My Prehistoric Saga: May 2019

Size calculations for pliosaurs.

Update (9/12/19): All specimens are up-to-date!

The Percentage Increase/Decrease Method:

1. Take new number and subtract it from original number.

2. Take that number and divide it by the original number and multiply by 100.

3. That number will by your percentage increase or decrease if it's negative.

Ex.: "Stan's" Femur is 130 and has a body length of 12.2 meters. "Wyrex" has a femur length of 132.7 cm.

132.7 - 130 = 2.7.

2.7 divided by (represented by "/") and multiplied by (represented by "*") equals 2.1.

(2.7/130*100 = 2.1)

2.1 is your percentage increase, or 2.1% increase.

12.2 m + 2.1% = 12.5 meters for "Wyrex."

Links:

Percentage Increase/Decrease Method Links:

"Percentage Change - Percentage Increase and Decrease." SkillsYouNeed:

https://www.skillsyouneed.com/num/percent-change.html

"Relative Increase." percentage.calculators.ro:

https://percentages.calculators.ro/15-percentage-increase-from-original-number-to-new-value.php

Once again, trying to find a method to get an accurate size of these animals proved to be trying. It's been stated a couple of times that comparing limb bones doesn't yield accurate sizes for pliosaurs (Knutsen et al., 2012, pg. 255-256) (Benson et al., 2013, "Discussion"), so I came up with two basic rules:

1. Focus on skull/mandible lengths first.

2. If that's no good, then go with other ways (vertebrae centrum lengths, limb bones, etc).

Links:

Benson et al., (2013) ("Discussion"):

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0065989

Knutsen et al., (2012) (pg. 255-256):

https://www.researchgate.net/publication/267927749_A_new_species_of_Pliosaurus_Sauropterygia_Plesiosauria_from_the_Middle_Volgian_of_central_Spitsbergen_Norway

Liopleurodon:

Time Period: Callovian of the middle Jurassic Period: 166-164 million years ago. (Noe et al., 2003)

Place: Europe.

Liopleurodon from Walking With Dinosaurs:

1. CAMSM J.27424:

Length: 21 feet (6.4 meters). (Noe et al., 2003, pg. 485)

Skull: 123.0 cm. (Noe et al., 2003, pg. 485)

Check:
-Based on specimen GPIT 1754/2:
Skull: 94 cm.
Body: 4.9 meters.

94 - 123 = 29.
29/94*199 = 30.9% increase.
4.9 m + 30.9% = 6.4 meters.

Link:

Noe et al., (2003) (pg. 485):

https://www.academia.edu/202692/The_first_relatively_complete_exoccipital-opisthotic_from_the_braincase_of_the_Callovian_pliosaur_Liopleurodon

2. NHM R2680:
Skull: 112 cm. (Noe et al., 2003, pg. 485)

CAMSM J.27424:

Length: 21 feet (6.4 meters).

Skull: 123.0 cm.

123 - 112 = 11.
11/123*100 = 8.9% decrease.
6.4 m - 8.9% = 5.8 meters.

Length: 19 feet (5.8 meters).

Link:

Noe et al., (2003) (pg. 485):

https://www.academia.edu/202692/The_first_relatively_complete_exoccipital-opisthotic_from_the_braincase_of_the_Callovian_pliosaur_Liopleurodon

3. NHM R3536:

Skull: 126.5 cm. (Noe et al., 2003, pg. 485)

CAMSM J.27424:

Length: 21 feet (6.4 meters).

Skull: 123.0 cm.

126.5 - 123 = 3.5.
3.5/123*100 = 2.9% increase.

6.4 m + 2.9% = 22 feet (6.6 meters).

Length: 22 feet (6.6 meters).

Link:

Noe et al., (2003) (pg. 485):

https://www.academia.edu/202692/The_first_relatively_complete_exoccipital-opisthotic_from_the_braincase_of_the_Callovian_pliosaur_Liopleurodon

4. Specimen with 154-cm skull:

CAMSM J.27424:

Length: 21 feet (6.4 meters).

Skull: 123.0 cm.

154 - 123 = 31.
31/123*100 = 25.2% increase.

6.4 m + 25.2% = 26 feet (8.0 meters).

