, 2003, 2004) – and interspecific adult scaling – which is isometric (Erickson et al., 2012). Regardless of these scaling differences, the PI is sufficiently broad to allow for the practical use of body-size metrics

as reliable predictors of bite-force capacity for nearly any crocodylian. The lone exception to Selleckchem DAPT such conservation of bite-force performance among living taxa (and presumably among its closest extinct relatives) may be the Indian gharial Gavialis gangeticus. This species was found to be the only extant crocodylian with statistically lower adult bite-force capacity than other taxa (Erickson et al., 2012). The cause of this appears to be due to this taxon’s diminutive and fusiform M. pterygoideus ventralis (Endo et al., 2002). This muscle is considered to be the primary contributor to bite force in other species (Iordansky, 1964; Schumacher, 1973; Sinclair & Alexander, 1987; Busbey, 1989; Cleuren, Aerts & De Vree, 1995; Holliday & Witmer, 2007; Gignac, 2010; Bona & Desojo, 2011) because of its relatively greater size among the jaw closing muscles and its characteristic pennate fiber arrangement (Gignac, 2010). The parallel fiber arrangement of this muscle in G. gangeticus is suited for rapid contraction at the expense of high force generation. Thus, it presumably facilitates rapid jaw closure in these highly piscivorous crocodylians. How this taxon develops its relatively

lower adult bite-force capacity

nevertheless remains unclear. Gavialis gangeticus may (1) share its ontogenetic Luminespib mouse bite-force scaling coefficient with A. mississippiensis and other extant taxa, but start life with an absolutely lower maximum bite-force capacity; (2) some unique combination of initial bite-force capacity and developmental scaling. (The goal of our current research is to test the bite forces throughout ontogeny in this biomechanically aberrant taxon.) Empirically derived bite forces are known for developmental series of A. mississippiensis (Erickson et al., 2003, 2004) as well as adults of all extant crocodylian species (Erickson et al., 2012). Extensive work has been done to assess and predict bite forces in extant and extinct archosaurs based on these selleck inhibitor regression data (Therrien, Henderson & Ruff, 2005; McHenry et al., 2006; Mazzetta et al., 2009; Gignac et al., 2010; Gong et al., 2010; Boyd, Drumheller & Gates, 2013; Walmsley et al., 2013). Similar approaches have also been taken through the development of explanatory models (Sinclair & Alexander, 1987; Busbey, 1989; Cleuren et al., 1995; McHenry, 2009; Gignac, 2010). Coupling our results with those of Erickson et al. (2012) now allows for the prediction of bite forces in crocodylian specimens representing any ontogenetic stage. That is, once a bite-force estimate is made (e.g. via musculoskeletal modeling, body-size scaling, tooth-indentation simulation, etc.