Excavations at Cueva Negra del Estrecho del Rio Quipar and Sima de las Palomas del Cabezo Gordo: two sites in Murcia (south-east Spain) with Neanderthal skeletal remains, Mousterian assemblages and late Middle to early Upper Pleistocene fauna
by Michael J. Walker (reproduced with permission)

SIMA DE LAS PALOMAS

Sima de las Palomas ('Dove Hole') is an 18 metre deep natural karstic shaft, opening at 120 metres above sea-level on the 312 metre high Triassic limestone Cabezo Gordo hill which dominates the coastal plain beside the 'Mar Menor' Mediterranean salt water lagoon (Walker and Gibert 1999b). A century ago, iron miners removed most of its breccia fill apart from an 18 metre high column against its rear wall which spans 130,000-60,000 BP. Recent work has focused on these deposits.

Dating

Age estimates have been obtained from uranium-thorium (U/Th), optical sediment luminescence (OSL) and electron spin resonance (ESR) determinations. To assist in this work, Derek Roe and John Mitchell took sediment cores where background irradiation had been determined using a y-ray spectrometer lent by Professor Michael Tite of Oxford University's Research Laboratory for Art and Archaeology, who, with Ed Rhodes, analyzed photon luminescence for OSL or optical sediment luminescence determination. Unfortunately, all but one of the samples failed and even this was only partially saturated and not ideal. However, it did provide a maximum age of 157 kyr on a core taken half way down the Sima de las Palomas breccia column where background irradiation implies 1.25 Gray per millennium. This, in turn, suggests that ESR determinations obtained by Dr Peter Pomery and David Hunter of Queensland University can be corrected. Their results were obtained on three splinters of bone with breccia adhering to them which were found in the mine rubble before the excavations began. Assuming background irradiation of 1 or 2 Gray per millennium, age estimates of 83,000/42,000 and 146,000/73,000 were determined (Gibert et al. 1994). A third determination of 532,000/26,000 BP is anomalous (ibid.). Given the background irradiation calculated by Oxford, a correction to 66,000 and 117,000 BP may be in order for the first value of each of the alternative ESR determinations from Queensland.

These corrections are in line with the uranium-thorium determinations made by Dr Juan Antonio Sanchez-Cabeza and J. Garcia-Orellana in the Department of Physics at the Autonomous University, Barcelona. An age of 56 kyr BP was achieved on an aragonite crystal found close to where the first hominid fossil was removed from the breccia column in 1991, near to the level now reached in our 'upper cutting'. An age of 124 kyr BP was obtained on another crystal removed from the foot of the column (Sanchez-Cabeza et al. 1999). As it gave only a maximum age, the OSL determination could fit with the two older U/ Th dates. A skull of the late Middle Pleistocene Panthera pardus cf. hmellensis was removed by spelaeologists from this low part of the breccia column. Charcoal samples submitted to Professor Robert Hedges of the Oxford laboratory contained insufficient carbon for radiocarbon dating.

Finds

Three six metre thick units of cemented lutite, silt, sand and angular stones are separated by calcretes that probably formed on partiallly eroded surfaces ofpleniglacial aggra-dations. At the top of the breccia column, our 'upper cutting' measures two metres long but varies from 60 to 120 cm wide according to what was left by the miners. An eighteen metre high scaffolding tower built inside the shaft gives access to it. Excavation here from 1994 to 2000 has removed two metres of fill. Surprisingly for a karstic shaft, it shows a mainly horizontal stratigraphy only sporadically interrupted by intrusive scree from rock falls. Important finds here include an adult Neanderthal hemimandible, an infant mandible, teeth and postcranial bones of juveniles and adults, including a molar with grooving probably caused by tooth-picks, Mousterian artefacts and, in 1999 and 2000, a 20 cm thick 'hearth'. Near here, an adult Neanderthal mandible fused to the maxillae but now separated, was extracted from the breccia in 1991 by a spelaeologist, just outside the deepest part of our 'upper cutting'. U/Th suggests an age of 65 kyr-55 kyr BP. Significant finds also come from mine rubble on the hillside and at the bottom of the shaft which we have sieved. Sediments in the floor of the Main Chamber are being investigated in our two metre deep 'lower cutting'.