Length: 26 feet (8.0 meters).

Benson et al., (2012) ("Discussion"):

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0065989#s4

Liopleurodon's Total Length: 19-26 feet (5.8-8.0 meters).

Megacephalosaurus:

Time Period: Turonian of the late Cretaceous period: 94-90 million years ago.
Place: Kansas.

USNM 50136 (Paratype) (Largest Specimen):
Skull: 175.0 cm. (Schumacher et al., 2013)

Liopleurodon Specimen with 154-cm Skull:
Skull: 154 cm.
Body: 8 meters.

175 - 154 = 21.
21/154*100 = 13.6% increase.
8 m + 13.6% = 30 feet (9.1 meters).

Link:
Schumacher et al., (2013):

https://www.academia.edu/5997965/A_new_Cretaceous_Pliosaurid_Reptilia_Plesiosauria_from_the_Carlile_Shale_middle_Turonian_of_Russell_County_Kansas

2nd Link:

https://www.researchgate.net/figure/Comparison-of-USNM-2361-left-referred-specimen-of-Brachauchenius-lucasi-USNM-4989_fig10_263690337

Megacephalosaurus Total Length: 30 feet (9.1 meters).

Kronosaurus:

Time Period: Aptian-Albian of the early Cretaceous period: 125-101 million years ago. (Kear, 2003, pg. 291-292)

Place: Australia.

Link:
Kear (2003) (pg. 291-292):
https://www.researchgate.net/publication/222825936_Cretaceous_marine_reptiles_of_Australia_A_review_of_taxonomy_and_distribution

K. queenslandicus:

1. QM F10113:

Skull: 187.6 cm. (McHenry, 2009, pg. 271 and 384)
Femur: 90 cm. (McHenry, 2009, pg. 386)
Humerus: 65 cm. (McHenry, 2009, pg. 386)

Megacephalosaurus Paratype USNM 50136 (Largest Specimen):
Skull: 175.0 cm.
Body: 9.1 meters.

187.6 - 175.0 = 12.6.
12.6/175*100 = 7.2% increase.
9.1 m + 7.2% = 32 feet (9.8 meters).

Length: 32 feet (9.8 meters).

Link:

McHenry (2009) (pg. 280):

https://nova.newcastle.edu.au/vital/access/%20/manager/Repository/uon:12164?view=null&f0=sm_subject%3A%22biomechanics%22&sort=sort_ss_title+asc

2. QM F2454:

Skull: 232.6 cm. (McHenry, 2009, pg. 271)

QM F10113:

Skull: 187.6 cm.
Body: 9.8 meters.

187.6 - 232.6 = 45.
45/187.6*100 = 24% increase.

9.8 m + 24% = 40 feet (12.2 meters).

Length: 40 feet (12.2 meters).

Link:

McHenry (2009) (pg. 281):

https://nova.newcastle.edu.au/vital/access/%20/manager/Repository/uon:12164?view=null&f0=sm_subject%3A%22biomechanics%22&sort=sort_ss_title+asc

3. MCZ 1285:
Skull: 285.0 cm. (Benson et al., 2013, "Discussion," "Body size of of pliosaurs kevani, and pliosaurid body evolution," par. 6)

QM F2454:

Skull: 232.6 cm.
Body: 12.2 meters.

285 - 232.6 = 52.4.
52.4/232.6*100 = 22.5% increase.

12.2 m + 162% = 49 feet (15.0 meters).

Link:

Benson et al., (2013):

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0065989

Kronosaurus' Total Length: 32-49 feet (9.8-15.0 meters).

Megalneusaurus:

Time Period: Oxfordian-Tithonian of the late Jurassic Period: 164-145 million years ago. (Wahl et al., 2007, "Abstract") (Weems and Blodgett, 1996, pg. 173-174) (Wilson et al., 2015, "Abstract") (Tropaff et al., 2005, "Abstract") (Hugh McClean, 1979, "Introduction") (Ralph W. Imlay, 1981, pg. 24-28)

Place: North America.

