The Jaw Adductors of Strepsirrhines in Relation to Body Size, Diet, and Ingested Food Size

Abstract

Body size and food properties account for much of the variation in the hard tissue morphology of the masticatory system whereas their influence on the soft tissue anatomy remains relatively understudied. Data on jaw adductor fiber architecture and experimentally determined ingested food size in a broad sample of 24 species of extant strepsirrhines allows us to evaluate several hypotheses about the influence of body size and diet on the masticatory muscles. Jaw adductor mass scales isometri- Whereas PCSA is isometric to body size estimates in frugivores, it is positively allometric in folivores. Independent of body size, fiber length is correlated with maximum ingested food size, suggesting that ingestive gape is related to fiber excursion. Comparisons of temporalis, masseter, and medial pterygoid PCSA in strepsirrhines of different diets suggest that there may be functional partitioning between these muscle groups. Anat Rec, 294:712-728, 2011. V V C 2011 Wiley-Liss, Inc.

Go big or go fish: morphological specializations in carnivorous bats

“…In addition to absolute differences in body and skull size, we found positive allometry in skull shape with respect to skull size across bats that consume animal prey. This adds to a body of work stressing the role of allometry in underlying morphological diversity in the mammalian feeding apparatus [17,[60][61][62][63][64][65]. In carnivorous bats, larger sizes are associated with cranial and mandibular traits that increase bite force, gape and jaw closing speed: a taller sagittal crest provides larger attachment area for the temporalis muscle; a longer rostrum produces a wider gape that can accommodate larger prey, and enables faster jaw closure in prey capture [66].…”

Flexibility in locomotor-feeding integration during prey capture in varanid lizards: effects of prey size and velocity

“…The effects include adaptation of the jaw apparatus (e.g. Rodriguez-Robles et al, 1999;Ferry-Graham et al, 2002;Van Cakenberghe et al, 2002;Metzger and Herrel, 2005;Santana et al, 2010;Hampton, 2011;Perry et al, 2011), teeth (e.g. Hotton, 1955;Herrel et al, 1997;Herrel et al, 2004;Santana et al, 2011;Kupczik and Stynder, 2012), hyolingual apparatus (e.g.…”

Maximum ingested food size in captive anthropoids

“…Thus, the lengths of the chewing muscle fibers, the pinnation angles of the muscle fibers, the positions of the muscles, and the locations of bite points should be adapted to the sizes and material properties of ingested foods. Indeed, chewing muscle fiber length is correlated with V b in strepsirrhines, independent of body size (Perry et al, 2011b). Given the many differences in the masticatory system that characterize anthropoids versus strepsirrhines (Hylander, 1979;Ravosa, 1999;Hylander et al, 2003Hylander et al, , 2005, it is important to compare ingested food size between these two taxa.…”

“…This model, referred to as "fracture scaling," relies on several assumptions, one of which is that ingested food volume scales isometrically to body mass (Lucas, 2004). This assumption about ingested food volume was essentially upheld by initial data on strepsirrhine V b (Perry and Hartstone-Rose, 2010); however, the attendant hypotheses about jaw adductor muscle dimensions were not (Perry et al, 2011b). The important role of dietary preference could affect the predictions of the model.…”