Shrews of the Genus Crocidura from El Harhoura 2
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Palaeogeography, Palaeoclimatology, Palaeoecology 436 (2015) 1–8 Contents lists available at ScienceDirect Palaeogeography, Palaeoclimatology, Palaeoecology journal homepage: www.elsevier.com/locate/palaeo Shrews of the genus Crocidura from El Harhoura 2 (Témara, Morocco): The contribution of broken specimens to the understanding of Late Pleistocene–Holocene palaeoenvironments in North Africa Raphaël Cornette a,b,⁎, Emmanuelle Stoetzel c, Michel Baylac a,b, Sibyle Moulin a, Rainer Hutterer d, Roland Nespoulet c, Mohammed Abdeljalil El Hajraoui e,ChristianeDenysa, Anthony Herrel f,g a Muséum National d'Histoire Naturelle (MNHN), Institut de Systématique, Évolution, Biodiversité, (ISYEB), UMR 7205 CNRS/MNHN/UPMC/EPHE, 45 rue Buffon, 75005 Paris, France b UMS CNRS/MNHN 2700, “Outils et Méthodes de la Systématique Intégrative”, Plate-forme de morphométrie, 45 Rue Buffon, 75005 Paris, France c UMR CNRS/MNHN 7194, “Histoire Naturelle de l'Homme préhistorique”, 43 rue Buffon CP 48, 75005 Paris, France d Zoologisches Forschungsmuseum Alexander Koenig, Section of Mammals, Adenauerallee 160, 53113 Bonn, Germany e Institut National des Sciences de l'Archéologie et du Patrimoine, angle rues 5 et 7 Rabat instituts, Madinat Al Irfane, Rabat Hay Riyad, Morocco f UMR CNRS/MNHN 7179, “Mécanismes adaptatifs: des organismes aux communautés”, 55 rue Buffon, 75005 Paris, France g Ghent University, Evolutionary Morphology of Vertebrates, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium article info abstract Article history: The El Harhoura 2 cave (Morocco) presents a high density of white-toothed shrew (Crocidurinae) remains in the Received 22 January 2015 eight studied archaeological levels, ranging from around 108,000 to 5800 BP. A detailed understanding of the spe- Received in revised form 5 May 2015 cies contained in these assemblages is important for palaeoecological studies, yet often difficult to achieve be- Accepted 12 June 2015 cause the remains are systematically broken. Here we apply geometric morphometric methods that use sliding Available online 21 June 2015 landmarks allowing us to assign broken mandibles to five potential species present in Morocco today. Four spe- cies were detected, with a distinct distribution in the different levels. Surprisingly, Crocidura russula, a species Keywords: Shrews typically associated with relatively humid habitats, was found to be more abundant in periods characterized Mandible by dry conditions. Moreover, the abundance of the Saharan species Crocidura tarfayensis and Crocidura lusitania Fragmentation followed an inverse pattern. Both groups appear to affect each other's abundance throughout the studied period. Species identification We suggest that the coastal position of El Harhoura 2 as well as the inter-specific competition between C. russula Taphonomy and other species may explain this pattern. Palaeoecology © 2015 Published by Elsevier B.V. 1. Introduction El Harhoura 2 cave is situated in the region of Témara, few kilometres to the south of Rabat on the Northern-Atlantic coast of 1.1. Background Morocco (Fig. 1). Caves in this region were formed by marine erosion of the sandstone cliff, probably during the MIS 6 to MIS 5 transition North Africa constitutes a transition zone between the arid Sahara (Nespoulet et al., 2008a, 2008b). The region of Témara has an important and the more humid Mediterranean regions. The Quaternary fossil role with respect to the understanding of the origin and dispersal of an- record in this region is rather well documented and allows one to follow atomically modern humans in and out of North Africa. The caves of the last climatic fluctuations and to document their effects upon the Témara offer a unique succession of different human occupations rang- different fossil communities (Stoetzel, 2013). Among these, small ing from the Middle and Upper Palaeolithic to the Middle Neolithic. At mammals are considered as good palaeoenvironmental indicators present, the El Harhoura 2 cave presents an archaeo-stratigraphy divid- (Valenzuela et al., 2009; Escudé et al., 2013), and they enable one to ed into eleven levels (Fig. 2): level 1 = Neolithic; level 2 = upper refine the palaeoecological interpretations when they are studied in a Palaeolithic (Iberomaurusian); levels 3 to 11 = middle Palaeolithic well-established chronological context and with appropriate tapho- (Aterian). However, the bedrock has not yet been attained and addition- nomic and taxonomic methods. al levels will probably be discovered in future excavations. New 14C, TL, OSL and U-Th/ESR datings are currently in progress and some are already available (Jacobs et al., 2012; Janati Idrissi et al., 2012)and provide a more detailed temporal framework for this