Size Ranges: 33-50 feet (10.0-15.1 meters):

Wahl et al., (2007) (pg. 98):

https://www.academia.edu/2903720/Rediscovery_of_Wilbur_Knights_Megalneusaurus_rex_site_New_material_from_an_old_pit

2nd Source:

http://oceansofkansas.com/Creisler_Plesiosaurs2.html

Bakker (1993):

http://discovermagazine.com/1993/sep/jurassicseamonst263

1. UW4602 (Holotype):
Humerus from Knight (1898) (Pg. 380-381):

Femur: 120 cm. (Science, 1895) (Probably Wahl et al., 2007, pg. 94, "Introduction")
Humerus: 99.1 cm. (Knight, 1898, pg. 380)
Dorsal Centrum Width: 15.2 cm. (Knight, 1898, pg. 380)

Dorsal Centrum Length: 11.1 cm. (Knight, 1898, pg. 380)

Anterior Cervical Centrum Width: 8 cm. (Science, 1895) (Knight, 1898, pg. 380)

Anterior Cervical Centrum Length: 6.5 cm. (Science, 1895) (Knight, 1898, pg. 380)

Femur Length:
The holotype's femur is the same size as the "Monster of Aramberri's" at 120 cm, so perhaps this specimen is really 52 feet (15.8 meters) long.

UW4602's Total Length: 52 feet (15.8 meters). (Based on UANL-FCT-R2)
Femur: 120 cm.
Skull: 300 cm. (Based on UANL-FCT-R2)

Links:

Wahl et al., (2007) (pg. 98):

https://www.academia.edu/2903720/Rediscovery_of_Wilbur_Knights_Megalneusaurus_rex_site_New_material_from_an_old_pit

Knight (1898) (pg. 380):

https://books.google.com/books?id=9FY7AQAAIAAJ&pg=PA380&lpg=PA380&dq=megalneusaurus+centrum+width&source=bl&ots=I0pjh9Mzig&sig=ACfU3U3BIE5eFVswQm7hKyhPl12Ik4AALw&hl=en&sa=X&ved=2ahUKEwia8c-ouaTiAhXo1FkKHSNQDNsQ6AEwAnoECAkQAQ#v=onepage&q=megalneusaurus%20centrum%20width&f=false

Science (1895):

https://science.sciencemag.org/content/2/40/449.1

2. USNM 418489:

Time: Oxfordian-Tithonian of the late Jurassic period: 164-145 million years ago.
Place: North America.

Humerus: 90 cm. (Measured in Weems and Blodgett, 1996, pg. 173) (Bucky, 2007, pg. 38, also gave 90 cm).

UW4602:
Humerus: 99.1 cm.
Length: 15.8 meters.

99.1 - 90 = 9.1.
9.1/99.1*100 = 9.2% decrease.
15.8 m - 9.2% = 47 feet (14.4 meters).

I know that measuring limb bones is not a good way to extrapolate a size estimate for pliosaurs, but there's no other way to estimate this specimen's size.

USNM 418489's Total Length: 47 feet (14.4 meters).
Skull: 272.4 cm. (9.2% smaller than UW4602's hypothetical skull length: 300 - 9.2%)

Links:
Weems and Blodgett (1996) (pg. 169):
https://books.google.com/books?id=kFdRAQAAIAAJ&pg=PA173&lpg=PA173&dq=megalneusaurus+humerus&source=bl&ots=2lz_AfTT0e&sig=ACfU3U2SF9blC3VoHyw5BkewmJSKlBjv-Q&hl=en&sa=X&ved=2ahUKEwih6Jfg0vHjAhVsm-AKHQkZBPIQ6AEwBXoECAkQAQ#v=onepage&q=megalneusaurus%20humerus&f=false

Pliosauroidae definition:

https://ecos.fws.gov/ServCat/DownloadFile/129372?Reference=85097

2nd Link:

https://images.app.goo.gl/YWQcwxWxVgfmqtwE7

3nd Link:

https://data.doi.gov/dataset/the-pliosaurid-megalneusaurus-a-newly-recognized-occurrence-in-the-upper-jurassic-naknek-f

Buchy (2007) (pg. 38):

https://webcache.googleusercontent.com/search?q=cache:gc2UxrBuhnkJ:https://publikationen.bibliothek.kit.edu/1000007307/21575+&cd=12&hl=en&ct=clnk&gl=us&client=safari

