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Post by Infinity Blade on Oct 18, 2014 4:05:56 GMT 5
Another question, just how comparatively strong do you conjecture a non-tyrannosaurid tyrannosauroid's (ex: Guanlong, Eotyrannus, Yutyrannus, Dryptosaurus, etc.) forelimbs would have been?
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Post by theropod on Oct 18, 2014 16:31:55 GMT 5
The Dinosauria gives some general characteristics for tyrannosauroidea, however some may be subject to revision, the record on basal tyrannosauroids isn’t that good, and it certaily wasn’t better 10 years ago:
• moderate development of the biceps tubercle
• coracoid about 1/3 the lenght of the scapula
• a large acromial expansion
• The ulna being about 60% the lenght of the humerus, except in Tarbosaurus were it is shorter (45%)
• a moderately well-developed but short olecranon (compared to Allosaurus, Acrocanthosaurus, Torvosaurus and Baryonyx, but also less massive)
• all but Eotyrannus have a weakly developed deltopectoral crest (by comparison with basal tetanurae probably)
• T. rex and Albertosaurus have the most prominant dorsal expansion of the scapular blade
• the manus of non-tyrannosaurids was (obviously) well-developed as compared to tyrannosaurids (retaining more digits and thus being generally broader and likely stronger), and Dryptosaurus bore a large claw on at least one digit, but more is not known.
I don’t think there is much of a difference in robusticity and strenght of the upper arm at the same lenght (but slightly different specializations), but the generally larger forelimbs and absence of distal reduction would certainly mean that at similar sizes, non-tyrannosaurid tyrannosauroids had generally stronger forelimbs, all the more since a degree of the robusticity seen in Tyrannosaurus and kin are probably size-dependant.
References:
Charig, Alan J.; Milner, Angela C.: Baryonyx walkeri, a fish-eating dinosaur from the Wealden of Surrey. Bulletin of the Natural History Museum, London (Geology), Vol. 53 (1997); 1; pp. 11-70
Currie, Philip J.; Carpenter, Kenneth: A new specimen of Acrocanthosaurus atokensis (Theropoda, Dinosauria) from the Lower Cretaceous Antlers Formation (Lower Cretaceous, Aptian) of Oklahoma, USA. Geodiversitas, Vol. 22 (2000); 2; pp. 207-246
Holtz, Thomas R.; Molnar, Ralph E.; Currie, Philip J.: Basal Tetanurae. In: Weishampel, David; Dodson, Peter; Osmólska, Halszka: The Dinosauria. Berkeley (2004); pp. 71-110
Holtz, Thomas R.: Tyrannosauroidea. In: Weishampel, David; Dodson, Peter; Osmólska, Halszka: The Dinosauria. Berkeley (2004); pp. 111-136
Madsen, James H.: Allosaurus fragilis: a revised Osteology. Salt Lake City (1976)
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Post by theropod on Jan 17, 2015 22:38:29 GMT 5
Anteroposterior ranges of motion of some theropods (interim result):  Acrocanthosaurus redrawn from figures and measurements in Currie & Carpenter 2000, movement range from Senter & Robins 2005. Allosaurus drawn as a composite from figures and proportions in Gilmore 1920 and Madsen 1976, movement range from Carpenter 2002. Herrerasaurus based on figures, measurements and movement ranges in Sereno 1993. All drawn to same humeral lenght. Note the peculiar development: from a basal theropod, over an allosaurid, to a carcharodontosaurid, we see the range of motion, especially in the elbow, but also the shoulder, first decreasing, then increasing again. On the other hand, there’s a clear (and logical) trend towards proportionately shorter and stouter forelimbs, larger scapulocoracoids and proportionately shorter (but more massive) distal elements, with reduction in the third digit and increasingly massive built in the other two. I plan on adding some more (that’s why it’s A, D, E for now), tough unfortunately there’s no information on movement ranges in all of them. It will be interesting to see this directly compared to abelisaurs, tyrannosaur and deinonychosaurs. References: Carpenter, Kenneth: Forelimb Biomechanics of Nonavian Theropod Dinosaurs in Predation. Senckenbergiana lethaea, Vol. 82 (2002); 1; pp. 59-76 Currie, Philip J.; Carpenter, Kenneth: A new specimen of Acrocanthosaurus atokensis (Theropoda, Dinosauria) from the Lower Cretaceous Antlers Formation (Lower Cretaceous, Aptian) of Oklahoma, USA. Geodiversitas, Vol. 22 (2000); 2; pp. 207-246 Gilmore, Charles W.: Osteology of the carnivorous Dinosauria in the United States National Museum, with special Reference ro the genera Antrodemus (Allosaurus) and Ceratosaurus. Smithsonian Institution United States National Museum Bulletin, Vol 110 (1920); pp. 1-159 Madsen, James H.: Allosaurus fragilis: a revised Osteology. Salt Lake City (1976) Senter, Phil; Robins, James H.: Range of motion in the forelimb of the theropod dinosaur Acrocanthosaurus atokensis, and implications for predatory behaviour. Journal of the Zoological Society of London, Vol. 266 (2005); pp. 307-318 Sereno, Paul C.: The Pectoral girdle and Forelimb of the basal Theropod Herrerasaurus ischigualastensis. Journal of Vertebrate Paleontology, Vol. 13 (1993); 4; pp. 425-450 |
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Post by Infinity Blade on Jan 19, 2015 6:38:15 GMT 5
I've recently looked at pictures of Deltadromeus and a picture of what they actually found. Am I the only one who finds it both weird and interesting that the coracoid is so massive but the actual forelimb elements (humerus, radius, ulna, that stuff) are so skinny/gracile?