study. This cave ⁎ Corresponding author at: Muséum National d'Histoire Naturelle (MNHN), Institut de has yielded both lithic and bone industries, ceramics, several human re- Systématique, Évolution, Biodiversité, (ISYEB), UMR 7205 CNRS/MNHN/UPMC/EPHE, 45 rue Buffon, 75005 Paris, France. Tel.: +33 40 79 80 15. mains and burials, and numerous faunal remains (Campmas et al., 2008, E-mail address: [email protected] (R. Cornette). in press; Nespoulet et al., 2008a, 2008b; Michel et al., 2009, 2010; El http://dx.doi.org/10.1016/j.palaeo.2015.06.020 0031-0182/© 2015 Published by Elsevier B.V. 2 R. Cornette et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 436 (2015) 1–8 Fig. 1. Distribution of the five extant white-toothed shrews present in Morocco (data from www.iucnredlist.org) and the localisation of the El Harhoura 2 cave. Hajraoui et al., 2012; Stoetzel et al., 2014). Moreover, a high concentra- This site is unique as it involves studies focusing on different verte- tion of small vertebrate remains has been discovered, which has brates including small mammals, amphibians, and reptiles. Indeed, a allowed for rather complete faunistic and palaeoecological studies of systematic, taphonomic, and palaeoecological approach was undertak- the region (Stoetzel et al., 2007, 2008, 2010, 2011, 2012, 2013; en for this North-African site. The study of the micro vertebrates from Stoetzel, 2009). El Harhoura 2 provided important information on the evolution of Fig. 2. Stratigraphy of the El Harhoura 2 cave with average 14C(Nespoulet and El Hajraoui, 2002–2003)andOSLages(Jacobs et al., 2012). Levels 1 to 8 are the levels included in the present study. R. Cornette et al. / Palaeogeography, Palaeoclimatology, Palaeoecology 436 (2015) 1–8 3 biodiversity and palaeoenvironments of this region during the Late suggest a North African origin with a recent expansion into Spain, Quaternary, particularly in the absence of palynological data. However, France and nearby countries of the Maghreb during the Late Pleistocene some North-African small vertebrates remain poorly understood with (Cosson et al., 2005; Nicolas et al., in press). Moreover, it has been sug- respect to their systematic position, ecology or bone morphology. gested that the dispersal across the Strait of Gibraltar may have been Moreover, as only limited reference collections exist, this makes identi- human-mediated (Cosson et al., 2005; Nicolas et al., in press). fications difficult for a considerable part of the fossil material, which is, In general, the identification to species level is difficult in Crocidura. in addition, often highly fragmented. Thus, it is necessary to develop Indeed, the genus Crocidura presents a conserved phenotype and for new methods for taxonomic identification and discrimination to allow several species, both the skull and mandible or the teeth need to be an improved identification of the fossil remains (e.g. Cornette et al., carefully studied to correctly discriminate species or populations 2015a). (Leroy et al., 2004; Cornette et al., 2012; Cornette et al., 2015a, 2015b). Consequently, misidentifications are common (Vogel et al., 2006). Cur- 1.2. Model rently, genetic or cytogenetic studies are often used to correctly assign specimens. But palaeogenetic analyses on fossil small mammals are Small mammals (Escudé et al., 2013), and especially shrews very difficult, mainly because of their small size and high degree of frag- (Stoetzel et al., 2007; Valenzuela et al., 2009), are considered very useful mentation. Although the russula and the whitakeri morphotypes have in the context of palaeoclimatic variation interpretation. Indeed, some been identified in the El Harhoura 2 material, some “intermediate” species such as Crocidura russula are ecologically specialized and, in forms and some other morphotypes were detected. But the similarity Morocco, are tied to Mediterranean climates, contrary to Crocidura in morphology between these taxa, as well as the high fragmentation lusitania or Crocidura tarfayensis that are more related to drier environ- of the material, renders precise identification difficult. Small mammals ments. Moreover, they allow the investigation of ancient human pres- represent the bulk of the small vertebrate material from El Harhoura 2 ence and displacements. Indeed, despite the fact that crocidurine (87.5% of the total number of remains), and Crocidura represents 5.8% shrews are not considered to be strictly commensal, some species, like (number of remains) and 17% (minimum number of individuals) of C. russula, are anthropophilic (Churchfield, 1990). Finally, shrews are the small mammal remains (Stoetzel, 2009). Nevertheless, recent known to interact with each other and with other small mammals studies have suggested that small fragments may offer a relevant way (Kirkland, 1991; Liesenjohann