 2.04 million year old skull, DNH 143, from Drimolen, South Africa, coexisting with the australopithecine Paranthropus robustus. H. erectus dispersed out of Africa soon after evolution, the earliest recorded instances being H. e. georgicus 1.85 to 1.78 million years ago in Georgia and the Indonesian Mojokerto and Sangiran sites 1.8 to 1.6 million years ago.

(The quoted Wikipedia summary hasn't been updated to reflect the Romanian discovery announced earlier this year.)

Half a million years and a few hundred meters away from this site, there are Homo antecessor remains, from a time when Homo erectus had gone extinct in Europe, almost 700,000 years before Homo erectus went extinct in Asia.

The New Discovery

ATE7-1 fossil face (right) with mirrored 3D model (left). Credit: Maria D. Guillén / IPHES-CERCA / Elena Santos / CENIEH

When the global timeline passed one million years ago, more than half the span of hominin presence in Eurasia had already passed by. The earliest archaeological evidence in Eurasia is more than two million years old—found in places like Shangchen, China, and the Dawqara Formation of Jordan. Just this year Grăunceanu, Romania, joined the list of early archaeological traces of hominins in Europe, dating to an estimated 1.97 million years ago.

Still, I think about the threshold of one million years ago quite often. The number of sites in Eurasia with hominin evidence before one million years ago has grown quite large. It would have been hard to imagine this in 1990, when many scientists wondered if any sites in Eurasia were really older than this. Today there are many. And yet, the number of sites with fossils of hominins is quite a lot smaller than the number with stone artifacts or cutmarked animal bones. Most are in China or Indonesia, in addition to the exceptional site of Dmanisi, Georgia.

In western Europe there may be only two such sites, both in Spain: Sima del Elefante and Barranco Léon.

This week Rosa Huguet and collaborators have reported on a significant new addition to this very humble record. In work at Sima del Elefante in 2022, excavators uncovered a fragmentary facial skeleton, designated as ATE7-1. The estimated age of this fossil face is between 1.4 million and 1.1 million years ago. The new fossil joins two other hominin fossils from this cave deposit, within the same range of ages, a finger bone and a fragment of the front portion of a mandible with several worn teeth, ATE9-1. These fossils have been previously published, the mandible in 2008.

None of these fossils provide much to go on. Huguet and coworkers compared the facial anatomy of ATE7-1 with fossil faces attributed to Homo erectus from Dmanisi, Georgia, and Sangiran, Indonesia. They also compared the face to fossils from Gran Dolina, Spain, attributed to Homo antecessor. This site is located only a few hundred meters from Sima del Elefante but represents hominins and stone artifacts from around 780,000 years ago—as much as a half million years or more later than Sima del Elefante.

The ATE7-1 face is more like most H. erectus faces than either is like the later Gran Dolina fossils.

From John Hawks.

Context

Where does this discovery fit in the larger narrative of archaic hominin evolution?

Neanderthals, Denisovans, and modern humans (i.e. Homo sapiens) all share a Homo erectus ancestor and probably also at least one intermediate archaic hominin ancestor that evolved from Homo erectus.

The oldest archaeological evidence of modern humans, which is, order of magnitude consistent with age estimates for the most recent common ancestor of all modern human uniparental Y-DNA and mtDNA lineages, is about 300,000 years ago in Africa. Modern humans first left Africa around 125,000 to 100,000 years ago, and did so via the Middle East rather than Iberia. But the lion's share of non-African modern humans appear to be descended from a later wave of modern human expansion out of Africa about 50,000-74,000 years ago, with the lion's share of that wave closer to 50,000 years ago than 74,000 years ago. Neanderthal populations largely stalled this expansion into Europe until about 40,000 years ago. One or more of the hominin populations of Southeast Asia, and the jungles of Southeast Asia, probably stalled modern human expansion via the Southern route into Asia until around the time of the Toba eruption around 74,000 years ago (with the eruption possibly weakening these barriers and possibly also creating a reason for the modern humans of South Asia to expand to the Southeast).