Wilson et al., (2015):

https://mrdata.usgs.gov/sim3340/show-sim3340.php?seq=B142&src=UG004_514
Tropaff et al., (2005):
https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/117/5-6/570/2164/sedimentology-and-provenance-of-the-upper-jurassic?redirectedFrom=fulltext
Hugh McClean (1979):
https://pubs.geoscienceworld.org/sepm/jsedres/article-abstract/49/4/1263/97241/sandstone-petrology-upper-jurassic-naknek?redirectedFrom=PDF
Ralph W. Imlay (1981) (Pg. 24-28):
https://books.google.com/books?id=7nBRAQAAIAAJ&pg=PA27&lpg=PA27&dq=Naknek+Formation+tithonian&source=bl&ots=BvkeTfeijZ&sig=ACfU3U02NHvXcuhr9kKd-I7hDdp0yZVJPQ&hl=en&sa=X&ved=2ahUKEwjJyfXR4v7mAhVDnuAKHc3xBwAQ6AEwAXoECAoQAQ#v=onepage&q=Naknek%20Formation%20tithonian&f=false

3. UANL-FCT-R2 ("Monster of Aramberri") (Vengeance from the Deep, "Pliosaur Size"):

Time Period: Kimmeridgian of the late Jurassic period: 157-152 million years ago.

Place: North America.

This specimen is an unidentified species of pliosaur that was discovered in Mexico back in the 1980's. It was originally assigned to Liopleurodon ferox, and used in Walking With Dinosaurs to give Liopleurodon a length of 82 feet (Henderson, 2002)! This was due to the preconception that this specimen was a juvenile (Buchy et al., 2007, pg. 37-40). This has been disputed (McHenry, 2009), and it is now assigned as an unidentified species of pliosaur (Buchy et al., 2007, pg. 37-40).

However, and I've been thinking about this for years now, since this animal was discovered in North America, and it has a long femur the same size to Megalneusaurus' (120 cm) (Science, 1895), and Megalneusaurus lived during the same time and place as the "Monster," I'm going to place this specimen as Megalneusaurus.

Body Length Ranges: 15-18 meters.

Skull (Mandible): 3.0 meters. (Buchy, 2007, pg. 37-38) (Henderson, 2002)
Femur: 120 cm. (Buchy, 2007, pg. 38)

Kronosaurus queenslandicus Specimen MCZ 1285:
Skull: 285.0 cm.
Body: 15.0 meters.

300 - 285 = 15.
15/285*100 = 5.3% increase.
15 m + 5.3% = 52 feet (15.8 meters).

Note: Both UANL-FCT-R2 and UW4602 had the same-sized femur, so both of these animals seem to have been the same size. Second, this might support the idea that UANL-FCT-R2 is Megalneusaurus.

Megalneusaurus' Total Length: 47-52 feet (14.4-15.8 meters).
Skull Length: 272.4-300 cm.

Links:

McHenry (2009) (pg. 416-417):
https://nova.newcastle.edu.au/vital/access/%20/manager/Repository/uon:12164?view=null&f0=sm_subject%3A%22biomechanics%22&sort=sort_ss_title+asc

Frey and Stinnesbeck (2002):

https://books.google.com/books?id=hQgiAwAAQBAJ&pg=PA87&lpg=PA87&dq=monster+of+aramberri+skull&source=bl&ots=FXl5M8fX8U&sig=ACfU3U1UqpB0ddI1qq-G7TS4XI0n40wJ9Q&hl=en&sa=X&ved=2ahUKEwj7jveV4fHjAhUFjlkKHVeWBtc4ChDoATAGegQIBhAB#v=onepage&q=monster%20of%20aramberri%20skull&f=false

Buchy et al., (2003):

https://www.academia.edu/3606036/First_occurrence_of_a_gigantic_pliosaurid_plesiosaur_in_the_Late_Jurassic_Kimmeridgian_of_Mexico

Buchy (2007) (pg. 36-40):

https://webcache.googleusercontent.com/search?q=cache:gc2UxrBuhnkJ:https://publikationen.bibliothek.kit.edu/1000007307/21575+&cd=12&hl=en&ct=clnk&gl=us&client=safari

