Utahraptor:
Time: Berriasian-Hauterivian of the early Cretaceous period, 145-129 million years ago.
Place: North America.
Length: 17-18 feet (5.2-5.6 meters).Weight: 1 ton.
Diet: Carnivore.
Say hello to the largest raptor that has ever lived!
Description:
Utahraptor was the largest and heaviest dromaeosaurid to have ever lived, at 17-18 feet long (5.2-5.6 meters) and weighing up to a ton (Asher Elbein, 2017, p. 4). The specimen CEU 184v.260 is 15 feet long. A 2016 adult individual, found with a pack, was 16 feet long. The holotype, CEU 184v.86, consists of a large sickle claw (pedal ungual II), the largest one ever discovered for the species (Kirkland et al., 1993, pg. 5). It is 22 centimeters long, but it is not complete. In total length, it would have measured 24 cm (Kirkland et al., 1993, pg. 10). Based on Dakotaraptor's 24-cm pedal ungual II (DePalma et al., 2015, pg. 10), CEU 184v.86 would be 18 feet, the same size as the Dakotaraptor holotype. Another specimen with a 56.5-cm femur also measures 18 feet as well. The largest recorded specimen is BYU 15465, at 19 feet long. Its femur is 60.0 cm long.
Carnivorous theropod dinosaurs had enamel in their teeth, so they must have had lips to cover and protect their teeth (Reisz and Larson, 2016, pg. 64-66) (Blake Eligh, 2016) (Mindy Weisberger, 2016) (Emanuela Grinberg, 2016) (Phys, 2016). Therefore, Utahraptor would have had lips covering its teeth. Interestingly, dinosaurs couldn't move its tongues (Mindy Weisberger, 2018) (ScienceDaily, 2018).
Utahraptor was also heavier and stockier than later raptors such as Dakotaraptor, which were more slender. Its tail was also shorter and more flexible than other dromeosaurs as well (Scott Hartman, 2017, p. 4).
According to Kenneth Carpenter (2002), in most predatory theropods used their mouths first to grab prey first, and then they would grab their prey "in a 'bear hug'" with their hands (pg. 72, "Conclusion"). Surprisingly, this might not have been true for dromeosaurs. In Deinonychus, it would have used its arms to grab prey first, and then use the sickle claws on its feet to slice its prey open (pg. 68, "Biomechanical Analysis"). Text-figure 9 shows Deinonychus', and other theropod's, range of motion for their hands (pg. 69). This method of attacking prey, by using hands for grabbing and feet for slashing, seems to have been what Utahraptor did as well.
As for how Utahraptor's hands were positioned casually, this is shown in Senter and Robins (2015) for Velociraptor (Figure 5 "B"; Figure 4 "B"). This would have been true for Utahraptor.
Dromaeosaur Hand Design (Senter and Robins, 2015, Figure 5, "B"):
Time:
As for its time period, it was originally though that Utahraptor lived in the Barremian (Kirkland et a;., 1993, pg. 5), which is 129-125 million years ago, according to the International Chronostratigraphic Chart (2019 Version). Then it was suggested that it lived in the Aptian (Kirkland et al., 2016, pg. 1-2, "Geological Setting") (Senter et al., 2012, pg. 4, "Geological Setting"). This is due to the fact that the Yellow Cat Member of the Cedar Formation, where Utahraptor was discovered, is now divided into two sections: the "lower" and "upper" parts. The lower part of the Yellow Cat Member is Barremian, while the "upper" part is Aptian (Senter et al., 2012, pg. 4, "Geological Setting"). Utahraptor is from the upper part (Kirkland et al., 2016, pg. 1-2, "Geological Setting"). Now, Utahraptor's time period has been pushed even further back into the Cretaceous. The entire Yellow Cat Member has now been dated to 143-130 million years ago (Milan et al., 2015, pg. 516, "Geological Setting") (Joeckel et al., 2019, "Abstract"). According to the International Chronostratigraphic Chart (2019 Version), this places Utahraptor in the Berriasian-Hauterivian of the early Cretaceous period, which is 145-129 million years ago.
Prey:
Utahraptor hunted the ankylosaur Gastonia, and hadrosaurs like Cedrorestes and the larger Iguanacolossus. It probably also hunted the young of the sauropod Cedarosaurus.
