Tania King

Effect of taphonomic processes on dental microwear

Taphonomic processes have the potential to affect microscopic wear on teeth and to modify the wear patterns so as to confound dietary reconstructions based on dental microwear which was formed during the lifetime of an animal. This study describes a series of experiments which were conducted to simulate various taphonomic agents and to record their effect on dental microwear. Three types of experiment were carried out in order to explain anomalous microscopic wear that had been found on the dentition of several hominoid specimens from the 15 M.a. site of Pasalar in Turkey. The effect of two different acids-citric and hydrochloric acid-on dental microwear was investigated. Modification to microscopic wear caused by alkali (carbonatite ash) was examined in the second set of experiments. Lastly, the effect of abrasion by three different size classes of sediment from the site of Pasalar-quartz pebbles (grain size varied from 2,000-11,000 microm), coarse sand (grain size ranged from 500-1,000 microm), and medium-sized sand (grain diameters were between 250 and 500 microm)-was investigated. Results confirm previous findings that the taphonomic modification of dental microwear is readily identifiable and causes the obliteration rather than secondary alteration of microwear features. The experiments show that both citric and hydrochloric acid affect dental microwear but to varying degrees, whereas alkali did not cause any modification of microscopic features. The different size classes of sediment also had different effects on the dental microwear. The largest size sediment (quartz pebbles) polished the enamel and removed finer microwear features. The coarse sand, however, did not have any effect on the microwear. The greatest amount of abrasion was caused by the smallest sediment particles -the medium-sized sand. Several hominoid dental specimens from Pasalar display similar microscopic wear to the two types of acid erosion and the abrasion caused by the medium-sized sands.

The Azokh Cave complex: Middle Pleistocene to Holocene human occupation in the Caucasus.

Azokh Cave is located near the village of the same name in the Nagorno-Karabagh region of the south-eastern part of the Lesser Caucasus (3937.09’ N and 4659.19’ E, 962 metres –a.s.l.). Azokh Cave and other relevant Acheulian sites in the Caucasus (Fig. 1) were described by Lioubine (2002). Together with Mousterian sites (Klein, 1969, 1999; Hoffecker and Cleghorn, 2000; Hoffecker, 2002; Stringer and Andrews, 2005) and sites producing evidence of the Middle-Late Palaeolithic transition (Joris and Adler 2008), the Caucasus region has provided evidence of continuous human settlement of the area throughout the Pleistocene. The geographical location of these sites indicates the persistence of a natural corridor that Lioubine (2002) named the ‘Caucasus isthmus’ and which we describe as the Trans-Caucasian corridor. Based on a geological survey of Quaternary deposits in collaboration with the Armenian Academy of Sciences (Ferna´ndez-Jalvo et al., 2004; King et al., 2003), we observe that the topography of the area has changed considerably due to tectonic compression and periglacial isostasy. This is in agreement with estimations by GPS studies (Mosar, 2006, Mosar et al., 2007) and ESR (Gru¨n et al., 1999) that establishedan uplift rate of12 to14 mm/year or 0.8–1.0 cm/year, respectively. The corridor has changed greatly since the middle Pleistocene, with uplift and erosion altering the landscape, but it is likely that passage through the Caucasian mountains has always been possible. The Trans-Caucasian corridor and other routes via Turkey and towards Asia (Bar-Yosef and Belfer-Cohen, 2001) were migration pathways during the Pleistocene. Fossil humans in the Caucasian area are scarce. The site of Dmanisi in Georgia yielded the earliest known Eurasian hominins (1.7 Ma, Gabunia et al., 2000; Rightmire et al., 2006; Martino´ n- Torres et al., 2008). Late surviving Neanderthals are present at several sites: Mezmaiskaya Cave, in the Northern Caucasus of Russia (30 ka, Skinner et al., 2005), provided remains of late surviving Neanderthals; a mandible of a 2–3 year old Neanderthal child was found at Barakay Cave (North Caucasus; Lubin et al., 2002). Two incisor fragments and one premolar from Kudaro I may be human (Lioubine, 2002). In this context, Azokh Cave fills an important temporal gap. Azokh Cave contains a nearly continuous stratigraphic section from >300 ka to the present, and mandible fragments of Homo heidelbergensis found at the site (Kasimova, 2001) represent the easternmost extent of this species. Here we review the finds of this long forgotten site and present results of our recent work.

