# The Facial Reconstruction of a Mesolithic Dog, Muge, Portugal
## 1 Introduction  
The Muge dog is one of the oldest almost complete dog skeletons found in Portuguese territory. Excavations at Muge started in 1864 by [PERSON] ([PERSON], 1867) [1] (Figure 1A), and the Muge dog was uncovered in 1880 when half of the shell mount was excavated in order to show the site to visiting scientists of the 9 th International Congress of Prehistoric Anthropology and Archaeology held in Lisbon, Portugal. Like most archaeological faunal remains found at the time, it did not garner much attention from the scientific community. The focus of the excavation campaigns was instead to determine the antiquity of man in the Tagus and Sado rivers' valleys (Portugal), a research triggered by the recently proposed theories on geology and biological evolution by [PERSON] and [PERSON] ([PERSON], 2018) [2]. The Muge dog was discovered in a shell midden located in the Tagus valley--Cabeco da Arruda (Figure 1B,C)--at a depth of 4 m ([PERSON] and [PERSON], 2010) [3]. This specific site was interpreted as a cemetery ground holding a minimum number of 110 humanskeletons ([PERSON] and [PERSON], 2003 [4], [PERSON], 2006 [5]). The Muge shell middens are nowadays considered as a national monument, since they provided one of the largest European osteological collections dated to the Mesolithic period. The Muge dog skeleton was only re-discovered \(c\). 120 years later, undisturbed inside a cabinet drawer at the Museu Geologico de Lisboa (Lisbon, Portugal) (Figure 2A,B). Only then was an extensive odontometric and osteometric study developed by [PERSON] and [PERSON] (2010) [3]. It was directly radiocarbon-dated to 7680-7450 years cal BP ([PERSON] et al., 2019) [6]. Today, this specimen is an important piece of the museum's permanent exhibition and is considered its 16 th wonder. Dog remains dated to the late Palaeolithic are rarely found. However, a few European examples do exist and are directly radiocarbon-dated such as Abri le Morin [9] Kesslerloch [10], Bonn-Oberkassel [11] and Pont d'Ambon [12]. In Iberia, the oldest known canid is a fragmented humerus from Erralla (Gipuzkoa, Spain) [13] dated by context from 12,500-17,000 years BP; in this case, from a late Magdalenian cave. A study conducted by [PERSON] and colleagues in 2011 [12] showed the small size of South-Western Europe Upper Palaeolithic dogs in contrast to those contemporaneous dogs living in the North-Eastern region of Europe. During the Mesolithic, in Iberia, a series of shell middens proliferated along the Atlantic coast, where burials of dogs in contexts close to human burials were common, demonstrating the unique and close relationship of these two species. From this region and chronology, two almost complete dog skeletons were excavated and studied [3,6]. These Mesolithic dogs are morphologically uniform and of medium size [6]. Figure 1: **(A)** A portrait of the archaeologist [PERSON], who excavated the Muge dog in 1880 (photograph kindly shared by Prof [PERSON] [7]); **(B)** map of the Iberian Peninsula displaying the Cabeco da Arruda shell middens location with detail about the place where human burials and the Muge dog were found. There is some imprecision regarding the exact place from where the dog was excavated. Adapted from ([PERSON] and [PERSON] 2000) [8]; **(C)** section of the Cabeco da Arruda stratigraphic complex profile (photograph kindly shared by [PERSON]), since it shows how the superficial layer and the others below lie in different directions. Additionally, the layers have been disturbed by animal burrows. The importance in reconstructing the face of one of these Mesolithic dogs--the Muge dog--is related to its antiquity (_c._ 7600 years cal BP), its completeness (almost complete skeleton) and its burial context, e.g. found within a human burial ground, at a depth of 4 m. The dog skeleton was very well preserved, likely meaning that it was buried by humans with care, which is interpreted as a strong emotional bond between humans and their dogs.