Russell Ciochon -- Early Homo and associated artefacts from Asia

Early Homo and associated
artefacts from Asia

Nature_cover

Fossils of a primitive form of Homo found near the Wu Xia Gorge of China's Yang tze River shown here appear to be at least 1.9 million years old, suggesting that Homo erectus was endemic to Asia. Hominids may therefore have entered Asia around the time of the earliest diversification of the genus Homo in Africa. Back in Africa, the discovery of a 3-million-year-old australopithecine jawbone from Chad is the earliest record of an early hominid outside the Rift Valley, and is a marked westward extension to the 'cradle of humanity'.

Reprinted from Nature Volume 378 No. 6554 16 November 1995

Early Homo and associated artefacts from Asia

Huang Wanpo*, Russell Ciochon†‡, Gu Yumin*, Roy Larick§, Fang Qiren||, Henry Schwarcz¶, Charles Yonge#, John de Vos¤ & William Rink

* Institute of Vertebrate Paleontology and Paleoanthropology, Academia Sinica, Beijing 100044, China
† Departments of Anthropology and Pediatric Dentistry, The University of Iowa, Iowa City, Iowa 52242, USA
§ Department of Anthropology, University of Massachusetts, Amherst, Massachusetts 01003, USA
|| Chongqing Museum of Natural History, 72 Loquat Hill Park Street, Chongqing, Sichuan 630013, China
¶ Department of Geology, McMaster University, Hamilton, Ontario L85 4M1, Canada
# Department of Physics and Astronomy, University of Calgary, Calgary, Alberta T2N 1N4, Canada
¤ National Museum of Natural History, Post Office Box 9517, 2300 RA Leiden, The Netherlands
‡ To whom correspondence should be addressed.

Abstract:

The site of Longgupo Cave was discovered in 1984 and excavated in 1985-1988 by the Institute of Vertebrate Paleontology and Paleoanthropology (Beijing) and the Chongqing National Museum (Sichuan Province). Important finds include very archaic hominid dental fragments, Gigantopithecus teeth and primitive stone tools. Paleomagnetic analysis and the presence of Ailuropoda microta (pygmy giant panda) suggeste that the hominid- bearing levels dated to the earliest Pleistocene1. In 1992, joint Chinese-American-Canadian geochronological research corroborated the age using electron spin resonance (ESR) analysis. We report here that the hominid dentition and stone tools from Longgupo Cave are comparable in age and morphology with early representatives of the genus Homo (H. habilis and H. ergaster) and the Oldowan technology in East Africa. The Longgupo dentition is demonstrably more primitive than that seen in Asian Homo erectus. Longgupo’s diverse and well- preserved Plio-Pleistocene fauna of 116 species provides a sensitive contextual base for interpreting the early arrival of the genus Homo in Asia.

Article:

Longgupo Cave or, as known in Chinese, the ‘Wushan Hominid Site’ lies 20 km south of the Yangtze River near the eastern border of Sichuan Province (Fig. 1). The cave infilling comprises two major units: an upper cave breccia with few fossils, and an underlying poorly cemented fossiliferous unit with three depositional zones (Fig. 2). The middle zone (excavation layers 2-12) has a clay facies localized along the north and south cave walls in longitudinal channels 2-3 m wide. Two hominid dental fragments and two stone artefacts derive from these channels. The middle zone yields 68 mammalian genera including Procynocephalus and Macaca as well as Gigantopithecus and Homo1. The presence of Sinomastodon, Nestoritherium, Equus yunnanensis, Ailuropoda microta and Cricetinae indeterminate (with molar structure similar to Sinocricetus and Nannocricetus) suggests a late Pliocene to earliest Pliocene age1-3. The occurrence of Mimomys peii places this zone within the Dachaian (mammal neogene reference level 17 (MN 17)) age of north China (late Pliocene)4,5.

Fig. 1
Longgupo Cave. a, Location in Sichuan Province, Wushan County (109deg 40' E, 30deg 50' N). b, Regional geology has massive Triassic limestones and and intercalated sandstones. The primary local geomorphic feature is an E-W trending syncline that exposes carbonates on its limbs and silicates within. The limbs are karstic and the consequent drainage forms a polje around Miao-yu village. Longgupo Cave is a remnant of this drainage that has been eroding the polje’s southern margin since Miocene times. c, The cave presents an infilled east-west passage, bi-truncated to leave its floor 130 m long and its vault 25 m long. Vertical passages are also common within the local complex. Just northwest of the Longgupo site, a lower north-south passage retains an even shorter vault between two dolines.

