Stenonychosaurus (North American Dinosaurs)

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However, Russell's thought experiment has been met with criticism from other paleontologists since the 1980s, many of whom point out that his Dinosauroid is overly anthropomorphic. Gregory S. Paul (1988) and Thomas R. Holtz, Jr., consider it "suspiciously human" and Darren Naish has argued that a large-brained, highly intelligent troodontid would retain a more standard theropod body plan, with a horizontal posture and long tail, and would probably manipulate objects with the snout and feet in the manner of a bird, rather than with human-like "hands". [9] Description [ edit ] Size compared to a human Fiorillo, Anthony R. (2008) "On the Occurrence of Exceptionally Large Teeth of Troodon (Dinosauria: Saurischia) from the Late Cretaceous of Northern Alaska" Palaios volume 23 pp.322-328

A few dinosaurs had relatively big brains for their body size, which implies intelligence but putting that factor alone against modern animals is obviously limiting. That’s when everything fell together and we were able to confirm that there were in fact two different species — named Latenivenatrix mcmasterae and Stenonychosaurus inequalis— in the Dinosaur Park Formation, instead of just one,” van der Reest said. CONVERGENCE: Professor Russell says dinosaurs could have developed along similar lines to us (Image: Canadian Museum of Nature) Yes, some corvids [crows] and parrots are very smart (and crocodiles are much smarter than most people realise) so the *capacity* for high intelligence would appear to be there.

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What does this have to do with the dinosauroid? Russell wrote several times that dinosauroid-like humanoids could have evolved in “some biospheres” (Naish & Tattersdill 2021, p. 8 unpaginated), and said more than once between 1979 and 1981 that he would be able to bring a hypothetical reconstruction of a big-brained dinosaur to SETI-themed meetings. Remember that all of this was happening a couple of years before the dinosauroid was brought to life in 3D form. I also think it’s important that, again, the dinosauroid was being used to promote ideas about intelligent aliens: it again makes me think that Russell’s focus wasn’t on speculative dinosaur evolution at all, but on promoting the idea of humanoid intelligences evolving elsewhere in the universe. Age determination studies performed on the Two Medicine troodont using growth ring counts suggest that this dinosaur reached its adult size probably in 3–5 years. [16] Eberth, D.A. (2005). "The geology". In Currie, P.J.; Koppelhus, E.B. (eds.). Dinosaur Provincial Park: A Spectacular Ancient Ecosystem Revealed. Indiana University Press. pp. 54–82. ISBN 978-0-253-34595-0. A more complete skeleton of Stenonychosaurus was described by Dale Russell in 1969 from the Dinosaur Park Formation, which eventually formed the scientific foundation for a famous life-sized sculpture of Stenonychosaurus accompanied by its fictional, humanoid descendant, the "dinosauroid". [6] Stenonychosaurus became a well-known theropod in the 1980s, when the feet and braincase were described in more detail. Along with Saurornithoides, it formed the family Saurornithoididae. Based on differences in tooth structure and the extremely fragmentary nature of the original Troodon formosus specimens, saurornithoidids were thought to be close relatives, while Troodon was considered a dubious possible relative of the family. Phil Currie, reviewing the pertinent specimens in 1987, showed that supposed differences in tooth and jaw structure among troodontids and saurornithoidids were based on age and position of the tooth in the jaw, rather than a difference in species. He reclassified Stenonychosaurus inequalis, Polyodontosaurus grandis, and Pectinodon bakkeri as junior synonyms of Troodon formosus. Currie also made Saurornithoididae a junior synonym of Troodontidae. [7] In 1988, Gregory S. Paul went farther and included Saurornithoides mongoliensis in the genus Troodon as T. mongoliensis, [8] but this reclassification, along with many other unilateral synonymizations of well known genera, was not adopted by other researchers. Currie's classification of all North American troodontid material in the single species Troodon formosus became widely adopted by other paleontologists and all of the specimens once called Stenonychosaurus were referred to as Troodon in scientific literature through the early 21st century. In the early summer of 2014, van der Reest discovered an intact troodontid pelvis in Dinosaur Provincial Park Formation of southern Alberta. This led to him conducting an in-depth analysis of previously collected troodontid fossils, including skull bones. His research concluded that the Dinosaur Provincial Park fossil record held two genera of troodontid and not one.

