Saturday, March 23, 2019

How Big was T.rex Specimen RSM 2523.8 ("Scotty")?

RSM 2523.8 ("Scotty"):
It looks like "Sue' has some competition as the largest T.rex specimen now. The T.rex specimen RSM 2523.8, also known as "Scotty," was discovered in Canada in 1991 and is now estimated to have been older and heavier than "Sue," dying at the age of 30+ and weighing 19,400 pounds (9.7 tons) (Persons IV et al., 2019). 

It is now also stated that "Scotty" was 42-43 feet long. I decided to check this out myself. I couldn't access the paper before, but now I have access to it. Persons IV et al., (2019) gave her femur a length of 133.0-133.3 meters, compared to "Sue's" 132.1-cm femur from Brochu (2003). Unfortunately, I couldn't get an accurate estimate of the femur, so I looked at her dentary and right pedal phalanx IV-1.

"Scotty's" and "Sue's" Measurements (Persons IV et al., 2019):
"Scotty":
Right Pedal Phalanx IV-1:
18.4 cm. (Persons IV et al., 2019)
My Length: 23.5 cm (at best). (Measured on 9/24/19)
Dentary Tooth Row:
59.5 cm. (Persons IV et al., 2019)
My Length (Right Dentary): 57.3 cm. (Measured on 3/20/21 in Persons IV et al., 2019, right dentary, "B", medial)
Femur Width: 21.0 cm. (Persons IV et al., 2019) (The Guardian, 2019 reports a width of 20.3 cm)
Right Fibula: 120 cm. (Measured twice in Persons IV et al., 2019)

"Scotty's" Dentaries (I measured from the tip of the jaw to the 14th-marked alveoli):
"Scotty's" Right Fibula:
"Sue":
Right Pedal Phalanx IV-1: 16 cm (my measurement from Brochu, 2003).
Dentary Tooth Row:
58.5 cm. (Persons IV et al., 2019)
My Length (Right Dentary): 56 cm (Brochu, 2003, pg. 41, right dentary, "D," medial)
Femur Width: 20 cm. (Brochu, 2003, pg. 112, "A")
Right Fibula: 119.0 cm. (Brochu, 2003, pg. 116, right, "C")

Update (8/23/19): "Scotty" is larger than I thought! I had some trouble trying to get a length of her femur, but I've FINALLY found a good pick of her femur that gave me an accurate length. It's longer than 138 cm...

Femur (Cast) from the Royal Saskatchewan Museum's Twitter Page:
(I measured the top picture, not the drawing)

Lengths: 
140 cm (Straight side).
142.5 cm (Other side with femoral head).
148.5 cm (Total length from femoral head to tip of longest end). (Measured on 9/8/19)

I'm going to go with the 140-cm length.

"Sue":
Femur: 137 cm.
Body: 13.0 meters.

140 - 137 = 3.
3/137*100 = 2.2% increase.
13.0 m + 2.2% = 13.3 meters.

Update (9/8/19): I've decided to go with the total femur length.

"Sue":
Femur (Total Length): 143 cm.
Body: 13.6 meters.

Here's how I got "Sue's" length:
https://psdinosaurs.blogspot.com/2018/11/how-big-was-sue-fmnh-pr-2081.html

148.5 - 143 = 5.5.
5.5/143*100 = 3.9% increase.
13.6 m + 3.9% = 46 feet (14.1 meters).

RSM 2523.8's Total Length: 46 feet (14.1 meters).
Femur Length: 148.5 cm.

Links:
Femur Picture:
Royal Saskatchewan Museum's Twitter:
Persons IV et al., (2019):
https://onlinelibrary.wiley.com/doi/epdf/10.1002/ar.24118?tracking_action=preview_click&r3_referer=wol&show_checkout=1
Abstract:
https://onlinelibrary.wiley.com/doi/pdf/10.1002/ar.24118
Version 2:
https://www.gbif.org/species/159236947
43 feet ("13 meters"):
https://www.folio.ca/paleontologists-identify-biggest-tyrannosaurus-rex-ever-discovered/
http://www.guinnessworldrecords.com/news/2019/4/scotty-the-dinosaur-skeleton-which-is-a-contender-for-the-largest-t-rex-ever-568750
https://earthsky.org/earth/worlds-biggest-tyrannosaurus-rex
https://www.sciencealert.com/palaeontologists-have-discovered-the-biggest-t-rex-yet-and-it-s-been-through-a-lot
https://www.iflscience.com/plants-and-animals/worlds-largest-carnivorous-dinosaur-discovered-in-canada-/
https://www.dailysabah.com/history/2019/03/25/worlds-biggest-oldest-t-rex-skeleton-identified-in-canada
https://www.businessinsider.com/t-rex-discovered-in-canada-biggest-oldest-2019-3
https://newatlas.com/worlds-largest-tyrannosaurus-rex/58991/
http://www.sci-news.com/paleontology/scotty-tyrannosaurus-rex-07024.html
https://www.geek.com/news/paleontologists-report-worlds-biggest-tyrannosaurus-rex-1779727/
https://www.ctvnews.ca/canada/world-s-largest-tyrannosaurus-rex-scotty-unveiled-in-saskatchewan-1.4428084
Weight:
https://www.folio.ca/paleontologists-identify-biggest-tyrannosaurus-rex-ever-discovered/
https://earthsky.org/earth/worlds-biggest-tyrannosaurus-rex
https://www.sciencealert.com/palaeontologists-have-discovered-the-biggest-t-rex-yet-and-it-s-been-through-a-lot
https://www.iflscience.com/plants-and-animals/worlds-largest-carnivorous-dinosaur-discovered-in-canada-/
https://www.dailysabah.com/history/2019/03/25/worlds-biggest-oldest-t-rex-skeleton-identified-in-canada
Femur Width (8 inches/20.3 cm):
The Guardian (2019):
https://www.theguardian.pe.ca/news/canada/unearthed-t-rex-is-the-largest-known-specimen-and-its-from-saskatchewan-295584/
Brochu (2003):
https://www.researchgate.net/publication/249022959_Osteology_of_Tyrannosaurus_rex_Insights_from_a_Nearly_Complete_Skeleton_and_High-Resolution_Computed_Tomographic_Analysis_of_the_Skull
Age:
https://www.ctvnews.ca/canada/world-s-largest-tyrannosaurus-rex-scotty-unveiled-in-saskatchewan-1.4428084
The Guardian (2019):
https://www.theguardian.pe.ca/news/canada/unearthed-t-rex-is-the-largest-known-specimen-and-its-from-saskatchewan-295584/
Female:
CBC (2018):
https://www.cbc.ca/natureofthings/features/scotty-canadas-home-grown-tyrannosaurus-rex-is-actually-a-female