Posted on 11/22/2002 2:18:45 PM PST by Sabertooth
Alfonso Arribas Museo Geominero, Instituto Tecnológico Geominero de España. Ríos Rosas, 23. 28003 Madrid, Spain. Paul Palmqvist Departamento de Geología y Ecología (Área de Paleontología), Facultad de Ciencias, Universidad de Málaga. 29071 Málaga, Spain.
African Species in the Lower Pleistocene of Europe
…The sabre-tooth genus Megantereon shares much in common with Smilodon, and both genera form the tribe Smilodontini. The earliest presence of Megantereon is recorded at 4.5 Ma in the Bone Valley Formation (Florida), where it is represented by M. cultridens. This species dispersed from North America between 3.5 and 3.0 Ma, and expanded all over the Old World. Europe was also home to M. cultridens until the lower Pleistocene, and in China it lingered well into the middle Pleistocene at Choukutien Locality I (Turner 1987). In Africa M. cultridens gave rise to a new species, M. whitei, which is characterized by a reduction in the size of both the maxillary carnassial (P4) and the mandibular premolars, which is reflected in a diastema between P3 and P4 (Martínez-Navarro & Palmqvist, 1995). M. whitei replaced M. cultridens in Western and Central Eurasia at the Plio-Pleistocene boundary, as recorded at Orce, Apollonia (Mygdonia Basin, Greece) and Dmanisi. The arrival of this carnivore species to Eurasia may have played a very significant role in facilitating the dispersal of Pachycrocuta and Homo outside Africa, since it was an ambush predator with great killing capability in relation to its flesh requirements, and presumably left large amounts of carrion for both hyaenas and hominids (Palmqvist et al., 1996b; Martínez-Navarro & Palmqvist, 1996).
Pachycrocuta brevirostris was a large, short-faced hyaena relatively common in lower Pleistocene European assemblages of large mammals. It had a body and skull 10-20% larger than the modern spotted hyaena, Crocuta crocuta, and was well adapted for destroying carcasses and consuming bone (Palmqvist et al., 1996b; Arribas & Palmqvist, 1998). This species differed from other hyaenids in having a relative shortening of the distal limb segments, what suggests a less cursorial life style, although such shortening could provide greater power and more stability for dismembering and carrying large pieces of carcasses obtained from aggressive scavenging (Turner & Antón, 1996). P. brevirostris is recorded in China from the end of the Pliocene (Nihowan) to middle Pleistocene times (Choukoutien Locality I). This hyaenid was present in India (Pinjor Formation) not before 2.5 Ma. Howell & Petter (1980) think that the South African hyaenid Hyaena bellax from Kromdraai could be a member of the genus Pachycrocuta, and suggest that it would be the direct ancestor of P. brevirostris. This species is recorded in South Africa at Kromdraai A (1.5 Ma), Sterkfontein (Members 4 and 5, 2.6-1.0 Ma) and Makapansgat (Member 3, 3.0 Ma) (Howell & Petter, 1980; Turner, 1990). If its presence at Laetoli (3.5-3.2 Ma, East Africa) is confirmed (specimens tentatively identified as H. bellax by Leakey & Hay, 1979), the age of the first appearance of this species on the austral continent would be older. The arrival of this hyaenid to Europe was a significant faunal event. P. brevirostris is first recorded in upper Pliocene deposits at Olivola (1.8 Ma), and its latest appearances are in early middle Pleistocene sites from Central Europe, like Süssenborn (Turner & Antón, 1996). In the Iberian Peninsula this species is found exclusively in early lower Pleistocene sites, and its record during middle Pleistocene times is not known. It is difficult at present to decide if P. brevirostris originated in Asia or in Africa; however, what seems clear is the presence of this hyaenid in Africa when it spread in Europe during the beginning of the Eburonian event. The extinction in Europe of P. brevirostris seems to have been linked to the decline and subsequent disappearance of machairodonts at approximately 0.5 Ma (Turner, 1990, 1992), particularly Megantereon whitei (Martínez-Navarro & Palmqvist, 1995), what implied the loss of an important source of partly-consumed carcasses, and thus a change in the interactions between flesh-eating and bone-consuming species of the carnivore guild (Turner & Antón, 1996).
As we have seen in the above discussion, it seems clear that a flux of African species to Eurasia, mainly to its western fringe, took place during the end of the Pliocene and the beginning of the Pleistocene. The fact that most African species are found in Southern Spain is explained if we consider that the Iberian Peninsula was faunally and climatically a part of Africa during the Neogene, far more than it was a part of Europe, which many palaeontologists consider to begin at the Pyrenees. This is the third approach to the dispersal of hominids to Europe, which allows inclusion of the genus Homo in a faunal set which expanded its palaeogeographical range during these times.