Artefacts

A total of 750 classifiable pieces, more than half of which are unretouched flakes, as well as 1650 fragments and spalls have been collected from the deposits. The material is considered to be Mousterian. The tools include Tayac, Levallois and pseudo-Levallois points, convergent scrapers ('stubby points'), side and endscrapers, as well as notched and denticulate pieces. There are also two thick retouched Levallois flakes which are carinated and have tiny awl-like noses and some hammerstones. The artefacts are made of flint, quartz, rock-crystal, limestone and quartzite. The source of the flint is unknown; no flint outcrops occur on Cabezo Gordo and the nearest known source of good quality flint is twenty kilometres away. A jasper core and flake must come from a known source twenty-five kilometres away.

Hominid remains

Over eighty fragmentary hominid bones and teeth have been recovered (Table 16.1; Walker and Gibert 1999a; Walker et al. 1998, 1999a, 1999b). Unstratified items include two right lateral parts of burnt frontal bones with supraorbital tori and lateral trigones which are compatible with a Neanderthal attribution, an infant's maxilla with tooth roots, a fragment of a juvenile mandible with an unerupted permanent canine from a child of about nine years old, two burnt adult hemimandibles (see below), and postcranial remains including long bones with typically narrow Neanderthal medullary cavities. Whilst these could come from high up in the breccia column (c. 55 kyr-65 kyr BP), it is more likely that the two unstratified burnt fragments with plesiomorphous pre-Neanderthal features came from burnt soil lenses low down in the breccia column where geophysical determinations imply an age of 130 kyr-115 kyr BP. Although gas chromatography did not indicate a high organic content within these lenses, X-ray diffraction analyses highlighted a preponderance of sand which indicates thermal effects, given the presence of carbonates, phosphates, as well as sand, in over- and underlying sediments. Of the first two hominid fragments attributed to these lenses, one is a burnt left temporal squama with a salient, vertically thick, zygomatic process presenting a preglenoid planum rather than articular tubercle before an anteroposterioriy wide, vertically shallow, mandibular fossa (a planum and shallow fossa flatter than in children today). The second fragment is a burnt frontal central fragment of a robust left supraorbital torus (and postorbital sulcus) lacking nasofrontal sinus extension (cf. Saccopastore 2, Hexian PA-830) lateral to a vast frontal notch (cf. Steinheim, Zuttiyeh, Kabwe, Yunxian EV-9002, Zhoukoudian XII). These two fragments would certainly seem out of place among the 'upper cutting' Neanderthals.

Two burnt hemimandibles from the mine rubble show interesting differences. One, perhaps male, has a low, wide body and is chinless, albeit with a vertical symphyseal profile with a hint of a mental trigone though lacking mental eminences. It has a marked digastric fossa, a triangular submaxillary fossa and an oval mental foramen of great size due to burning at high temperature, and it resembles Middle Pleistocene specimens including those from Atapuerca Sima de los Huesos. The other, perhaps female, has a higher, narrower body containing crazed fragments of all the permanent teeth although only M@ and M are preserved above the neck. It has a chinless, vertical symphyseal profile (Sanchez et al. 1999).

Fauna

The faunal assemblage (Table 16.2) now exceeds 8000 classifiable skeletal elements, several of which are burnt. These occur in a rough ratio of five mammalian bones for every one tortoise and one avian bone. Twelve thousand indeterminate splinters have also been recovered. It should be mentioned that although signs of burning are seen on several human remains found in the mine rubble, relatively few human remains from the 'upper cutting' show these, notwithstanding the presence of a hearth.

