Christiansen & Harris (2012) proposed a similar explanation for the craniodental sexual dimorphism in Smilodon and Panthera genera. A general consensus on killing behaviours of fossil sabretoothed predators is that the canines were used to deliver a throat bite that

severed the main blood vessels to kill the prey quickly (Turner & Antón, 1997). This behaviour Selumetinib in vitro is thought to reduce the likelihood of tooth breakage, while still bringing about the rapid death of large prey (Biknevicius & Van Valkenburgh, 1996; Turner & Antón, 1997; Antón & Galobart, 1999; Salesa et al., 2005). It was suggested that the strong forelimbs of sabretooth predators were needed to restrain the prey before the delivery of the killing bite, thus reducing the probability of canine breakage (Gonyea, 1976; Van Valkenburgh, 1987; Meachen-Samuels & Van Valkenburgh, 2010; Meachen-Samuels, 2012). This could be the case in M. dimidiata when killing prey larger than itself. The humeral head is relatively larger than that of any other marsupial predator, indicating an ability to transmit greater forces through

the shoulder. Similarly, selleck screening library the epicondyles are relatively wider, indicating that M. dimidiata has more powerful forearm musculature than that of the other marsupial predators (see Table 3, Supporting Information Appendix S1 and Fig. 5 for a visual comparison with the robust humerus of Didelphis albiventris). Other MCE公司 authors observed similar humeral robusticity in large-prey specialists (Meachen-Samuels & Van Valkenburgh, 2009). The epicondyles are the origin of carpal and digital muscles that facilitate grasping of large prey during capture. Further studies on the forearm of M. dimidiata would allow comparison with other predators, but the constraints on the morphological evolution of the marsupial forelimb and its precocial development for accessing the mother’s

pouch immediately after birth must be taken into account (Sears, 2004). The difficulties of small carnivores to catch prey of their own size or larger were recently analysed theoretically by Carbone, Teacher & Rowcliffe (2007). The observed killing behaviour of M. dimidiata involves extensive manipulation with forelimbs before the bite. In the case of killing mice larger than itself, the bite is described as a single ‘neck bite’ delivered after a long struggle with the forelimbs (González & Claramunt, 2000). This ‘neck bite’ actually refers to a bite to the throat with a low probability of biting the cervical vertebrae (E. González, pers. comm.). This behaviour could be an alternative explanation for the convergent morphological features that M. dimidiata shares with sabretooth predators of the past. Further evolutionary, behavioural and ecological studies of M. dimidiata and Neofelis spp. will provide a better understanding of these species and of the origin and behaviour of sabretooths in the past. In the case of M.