The Role of Sabre-tooths in Facilitating the First Dispersal of Homo to Europe
The marked seasonality which characterized temperate Europe for most of the Pleistocene, with cooler and drier conditions than those of tropical Africa, made the availability of large ungulate carcasses for scavenging a key resource for hominids to survive during the cool season (Turner, 1990, 1992). Between 1.5 and 0.5 Ma the composition of the European carnivore guild was quite different from that of East Africa, including two species of sabre-tooth cats (Homotherium latidens and Megantereon whitei), which presumably maximized the amount of flesh that remained on their kills, thus opening broad opportunities of scavenging for both hyaenas and hominids.
Sabre-tooth cats, which belong to the subfamily Machairodontinae, share among others the following craneodental derived characters (see for review and references Emerson & Radinsky, 1980; Marean, 1989; Van Valkenburgh & Ruff, 1987; Martin, 1989; Biknevicius et al., 1996; Arribas & Palmqvist, 1998):
1. Elongate and flattened upper canines of two basic types: Homotherium (tribe Homotherine) had scimitar-shaped canines relatively short and broad, which were serrated bearing coarse crenulations, while Megantereon (tribe Smilodontini) showed dirk-shaped canines, extremely long, narrow, and without serrations.
2. Enlarged upper incisors, which are relatively longer, thicker, more pointed and procumbent than in modern felids, and reduced, incisor-shaped lower canines. The incisor row is long and strongly curved, what suggests for sabre-tooths a functional emphasis on these teeth for tearing and stripping flesh from carcasses, a task that modern felids perform with the assistance of their stout and conically shaped canines; the extremely large upper canines of the sabre-tooths would probably be ineffective at the manipulation of chunks of flesh.
3. Upper carnassials (P4) with a reduced or absent protocone (lingual lobe), which is lowered away from the occlusal surface in Megantereon, thus removing it from its role as a hammer for bone crushing (a condition that is present among extant felids in the hypercarnivorous cheetah), and is lost in Homotherium, in which there is also an anteriorly added accesory cusp. This tooth forms in sabre-tooths a long thin blade, which is extremely specialized for slicing flesh, and allowed them to deflesh their prey rapidly.
4. A lowered glenoid fossa, a reduced height of the coronid process, a laterally shifted angular process, and a shortened zygomatic arch. All these features allow a wider gape than that of modern felids, but suggest that the temporalis muscle was weaker. However, the temporal fossae were shorter and narrower, which indicates that the temporalis was oriented in sabre-tooths more vertically and perpendicular to the tooth row than in modern felids. This increased the bite force at the carnassial (M1), which was closer to the mandibular condyle, although it remained significantly lower than in felids.
5. An enlarged, lowered and ventrally extended mastoid process, which is enormous relative to modern felids, thus indicating that the cleido- and sterno-mastoid muscles must have been correspondingly large. The occiput is in most sabre-tooths relatively higher and narrower than in felids, and the temporomandibular joint is located more ventrally. The mastoid process is rotated further below the skull joint so that the leverage of the neck muscle is increased, thus suggesting that a head-depressing motion was involved in the penetration of the canines.
The postcranial skeletons of scimitar-toothed and dirk-toothed machairodonts are quite different (Martin, 1989). Homotherium was a relatively long legged pursuit predator with the size of a modern lion (150-220 kg, according to regressions of body mass against postcranial measurements in modern carnivores; Anyonge, 1993), which had a comparatively large brain with an enlargedment of the optic centre, a condition similar to that of the cheetah (Rawn-Schatzinger, 1992). The morphology of Homotherium is unique among extant and past felids, showing relative limb proportions which indicate increased cursoriality and less prey grappling capabilities than other sabre-tooths. Given the strikingly elongated forelimbs but rather short hindlimbs that characterize the species within this genus, they probably had a sloping back. The brachial index in Homotherium (radius length/humerus length) takes values close to or above 100%, what implies that most species of this genus preferred open habitats (Lewis, 1997). According to the results obtained by Anyonge (1996) in a comparative multivariate analysis of the locomotor behaviour of both extinct and modern species of large carnivores, based on cross-sectional geometric properties and linear dimensions of their femora and humeri, the North American species H. serum was classified by the discriminant functions in the cursorial category but with a probability of only 0.6; the next group of most likely membership (0.4) was the ambush category. The mean brachial index (103%) is intermediate to that in hyaenids and canids, whereas the mean crural index (tibia length/femur length, 78%) compares with that of the larger living felids; this species therefore had a postural stance that was rather intermediate between cursors and ambushers.