Second Skull Length (10 feet):

Henderson (2002):

https://www.google.com/amp/s/amp.independent.ie/world-news/fossil-hunters-find-50ton-sea-monster-who-chewed-granite-26025589.html

Skull Picture:
Vengeance from the Deep. "Pliosaur Size":

http://vengeancefromthedeep.com/pliosaur-size

15-18 meters:

http://plesiosauria.com/mines-bigger-than-yours-the-monster-of-aramberri-predator-x-and-other-monster-pliosaurs-in-the-media/

Pliosaurus:

Time Period: Kimmeridgian-Tithonian of the late Jurassic period: 157-145 million years ago (Benson et al., 2013).

Place: North America.

Link:
Benson et al., (2013):
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0065989

P. funkei:

Pliosaurus funkei ("Predator X") from Planet Dinosaur:

Size Range: 10-15 meters:

15 meters:

2008:

https://www.sciencedaily.com/releases/2008/02/080229101002.htm

2009:

https://www.newscientist.com/article/dn16785-fossil-of-ultimate-predator-unearthed-in-arctic/
Link 2:

https://www.reuters.com/article/us-fossil-seamonster/fossil-sea-monsters-bite-makes-t-rex-look-feeble-idUSTRE52F6D120090317
Link 3:

https://web.archive.org/web/20090321025902/http://www.news24.com/News24/Technology/News/0,,2-13-1443_2486573,00.html

Link 4:

https://www.nytimes.com/2009/03/17/science/17foss.html

10-13 meters (2012):

https://scitechdaily.com/predator-x-officially-named-pliosaurus-funkei/

1. PMO 214.135 (Holotype):

Skull Length Range: 160-200.0 cm. (Knutsen et al., 2012, pg. 255)

I'll go with the 160-cm skull length, just to be safe.

Liopleurodon Specimen with 154-cm Skull:
Skull: 154 cm.
Body: 8 meters.

160 - 154 = 6.
6/154*100 = 3.9% decrease.
8 m - 3.9% = 27 feet (8.3 meters).

Length: 27 feet (8.3 meters).

Link:

Knutsen et al., (2012) (Pg. 242, 250, 255):

https://www.researchgate.net/publication/267927749_A_new_species_of_Pliosaurus_Sauropterygia_Plesiosauria_from_the_Middle_Volgian_of_central_Spitsbergen_Norway

2. PMO 214.136:
Skull Length Range: 200-250 cm. (Knutsen et al., 2012, pg. 255)

I'll go with the 200-cm skull length, just to be safe.

Megacephalosaurus Paratype USNM 50136 (Largest Specimen):
Skull: 175.0 cm.
Body: 9.1 meters.

175 - 200 = 25.
25/175*100 = 14.3% increase.
9.1 m + 14.3% = 34 feet (10.4 meters).

Length: 34 feet (10.4 meters).

Link:

Knutsen et al., (2012) (Pg. 242, 250, 255):

https://www.researchgate.net/publication/267927749_A_new_species_of_Pliosaurus_Sauropterygia_Plesiosauria_from_the_Middle_Volgian_of_central_Spitsbergen_Norway
Other:
http://plesiosauria.com/mines-bigger-than-yours-the-monster-of-aramberri-predator-x-and-other-monster-pliosaurs-in-the-media/

P. funkei's Total Length: 27-34 feet (8.3-10.4 meters).

P. kevani:
DORCM G. 13,675 (Holotype) ("Weymouth Bay"/"Dorset Pliosaur"):

Discovered and collected in 2003-2008.

Body Length Ranges: 12-16 meters.

Original Mandible/Skull Length: 2.1-2.4 meters. (2009-2011)
New Mandible/Skull Length: 204.5 cm (excluding the retroarticular process [back of skull] and tip of dentary). (Benson et al., 2013) (Foffa et al., 2014)
*My Mandible/Skull Measurement: 244.0 cm:
Left Mandible (Fragmentary): 185.0 cm. (Benson et al., 2013, "A," lateral)
Dentary Tip (Reconstructed): 59.0 cm. (Benson et al., 2013) (I got it twice)
Complete Mandible/Skull Length: 244.0 cm.