For Aaron, being able to name a new dinosaur has been an especially emotional experience. The species name for Latenivenatrix mcmasterae honours his late mother, Lynne (McMaster) van der Reest who did so much to encourage him to pursue a career in palaeontology.a b Sternberg, C.M. (1951). "The lizard Chamops from the Wapiti Formation of Northern Alberta: Polyodontosaurus grandis is not a lizard". Annual Report of the National Museum of Canada Bulletin. 123: 256–258. The first specimens currently assigned to Troodon that were not teeth were both found by Sternberg in 1928, in the Dinosaur Park Formation of Alberta. The first was named Stenonychosaurus inequalis by Sternberg in 1932, based on a foot, fragments of a hand, and some tail vertebrae. A remarkable feature of these remains was the enlarged claw on the second toe, which is now recognized as characteristic of early paravians. Sternberg initially classified Stenonychosaurus as a member of the family Coeluridae. The second, a partial lower jaw bone, was described by Gilmore (1932) as a new species of lizard which he named Polyodontosaurus grandis. Later, in 1951, Sternberg recognized P. grandis as a possible synonym of Troodon, and speculated that since Stenonychosaurus had a "very peculiar pes" and Troodon "equally unusual teeth", they may be closely related. Unfortunately, no comparable specimens were available at that time to test the idea. The holotype of Stenonychosaurus inequalis, CMN 8539, is a partial skeleton consisting of six caudal vertebrae, hand bones, the distal end of the left tibia and astragalus, and a complete left foot. A couple of cranial specimens were also referred to the genus: UALVP 52611 (a nearly complete skull roof) and TMP 1986.036.0457 (a partial braincase). If that unwelcome intruder from outer space hadn’t slammed into our planet 65 million years ago might Russell’s "dinosaurids" have used all this millennia to develop a civilisation far in advance of our own? In 1982, Dale A. Russell, then curator of vertebrate fossils at the National Museum of Canada in Ottawa, conjectured a possible evolutionary path for Stenonychosaurus, if it had not perished in the Cretaceous–Paleogene extinction event, suggesting that it could have evolved into intelligent beings similar in body plan to humans. Over geologic time, Russell noted that there had been a steady increase in the encephalization quotient or EQ (the relative brain weight when compared to other species with the same body weight) among the dinosaurs. Russell had discovered the first Troodontid skull, and noted that, while its EQ was low compared to humans, it was six times higher than that of other dinosaurs. Russell suggested that if the trend in Stenonychosaurus evolution had continued to the present, its brain case could by now measure 1,100cm 3 (67cuin), comparable to that of a human (on average, 1,260cm 3 (77cuin) for men and 1,130cm 3 (69cuin) for women). [1]

The teeth of these types of dinosaurs are recurved and have large serrations, unlike any dinosaur teeth found previously and so Leidy erected a new genus – Troodon (the name means “wounding tooth”). This staple of dinosaur books and academic literature for the best part of 160 years had been established on fairly shaky ground to begin with. Now thanks to some new research from University of Alberta graduate student Aaron van der Reest, T. formosus has been replaced by two taxa, one new one Latenivenatrix mcmasterae and one resurrected one.Troodontids are known from both Asia and North America, the most complete specimens come from Upper Jurassic Strata of China, Lower Cretaceous strata of China (western Liaoning Province) and the Cretaceous of Mongolia. In contrast, troodontids from the western hemisphere, specifically Mexico, USA and Canada are very poorly known with a very fragmentary fossil record. Previously unassigned fossils from the lower part of the Dinosaur Park Formation have now been assigned to the resurrected troodontid species Stenonychosaurus inequalis.

Cullen, Thomas M.; Zanno, Lindsay; Larson, Derek W.; Todd, Erinn; Currie, Philip J.; Evans, David C. (June 30, 2021). "Anatomical, morphometric, and stratigraphic analyses of theropod biodiversity in the Upper Cretaceous (Campanian) Dinosaur Park Formation1". Canadian Journal of Earth Sciences. 58 (9): 870–884. doi: 10.1139/cjes-2020-0145. Freimuth, William (2021). "Mammal-bearing gastric pellets potentially attributable to Troodon formosus at the Cretaceous Egg Mountain locality, Two Medicine Formation, Montana, USA". Palaeontology. 64 (5): 699–725. doi: 10.1111/pala.12546. S2CID 237659529.

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a b c Russell, D.A. (1969). "A new specimen of Stenonychosaurus from the Oldman Formation (Cretaceous) of Alberta". Canadian Journal of Earth Sciences. 6 (4): 595–612. Bibcode: 1969CaJES...6..595R. doi: 10.1139/e69-059.