Dirk-toothed machairodonts (Megantereon, Smilodon) were relatively short limbed ambush hunters, with a comparatively smaller brain, showing olfactory lobes well developed. They had powerfully developed forelimbs, what suggests that a killing bite in the throat may have been coupled with the immobilization of the prey by the front limbs. Comparative multivariate analyses of postcranial measurements (Lewis, 1997) indicate for Megantereon an overall morphology similar to that of extant jaguars, with tree catching and long distance dragging capabilities; the low value for the brachial index (slighty greater than 80% in eurasian M. cultridens; Lewis, 1997) suggests closed habitat preferences. Morphofunctional studies of African M. whitei (Palmqvist et al., 1996b; Martínez-Navarro & Palmqvist, 1996) indicate that this predator generated large amounts of carrion, since it would exploit the carcasses of its prey to a smalll degree. According to the results obtained by Anyonge (1996) in the multivariate analysis of postcranial measurements in extant and extinct carnivores cited above, the larger and related New World species Smilodon fatalis (350 kg; Anyonge, 1993), a descendant of M. hesperus, was placed in the ambush category with a probability of 0.51, and the next most likely category was ambulator (i.e. that of ursids); femoral and humeral cross-sectional properties in Smilodon approach those of modern bears. The metapodials of this species were shorter than those of large modern felids and, in addition to slighty smaller brachial and crural indices, the possession of a relatively short tail argues for slower locomotory speeds in this sabre-tooth cat (Anyonge, 1996).
All these craniodental and postcranial features indicate (1) that sabre-tooth felids were able to hunt very large prey relative to their own size, and (2) that they left on the carcasses of the ungulates hunted large amounts of flesh and all within bone nutrients, which were available to be subsequently scavenged by hyaenas and hominids (Marean, 1989). Sabre-tooths became extinct in East Africa by 1.5 Ma ago, what coincides with the emergence of the Acheulean Industrial Complex, but inhabited Eurasia until 0.5 Ma (Turner, 1990, 1992). Their persistence may then explain the success of the Oldowan tools in Eurasia, where the Oldowan/Acheulean transition took place much later than in Africa, at approximately 0.5-0.4 Ma (i.e. when sabre-tooths disappeared in this continent), since the sharp flakes characteristic of Oldowan assemblages were fully appropiate to scavenge on partially defleshed carcasses and the cores were used in breaking bones for their marrow content. In this context, the striding gait for the emergence of the genus Homo, the elementary Oldowan stone tools and the expansive pattern of scavenging, also served its initial dispersal from Africa (Larick & Ciochon, 1996), which was facilitated by the availability of ungulate carcasses supplied by sabre-tooth cats.
An opposite interpretation of the ecological opportunities opened by sabre-tooths for the hominids has been argued by Turner (1990, 1992), who considers that the competition with the large and efficient bone-cracking hyaenid P. brevirostris made it difficult for hominids to develop an adaptive pattern of scavenging on the carcasses left by sabre-tooth cats, and that a stable and productive niche for the hominids in Europe was only possible after the replacement during middle Pleistocene times (0.5 Ma) of sabre-tooths and giant hyaenas by modern African carnivores like the lion, the leopard and the spotted hyaena.
However, this argument is contradicted by the results obtained recently in two independent comparative studies (Capaldo, 1997; Selvaggio, 1998) of the incidence and distribution of tool marks and tooth marks on bovid long bone specimens from the FLK 22 assemblage at Olduvai Bed I ('Zinjanthropus' site, 1.8-1.76 Ma) and different experimental control samples, which have shown a three stage sequence (carnivore to hominid to carnivore involvement) of site formation. In stage one flesh-eating carnivores (probably sabre-tooths in most cases) partially defleshed long bones, as deduced from the high frequency of tooth marks on midshaft fragments; in stage two hominids processed intact long bones for their marrow content, as inferred from percussion mark percentages, and the presence of cut marks indicates that the bones still retained at this stage variable amounts of flesh; finally, in stage three bone-cracking carnivores consumed long bone epiphyses for grease, as inferred from the under-representation of these elements in the assemblage (the abundance of major long bone epiphyses is inversely correlated with their structural density) and the high percentage of tooth marks on near-epiphyses and surviving epiphyses. Therefore, the results obtained clearly indicate that competition between hominids and bone-cracking carnivores was low at FLK 22, and that hominids had access before than hyaenids to those carcasses partially defleshed by sabre-tooths; such situation was probably the same in Europe during lower Pleistocene times.