Kronosaurus queenslandicus Specimen QM F2454:

Skull: 232.6 cm.
Body: 12.2 meters.

244.0 - 232.6 = 11.4.
11.4/232.6*100 = 4.9% increase.

12.2 m + 4.9% = 42 feet (12.8 meters).

Link:

Benson et al., (2013):

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0065989

Foffa et al., (2014):

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4111928/
Other:
http://plesiosauria.com/pliosaurus-kevani-the-weymouth-bay-pliosaur/
Link 2:
http://plesiosauria.com/mines-bigger-than-yours-the-monster-of-aramberri-predator-x-and-other-monster-pliosaurs-in-the-media/
Link 3:
https://www.bbc.com/news/science-environment-14061347
Link 4:
https://www.telegraph.co.uk/news/science/dinosaurs/6444098/Skull-of-pliosaur-that-could-have-bitten-a-car-in-half-found-on-Britains-Jurassic-Coast.html
Link 5:
https://www.theguardian.com/science/2009/oct/27/dinosaur-pliosaur-skull-found-dorset-coast
Date of Discovery:
https://dorsetcountymuseum.wordpress.com/2015/06/15/jurassic-world-come-and-see-the-worlds-biggest-bite/

P. kevani's Total Length: 42 feet (12.8 meters).

P. rossicus:

OFXUM J. 10454:
Originally assigned to P. macromerus (Tarlo, 1950), OFXUM was assigned to P. rossicus (Benson et al., 2013).

Mandible/Skull Length Range: 287.5-300 cm. (Tarlo, 1959, pg. 51) (Benson et al., 2013, "Discussion" Section)

OFXUM J. 10454's Skull:

It is reconstructed as being 287.5 meters, but Tarlo (1959) said that it wasn't reconstructed correctly. Correctly, the mandible would have been 300 cm long.

Length (Based on UANL-FCT-R2/"Monster of Aramberri"): 52 feet (15.8 meters).

Tarlo (1959) (pg. 51):

https://www.palass.org/sites/default/files/media/publications/palaeontology/volume_2/vol2_part1_pp39-55.pdf

Benson et al., (2013) ("Discussion" Section):

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0065989

P. rossicus' Total Length: 52 feet (15.8 meters).

P. macromerus:

Andrew Cock Specimen:
(Discovered in 2009)

Mandible/Skull Length: 240 cm. (Hawthorne, no date)

Kronosaurus queenslandicus Specimen QM F2454:

Skull: 232.6 cm.
Body: 12.2 meters.

232.6 - 240 = 7.4.
7.4/232.6*100 = 3.2% increase.

12.2 m + 3.2% = 41 feet (12.6 meters).

Links:
Hawthorne (no date):

https://www.kronosrising.com/apex-predator-spotlight-pliosaurus-macromerus/

P. macromerus' Total Length: 41 feet (12.6 meters).

P. almanzaensis:

MOZ 3728P (Holotype) (Google searched):

Skull: 129 cm. (My Measurement from O'Gorman et al., 2018)

Liopleurodon Specimen CAMSM J.27424:

Length: 21 feet (6.4 meters).

Skull: 123.0 cm.

123 - 129 = 6.
6/123*100 = 4.9% increase.

6.4 m + 4.9% = 22 feet (6.7 meters).

Links:

Paper:

O'Gorman et al., (2018):

https://bioone.org/journals/Journal-of-Paleontology/volume-92/issue-2/jpa.2017.82/A-new-iPliosaurus-i-species-Sauropterygia-Plesiosauria-from-the-Upper/10.1017/jpa.2017.82.short

Skull Picture:

https://images.app.goo.gl/2DgTtNXqkzDzbw1r5

P. almanzaensis' Total Length: 22 feet (6.7 meters).

Pliosaurus sp. indet. (P. brachyspondylus?)
Skull: 1.8 meters. (Sassoon et al., 2012)

Megacephalosaurus Paratype USNM 50136 (Largest Specimen):
Skull: 175.0 cm.
Body: 9.1 meters.

180 - 175 = 5.
5/175*100 = 2.9% increase.
9.1 m + 2.9% = 31 feet (9.4 meters).

