Megafaunal Extinctions and the Disappearance of a Specialized Wolf Ecomorph

Abstract

The gray wolf (Canis lupus) is one of the few large predators to survive the Late Pleistocene megafaunal extinctions [1]. Nevertheless, wolves disappeared from northern North America in the Late Pleistocene, suggesting they were affected by factors that eliminated other species. Using skeletal material collected from Pleistocene permafrost deposits of eastern Beringia, we present a comprehensive analysis of an extinct vertebrate by exploring genetic (mtDNA), morphologic, and isotopic (delta(13)C, delta(15)N) data to reveal the evolutionary relationships, as well as diet and feeding behavior, of ancient wolves. Remarkably, the Late Pleistocene wolves are genetically unique and morphologically distinct. None of the 16 mtDNA haplotypes recovered from a sample of 20 Pleistocene eastern-Beringian wolves was shared with any modern wolf, and instead they appear most closely related to Late Pleistocene wolves of Eurasia. Moreover, skull shape, tooth wear, and isotopic data suggest that eastern-Beringian wolves were specialized hunters and scavengers of extinct megafauna. Thus, a previously unrecognized, uniquely adapted, and genetically distinct wolf ecomorph suffered extinction in the Late Pleistocene, along with other megafauna. Consequently, the survival of the species in North America depended on the presence of more generalized forms elsewhere.

Genome-wide signatures of population bottlenecks and diversifying selection in European wolves

“…This is consistent with the growing evidence from ancient DNA studies showing that large mammal species experienced a considerable loss of genetic diversity since the late Pleistocene (reviewed in Hofreiter and Barnes 2010). In particular, the loss of mtDNA haplotypes has been documented in North American (Leonard et al, 2007) and European grey wolves (Pilot et al, 2010), and this was correlated with the loss of morphological and ecological diversity (Leonard et al, 2007;Germonpré et al, 2009).…”

Dedication. Acknowledgments

“…The dissimilarity between Canis and Ursus diets over both space and time highlights their ecological plasticity, particularly during the post-Glacial. Although previous studies have shown Canis to be a generalist predator during the Pleistocene [95,59], we show that their reliance on prey species is both general and highly flexible. Modern wolves are opportunistic predators [133,174], but often specialize on locally abundant cervids [120].…”

“…Modern wolves are opportunistic predators [133,174], but often specialize on locally abundant cervids [120]. The variability of Pleistocene canid diets may be due, in part, to a higher diversity of wolf morphs during the late Pleistocene, with the Beringian population noted for a cranial morphology associated with scavenging [95]. Although the intercontinental ranges shared by felids, Canis, and Ursus, are a testament to their success, felids appear to have more constrained diets over the mammoth steppe ecosystem.…”

Phylogeny and phylogeography of Altolamprologus: ancient introgression and recent divergence in a rock-dwelling Lake Tanganyika cichlid genus

“…Lamprologine species can produce interspecific offspring for long periods of time following their divergence (Koblmüller et al, 2007b;Sturmbauer et al, 2010), which may explain the frequency of interspecific introgressions detected in this group. When small population size contributes to rapid sorting of lineages, as in A. compressiceps, mitochondrial replacement by the introgressed lineage is not an altogether unlikely outcome (Leonard et al, 2007;Ray et al, 2007).…”