The oldest Neanderthal remains are about 430,000 years old. Neanderthals were moribund by 40,000 years ago (with modern human Cro-Magnon people entering Europe around the same time that Neanderthals became extinct and overlapping with them for periods of a thousand or two thousand years or so in any one place), with the final relict population going extinct around 29,000 years ago. The leading explanations for Neanderthal extinction include a wave of volcanic eruptions, climate change, and the growing superiority of modern human hunter-gatherers due to their cultural evolution (e.g. stone technologies and the domestication of dogs) and/or genetic evolution. The range of Neanderthals extended from Northern Wales to the Middle East to South Asia and the Altai Mountains. There was significant Neanderthal admixture with modern humans, probably around 50,000-100,000 years ago (the latest estimates tend to favor a more recent date) in the vicinity of the Middle East or Iran (leaving a DNA legacy in all non-African modern humans), and there was also a more modern admixture with Altai Neanderthals (leaving a DNA legacy in Asian modern humans). Non-Africans today have up to 2% Neanderthal DNA, with Asians having a little more than Europeans, although ancient DNA from modern humans in ancient Eurasia, much closer to Neanderthal admixture sometimes have higher percentages of Neanderthal admixture. Neanderthals had bigger brains than modern humans, but also a more static material culture and less diverse range of hunting prey heavily concentrated around large megafauna (suggesting reduced brain plasticity and less ability to adapt culturally rather than genetically), with modern humans also relied on a wider array of smaller prey like rabbits, smaller birds, fish, and other seafood. At the time of first contact with modern humans, the effective population size of Neanderthals was about ten times smaller than the effective population size of modern human Cro-Magnons, and the effective Neanderthal effective population size ranged from about 3,000-12,000 throughout their existence and was fractured into multiple more or less isolated regional subpopulations.

Wikipedia says this about the extinction of Neanderthals:

The extinction of Neanderthals was part of the broader Late Pleistocene megafaunal extinction event. Neanderthals were replaced by modern humans, indicated by the near-complete replacement of Middle Palaeolithic Mousterian stone technology with modern human Upper Palaeolithic Aurignacian stone technology across Europe (the Middle-to-Upper Palaeolithic Transition) from 41,000 to 39,000 years ago. Iberian Neanderthals possibly persisted until about 35,000 years ago, modern human expansion perhaps impeded by the Ebro River. Neanderthals in Gibraltar may have survived as late as 28,000 years ago at Gorham's Cave. The dating of these late Iberian sites is contested.

Historically, the cause of extinction of Neanderthals and other archaic humans was viewed under an imperialistic guise, with the superior invading modern humans exterminating and replacing the inferior species.

When sapiens began to expand and spread, he eliminated the other contemporary races [including Neanderthals] just as the white man drove out the Australian aborigines and the North American Indians.

— Ernst Mayr, 1950

The assimilation of Neanderthal populations into modern human populations had long been hypothesised with supposed hybrid specimens, and was revitalised with the discovery of archaic human DNA in modern humans. Similarly, the Châtelperronian industry of central France and northern Spain may represent a culture of Neanderthals adopting modern human techniques, via acculturation. Other ambiguous transitional cultures include the Italian Uluzzian industry, and the Balkan Szeletian industry.

Aside from competition with modern humans, Neanderthal extinction has also been ascribed to their low population as well as the resulting mutational meltdown, making them less adaptable to major environmental changes (specifically Heinrich event 4) or new diseases.

The admixture between modern humans and Neanderthals went in both directions. And, some of the late archaeological tool cultures of Neanderthal, which coincide with the arrive of modern humans in Europe, may reflect the increased brain plasticity of hybrid Neanderthal-modern human individuals.

