Patagonian partnerships: the extinct Dusicyon avus and its interaction with prehistoric human communities

Abstract

The southern Mendoza province, located in the northern region of Patagonia, was inhabited by hunter-gatherer groups until historic times. Previous archaeological studies have reported canid remains among faunal assemblages, which were assumed to be part of the human diet. However, the taxonomic identification and significance of these canids within human groups have raised questions. In this study, we used ancient DNA analysis, morphological examination and stable isotope analysis (δ¹³C_col and δ¹⁵N) to re-evaluate the taxonomic assignment of a canid discovered at the Late Holocene burial site of Cañada Seca. Previous morphological identifications suggested that it belonged to the genus Lycalopex, but our results conclusively demonstrate that the individual belongs to the extinct fox species Dusicyon avus. This finding expands Dusicyon avus' known geographical distribution to Patagonia's northern extremity. Furthermore, statistical predictions based on genetic divergence undermine the hypothesis that hybridization between Canis and Dusicyon, facilitated by the introduction of domestic dogs, played a role in the extinction of Dusicyon species. On the other hand, our findings indicate that a Dusicyon avus individual shared a similar diet and was probably buried alongside humans, suggesting a close relationship between the two species during their lives and deaths.

Keywords: Dusicyon avus; South American canid; ancient DNA; extinct fox; stable isotope analysis (δ13Ccol, δ15N).

Figure 1.

Map of the Southern Cone of South America. The red star indicates the location of the Cañada Seca (CS) archaeological site, while the green stars represent other sites with available Dusicyon sequences on GenBank.

Figure 2.

Cranial and mandible remains of the CS/91. (a) Maxilla in lateral view. (b) Maxilla in ventral view. (c) Right mandible in lateral view. (d) Right mandible right in dorsal view. (e) Braincase in right lateral view.

Figure 3.

Bivariate graphs of craniodental measurements. Blue circle: specimen CS/91; white square: Dusicyon avus; red square: D. australis; black triangle: Lycalopex culpaeus; black rhombus: L. gymnocercus. (a) Length (LB) versus width (WB) of the bulla (mm). (b) Length of the fourth upper premolar (LP4) versus the length of the third upper premolar (LP3; mm). (c) Length of the first lower canine (Lc1) versus the length of the first lower molar (Lm1; mm). (d) Length of the third lower premolar (Lp3) versus the length of the first lower molar (Lm1; mm).

Figure 4.

Phylogenetic relationship of South American canids. The phylogenetic tree illustrates the placement of the CS/91-1 sample within the Dusicyon genus. The tree is based on analysing the concatenated 1825 bp of mitochondrial COII and cytb genes. Nodal support values indicate the Bayesian posterior probabilities/maximum likelihood bootstrap values, with values above 0.5/50 displayed. The CS/91-1 sample is highlighted in yellow.

Figure 5.

Radiocarbon dating of canid bone CS/91-1 shows contemporaneity with three previously dated human bones (1520 ± 13 yr ¹⁴C BP) [49].

Figure 6.

Carbon and nitrogen stable isotope values (δ¹³C_col and δ¹⁵N) comparison among wild carnivores (Puma concolor, Lycalopex culpaeus and Lycalopex griseus), human bones and CS/91-1 canid specimen.

Figure 7.

Distribution of D. avus and location of the CS/91 site in the Southern Cone of South America during the Holocene. This map illustrates the previous distribution of D. avus, represented by shading. The red star indicates the location of the CS site, where the CS/91 fox specimen was discovered. Note the presence of the CS/91 specimen outside the previously known distribution range of D. avus.