Link:
Sassoon et al., (2012):
https://onlinelibrary.wiley.com/doi/full/10.1111/j.1475-4983.2012.01151.x
P. brachyspondylus(?):
https://www.jstor.org/stable/55696?seq=1#page_scan_tab_contents
Others:
http://www.natural-history-conservation.com/MountingPliosauruscarpenteri.htm
http://www.bris.ac.uk/news/2012/8488.html

Pliosaurus sp. indet. (P. brachyspondylus?)'s Total Length: 31 feet (9.4 meters).

P. portentificus (nomen dubium):
CAMSM J.46380 (Holotype) (Noe et al., 2004):
Skull (Mandible): 3.0 meters. (Buchy, 2007, pg. 38-40)

Length (Based on P. rossicus specimen OFXUM J. 10454): 52 feet (15.8 meters).

Link:

Buchy (2007) (pg. 38-40):

https://webcache.googleusercontent.com/search?q=cache:gc2UxrBuhnkJ:https://publikationen.bibliothek.kit.edu/1000007307/21575+&cd=12&hl=en&ct=clnk&gl=us&client=safari
Noe et al., (2004):

https://www.sciencedirect.com/science/article/abs/pii/S0016787804800312
Fossilworks:
http://fossilworks.org/bridge.pl?a=taxonInfo&taxon_no=243152
Nomen Dubium:
Knutsen et al., 2012 (pg. 272):
https://www.geologi.no/images/NJG_articles/NJG_2_3_2012_14_Knutsen_Scr.pdf

P. portentificus (nomen dubium)'s Total Length: 52 feet (15.8 meters).

Pliosaurus' Total Length: 22-52 feet (6.7-15.8 meters).

Sachicasaurus:
Time Period: Barremian of the early Cretaceous period: 129-125 million years ago. (Paramo et al., 2018)
Place: South America.

MP111209-1 (Holotype):
Mandible/Skull Length: 273 cm. (Paramo et al., 2018, pg. 229)

Kronosaurus queenslandicus Specimen QM F2454:

Skull: 232.6 cm.
Body: 12.2 meters.

232.6 - 273 = 40.4.
40.4/232.6*100 = 17.4% increase.

12.2 m + 17.4% = 47 feet (14.3 meters).

Link:

Paramo et al., (2018):

https://www.researchgate.net/publication/331043547_A_new_large_Pliosaurid_from_the_Barremian_Lower_Cretaceous_of_Sachica_Boyaca_Colombia

Sachicasaurus Total Length: 47 feet (14.3 meters).

Stenorhynchosaurus:

Time Period: Barremian of the early Cretaceous period: 129-125 million years ago.
Place: South America.

VL17052004-1 (Holotype):
Skull: 136 cm. (Paramo-Fonseca et al., 2016)

Liopleurodon Specimen CAMSM J.27424:

Length: 21 feet (6.4 meters).

Skull: 123.0 cm.

136 - 123.0 = 13.
13/123*100 = 10.6% increase.

6.4 m + 10.6% = 23 feet (7.1 meters).

Link:

Paramo-Fonseca et al., (2016):

http://www.scielo.org.co/scielo.php?script=sci_arttext&pid=S0370-39082016000100010

Stenorhynchosaurus' Total Length: 23 feet (7.1 meters).

Brachauchenius:

Time Period: Turonian of the late Cretaceous period: 94-90 million years ago.
Place: North America.

USNM 4989 (Holotype, largest specimen):

Skull Length: 112.0 cm. (Measured in Schumacher et al., 2013, pg. 626)

Liopleurodon Specimen CAMSM J.27424:

Length: 21 feet (6.4 meters).

Skull: 123.0 cm.

112 - 123 = 11.
11/123*100 = 8.9% decrease.

6.4 m - 8.9% = 19 feet (5.8 meters).

Links:

Schumacher et al., (2013) (pg. 626):

https://www.academia.edu/5997965/A_new_Cretaceous_Pliosaurid_Reptilia_Plesiosauria_from_the_Carlile_Shale_middle_Turonian_of_Russell_County_Kansas

Brachauchenius' Total Length: 19 feet (5.8 meters).

Luskhan:
Time: Hauterivian of the lower Cretaceous period: 133-129 million years ago.
Place: Europe.