Denisovans (named after the cave in the Altai where the type remains were discovered) probably existed from at least 285,000 years ago to about 25,000 years ago, general in Asia to the east of the Neanderthal range from Altai and Tibet to Southeast Asia, and overlapping with the Neanderthal range in the Altai region. High altitude adaptation DNA admixed from Denisovans are found in Tibetans. Trace levels of Denisovan admixture are found in mainland Southeast Asia and East Asia, and in island Southeast Asia up to the Wallace Line. Modern humans with Australian aboriginal ancestry or Papuan ancestry or Filipino negrito ancestry have substantial Denisovan ancestry (up to 6%) in addition to their Neanderthal ancestry (up to 2%). Presumably, the Denisovan-modern human admixture whose legacies exist in Australian aborigines, Papuans, Filipino negritos, and mainland Southeast Asians and East Asians must have occurred around the time of first contact between the first wave of modern humans in Asia around 50,000 to 75,000 years ago, and was then greatly diluted by subsequent waves of modern human migration west of the Wallace line in Asia. Also, Denisovans presumably went extinct within a thousand or two thousand years or so of first contact with modern humans (which took place much later in Tibet than almost everywhere else).

The exact path from Homo erectus to modern humans, Neanderthals, and Denisovans (and possibly other now extinct archaic species derived from Homo erectus) is a matter of ongoing investigation and debate.

Denisovan mtDNA diverged from that of modern humans and Neanderthals about 1,313,500–779,300 years ago; whereas modern human and Neanderthal mtDNA diverged 618,000–321,200 years ago. Krause and colleagues then concluded that Denisovans were the descendants of an earlier migration of H. erectus out of Africa, completely distinct from modern humans and Neanderthals.

However, according to the nuclear DNA (nDNA) of Denisova 3—which had an unusual degree of DNA preservation with only low-level contamination—Denisovans and Neanderthals were more closely related to each other than they were to modern humans. Using the percent distance from human–chimpanzee last common ancestor, Denisovans/Neanderthals split from modern humans about 804,000 years ago, and from each other 640,000 years ago. 

Using a mutation rate of 1×10^−9 or 0.5×10^−9 per base pair (bp) per year, the Neanderthal/Denisovan split occurred around either 236–190,000 or 473–381,000 years ago respectively. Using 1.1×10^−8 per generation with a new generation every 29 years, the time is 744,000 years ago. Using 5×10^−10 nucleotide site per year, it is 616,000 years ago. Using the latter dates, the split had likely already occurred by the time hominins spread out across Europe. 

H. heidelbergensis is typically considered to have been the direct ancestor of Denisovans and Neanderthals, and sometimes also modern humans. Due to the strong divergence in dental anatomy, they [i.e. Denisovans] may have split before characteristic Neanderthal dentition evolved about 300,000 years ago.

The more divergent Denisovan mtDNA has been interpreted as evidence of admixture between Denisovans and an unknown archaic human population, possibly a relict H. erectus or H. erectus-like population about 53,000 years ago. Alternatively, divergent mtDNA could have also resulted from the persistence of an ancient mtDNA lineage which only went extinct in modern humans and Neanderthals through genetic drift. Modern humans contributed mtDNA to the Neanderthal lineage, but not to the Denisovan mitochondrial genomes yet sequenced. The mtDNA sequence from the femur of a 400,000-year-old H. heidelbergensis from the Sima de los Huesos Cave in Spain was found to be related to those of Neanderthals and Denisovans, but closer to Denisovans, and the authors posited that this mtDNA represents an archaic sequence which was subsequently lost in Neanderthals due to replacement by a modern-human-related sequence.

The intermediate species that is the most recent common ancestor of Neanderthals, Denisovans, and modern humans probably arose not long after a genetic bottleneck which has been inferred from modern DNA. This genetic bottleneck probably occurred in the clade of H. erectus which is ancestral to modern humans. As one secondary source explaining this notes:

Between 930,000 and 813,000 years ago, something nearly ended humanity before it even began. A mysterious bottleneck reduced the human breeding population to just 1,280 individuals, pushing our ancestors to the brink of extinction for an astonishing 117,000 years. 

