This paper is the second of a three-part series that investigates the architecture of cancellous bone in the main hindlimb bones of theropod dinosaurs, and uses cancellous bone architectural patterns to infer locomotor biomechanics in extinct non-avian species. Cancellous bone is widely known to be highly sensitive to its mechanical environment, and therefore has the potential to provide insight into locomotor biomechanics in extinct tetrapod vertebrates such as dinosaurs. Here in Part II, a

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... biomechanical modelling approach is outlined, one which mechanistically links cancellous bone architectural patterns with three-dimensional musculoskeletal and finite element modelling of the hindlimb. In particular, the architecture of cancellous bone is used to derive a single 'characteristic posture' for a given species -one in which bone continuum-level principal stresses best align with cancellous bone fabric -and thereby clarify hindlimb locomotor biomechanics. The quasi-static approach was validated for an extant theropod, the chicken, and is shown to provide a good estimate of limb posture at around mid-stance. It also provides reasonable predictions of bone loading mechanics, especially for the proximal hindlimb, and also provides a broadly accurate assessment of muscle recruitment insofar as limb stabilization is concerned. In addition to being useful for better understanding locomotor biomechanics in extant species, the approach hence provides a new avenue by which to analyse, test and refine palaeobiomechanical hypotheses, not just for extinct theropods, but potentially many other extinct tetrapod groups as well. PeerJ reviewing PDF | (2017:12:22648:2:0:REVIEW 8 Sep 2018) Manuscript to be reviewed 1 Cancellous bone and theropod dinosaur locomotion. 2 Part II -A new approach to inferring posture and 3 locomotor biomechanics in extinct tetrapod 4 vertebrates 5 6 7 P.Abstract 31 32 This paper is the second of a three-part series that investigates the architecture of cancellous bone 33 in the main hindlimb bones of theropod dinosaurs, and uses cancellous bone architectural patterns 34 to infer locomotor biomechanics in extinct non-avian species. Cancellous bone is widely known 35 to be highly sensitive to its mechanical environment, and therefore has the potential to provide 36 insight into locomotor biomechanics in extinct tetrapod vertebrates such as dinosaurs. Here in 37 Part II, a new biomechanical modelling approach is outlined, one which mechanistically links 38 cancellous bone architectural patterns with three-dimensional musculoskeletal and finite element 39 modelling of the hindlimb. In particular, the architecture of cancellous bone is used to derive a 40 single 'characteristic posture' for a given species -one in which bone continuum-level principal 41 stresses best align with cancellous bone fabric -and thereby clarify hindlimb locomotor 42 biomechanics. The quasi-static approach was validated for an extant theropod, the chicken, and is 43 shown to provide a good estimate of limb posture at around mid-stance. It also provides 44 reasonable predictions of bone loading mechanics, especially for the proximal hindlimb, and also 45 provides a broadly accurate assessment of muscle recruitment insofar as limb stabilization is 46 concerned. In addition to being useful for better understanding locomotor biomechanics in extant 47 species, the approach hence provides a new avenue by which to analyse, test and refine 48 palaeobiomechanical hypotheses, not just for extinct theropods, but potentially many other 49 extinct tetrapod groups as well. 50 51 52 53 54 55 56 57 58 59 PeerJ reviewing PDF |