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Post by theropod on Jan 23, 2015 20:42:49 GMT 5
That isn’t so unusual actually. Frequently, theropods with relatively gracile and/or small forelimbs have very large coracoids (think T. rex, Majungasaurus, Carnotaurus).
The Deltadromeus type is poorly described, but as illustrated by Sereno et al (1996), what’s preserved of them seems moderately robust. Usually their humeri are a whole lot thicker transversely than anteroposteriorly (probably that’s the plane they experience the greatest forces in when holding a struggling prey item), so I don’t think it’s forelimbs can be considered particularly gracile.
References:
Sereno, Paul C.; Dutheil, Didier B.; Iarochene, M.; Larsson, Hans C. E.; Lyon, Gabrielle H.; Magwene, Paul M.; Sidor, Christian A.; Varricchio, David J.; Wilson, Jeffrey A. (That’s almost twice as many authors as there are pages in that paper, even tough they are supposed to describe major new specimens!): Predatory Dinosaurs from the Sahara and Late Cretaceous Faunal Differentiation. Science, New Series, Vol. 272 (1996); 5264; pp. 986-991
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Post by Infinity Blade on Jan 24, 2015 1:38:17 GMT 5
Well, those examples you mentioned had really tiny forelimbs while it looks like Deltadromeus didn't, that's why I thought it looked weird.
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Post by theropod on Jan 24, 2015 4:04:21 GMT 5
Different example then:
Deinonychus. Really long forelimbs in proportion to its body, but not overly robust (to a similar extend as here), really short scapulae but a large, anteriorly projecting coracoid.
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Post by theropod on Jan 31, 2015 16:34:10 GMT 5
 I originally planned to add Baryonyx, but I failed to find footage of a complete megalosauroid manus for completing it, and there was no measurement given for the scapulocoracoid, except for the coracoid foramen, which is so small it was basically useless. all drawn to unit humeral lenght. Note that the allosauroid claws are permanently flexed, that’s why they aren’t visible in lateral view. ––– References:Brochu, Christopher A.: Osteology of Tyrannosaurus rex: Insights from a Nearly Complete Skeleton and High-Resolution Computed Tomographic Analysis of the Skull. Memoir (Society of Vertebrate Paleontology), Vol. 7 (2003); pp. 1-138 Carpenter, Kenneth: Forelimb Biomechanics of Nonavian Theropod Dinosaurs in Predation. Senckenbergiana lethaea, Vol. 82 (2002); 1; pp. 59-76 Currie, Philip J.; Carpenter, Kenneth: A new specimen of Acrocanthosaurus atokensis (Theropoda, Dinosauria) from the Lower Cretaceous Antlers Formation (Lower Cretaceous, Aptian) of Oklahoma, USA. Geodiversitas, Vol. 22 (2000); 2; pp. 207-246 Gilmore, Charles W.: Osteology of the carnivorous Dinosauria in the United States National Museum, with special Reference ro the genera Antrodemus (Allosaurus) and Ceratosaurus. Smithsonian Institution United States National Museum Bulletin, Vol 110 (1920); pp. 1-159 Lambe, Lawrence M.: The Cretaceous Theropodous Dinosaur Gorgosaurus. Geological Survey of Canada Memoir, Vol. 100 (1917); 83; pp. 85-179 Lipkin, Christine; Carpenter, Kenneth: Looking again at the Forelimb of Tyrannosaurus rex. In: Larson, Peter; Carpenter, Kenneth: Tyrannosaurus rex the Tyrant King. Bloomington (2008); pp. 167-190 Madsen, James H.: Allosaurus fragilis: a revised Osteology. Salt Lake City (1976) Ostrom, John H.: Osteology of Deinonychus antirrhopus, an Unusual Theropod from the Lower Cretaceous of Montana. Peabody Museum of Natural History Bulletin, Vol. 30 (1969); pp. 1-165 Ostrom, John H.: The pectoral Girdle and Forelimb Function of Deinonychus (Reptilia: Saurischia): A Correction. Postilla, Vol. 165 (1974); pp. 1-11 Senter, Phil; Robins, James H.: Range of motion in the forelimb of the theropod dinosaur Acrocanthosaurus atokensis, and implications for predatory behaviour. Journal of the Zoological Society of London, Vol. 266 (2005); pp. 307-318 |
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Post by Infinity Blade on Jan 31, 2015 17:15:35 GMT 5
Lol at Majungasaurus.  |
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Deathadder
Junior Member
aspiring paleontologist. theropod enthusiast.
Posts: 240 
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Post by Deathadder on Jun 17, 2015 1:16:16 GMT 5
I know right:D
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Deathadder
Junior Member
aspiring paleontologist. theropod enthusiast.
Posts: 240
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Post by Deathadder on Jun 17, 2015 20:36:36 GMT 5
have you ever had a burning question you had since you were a little kid? i have, my question is how strong do you think there arms were compared to modern carnivorans. they have short arms but highly robust bones and large claws. can you give me a list of the strongest theropod arms and why? i know there are some theropods like the megalosaurid Xuanhanosaurus qilixiaensis has such large arms that they thought it was a quadruped. so how would that particular theropod compare?
sorry for so many questions.
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Post by Infinity Blade on Jun 17, 2015 20:59:29 GMT 5
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Deathadder
Junior Member
aspiring paleontologist. theropod enthusiast.
Posts: 240
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Post by Deathadder on Jun 17, 2015 21:08:42 GMT 5
Thanks for your help!
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Post by creature386 on Jun 17, 2015 22:07:48 GMT 5
Macro payed attention.  Anyway, I think I can move the three posts here. |
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Post by Infinity Blade on Jun 30, 2015 2:38:44 GMT 5
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