Basic taphonomic observations suggest how the fauna accumulated within the middle zone channels. About 750 large mammal long bones derive from the channels, usually without surface erosion and sometimes as complete limb elements. Many shafts are punctured, split or shattered to indicate processing by Pachycrocuta or Homotherium, and many long bones were also gnawed, probably by Hystrix and smaller rodents while fresh. Pachycrocuta is the most common carnivore at Longgupo, and numerous hyaenid-sized coprolites suggest the cave occasionally served as a lair. Two accumulation processes are therefore possible. The large scavengers/carnivores may have brought carcasses into a horizontal passage, eventually to be interred by gentle fluvial action. Alternatively, the representation and condition of the Longgupo fossils also recalls the assemblages from Yanjinggou (about 50 km NW), where carcasses accumulated in vertival passages, the result of predation and falls^6,7.
Palaeomagnetic data also suggest great antiquity for the middle zone clay facies where 100 sediment samples were taken in overlapping columns. Sample natural remanent magnetization was determined after thermal demagnetization to 700 ºC. Sediment at the top of the lower unit is magnetically reversed, indicating an age of at least 0.78 million years (Myr). There are 7 magnetic reversals between levels 1 and 20 with magnetic normal sediment sections thinner (about 1-2 m) than reversed sections (about 3-4 m) (Fig. 2). Thermal demagnetization properties are similar in normal and reversed sediments, suggesting both remanence types are of the same (detrital) origin. Although we do not have sufficient rock magnetic data to exclude completely the possibility that selective remagnetization may have led to a spurious magnetostratigraphy, we do not believe that this is likely. We therefore assign the magnetically normal hominid-bearing levels 7-8 to the Olduvai event that spans the interval 1.96 to 1.78 Myr7,8. A few depositional breaks (such as the 13/12 boundary) may correspond to lengthy time gaps in which further reversals could have occurred. Therefore this is a minimum age estimate for the hominids.

FIG. 2.
Longgupo Cave stratigraphy and suggested age. The upper sedimentary unit is a 12-m-thick fossil-poor cave breccia where clasts range to 50 cm x 90 cm within a highly cemented sandy clay. The underlying poorly cemented fossiliferous unit has three depositional zones excavated in 1 m levels. The upper zone (within level 1) consists of a few spatially discrete sandy clay lenses with some gravels and localized areas of calcite concretion. The middle zone (levels 2-12) has a clay facies localized along the north and south cave walls in longitudinal channels (2-3 m wide), while a gravel facies occupies the passage centre. Clast size ranges to 2 cm x 3 cm in the clay facies and to 10 cm x 20 cm in the gravels with limestone clasts dominating shale and mudstone. The lower zone (levels 13-20) has primary silts in parallel horizontal beds that indicate stagnant fluvial or lacustrine deposits.