Dispersal Routes to Europe Most palaeoanthropologists consider that Homo spread out of Africa by the Eastern Mediterranean or levantine land corridor ('Ubeidiyah), reaching Europe through the Straits of Dardanelles, which were closed by low water levels during the glacial cycles. However, it has been suggested that these hominids could have also crossed the Mediterranean via the Gibraltar Strait or even through Sicily (Alimen, 1975; Martínez-Navarro & Palmqvist, 1995, 1996); this possibility would require crossing open waters, even at lowest sea-levels.
The minimum width of the Strait of Gibraltar is nowadays 14.5 km, but a sea-level fall of 200 m during the Aullan event (1.8-1.6 Ma) would result in the narrowing of this passage up to 6.5 km approximately and a drop of 300 m would nearly close it. No evidence confirming the ability of Homo to cross stretches of open waters has been yet found in Spain or Italy, although the presence of narrow sea stretches does not seem to have represented and effective geographical barrier for human dispersal during the Plio-Pleistocene, as suggested by recent data on the colonization of Flores by H. erectus (as well as by other species of continental Southeast Asian fauna), dated at 0.9-0.8 Ma by zyrcon fission-tracks (Morwood et al., 1998): even when the sea level was at its lowest, these human populations would have to cross 19 km of water to get to Flores from the closest island of Sumbawa.
There are two additional lines of reasoning that support the possibility of a dispersal through Gibraltar (and perhaps even through the passage between Tunicia and Sicily): (1) the levantine corridor requires longer distance movements to reach Western Europe, crossing large rivers and mountainous chains, with adaptations to different vegetation zones and to broader ranges of temperature and rainfall, and (2) a simultaneous colonization of Europe through Gibraltar, perhaps Sicily, and the Eastern Mediterranean helps to explain the presence in several north circummediterranean sites of Spain (Orce), Italy (Pirro Nord), Greece (Apollonia) and Georgia (Dmanisi) of certain African species of large mammals which have not been found by the moment in Central Europe during lower Pleistocene times, such as M. whitei, whose dispersal seems to have been limited up to the 40ºN parallel (Martínez-Navarro & Palmqvist, 1996).
The Dispersal of Homo out of Africa: Alone or Lonely with Others? Until now, three chronological hypotheses regarding the first arrival of humans to Europe had been proposed: the Europe of 0.5 Ma (the ‘Young Europe’ of Carbonell et al., 1995a), which was accepted until 1994; the Europe of 1.0 Ma (called the ‘Mature Europe’), which has been followed since then by most palaeoanthropologists; and the Europe of 1.5 Ma (the ‘Old Europe’), which is for us the most reliable chronological scenario, although there are still reservations about this possibility due to disputes on the human affinities of some controversial fossil remains from Orce (see Palmqvist, 1997), and also due to uncertainties on the age of Dmanisi. In order to decide in favour of any of them, it is neccesary to answer the following question: Did humans leave Africa alone or simultaneously a set of large mammals? This question has fortunately only two possible answers: 1. Humans left the austral continent alone. If this hypothesis were correct, the dispersal of Homo out of Africa would not depend on any extrinsic factor, but on intrinsic ones (i.e. population 'saturation', technological advances in tool making, etc) and supposed abilities or attitudes which need to be further established and demonstrated. From this premise, if humans left Africa alone they could do so at any given moment from the time of their origin whenever the geographical and climatic barriers allowed them to disperse. According with the available palaeoanthropological record, the oldest presence of Homo in Asia would be then restricted to 1.8-1.6 Ma (Java, Southern China), in the Caucasus to 1.6 Ma (Dmanisi, Georgia), and in Western Europe to approximately 0.8 Ma (Atapuerca, Spain). In this case it would make no sense to consider in this discussion those aspects related with the technological level adquired by the genus Homo or with faunal dispersal events during the Plio-Pleistocene. The oldest archaeological and palaeontological evidences recovered in Southeast Spain (Orce) would not be relevant for this history, since the information supplied by these sites points to a faunal turnover which is not detected in Atapuerca (where the record comprises species originating more recently in Asia, during the middle Galerian). In this case the arrival of Homo to Europe would be independent of other palaeobiological factors, and thus the dispersal would be monospecific. 2. Humans left Africa accompanied by other animals. If this scenario is correct, the fossil record should preserve species originating in Africa within the Eurasian ecosystems of lower Pleistocene times, and the faunal turnover should concentrate on a restricted chronological interval. This hypothesis is widely corroborated by the fossil record in Europe, as discussed before. If we consider the partial faunal replacement of large mammals which took place in Europe at the Plio-Pleistocene limit (‘Wolf event’: Asian species, ‘Homo event’: inmigrants from Africa), it is then possible to explain the presence of both African carnivores and Asian ruminants in the lower Pleistocene of the circummediterranean area, and their coexistence with members of the genus Homo, who showed anatomical affinities with H. ergaster and possesed the Oldowan Industrial Complex.