Links:
Original Paper:
Kirkland et al., (1993):
https://www.academia.edu/225747/A_large_dromaeosaurid_Theropoda_from_the_Lower_Cretaceous_of_Eastern_Utah
Time:
Joeckel et al., (2019) ("Abstract"):
https://sp.lyellcollection.org/content/498/1/75
Milan et al., (2015) (Pg. 516, "Geological Setting"):
https://geojournals.pgi.gov.pl/asgp/article/view/24870/17008
Link 2:
https://geojournals.pgi.gov.pl/asgp/article/view/24870
Senter et al., (2012) (Pg. 4, "Geological Setting"):
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3352940/
Kirkland et a., (2016) (Pg. 1-2, "Geological Setting"):
https://www.researchgate.net/publication/308041652_Depositional_constraints_on_the_Lower_Cretaceous_stikes_quarry_dinosaur_site_Upper_yellow_cat_member_cedar_mountain_formation_Utah
Kirkland et al., (1993) (Pg. 5):
https://www.academia.edu/225747/A_large_dromaeosaurid_Theropoda_from_the_Lower_Cretaceous_of_Eastern_Utah
International Commission of Stratigraphy Website:
https://stratigraphy.org/news/130
Size:
https://psdinosaurs.blogspot.com/2018/10/calculations-for-largest-theropods.html
Weight:
Asher Elbein (2017) (P. 4):
https://www.nytimes.com/2017/08/28/science/utah-paleontologists-turn-to-crowdfunding-for-raptor-project.html
Lips:
Reisz and Larson (2016) (Pg. 64-66):
https://cansvp.files.wordpress.com/2013/08/csvp-2016-abstract-book-compressed.pdf
Blake Eligh (2016):
https://www.utoronto.ca/news/did-dinosaurs-have-lips-ask-university-toronto-paleontologist
Mindy Weisberger (2016):
https://www.livescience.com/54912-did-t-rex-have-lips.html
Emanuela Grinberg (2016):
https://www.cnn.com/2016/05/22/world/dinosaur-lips-teeth-study/index.html
Phys (2016):
https://phys.org/news/2016-06-dinosaurs-lips.html
Tongue:
Mindy Weisberger (2018):
https://www.scientificamerican.com/article/t-rex-couldnt-stick-out-its-tongue/
ScienceDaily (2018):
https://www.sciencedaily.com/releases/2018/06/180620150129.htm
Hands:
Kenneth Carpenter (2002):
https://www.researchgate.net/publication/225366451_Forelimb_biomechanics_of_nonavian_theropod_dinosaurs_in_predation
Senter and Robins (2015):
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0144036
Body Design:
Scott Hartman (2017):
http://www.skeletaldrawing.com/home/at-long-last-utahraptor
Prey:
Gastonia:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Iguanacolossus:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Cedarosaurus:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Cedrorestes:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Say hello to the largest raptor that has ever lived!
Description:
Utahraptor was the largest and heaviest dromaeosaurid to have ever lived, at 17-18 feet long (5.2-5.6 meters) and weighing up to a ton (Asher Elbein, 2017, p. 4). The specimen CEU 184v.260 is 15 feet long. A 2016 adult individual, found with a pack, was 16 feet long. The holotype, CEU 184v.86, consists of a large sickle claw (pedal ungual II), the largest one ever discovered for the species (Kirkland et al., 1993, pg. 5). It is 22 centimeters long, but it is not complete. In total length, it would have measured 24 cm (Kirkland et al., 1993, pg. 10). Based on Dakotaraptor's 24-cm pedal ungual II (DePalma et al., 2015, pg. 10), CEU 184v.86 would be 18 feet, the same size as the Dakotaraptor holotype. Another specimen with a 56.5-cm femur also measures 18 feet as well. The largest recorded specimen is BYU 15465, at 19 feet long. Its femur is 60.0 cm long.
Carnivorous theropod dinosaurs had enamel in their teeth, so they must have had lips to cover and protect their teeth (Reisz and Larson, 2016, pg. 64-66) (Blake Eligh, 2016) (Mindy Weisberger, 2016) (Emanuela Grinberg, 2016) (Phys, 2016). Therefore, Utahraptor would have had lips covering its teeth. Interestingly, dinosaurs couldn't move its tongues (Mindy Weisberger, 2018) (ScienceDaily, 2018).
Utahraptor was also heavier and stockier than later raptors such as Dakotaraptor, which were more slender. Its tail was also shorter and more flexible than other dromeosaurs as well (Scott Hartman, 2017, p. 4).
According to Kenneth Carpenter (2002), in most predatory theropods used their mouths first to grab prey first, and then they would grab their prey "in a 'bear hug'" with their hands (pg. 72, "Conclusion"). Surprisingly, this might not have been true for dromeosaurs. In Deinonychus, it would have used its arms to grab prey first, and then use the sickle claws on its feet to slice its prey open (pg. 68, "Biomechanical Analysis"). Text-figure 9 shows Deinonychus', and other theropod's, range of motion for their hands (pg. 69). This method of attacking prey, by using hands for grabbing and feet for slashing, seems to have been what Utahraptor did as well.