Electron spin resonance (ESR) analysis of tooth enamel further constrains the age of the middle zone channels. This method has been successfully applied to fossils older than 2 Myr10,11. From level 4, a large cervid premolar fragment (recovered within the sediment-filled interior of a long bone) yields about 400 mg of enamel and dentine, containing 0.85 and 39 p.p.m. uranium, respectively. External gamma dose-rates were estimated from U, Th and K contents of sediment adhering outside the long bone; beta dose-rates alone were determined from sediment within the long bone cavity. Age calculation depends on an assumed uranium uptake history of the tooth: early uptake gives a minimum age of 0.75±0.09 Myr; a linear uptake model, which generally has given ages close to independent estimates, yields 1.02±0.12 Myr11. The linear uptake age places the level 4 sediment within the Matuyama reversed magnetic chron, consistent with the paleomagnetic interpretation for levels 7-8.
Within the middle zone channels, levels 7-8 yield two hominid dental fossils, a fragmentary left mandible (with P4, M1 and M2 alveolus) and a right upper lateral incisor (Fig. 3). These specimens were originally described as a new subspecies of Homo erectus, H. e. wushanensis1, but joint reanalysis demonstrates morphology different from and sometimes more primitive than Asian H. erectus. The Longgupo dentition exhibits affinities with representatives of East African early Pleistocene Homo, including H. ergaster and H. habilis (Fig. 3 legend). For the mandibular teeth, relevant features include, for P4: cusp placement and inflection, relationship between cusps and talonid, and root morphology; and for M1: cusp number and spatial relationship, enamel surface thickness, and surface texture. Basic dimensions of the Longgupo mandibular corpus, P4 and M1 (Fig. 3 legend) are very small. These fall outside the lower range for Zhoukoudian (G1, H1, 29, 30, 34, 89-93, 96-102)12 and Sangiran (1b, 9) specimens13,14, while lying near the lower limit for any East African Plio-Pleistocene hominine (such as OH 7, OH 13, OH 16, ER 992 and WT 15000)14-16. I2 crown shape index (BL/LL * 100) also distinguished Longgupo from Asian H. erectus. The Longgupo index (116) is quite high compared with Zhoukoudian 6 and 7 (101), but falls within the range for OH 6, OH 16, OH 39 and ER 1813 (H. habilis) (96-127 (mean = 109))15. Finally, the shovel-shaped character of the Longgupo I2 is also found in OH 6 and OH 16 (H. habilis)15, and WT 15000 (H. ergaster)16 as well as at Zhoukoudian12. Indeed, Tobias concludes that “shovelling is a virtually universal feature of all early hominids up to Homo erectus” (p. 614) 15.
Sixteen teeth of Gigantopithecus blacki come from levels 5-8 (Fig. 2): one C1, three P3, one P3, four P4, three P4 and four M1-2. In size and morphology the Longgupo teeth match the >900 isolated teeth from Liucheng Cave, Guangxi, China17,18, where amino-acid racemization measurements suggest an age greater than 1.2 Myr19. The Longgupo Gigantopithecus teeth, like those of Liucheng, exhibit high sexual dimorphism, lower molars with a distinctive accessory internal tubercle between metaconid and entoconid and very thick enamel (5-6 mm). Nearly all of the roots show evidence of rodent gnawing, probably by Hystrix. Longgupo marks the northernmost extent of Gigantopithecus in China. It also represents the third east Asian cave where Gigantopithecus and Homo lie within the same stratigraphic interval. The others are Tham Khuyen Cave, Lang Son, Vietnam dated to 0.475 Myr20, and at Jianshi Cave, Hubei, Chiona, where the co-occurrence remains undated21. With the Longgupo date indicating the earliest presently known association, Gigantopithecus and Homo evidently coexisted for more than 1 Myr in east Asia.