CUEVA NEGRA

Cueva Negra del Estrecho del Rio Quipar ('Black Cave' of the river Quipar Gorge) lies ninety kilometres from Sima de las Palomas. Systematic excavation began in 1990. It is a north-facing rock-shelter in the north-western Murcian uplands lying 40 metres above the river, at 780 metres above sea-level in an Upper Miocene fossiliferous sandy limestone (biocalcarenite), where test-pits were dug in 1981 (Martinez Andreu et al. 1989). Neanderthal remains here comprise an ulnar shaft, part of a humeral shaft and six permanent teeth (Table 16.3). There are many Middle Palaeolithic stone tools made of flint, chert, quartzite and limestone, and three whittled-down antler pedicles, one retaining the dense skull bone of its insertion, which are probably soft hammer knapping billets. The scars were probably made artificially in order to cut away the rest of the antler. No distal antler fragments show such scars, nor do horns or bones, hence these objects are unlikely to be due to animal-gnawing. Furthermore no porcupine bones, teeth or quills have been found, an animal that often sharpens its teeth on the ends of broken horns or long bones (Brain 1981, 109-117).

Fauna

There is a rich fauna consisting of some 7000 mammalian, 2200 avian and 1300 tortoise remains, as well as 11,000 unclassifiable splinters and fragments (Table 16.4). A late Middle or earliest Upper Pleistocene chronology is suggested by Prolagus, Macaco, (teeth and a maxillary fragment), and a skull fragment of Megaceros with attached massive crown-beam antlers which was excavated in unit 3. As stags bear antlers in the colder months of the year, this fossil might suggest that people frequented the Murcian uplands during that season when crown beams with cranial bone attached to the pedicle were available for whittling down into knapping billets, from cervids either killed by predators or hunted. Indeed, they may have been easier prey at this time of year because I have seen wild deer approach humans holding out forage when the Scottish Highlands are covered in deep snow, although in summer they avoid people. Cold conditions are implied by the 15 loess content of the soil and numerous retraction fissures. Faunal analysis suggests that different biotopes intersected at Cueva Negra: gallery woodland in the valley, perhaps with refuges of deciduous plants and trees (acorn-loving jays and wood-pigeons; monkeys); areas of swamps and even deep lakes (waterfowl including wading and even diving species, and migrants present only in the colder months of the year); grassland, scrub and stands of pine trees. The intersection of different biotopes occurs at other Mousterian sites (cf. Eastham 1989, 1999).

Rhinocerotid mandibles (Stephanorhinus (Dicerorhinus) cf. hemitoechus) have been found in unit 2. An adult hemimandible had its ascending ramus gnawed by a carnivore, a juvenile mandible lay beside its cranium within which were found a Neanderthal canine tooth and three chert pieces, and a Neanderthal ulnar shaft lay nearby. Other large herbivore remains include elephant, bison, aurochs, equids, cervids, boar and wild goat (ibex). Small game is plentiful, and some of the remains show signs of burning. These include fragments of bird bones and eggshell, tortoise, rabbit and hare, and may suggest intentional roasting. Hyaenas and bears were present, perhaps when humans were absent, and may have been responsible for introducing several of the cranial elements and teeth of the large herbivores excavated. However, detailed taphonomic and statistical analyses of the faunal assemblage are far from complete, and the chert fragments and Neanderthal tooth found touching a rhinocerotid skull might excite a different conjecture here.

Geochronology

Palaeopalynological (Carrion et al. 1999) and geophysical research has so far failed to provide geochronological information, but is continuing. The sediments inside the cave cannot be younger than the contiguous river terrace outside that stopped aggrading 40,000 years ago throughout the Segura drainage basin. Geological comparison with geophysical determinations from similar terraces elsewhere in Murcia and nearby Alicante implies an early Upper Pleistocene age for the fluviatile terrace which is apparently continuous with the sedimentary fill of Cueva Negra. Throughout the region, this 'glacis-menace B', the surface of which lies, here as elsewhere, at 35 to 40 metres above modem valley floors, aggraded during very cold conditions with low fluviatile activity, low rainfall, and low evapo-transpiration, capable only of permitting seasonal summer swamps on riverine floodplains (cf. Cuenca Paya and Walker 1985,1986,1995; Cuenca Paya et al. 1986; Walker et al. 1998). The absence of sorted gravels from our excavation implies cold conditions, low fluviatile activity, low rainfall and low evapo-transpiration. Rounded cobbles (>5 centimetres across) excavated from the deposits do not come from the Miocene biocalcarenite bedrock; these cobbles of flint, chert, quartzite, quartz and fine-grained siliceous metamorphosed Jurassic dolomite clasts were brought as manuports from a conglomerate outcrop exposed by Quaternary erosion some 800 metres away. In Upper Miocene Vindobonian (Tortonian) times this outcrop had been a pebble beach where the Tethys Sea lapped against Jurassic limestone cliffs. The use of this outcrop as a source of raw materials during the Middle Palaeolithic is confirmed by the presence of discoidal cores both here and at the cave. Cobbles were also carried back to Cueva Negra for knapping and for use as hammerstones.

