Habitat changes and changing predatory habits in North American fossil canids

Abstract

The spread of open grassy habitats and the evolution of long-legged herbivorous mammals with high-crowned cheek teeth have been viewed as an example of coevolution. Previous studies indicate that specialized predatory techniques in carnivores do not correlate with the spread of open habitats in North America. Here we analyse new data on elbow-joint shape for North American canids over the past B37 million years and show that incipiently specialized species first appeared along with the initial spread of open habitats in the late Oligocene. Elbow-joint morphologies indicative of the behavior of modern pounce-pursuit predators emerged by the late Miocene coincident with a shift in plant communities from C 3 to C 4 grasses. Finally, pursuit canids first emerged during the Pleistocene. Our results indicate that climate change and its impact on vegetation and habitat structure can be critical for the emergence of ecological innovations and can alter the direction of lineage evolution.

Ecomorphological determinations in the absence of living analogues: the predatory behavior of the marsupial lion (Thylacoleo carnifex) as revealed by elbow joint morphology

“…The articular surface of the Thylacoleo elbow is also characterized by a large trochlear crest, which increases stabilization of the forearm (Jenkins 1973;Figueirido and Janis 2011;Figueirido et al 2015). Our results thus indicate that Thylacoleo was able to stabilize the forearm to a greater degree than the koala but less so than other more terrestrial taxa (excluding the wombat, see discussion below).…”

“…We use the shape of the elbow joint, a highly functional morphological trait considered an indicator of forearm maneuverability (Andersson and Werdelin 2003;Andersson 2004Andersson , 2005Figueirido and Janis 2011;Figueirido et al 2015), and we employ landmark-based methods of geometric morphometrics to compare the elbow of Thylacoleo with the elbow of extant mammals.…”

Elbow Joint Geometry in Bears (Ursidae, Carnivora): a Tool to Infer Paleobiology and Functional Adaptations of Quaternary Fossils

“…geometric morphometric approaches (Ercoli et al 2012;Fabre et al 2013aFabre et al , b, 2015bMartin-Serra et al 2014;Botton-Divet et al 2016. Size and shape of humeral epiphyses discriminate habitat exploited, feeding strategies, locomotor adaptation, and evolutionary history for many groups of Carnivora (Andersson and Werdelin 2003;Walmsley et al 2012;Meloro et al 2013;Figueirido et al 2015). These studies support the elbow joint (distal humerus epiphysis) as more informative than the humeral proximal epiphysis to infer ecological adaptations in carnivorans due to its load bearing function and its involvement in pronation/supination movements.…”

Continental faunal exchange and the asymmetrical radiation of carnivores

“…For instance, in Eurasia, taxa adapted to open habitats such as equids and giraffids benefited from the expansion of grasslands in the Late Miocene [42]. The radiation of Caninae, which were well adapted to hunting in open habitats in North America [63], might have been favoured by such climatic and vegetation changes also in Eurasia [48].…”