FIG. 3. Longgupo Cave hominids. a, Left mandible fragment (CV.939.1, level 8), occlusal (top) and lingual views. The mandibular corpus is nearly complete directly below M1, where the in ferior margin is damaged. The buccal and lingual faces bulge little and remain parallel as they descend to the inferior margin. Behind M1, the buccal face begins to thicken. Below M1, corpus height is 21 mm and width is 13 .5 mm. For the limited morphology preserved, the Longgupo mandibular corpus is gracile compared with As ian H. erectus (Zhoukoudian G1, H1; Sangiran 1b, 9)12-14, and more closely resembles specimens of early Pleistocene East African Homo such as KNM-WT 15000, KNM-ER 730 (H. ergaster) and OH 13 (H. habilis)14-16. P4 (mesio- distal (MD) = 7.4, buccal-lingual (BL) = 9.1): The crown is slightly subcircula r with a buccal-lingual long axis. No cingulum is present. The cusps are placed mesially and inflected centrally t o be separated only by a central sagittal groove, while a long, wide talonid, with no cusps or ridges, occupies t he distal two-thirds of the tooth. The neck is constricted, and a long robust root bifurcates for 2/3 of its length . In comparison, the seven Asian H. erectus P4 from Zhoukoudian (29, 30, 89-93) have an obliquely oval crown with the greatest diameter running mesio-buccally to distal-lingually, with distinct buccal and lingual cusps, and with a small talonid having numerous short accessory ridges and wrinkles. The buccal surface of these teeth has a well developed cingulum and the root structure shows a single tapering root that is compressed mesio-dis tally. In the Longgupo P4, the buccal-lingually expanded crown resembles ER 992 (H. ergaster), the posit ion of the mesial cusps and large talonid compares with OH 7 and OH 13 (H. habilis), and the bifid root is like ER 992 (H. ergaster) and to a lesser extent OH 13 (H. habilis). M1 (MD = 11.0, BL = 10.1): the tooth is low-crowned and possesses two strong roots and five cusps. In occlusal view the crown is sub-rectangular with rounded corners. The metaconid is larger than the entoconid and is the highest cusp. The enamel is relatively thin and uncrenulated; perforations expose dentine at the protoconid, hypoconid and hypoconulid. In comparison, the seven in situ M1 of H. erectus, as well as Black^Rs type specimen (Zhoukoudian 96-102, 34)12 exh ibit six cusps (including tubercle 6), thickened enamel, cusps covered by wrinkles, furrows and accessory ridges, and l arger size. The cusp arrangement and size of the Longgupo M1 may be likened with ER 992 (H. ergast er) and OH 13 (H. habilis). b, Right I2 (CV.939.2, level 7) labial (left) and lingual views (x 1.5 the scale of a). This isolated tooth is complete and unerupted with the root intact (MD = 8.1, labio-lingual (LL) = 7.0, crown he ight (CH) = 10.3). In lingual view, the mesial and distal marginal ridges are both high and well defined. A s mall tubercle is present at the base of the lingual surface where the mesial and distal marginal ridges converge upwa rd to meet. The lingual surface is concave and quite shovel-shaped. A central ridge runs from the tubercle to t he occlusal edge and divides into two branches at the middle of its crown. The labial surfave is moderately conve x. A mamelonated incisal ridge shows that the tooth was never in occlusion. The Longgupo I2 differs from Zhouk oudian 6 and 7 (ref. 12) in its significantly lower crown height, less buccal-lingual expansion of the crown, si gnificantly thicker mesial and distal marginal ridges, and a less wedge-shaped appearance when viwed from the l ingual side of the occlusal surface. These features are variably expressed in the OH 6, 16, 39, ER 1813 (H. habilis)15 and WT 15000 (H. ergaster)16.

FIG. 4.Longgupo Cave andesite/porphyrite stone artefacts. a, The elongated, sph erical cobble (P.6524, level 5) has a heavily weathered cortical surface. Three relatively discrete areas (left , centre, and right) have reweathered crushing and pitting. The area at centre has a concentrated pattern of pits (4m m depth) that suggest repeated battering. b, the lenticular flake (P.6523, level 8) represents a larger cobble that has split near a natural waist. The heavily abraded and weathered ventral surface consists of a few lare scars ( centre). The dorsal surface (left) shows two stages of weathering: rough, highly pitted areas confined to recesses , and smoother crests and convexities covering most of the surface. The dorsal surface recurves onto the ventral surface to indicate the waist in the original cobble (right). Heavily weathered crest damage occurs (le ft) clockwise from bottom centre at 0 -85 and at 180 -270 . The dorsal faceting at 270 -350 also has heavy cre st damage.