Scientists have long puzzled over a gap in the African and Eurasian fossil records, and now, a team of researchers may have found the answer. Using a groundbreaking method called FitCoal, they analyzed the genomes of 3,154 modern humans to reconstruct ancient population sizes. What they found was staggering. Nearly 99% of early humans vanished, likely due to extreme climate events such as glaciations, severe droughts, and the collapse of ecosystems.

The world was changing. Glaciation, extreme droughts, and collapsing ecosystems made survival nearly impossible. Food sources vanished, and so did most of our ancestors. Those who remained – just a tiny fraction of the original population – fought to endure in a harsh and unpredictable environment. 

But against all odds, they survived. And in doing so, they may have changed the course of human evolution forever. Scientists believe this bottleneck could have led to the merging of two ancestral chromosomes, forming what we now know as chromosome 2 – a key feature that separates modern humans from other primates.

Around 813,000 years ago, the climate began to shift. Our ancestors may have mastered fire, allowing them to cook food, stay warm, and fend off predators. Populations rebounded, and from that tiny group of survivors, the future of humanity was born. 

This discovery reshapes our understanding of human history, and raises new questions. Where did these survivors live? How did they overcome such extreme conditions? Did this struggle push human intelligence to evolve faster?

The paper that is the basis for this account is Wangjie Hu, et al., "Genomic inference of a severe human bottleneck during the Early to Middle Pleistocene transition" 381(6661) Science 979-984 (August 31, 2023). Its abstract materials state:

Editor’s summary 

Today, there are more than 8 billion human beings on the planet. We dominate Earth’s landscapes, and our activities are driving large numbers of other species to extinction. Had a researcher looked at the world sometime between 800,000 and 900,000 years ago, however, the picture would have been quite different. Hu et al. used a newly developed coalescent model to predict past human population sizes from more than 3000 present-day human genomes (see the Perspective by Ashton and Stringer). The model detected a reduction in the population size of our ancestors from about 100,000 to about 1000 individuals, which persisted for about 100,000 years. The decline appears to have coincided with both major climate change and subsequent speciation events. —Sacha Vignieri 

Abstract 

Population size history is essential for studying human evolution. However, ancient population size history during the Pleistocene is notoriously difficult to unravel. In this study, we developed a fast infinitesimal time coalescent process (FitCoal) to circumvent this difficulty and calculated the composite likelihood for present-day human genomic sequences of 3154 individuals. Results showed that human ancestors went through a severe population bottleneck with about 1280 breeding individuals between around 930,000 and 813,000 years ago. The bottleneck lasted for about 117,000 years and brought human ancestors close to extinction. This bottleneck is congruent with a substantial chronological gap in the available African and Eurasian fossil record. Our results provide new insights into our ancestry and suggest a coincident speciation event.

The proposed climate event was part of the Mid-Pleistocene Transition. Some key aspects of this, in places where Homo erectus reached, were as follows:

Europe

In Europe, the MPT was associated with the Epivillafranchian-Galerian transition and may have led to the local extinction of, among other taxa, Puma pardoides, Megantereon whitei, and Xenocyon lycaonoides. The prevalence of ungulates adapted for grazing increased in the Mediterranean region after the "0.9 Ma event". The northern North Sea Basin was first glaciated during the MPT. The increased intensity of transgressive-regressive cycles is recorded in northern Italy.

Asia

The cooling brought about by the MPT increased westerly aridity in the western Tarim Basin. East Asian Summer Monsoon (EASM) precipitation declined. Grasslands expanded across the North China Plain as forests contracted.

During the MPT, the Indian Summer Monsoon (ISM) decreased in strength. In the middle of the MPT, there was a sudden decrease in denitrification, likely due to increased solubility of oxygen during lengthened glacial periods. After the MPT, the Bay of Bengal experienced increased stratification as a result of the strengthening of the ISM, which resulted in increased riverine flux, inhibiting mixing and creating a shallow thermocline, with stratification being stronger during interstadials than stadials. Paradoxically, variability in Δδ18O in the Bay of Bengal between glacials and interglacials decreased following the MPT.