The first evidence of this faunal dispersal is recorded at the Plio-Pleistocene transition (1.8-1.6 Ma) in Western Europe, within the Olivola and Tasso faunal units, and in Central Eurasia (Dmanisi), where exists a complete record of this dispersal event, including human remains and evidence of cultural activity. Southeast Spain (Orce-Cueva Victoria, 1.4-1.1 Ma) has an exceptional record of these faunal assemblages, as well as the technological evidence of the first human populations. Finally, the most complete anatomical and cultural evidence of the hominids who could have been the descendant of those directly implied in the first colonization of Eurasia is found at the Gran Dolina of Atapuerca (< 0.8 Ma).
Therefore, the recent findings in Atapuerca TD-6 Level do not support the scenario of the mature hypothesis for a colonization of Europe at around 1.0 Ma, given (1) the anatomical features of the hominid remains (which could be better related to H. ergaster), (2) the lack of fit between the age proposed for the site, its geographical location and the Oldowan/Acheulean chronology, and (3) the faunal incongruity (i.e. Asian origin of the middle Galerian species preserved in the assemblage). On the contrary, the record from Atapuerca fills in part the palaeoanthropological hiatus of the old hypothesis, i.e. the colonization of Europe before 1.5 Ma ago. It is then possible that the hominids from TD-6 represent one of the latest European populations, descended from the ancestor lineage defined by H. ergaster, which retained its initial Oldowan technology and survived in Europe after the extinction that affected other African species of large mammals. It is also possible that this species, which has been called ‘Homo antecessor’, could coexist in Europe with other populations of hominids originating in Asia, as H. erectus (Ceprano, Italy), which arrived to Western Europe within the middle Pleistocene faunal set from Asia, but this would be another history.
Discovery Channel Illustrations
True. The similarity in debating technique between Homo academis and Alouatta caraya argues strongly for a South American origin.
Yup, I read that.
There are claims/reports of 2.25 million yo human bones (with tools) in a cave in China. Disputed, of course.
A friend of mine told me that when he was young, his father had told him the natural gas bubbles that can be seen rising in the tar pits, were Imperial Mammoth farts. What a laugh. Everybody knows that they are sabertooth's farts! ;^)
**Nothing like a little self promotion :)
Y'all got a bone to pick with my vanity post?
You have the Saberteeth going West to East along with Horses and several other species, temperate animals for temperate times, no icebergs to float over on and the sea is deep.
I bet these little beasties would have had a field day in the Roman Colliseum.
This apparently casts doubt on the ‘out of Africa’ idea, and supports the opposing view, called the ‘regional-continuity theory’ (or ‘multi-regional’ or ‘candelabra’ theory), which suggests ‘modern man evolved from Homo erectus[3] in several different places.’4"
If you read Heradotos pygmies were living in Chad about the time he was writing, they are now in the Congo. The Bushmen were pushed out by the Hottentots, who were pushed out by the Bantu, etc, ad nausium. The movement is North To South, the remnants are on the fringes.
Yeah, I understand what you mean. I am a 'multi-regionalist' in the Milton Wolpoft mold.
Yup. I've read three books on the San Bushmen. They are not 'black' Africans, they are Asian and their children even have Mongol spots.
The ancient Egyptians mentioned them in their glyphs and I even saw one reference that they may be the Leprechauns of Irish legend. The female Bushmen are physically 'different' in that they have an 'apron' (skin) over the genital area, this was also mentioned by the Egyptians.
All the other races in Africa refer to the Bushmen as the 'ancient ones'.
The Hottentotts, did also. I have found it passing strange, that the loosers live on the edge, the nexis seems to be Central Asia, alot of strange stuff seems to have happened out there.
The fact that most African species are found in Southern Spain is explained if we consider that the Iberian Peninsula was faunally and climatically a part of Africa during the Neogene, far more than it was a part of Europe, which many palaeontologists consider to begin at the Pyrenees.
Good point. Outstanding thread, Saber. You did an excellent job.
Bookmarked.
Yup. Do a search on Negtitos if you want to see another group that lived 'all over' and are now on the fringes that you talked about.
Are you claiming to be African American?
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.