Two items from the clay facies show three characteristics of early stone artefacts (Fig. 4). They have exotic petrological composition (andesite-porphyrite), they are twice the size of the largest normal deposit clasts, and they exhibit surface damage inconsistent with natural cause. The closest primary outcrops for andesite- porphyrite rocks lie 130 km ENE and 150 km NNW. Derived sources occur within the non-carbonate sediments of the Miao-yu polje, a function of pre-Yangtze Valley (Pliocene and earlier) fluvial systems. Potential sources are to be found about 2km downstream from Longgupo, but andesite-porphyrite remains undocumented. As both objects are more than twice as large as the largest clay facies casts, fluviatile transport does not explain their presence. Assuming artefact status, these specimens recall the Oldowan technology of early Pleistocene East Africa22 in two ways. First, they were chosen from the natural environment for inherent qualities of raw material and morphology and thus used with little modification23. The andesite-porphyrite raw material is resilient to repeated battering, and both implements fit within the hand to offer numerous surfaces and edges for use. Second, the tightly patterned distribution of surface and edge damage indicates deliberate and consistent gestures of use24. If, eventually, andesite-porphyrite cobbles prove unavailable within several kilometers of the Longgupo cave site, curation may distinguish this potentially earliest Asian technology from its African contemporaries.
We have estimated the age of the Longgupo hominid specimens and artefacts in three ways. The co- occurrence of Sinomastodon, Nestoritherium, Equus yunnanensis, Ailuropoda microta and Mimomys peii place the middle zone clay facies in the late Pliocene and earliest Pleistocene. Palaeomagnetic data then bracket levels 7-8 within the Olduvai chron, 1.96 to 1.78 Myr. Finally, the ESR determination of 1.02±0.1 Myr, on material from level 4 (3 m above levels 7-8), constrains and reinforces these interpretations. The Longgupo specimens are therefore older than any reported for China and at least as old as Indonesian Homo erectus25. The Longgupo specimens closely resemble East African fossils representing the earliest species of the genus Homo. They share few characters in common with Asian Homo erectus. As their incompleteness precludes designating a new species, we assign the Longgupo hominids to Homo species indeterminate, while noting affinities with H. habilis and H. ergaster. The stone tools are consistent with this interpretation. Given the early date and primitive morphology for the Longgupo specimens, and the older age estimates for H. erectus in Java25, we must recognize more than one Plio-Pleistocene hominid species in east Asia. The new evidence suggests that hominids entered Asia before 2 Myr, coincident with the earliest diversification of the genus Homo in Africa(26,27). Clearly, the first hominid to arrive in asia was a species other than true H. erectus, and one that possessed a stone-based technology. A pre-erectus hominid in China as early as 1.9 Myr provides the most likely antecedents for the in situ evolution of Homo erectus in Asia27-29.

Notes and References:
Received 12 May; accepted 20 September 1995

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ACKNOWLEDGEMENTS. For assistance and permission to conduct research at Longgupo, we thank the Institute of Vertebrate Paleontology and Paleoanthropology (IVPP), the Chinese Academy of Sciences, the National Cultural Relics Bureau, and the Chongqing Museum of Natural History, Sichuan. We specifically acknowedge Li Chuankuei, Jia Lanpo, Zhou Shiw, J. Olsen and D. Gifford-Gonzalez. Fieldwork was funded by the L. S. B. Leakey Foundation. laboratory support has been provided by the Wenner-Gren Foundation and the Human Evolution Research Fund at the University of Iowa Foundation. ESR dating was funded by a grant from the NSF. Special thanks to H. Ruíz for composing Figs. 1 and 2 and to L. González for helpful discussions.

