The Upper Pleistocene brown bear (Carnivora, Ursidae) in the Zagros: Evidence from Wezmeh Cave, Kermanshah, Iran

Abstract

While bears (Ursidae) are well represented in Western Europe and the Caucasus during the Pleistocene, bear remains from this period are rare in Southwest Asia. Only a limited number of sites, both natural and archaeological, have yielded evidence of brown bear (Ursus arctos Linnaeus, 1758). Skeletal remains for this species are often represented by a limited number of elements. The discovery of 192 remains identified as brown bear in Wezmeh Cave (Kermanshah Province, Iran) is exceptional. This paper presents a detailed description of the Wezmeh osteological assemblage, which confirms that U. arctos was already present in Zagros during the Upper Pleistocene.

Résumé

Si les ours (Ursidae) sont bien représentés en Europe occidentale, y compris dans le Caucase, pendant le Pléistocène, ils sont plus rares en Asie du Sud-Ouest. Seul un nombre limité de sites naturels ou archéologiques ont livré des ossements d’ours brun (Ursus arctos Linnaeus, 1758) et généralement les restes squelettiques de cette espèce sont souvent représentés par peu de spécimens. La découverte de 192 restes identifiés comme appartenant à des ours bruns dans la grotte de Wezmeh (province de Kermanshah, Iran) constitue une exception. Cet article a pour but de décrire en détail cet assemblage ostéologique qui confirme la présence déjà d’Ursus arctos au Pléistocène supérieur dans le Zagros.

Introduction

The brown bear (Ursus arctos Linnaeus, 1758) is a terrestrial mammal species with a very broad geographic distribution across Europe, Asia and North America. The Syrian brown bear subspecies (Ursus arctos syriacus Hemprich and Ehrenberg, 1928), which is smaller than the nominate U. arctos arctos, is native to Southwest Asia and is found in Turkmenistan, Iran, Iraq and Turkey. It is extinct in Palestine and more recently, in Syria, although a few Syrian brown bears still exist along the border between Lebanon and Syria (e.g. Hatt, 1959, Heptner and Naumov, 1998, Masseti, 2009). The Iranian brown bear is found in the present day in the north and west of Iran, primarily in the Zagros Mountains from the Azerbaijan border to the Shiraz region in Fars, and also in the Alborz Mountains from Astara to eastern Golestan. Generally found in the mountainous areas throughout its home range, the Syrian brown bears appear to den and hibernate in caves and tree hollows in high elevation forests (e.g. Lay, 1967, Etemad, 1985, Ziaie, 2008, Farhadinia and Valizadegan, 2015).

The majority of the Pleistocene sites in Southwest Asia that contain ursid bones are located along the Levantine coast from northern Palestine to the Lebanese mountains (Table 1; Fig. 1). The earliest evidence of bear was found in the Lower Pleistocene site of Ubeidiya in the Jordan valley where 13 remains of Ursus etruscus (Cuvier, 1823) were recovered (Martínez-Navarro et al., 2009). The only sites during the Middle Pleistocene with the presence of ursid remains are Cave Bear in the Upper Galilee (Tchernov and Tsoukala, 1997) and Darband Cave in the Alborz (Biglari and Shidrang, 2006, Biglari et al., 2007). These comprise large assemblages of teeth and bones identified as Ursus deningeri (von Reichenau, 1904) (Argant unpublished report; interested readers may refer in particular to Argant and Philippe (2002) for an overview of the complex phylogeny of Plio-Pleistocene Eurasian Ursidae). Finally, during the Upper Pleistocene only U. arctos has been identified, from remains found in Mount Carmel, in northern Levant/Galilee, in the Lebanon Mount (e.g. Kurtén, 1965, Hooijer, 1961, Garrard, 1980) and in Northwest Syria (Griggo, 2004). In the Zagros Mountains the brown bear has only been identified in Shanidar (Evins, 1982), although a bear tooth was also collected on the surface of the Mar Koulian cave, an Upper Pleistocene/Holocene site near Rawansar (Biglari and Taheri, 2000). To date, no remains of cave bear (Ursus spelaeus Rosenmüller, 1794) have been described in Southwest Asia. Although common in the Caucasus (e.g. Baryshnikov, 1998, Bar-Oz et al., 2012, Van der Made et al., 2016), it seems that this species never reached the Zagros-Taurus and Alborz mountain ranges.

Several recent studies have investigated the phylogeny of the Syrian brown bear (Murtskhvaladze et al., 2010, Calvignac et al., 2009). A genetic study on mitochondrial DNA shows that all brown bears occurring in the Caucasus appear to be monophyletic, and are a subspecies of the Eurasian brown bear (U. arctos arctos) (Murtskhvaladze et al., 2010, Lortkipanidze, 2010). However, the taxonomic status of the species in this region remains unclear and its distribution and our understanding of its evolution during the Pleistocene in this part of the world remains fragmentary. The discovery of 192 brown bear bones in Wezmeh cave in the Zagros Mountains is therefore an important contribution to the history of this taxon in Southwest Asia.