As for how Utahraptor's hands were positioned casually, this is shown in Senter and Robins (2015) for Velociraptor (Figure 5 "B"; Figure 4 "B"). This would have been true for Utahraptor.
Dromaeosaur Hand Design (Senter and Robins, 2015, Figure 5, "B"):
As for its time period, it was originally though that Utahraptor lived in the Barremian (Kirkland et a;., 1993, pg. 5), which is 129-125 million years ago, according to the International Chronostratigraphic Chart (2019 Version). Then it was suggested that it lived in the Aptian (Kirkland et al., 2016, pg. 1-2, "Geological Setting") (Senter et al., 2012, pg. 4, "Geological Setting"). This is due to the fact that the Yellow Cat Member of the Cedar Formation, where Utahraptor was discovered, is now divided into two sections: the "lower" and "upper" parts. The lower part of the Yellow Cat Member is Barremian, while the "upper" part is Aptian (Senter et al., 2012, pg. 4, "Geological Setting"). Utahraptor is from the upper part (Kirkland et al., 2016, pg. 1-2, "Geological Setting"). Now, Utahraptor's time period has been pushed even further back into the Cretaceous. The entire Yellow Cat Member has now been dated to 143-130 million years ago (Milan et al., 2015, pg. 516, "Geological Setting") (Joeckel et al., 2019, "Abstract"). According to the International Chronostratigraphic Chart (2019 Version), this places Utahraptor in the Berriasian-Hauterivian of the early Cretaceous period, which is 145-129 million years ago.
Prey:
Utahraptor hunted the ankylosaur Gastonia, and hadrosaurs like Cedrorestes and the larger Iguanacolossus. It probably also hunted the young of the sauropod Cedarosaurus.
Links:
Original Paper:
Kirkland et al., (1993):
https://www.academia.edu/225747/A_large_dromaeosaurid_Theropoda_from_the_Lower_Cretaceous_of_Eastern_Utah
Time:
Joeckel et al., (2019) ("Abstract"):
https://sp.lyellcollection.org/content/498/1/75
Milan et al., (2015) (Pg. 516, "Geological Setting"):
https://geojournals.pgi.gov.pl/asgp/article/view/24870/17008
Link 2:
https://geojournals.pgi.gov.pl/asgp/article/view/24870
Senter et al., (2012) (Pg. 4, "Geological Setting"):
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3352940/
Kirkland et a., (2016) (Pg. 1-2, "Geological Setting"):
https://www.researchgate.net/publication/308041652_Depositional_constraints_on_the_Lower_Cretaceous_stikes_quarry_dinosaur_site_Upper_yellow_cat_member_cedar_mountain_formation_Utah
Kirkland et al., (1993) (Pg. 5):
https://www.academia.edu/225747/A_large_dromaeosaurid_Theropoda_from_the_Lower_Cretaceous_of_Eastern_Utah
International Chronostratigraphic Chart (2020):
https://stratigraphy.org/timescale/International Commission of Stratigraphy Website:
https://stratigraphy.org/news/130
Size:
https://psdinosaurs.blogspot.com/2018/10/calculations-for-largest-theropods.html
Weight:
Asher Elbein (2017) (P. 4):
https://www.nytimes.com/2017/08/28/science/utah-paleontologists-turn-to-crowdfunding-for-raptor-project.html
Lips:
Reisz and Larson (2016) (Pg. 64-66):
https://cansvp.files.wordpress.com/2013/08/csvp-2016-abstract-book-compressed.pdf
Blake Eligh (2016):
https://www.utoronto.ca/news/did-dinosaurs-have-lips-ask-university-toronto-paleontologist
Mindy Weisberger (2016):
https://www.livescience.com/54912-did-t-rex-have-lips.html
Emanuela Grinberg (2016):
https://www.cnn.com/2016/05/22/world/dinosaur-lips-teeth-study/index.html
Phys (2016):
https://phys.org/news/2016-06-dinosaurs-lips.html
Tongue:
Mindy Weisberger (2018):
https://www.scientificamerican.com/article/t-rex-couldnt-stick-out-its-tongue/
ScienceDaily (2018):
https://www.sciencedaily.com/releases/2018/06/180620150129.htm
Hands:
Kenneth Carpenter (2002):
https://www.researchgate.net/publication/225366451_Forelimb_biomechanics_of_nonavian_theropod_dinosaurs_in_predation
Senter and Robins (2015):
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0144036
Body Design:
Scott Hartman (2017):
http://www.skeletaldrawing.com/home/at-long-last-utahraptor
Prey:
Gastonia:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Iguanacolossus:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Cedarosaurus:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
Cedrorestes:
https://psdinosaurs.blogspot.com/2018/12/size-calculations-for-herbivorous.html