Azokh Cave Hominin Remains

Hominin remains have been discovered at Azokh Cave from three different entrance passageways during the early and present phases of excavation. Evidence for three different species of hominin – Homo heidelbergensis, Homo neanderthalensis, and Homo sapiens – has been found at Azokh Cave. A fragment of hominin mandible was found in Azokh 1 in 1968. Previous studies, published in Russian and summarized here, suggest this specimen is most similar to the Ehringsdorf (adult) specimen which may now be considered as an early Neanderthal. An original assessment of a replica of the mandible carried out here indicates the specimen is similar to European Middle Pleistocene hominins, and we assign it tentatively to Homo heidelbergenis. A complete permanent first upper left molar tooth was found higher in the Azokh 1 sequence by the present excavation team. Preliminary description and metric analyses of the tooth indicate the specimen is typical of Neanderthal first upper molars and is most similar to Neanderthal specimens from Krapina, Croatia. A partial skeleton and two teeth of modern Homo sapiens have been found in Azokh 2 by the current excavation team, and evidence suggests death was accidental. Eight modern Homo sapiens teeth, discovered in Azokh 5 and thought to represent a minimum of three individuals (a child, a juvenile and an adolescent), are described here.

Introduction: Azokh Cave and the Transcaucasian Corridor

Azokh Cave (also known as Azikh or Azykh) contains Pleistocene and Holocene stratified sediment infill. The site was discovered by M. Huseinov (also named Guseinov by other authors) who led the previous phase of excavations. The geographic location of the site is at an important migratory route between Africa and Eurasia. The site has yielded Middle Pleistocene hominin remains (a mandible fragment) recovered in the 1960s during a previous phase of excavation work, together with Acheulean (Mode 2) stone tools and contemporaneous fauna. An important characteristic of the Azokh 1 cave site is a continuous sedimentary record along a 7 m section, ranging in age from Middle Pleistocene (MIS 9-8) to Late Pleistocene (Mousterian industry/Mode 3, MIS 5), and to Holocene periods at the top of the series. This detailed record documents three species of Homo: ancestors of Neanderthals, Homo neanderthalensis and Homo sapiens. In addition, two new fossiliferous sites, Azokh 2 and Azokh 5 (which are currently being explored), constitute a potential new source of information, especially about the Middle to Late Paleolithic transition and Holocene periods in the area. Plans for preservation and protection of the whole site are currently in progress.

Paleoecology of Azokh 1

The fauna and flora from Azokh 1 are analyzed to provide evidence on past and present environments. The large mammal fauna was accumulated by carnivore and human agents, and it is dominated by woodland species. The small mammals, amphibians and reptiles were accumulated mainly by avian predators, barn owls and eagle owls which hunt over open areas, and their prey may have been brought to the cave from some distance away. The amphibians and reptiles indicate warm dry conditions, with some taxa specific to mountainous regions and many indicating warm arid conditions. The small mammals similarly indicate mainly arid environments with minor elements from deciduous woodland. The difference between small vertebrates and large mammals is taphonomic, and all four groups indicate slight transition to more arid conditions up the section. Bats are present in all units, and it appears likely that they are derived from natural deaths within the cave. They indicate woodland conditions low in the section changing to a treeless, arid and cold environment towards the top. Plant data from charcoal indicate that the regional vegetation was broadleaved deciduous woodland with mainly small trees and shrubs. The location of the cave on the lower slopes of the mountains of the Lesser Caucasus is close to the forest/steppe boundary, with forest on the mountain slopes and steppe on the lowlands to the east, and relatively minor fluctuations in climate would shift the boundary or and down slope, towards or away from the cave, with changes in climate. It is concluded, therefore, that the large mammals and flora represent the local woodland environment, and the small mammals, reptiles and amphibians represent prey species brought from further away.

