The arctometatarsalian pes, an unusual structure of the metatarsus of Cretaceous Theropoda (Dinosauria: Saurischia)

Holtz, Thomas R.

doi:10.1080/02724634.1995.10011574

Cited by 152 publications

(203 citation statements)

References 47 publications

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“…Tyrannosaurids display the elongate yet strong arctometatarsalian foot (Holtz 1995) whose complex dynamics probably augmented agility (Snively & Russell 2003). Healed bite marks (Carpenter 2000) and bone fragments found in a coprolite (Chin et al 1998) indicate that T. rex, the largest theropod in this study, preyed on adult and juvenile orniProc.…”

Section: Discussionmentioning

confidence: 96%

Tyrannosaurus en pointe: allometry minimized rotational inertia of large carnivorous dinosaurs

Henderson

Snively

2004

Proc. R. Soc. Lond. B

479

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Theropod dinosaurs attained the largest body sizes among terrestrial predators, and were also unique in being exclusively bipedal. With only two limbs for propulsion and balance, theropods would have been greatly constrained in their locomotor performance at large body size. Using three-dimensional restorations of the axial bodies and limbs of 12 theropod dinosaurs, and determining their rotational inertias (RIs) about a vertical axis, we show that these animals expressed a pattern of phyletic size increase that minimized the increase in RI associated with increases in body size. By contrast, the RI of six quadrupedal, carnivorous archosaurs exhibited changes in body proportions that were closer to those predicted by isometry. Correlations of low RI with high agility in lizards suggest that large theropods, with low relative RI, could engage in activities requiring higher agility than would be possible with isometric scaling.

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Section: Discussionmentioning

confidence: 96%

Tyrannosaurus en pointe: allometry minimized rotational inertia of large carnivorous dinosaurs

Henderson

Snively

2004

Proc. R. Soc. Lond. B

479

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“…Indeed, the relatively shorter metatarsals of Tyrannosaurus (among other anatomical features) testify that it could not (Holtz, 1995). Nonetheless, it seems likely that the high relative M. caudofemoralis mass of Tyrannosaurus did evolve as partial compensation for its colossal body size, and it is worth noting how this increased M. caudofemoralis mass was achieved.…”

Section: Discussionmentioning

confidence: 99%

The Tail of Tyrannosaurus: Reassessing the Size and Locomotive Importance of the M. caudofemoralis in Non‐Avian Theropods

Persons

Currie

2010

The Anatomical Record

165

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Unlike extant birds and mammals, most non-avian theropods had large muscular tails, with muscle arrangements similar to those of modern reptiles. Examination of ornithomimid and tyrannosaurid tails revealed sequential diagonal scarring on the lateral faces of four or more hemal spines that consistently correlates with the zone of the tail just anterior to the disappearance of the vertebral transverse processes. This sequential scarring is interpreted as the tapering boundary between the insertions of the M. caudofemoralis and the M. ilioischiocaudalis. Digital muscle reconstructions based on measurements of fossil specimens and dissections of modern reptiles showed that the M. caudofemoralis of many non-avian theropods was exceptionally large. These high caudofemoral mass estimates are consistent with the elevation of the transverse processes of the caudal vertebra above the centrum, which creates an enlarged hypaxial region. Dorsally elevated transverse processes are characteristic of even primitive theropods and suggest that a large M. caudofemoralis is a basal characteristic of the group. In the genus Tyrannosaurus, the mass of the M. caudofemoralis was further increased by dorsoventrally lengthening the hemal arches. The expanded M. caudofemoralis of Tyrannosaurus may have evolved as compensation for the animal's immense size. Because the M. caudofemoralis is the primary hind limb retractor, large M. caudofemoralis masses and the resulting contractile force and torque estimates presented here indicate a sizable investment in locomotive muscle among theropods with a range of body sizes and give new evidence in favor of greater athleticism, in terms of overall cursoriality, balance, and turning agility. Anat Rec, 294:119-131, 2011. V V C 2010 Wiley-Liss, Inc.

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“…78), and a large piece of the left metatarsal V. Most importantly, these various pieces show that the metatarsus is arctometatarsalian, with a third metatarsal that is pinched between metatarsals II and IV proximally (Holtz, 1995). This condition is present in all tyrannosaurids (e.g., Lambe, 1917;Holtz, 1995;Brochu, 2003), as well as the non-tyrannosaurid taxa Appalachiosaurus (RMM 6670; Carr et al, 2005), Bistahieversor (NMMNH P-25049), Dryptosaurus (ANSP 9995; Brusatte et al, 2011), and Raptorex (Sereno et al, 2009). In contrast, a more normal theropod metatarsus, in which metatarsal III is large and unpinched, is seen in the basal tyrannosauroids Dilong (IVPP V14243), Eotyrannus (MIWG 1997.550), and Guanlong (IVPP V14531).…”

Section: The Appendicular Skeletonmentioning

confidence: 99%

The Osteology of Alioramus, A Gracile and Long-Snouted Tyrannosaurid (Dinosauria: Theropoda) from the Late Cretaceous of Mongolia

Brusatte¹,

Carr²,

Norell³

2012

Bulletin of the American Museum of Natural History

107

189

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The arctometatarsalian pes, an unusual structure of the metatarsus of Cretaceous Theropoda (Dinosauria: Saurischia)

Cited by 152 publications

References 47 publications

Tyrannosaurus en pointe: allometry minimized rotational inertia of large carnivorous dinosaurs

Tyrannosaurus en pointe: allometry minimized rotational inertia of large carnivorous dinosaurs

The Tail of Tyrannosaurus: Reassessing the Size and Locomotive Importance of the M. caudofemoralis in Non‐Avian Theropods

The Osteology of Alioramus, A Gracile and Long-Snouted Tyrannosaurid (Dinosauria: Theropoda) from the Late Cretaceous of Mongolia

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