Artefacts

Twenty-five square metres of Cueva Negra are under excavation. To date this area has yielded 350 retouched artefacts and large unretouched flakes, as well as 4000 knapping spalls or fragments. Eighty percent of these are chert, while the remainder are limestone and quartzite. Amongst the tools, scrapers, denticulates and notched pieces predominate, with occasional burins and carinated pieces. Hammerstones have also been found. Two rock crystal fragments probably came from as far away as (or further than) Cabezo Gordo, which is the nearest source, although the rarity of exotic raw materials may imply little long-distance movement or exchange. The nature of the non-flint raw materials, and a tendency of the poor quality chert to break up into blocks along fracture planes, mean that even retouched pieces often lack distinct butts. Those that do exist are plain or facetted. Hints of spatio-temporal groupings of Palaeolithic artefacts in different layers and separate zones are being investigated with attention to conjoining analysis. The problem of comparing the relative abundance of artefacts in units 2 and 3 at Cueva Negra (Walker et al. 1998, 1999a) are gradually being overcome by extending the area under excavation. Although a one square metre test pit has reached a depth of 4 metres where in stratigraphical unit 4 a rhinoceros mandible, charcoal and chert artefacts were found, most of the twenty-five square metres in stratigraphical units 2 and 3 are still under excavation, in a series of steps leading down from the cave entrance where there are standing sections. Horizontal bedding predominates (Walker 1996, 1997, 1999).

CONCLUSIONS

Comparing Cueva Negra and Sima de las Palomas is still difficult because of the considerable difference in the areas excavated within them and the vast number ofunstratified finds from mine rubble at the latter site (Walker and Gibert 1999a; Walker et al. 1999b). Excavation is slow because at both sites excavated sediment is washed over nested geological sieves of 8, 6 and 2 mm mesh, so that micro-faunal remains and tiny knapping spalls are collected. It would certainly be imprudent to propose site-catchment interpretations of plausible hominid behaviour until the role of non-human predators has been fully investigated. Likewise, despite the inhospitable winter climate at Cueva Negra even today, let alone in Ice Age times, our uncertainty as to whether there was any contemporaneity between the levels under excavation makes any speculation about possible seasonal palaeoeconomic complementarity between our two sites quite unwarranted. In any case, apart from having hominid skeletal remains, they do not otherwise stand alone in our region, because other undated Mousterian sites occur both upstream and downstream from Cueva Negra in the Quipar valley itself and several occur elsewhere throughout the Segura drainage basin, as well as near the Murcian coast, especially from Cartagena southwards.

ACKNOWLEDGEMENTS

We are most grateful to the Directorate-General for Scientific and Technological Research of the Spanish government for financial assistance during two three year-long major reseach projects (PB92-0971 and PB98-45) and for two Anglo-Spanish Joint Actions (HB 1992-104, HB 1995-0002), the Murcian Autonomous Community's Directorate-General for Culture for annual grants-in-aid from 1991 for excavation of either one or the other of our two sites and for providing gates and scaffolding at Sima de las Palomas, and The Earthwatch Institute for the support of its staff and members since 1994. The town councils of Caravaca de la Cruz and Torre Pacheco are thanked for greatly assisting us in many practical aspects of our annual field campaigns. I am also indebted to my co-directors: Dr Jose Gibert at Sima de las Palomas and Isaac Serrano and, formerly, Abel Gomez at Cueva Negra. Particular thanks are due to Anne Eastham for her analysis of the avifauna, and Alfonso Legaz for the micromammalian data. Many esteemed colleagues from several disciplines have and are continuing to make vital contri-butions to our research. I extend my gratititude to all of them.