Ecomorphological study of large canids from the lower Pleistocene of southeastern Spain

Abstract

An ecomorphological analysis of the skeletal remains of large canids, Canis (Xenocyon) falconeri and Canis etruscus (Mammalia, Carnivora, Canidae), preserved in an assemblage of large mammals from the lower Pleistocene site at Venta Micena (Guadix-Baza Basin, Orce, Granada, southeastern Spain) is reported. Mean body mass of adult individuals was estimated to be around 10 kg for C. etruscus and approximately 28 kg for C. falconeri using multiple regression.A comparative study of tooth measurements in modern canids, using principal components and discriminant function analysis, infers quite different ecomorphological adaptations and feeding behavior for both fossil species. The craniodental morphology of C. falconeri is similar to that shown by extant hypercarnivorous canids whose diet include more than 70% of vertebrate meat, whereas C. etruscus shows a cranial morphology similar to those of modern omnivorous species, thus indicating a dietary niche in which vertebrate meat represented less than 70% of its diet, with other feeding resources making up the balance. These results suggest that there was a marked ecological segregation between both sympatric species of large canids. The find of a complete skull of C. falconeri showing bilateral asymmetry and marked dental anomalies could suggest high levels of genetic homozygosis in the population which inhabited this region during early Pleistocene times, possibly as a consequence of isolation and the low number of individuals. This may have subsequently led to the extinction of C. falconeri in the Western fringe of Europe. The survival of this pathological individual to adulthood indicates that this species may have developed cooperative behavior similar to that of modern African wild dogs. OCANIS (XENOCYON) FALCONER], CANIS ETRUSCUS, ecomorphology, principal component analysis, discriminant analysis, cranial fluctuating asymmetry, Venta Micena, lower Pleistocene. Paul Palmqvist [Paul.Palmqvist@uma.es],

Community Structure of South American Carnivores in the Past and Present

“…They studied the diet and morphometric indexes of some carnivorans of Patagonia and found a good correspondence in one season (spring-summer) but not in the other (fall-winter). This work showed that at fine scales (e.g., annual variation) morphology could not correctly reconstruct prey-predator relationships, but at a larger scale there is a good correlation between morphology and diet as was reported by other authors (e.g., Van Valkenburgh 1988, 1989Palmqvist et al 1999;Friscia et al 2007). …”

Fluctuating Asymmetry: Methods, Theory, and Applications

“…Palmqvist et al [296] attributed bilateral asymmetry and dental anomalies in a single complete skull of the large lower-Pleistocene canid Canis (Xenocyon) falconeri to possible isolation and small population size. Of 66 skeletal remains of this species, all but this one skull were fragmented and scattered; most teeth could not be assigned to particular individuals.…”

Dental anomalies in Didelphis albiventris (Mammalia, Marsupialia, Didelphidae) from Argentina, Brazil and Uruguay

“…II). Moreover, developmental instability and fluctuating asymmetry have already been used as an explanation for dental anomalies in canids (Palmqvist et al, 1999), and in otters (Hauer, 2002). Ongoing morphometric analyses to determine the level of fluctuating asymmetry will help establish the influence of environmental stressors in this species, and consequently find support for this hypothesis.…”