Africa

In Central Africa, detectable floral changes corresponding to glacial cycles were absent prior to the MPT. Following the MPT, a clear cyclicity became evident, with interglacials being characterised by warm and dry conditions while glacials were cool and humid.

According to one of the leading papers on the 0.9 Ma Event, closely associated with the Homo erectus genetic bottleneck:

The Early-Middle Pleistocene Transition (EMPT) (ca. 1.4–0.4 Ma) represents a fundamental transformation in the Earth's climate state, starting at 1.4 Ma with a progressive increase in the amplitude of climatic oscillations and the establishment of strong asymmetry in global ice volume cycles. The progressive shift from a 41kyr–100kyr orbital rhythm was followed by the first major build-up of global ice volume during MIS 24-22, the so-called “0.9 Ma event”. The Vallparadís Section (Vallès-Penedès Basin, NE Iberian Peninsula) is one of the few Pleistocene series in Europe that spans the onset of the transition (from 1.2 to 0.6 Ma), thus representing a pivotal array of localities to investigate the effect of glacial dynamics on environmental conditions in Southern Europe. Here we inspect the effects of the EMPT on terrestrial ecosystems by examining the dietary adaptations (through dental meso- and microwear patterns) of fossil ungulates from the Vallparadís Section dated before and after the “0.9 Ma event”. Results show a steady presence of open grasslands before MIS 22 and more humid conditions at MIS 21. Both before and after MIS 22, a consistent presence of ungulates with long-term patterns that point to a grazing or grass-rich mixed feeding behaviour is observed, while noticeably, short-term patterns point to increased seasonality right after the “0.9 Ma event” glacial period. This increment of seasonality may have had an important effect on the Mediterranean habitats leading to recurring changes in the quality of plant resources available to large herbivores, which in response periodically adopted more mixed feeding behaviours widening their dietary breadth to consume also sub-optimal food items during adverse seasons.

In particular, during this event, global ice volumes increased substantially, and the Northern Hemisphere experienced increased seasonality and aridity, and surface sea temperatures in the North Atlantic reached their lowest values during the EMPT at this time. Also, grasslands expanded across the North China Plain as forests contracted.

This hypothesis is model dependent, could be impacted by sources of systemic error, like the possible much later extinction of Homo erectus populations derived from the same source population, later hard genetic sweeps of Homo erectus source genes, the effective extinction of modern humans arising from other clades of Homo erectus at some much later time, a lack of consideration of Neanderthal or Denisovan genes in the analysis, and a complete lack of ancient Homo erectus genomes. 

Also, in understanding this narrative one has to recognize that genetics researchers call an "effective population" of 1,280 individuals could have involved a census population at any one time that was many times larger than that. And, this is still about five times as large as the effective population size of the founding population of the Americas, for example. So, the bottleneck wasn't quite as extreme as some popular accounts of it would imply.

But the oldest examples of the species Homo antecessor does first appear in Europe, shortly after this inferred bottleneck, and there are no Homo erectus remains in Europe during or after the time of this inferred bottleneck.

Homo antecessor (Latin "pioneer man") is an extinct species of archaic human recorded in the Spanish Sierra de Atapuerca, a productive archaeological site, from 1.2 to 0.8 million years ago during the Early Pleistocene. Populations of this species may have been present elsewhere in Western Europe, and were among the first to settle that region of the world, hence the name. The first fossils were found in the Gran Dolina cave in 1994, and the species was formally described in 1997 as the last common ancestor of modern humans and Neanderthals, supplanting the more conventional H. heidelbergensis in this position. H. antecessor has since been reinterpreted as an offshoot from the modern human line, although probably one branching off just before the modern human/Neanderthal split.