Azokh Cave and the Transcaucasian Corridor

Azokh Cave (also known as Azikh or Azykh) contains Pleistocene and Holocene stratified sediment infill. The site was discovered by M. Huseinov (also named Guseinov by other authors) who led the previous phase of excavations. The geographic location of the site is at an important migratory route between Africa and Eurasia. The site has yielded Middle Pleistocene hominin remains (a mandible fragment) recovered in the 1960s during a previous phase of excavation work, together with Acheulean (Mode 2) stone tools and contemporaneous fauna. An important characteristic of the Azokh 1 cave site is a continuous sedimentary record along a 7 m section, ranging in age fromMiddle Pleistocene (MIS 9-8) to Late Pleistocene (Mousterian industry/Mode 3, MIS 5), and to Holocene periods at the top of the series. This detailed record documents three species of Homo: ancestors of Neanderthals, Homo neanderthalensis and Homo sapiens. In addition, two new fossiliferous sites, Azokh 2 and Azokh 5 (which are currently being explored), constitute a potential new source of information, especially about the Middle to Late Paleolithic transition and Holocene periods in the area. Plans for preservation and protection of the whole site are currently in progress. Резюме Пещера получила свое название от деревни Азох, расположенной в двухстах метрах от нее в долине. Это карстовый комплекс Южного Кавказа с узкими коридорами и входами, заканчивающимися более широкими камерами, в которых в настоящее время обитает большая популяция летучих мышей. Карст имеет сложное происхождение, и седиментные наполнения содержат информацию о различных стадиях развития пещеры и ее экологии. Некоторые входы пещеры богаты ископаемыми организмами, указывая тем самым, что эти пространства в прошлом – от среднего плейстоцена до голоцена – были заселены людьми и различными формами животных. Главный и самый большой вход, известный в литературе как Азых, был обнаружен в 1960 г. М.Гусейновым, который до 1980 г. возглавлял раскопки стоянки. Ископаемые организмы в двух новых входах и соединениях последних с внутренними камерами, как и остатки отложений в задней части главного входа, в настоящее время исследуются международной экспедицией, с 2002 г. проводящей здесь раскопки. Стоянка расположена на естественной магистрали через Кавказ, по которой ранние гоминиды и животные могли мигрировать из Африки в Европу и Азию. Азохская пещера была поочередно заселена тремя видами гоминид – Homo heidelbergensis, Homo neanderthalensis и Homo sapiens, ископаемые останки которых, хотя и разрозненные, найдены здесь. Среди видов животных наиболее богато представлен гигантский пещерный медведь, здесь обнаружены и другие травоядные и плотоядные формы. Каменные орудия, встречающиеся вместе с ископаемыми костями животных, со следами разрезов указывают на активную деятельность людей на данной стоянке. Непрерывный слой плейстоценовых отложений содержит сведения о переходе от среднего к позднему плейстоцену, которые могут быть ключевыми для понимания происхождения неандертальцев и их предков. Ископаемая фауна и культурные свидетельства предоставляют информацию Y. Fernández-Jalvo (&) Museo Nacional de Ciencias Naturales (CSIC), José Gutiérrez Abascal 2, 28006 Madrid, Spain e-mail: yfj@mncn.csic.es T. King Blandford Town Museum, Bere’s Yard, Blandford, Dorset, DT11 7AZ, UK e-mail: taniacking@gmail.com L. Yepiskoposyan Institute of Molecular Biology, National Academy of Sciences, Yerevan, Armenia e-mail: lepiskop@yahoo.com P. Andrews Natural History Museum, Cromwell Road, London, SW7 5BD, UK e-mail: pjandrews@uwclub.net