Out of Africa and into Asia

Bernard Wood and Alan Turner

Few doubt that Africa was the birthplace of the hominid lineage, but there is no equivalent consensus about when hominids first moved out of that continent. Despite the announcement of early dates for a juvenile Homo erectus from Indonesia1, the circumstances surrounding the recovery of many of the fossil hominids from the island will always hinder attempts to date them. Thus the excavation of hominid remains, in combination with crudely fashioned artefacts in what are claimed to be early Pleistocene deposits at Longgupo Cave in central China (Huang and co-workers, page 275 of this issue2), is of major importance. Most notably, the remains lend support to the idea3 that representatives of the hominid lineage were established in mainland Asia as early as about 1.9 million years (Myr) ago.
Africa has been the focus for research into human evolutionary history for the past three decades, but it was not always thus. A century ago, space in the correspondence column of Nature was regularly claimed to debate the significance of the finds Eugene Dubois had made, eginning in 1891, at Trinil in Indonesia. Although initially allocated to Pithecanthropus erectus, the species distinction of the Trinil hominid has survived but the genus has long since been sunk into Homo.
Two decades later, excavations were instigated by the Canadian anatomist Davidson Black in the cave deposits at Choukoutien, now called Zhoukoudian, and the first of the series of remains of what became known as ‘Peking Man’ was discovered. Despite being allocated to a new genus and species, their affinities with the hominids from Trinil, and with similar material that was subsequently recovered at Sangiran, also in Indonesia, was evident, and the Chinese remains have also been subsumed within H. erectus. There have been sporadic attempts to demonstrate both that the hominid remains from the Indonesian sites are from more than one species4,5,and that they include specimens that should be allocated to Australopithecus6 or Paranthropus7, and thus to an earlier, more primitive phase of hominid evolution. But none of these claims has survived close scrutiny8. Likewise, until recently there has been little compelling evidence to suggest that any of the Asian hominid sites were yielding hominids more than one million years old3.
The importance of the material from Longgupo Cave is twofold. Not only does it support an early date for the hominid occupation of Asia, but the morphological details of the admittedly fragmentary fossil evidence also means that it may represent not H. erectus but a more primitive species akin to H. ergaster, thus far known only from Africa.
Of course, dating the material is crucial to the argument. Longgupo Cave has several lines of evidence, none of them contradictory. Paleomagnetic stratigraphy shows a reversed polarity for most of the sediments, with the hominid fossils and lithic items associated with the lower of two normal events and therefore referred to the Olduvai magnetic event. The magnetic evidence is broadly supported by analysis of tooth enamel from the sediments, using electron spin resonance, which gives a minimum age of 0.75 ± 0.09 Myr based on an early uranium uptake model. It could be argued that the normal magnetic event associated with the material is therefore likely to be Jaramillo, but the associated mammalian fauna is really too archaic and point instead to the earlier Olduvai event. Of particular interest here is the presence of Nestoritherium, a genus of the family Chalicotheriidae, an extinct, bizarre, claw-hoofed member of the Perissodactyla, today represented by tapirs, rhinos and horses.
The lithic items identified as primitive stone tools do seem to be exotic, and they are notably larger than the rest of the sediments. They look as much like stone tools as anything of this age ever does, and they fall into the category of items in finer sediment deposits that, as Gamble9 has pointed out, tend to categorize genuine archaeological assemblages as opposed to naturally bashed stones. Moreover, the uneroded state of the bone in clay facies channels is consistent with primary deposition rather than intrusive burial. But we are unlikely to be dealing with a site of hominid occupation. The giant hyaena, Pachycrocuta, is a perfectly plausible agent of accumulation10 (it is less likely that the sabre-toothed Homotherium did much bone destroying).
The authors draw attention to the presence of Gigantopithecus, a large, gorilla-like and presumably herbivorous primate, in the same level as the hominid fossils, and stress that this is the third such co-occurrence at Asian localities over a time span of some 1 Myr. Such co-occurrences are always intriguing, but the evidence of hyaena activity reduces the likelihood that Gigantopithecus was prey to the more advanced hominid. The remaining elements of the mammalian fauna at Longgupo shed little light on the local environment of the site, although both woodland and more open-country taxa seem to be represented.
The hominid remains -- part of the left side of an adult mandible and an isolated upper incisor -- are meagre pickings froma taxonomic point of view. However, the mandibular fragment includes both the crown and the root of a premolar tooth (P4), and they provide the best evidence about the affinities of the material. The crowns of the P4 teeth of H. erectus are generally relatively simple and the teeth are usually single-rooted, like those of modern humans. In contrast, the Longgupo P4 root is bifid for most of its length. This, and other features of the mandible and the dentition, suggest that the Longgupo hominid may be much more primitive than H. erectus11. This opens up the possibility that the first hominid to leave Africa was at least as primitive as H. ergaster12, and implies that H. erectus may have evolved within Asia and then spread back into Europe and Africa.
In terms of overall patters of mamalian movement, there is nothing inherently implausible about the age of the material and the implications that it holds for human dispersions from Africa. Hominid remains and lithic items from Dmanisi13 in Georgia point to at least an initial presence at the gates of Europe by around the same time as the age of the Longgupo evidence. And it is clear that a Late Pliocene dispersion across Arabia, probably via the Levant, and perhaps through the Bab-el-Mandab straits, was possible for several mammalian taxa14,15, while the presence of hominids in the Levant itself by 1.4 Myr ago is evident at the Israeli site of ‘Ubeidiya14. The new report from Huang et al. adds weight to other, less well-substantiated claims that hominids travelled even further, and occupied China in the latest Pleistocene some 1.9 Myr ago.

The evidence from Longgupo Cave in China, described by Huang et al.2 and discussed here, suggests that hominids were established in Asia just after two million years ago. Given the primitive nature of the premolar teeth, it seems that the first hominid to occupy Asia may not have been Homo erectus, but perhaps a variant of H. ergaster or even H. habilis.

Bernard Wood and Alan Turner are in the Department of Human Anatomy and Biology, The University of Liverpool, PO Box 147, Liverpool L69 3BX, UK.

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