Despite being so ancient, the face is unexpectedly similar to that of modern humans rather than other archaic humans—namely in its overall flatness as well as the curving of the cheekbone as it merges into the upper jaw—although these elements are known only from a juvenile specimen. Brain volume could have been 1,000 cc (61 cu in) or more, but no intact braincase has been discovered. This is within the range of variation for modern humans. Stature estimates range from 162.3–186.8 cm (5 ft 4 in – 6 ft 2 in). H. antecessor may have been broad-chested and rather heavy, much like Neanderthals, although the limbs were proportionally long, a trait more frequent in tropical populations. The kneecaps are thin and have poorly developed tendon attachments. The feet indicate H. antecessor walked differently than modern humans.

H. antecessor was predominantly manufacturing simple pebble and flake stone tools out of quartz and chert, although they used a variety of materials. This industry has some similarities with the more complex Acheulean, an industry which is characteristic of contemporary African and later European sites. Groups may have been dispatching hunting parties, which mainly targeted deer in their savannah and mixed woodland environment. Many of the H. antecessor specimens were cannibalised, perhaps as a cultural practice. There is no evidence they were using fire, and they similarly only inhabited inland Iberia during warm periods, presumably retreating to the coast otherwise.

Meanwhile:

Homo heidelbergensis (also H. erectus heidelbergensis, H. sapiens heidelbergensis) is an extinct species or subspecies of archaic human which existed from around 600,000 to 300,000 years ago, during the Middle Pleistocene. Homo heidelbergensis was widely considered the most recent common ancestor of modern humans and Neanderthals, but this view has been increasingly disputed since the late 2010s.

In the Middle Pleistocene, brain size and height were comparable to modern humans. Like Neanderthals, H. heidelbergensis had a wide chest and robust frame.

Fire likely became an integral part of daily life after 400,000 years ago, and this roughly coincides with more permanent and widespread occupation of Europe (above 45°N), and the appearance of hafting technology to create spears. H. heidelbergensis may have been able to carry out coordinated hunting strategies, and consequently they seem to have had a higher consumption of meat.

It is debated whether or not to constrain H. heidelbergensis to only Europe or to also include African and Asian specimens, and this is further confounded by the type specimen (Mauer 1) being a jawbone, because jawbones feature few diagnostic traits and are generally missing among Middle Pleistocene specimens.

H. heidelbergensis was subsumed in 1950 as a subspecies of H. erectus but today it is more widely classified as its own species. H. heidelbergensis is regarded as a chronospecies, evolving from an African form of H. erectus (sometimes called H. ergaster).

At least three other archaic hominin species overlapped with hominins from the H. erectus era or later.

• Homo floresiensis – Extinct small human species found in Flores
• Homo luzonensis – Archaic human from Luzon, Philippines
• Homo naledi – South African archaic human species

H. floresiensis and H. luzonensis may have been regional variations of the same species and show similarities with each other. The most plausible theory of their phylogenetic position, in my view, is that both of them were sub-species of H. habilis, and may have left Africa, either independently, or together with either H. erectus, the Denisovan ancestor, or Denisovans themselves. H. floresiensis and Denisovans (and possibly the earliest modern humans to arrive there as well) may have co-existed on the island of Flores, Indonesia (which is past the Wallace line) at some point in  time. There are no remains of H. floresiensis, H. luzonensis, H. habilis, or any other archaic hominins before H. erectus disperses from Africa. 

H. naledi was a South African archaic hominin species that flourished from 335,000 to 226,000 years ago, that was probably not directly ancestral to modern humans or any other non-African archaic hominins, but would have co-existed in time (and possibly space) with the earliest modern humans in Africa.

A November 6, 2024 post at this blog recapped some other possible non-African archaic hominins who existed at the same time that modern humans did: 

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 ... 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 geographic proximity. H. juluensis is found in association with early Paleolithic tools and remains of Paleoarctic 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).