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Judith River Formation

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Judith River Formation
Stratigraphic range: Campanian, 79–75.3 Ma
↓
Judith River Formation, Upper Missouri Breaks National Monument
TypeGeological formation
Unit ofJudith River Group
Sub-unitsParkman Sandstone Member, McClelland Ferry Member, Coal Ridge Member, Woodhawk Member
UnderliesBearpaw Formation
OverliesClaggett Formation, Pakowki Formation
Thicknessmax 360 meters (1,180 ft)[1]
Lithology
PrimaryMudstone and sandstone
Location
Region Montana
Country United States
Type section
Named forJudith River near the confluence with the Missouri River
Named byF.V. Hayden, 1871;[2] F.B. Meek, 1876.[3]

The Judith River Formation is a fossil-bearing geologic formation in Montana, and is part of the Judith River Group. It dates to the Late Cretaceous, between 79 and 75.3 million years ago,[4] corresponding to the "Judithian" land vertebrate age. It was laid down during the same time period as portions of the Two Medicine Formation of Montana[5] and the Oldman Formation of Alberta.[6] It is an historically important formation, explored by early American paleontologists such as Edward Drinker Cope, who named several dinosaurs from scrappy remains found here on his 1876 expedition (such as Monoclonius). Modern work has found nearly complete skeletons of the hadrosaurid Brachylophosaurus.

Lithology

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The Judith River Formation is composed of mudstone, siltstone and sandstone.[1] Coal beds, bentonite and coquinas are also observed.

Judith River Formation, Upper Missouri Breaks National Monument

Relationship with other units

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The Judith River Formation conformably overlies the Claggett Formation and Pakowki Formation. It is overlain by the Bearpaw Formation.[1] It is equivalent to the Belly River Formation in the southern Canadian Rockies foothills, the Lea Park Formation in central Alberta and the Wapiti Formation in the northwestern plains.

Sub-divisions

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Missouri River carved through the Judith River Formation, Upper Missouri Breaks National Monument

The Judith River Formation is divided into four members, the Parkman Sandstone Member, the McClelland Ferry Member, the Coal Ridge member, and the Woodhawk Member.[7] The McClelland Ferry Member (78.7-76.3 Ma) is believed to be equivalent to the Oldman Formation, with the Coal Ridge Member (76.3-75.3 Ma) equivalent to the Dinosaur Park Formation.[4]

Fauna

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Dinosaurs of Judith River Formation

Faunal list follows a review published by Ashok Sahni in 1972 unless otherwise noted.[8]

Color key
Taxon Reclassified taxon Taxon falsely reported as present Dubious taxon or junior synonym Ichnotaxon Ootaxon Morphotaxon
Notes
Uncertain or tentative taxa are in small text; crossed out taxa are discredited.

Amphibians

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There are three potential species of discoglossid frogs. Hip bones, possibly representing a North American member of the European spadefoot toad family are also known from the formation.

Amphibians of the Judith River Formation
Genus Species Location Stratigraphic position Abundance Notes Images

Habrosaurus

H. dilatus

A siren.

Lisserpeton

L. bairdi

A scapherpetonid salamander.

Opisthotriton

O. kayi

A possible lungless salamander.

Prodesmodon

P. copei

A lungless salamander.

Scapherpeton

S. tectum

A scapherpetonid salamander.

Fish

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Bony fish

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Bony fishes of the Judith River Formation
Genus Species Location Stratigraphic position Abundance Notes Images
Belonostomus Belonostomus longirostris An aspidorhynchiform.
Cyclurus C. fragosus A bowfin.[9]
Lepisosteus L. occidentalis Scales[10] A gar.
?Paralbula ?P. sp. A bonefish.
Priscosturion P. longipinnis McClelland Ferry[11] Upper Campanian[11] A sturgeon.
Psammorhynchus P. longipinnis McClelland Ferry[11] Upper Campanian[11] Preoccupied name, renamed Priscosturion.[12]
Polyodontidae Indeterminate A paddlefish. Known remains exceeded size of Chinese paddlefish, total length would exceed 2 metres (6.6 ft).[13]


Cartilaginous fish

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Cartilaginous fishes of the Judith River Formation
Genus Species Location Stratigraphic position Abundance Notes Images

Myledaphus

M. bipartitus

A stingray.

Choristoderes

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Choristoderes of the Judith River Formation
Genus Species Location Stratigraphic position Abundance Notes Images

Champsosaurus

C. sp.

Champsosaurus

Crocodilians

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Crocodilians of the Judith River Formation
Genus Species Location Stratigraphic position Abundance Notes Images

Brachychampsa

B. montana

An alligatorid.
Brachychampsa
Deinosuchus

Leidyosuchus

L. canadensis

An alligatoroid.
Deinosuchus D. hatcheri[14] Two giant dorsal vertebrae and a number of osteoderms. An enormous alligatoroid.

Lizards

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Lizards of the Judith River Formation
Genus Species Location Stratigraphic position Abundance Notes Images

Chamops

C. segnis

A whiptail.

Exostinus

E. lancensis

A knob-scaled lizard.

Leptochamops

L. denticulatus

A whiptail.

Paraderma

P. bogerti

A parasaniwid.

Parasaniwa

P. wyomingensis

A parasaniwid.

Ornithischians

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Ankylosaurs

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Ankylosaurs reported from the Judith River Formation
Genus Species Location Member Material Notes Images
Edmontonia E. longiceps Isolated teeth[15] A nodosaurid.
Edmontonia
Zuul
Zuul Z. crurivastator middle Coal Ridge Cranial and postcranial skeletal remains and soft tissue, type specimen An ankylosaurid

Hadrosaurs

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Hadrosaurs reported from the Judith River Formation
Genus Species Location Member Material Notes Images

Brachylophosaurus

B. canadensis

middle McClelland Ferry

A hadrosaurid which was one of the more common dinosaurs in the area.[16]

Brachylophosaurus
Probrachylophosaurus
Corythosaurus C. sp.[17] middle Coal Ridge two partial skeletons A lambeosaurine hadrosaurid

Diclonius

D. calamarius

"Teeth."[18]

Nomen dubium

D. pentagonius

"Fragmentary dentary with teeth,"[18] type specimen

A dubious hadrosaurid

D. perengulatus

"Teeth."[18]

Nomen dubium

Hadrosaurus

H. paucidens

Reclassified as Lambeosaurus? paucidens

?"Kritosaurus"

?"K." breviceps

A dubious hadrosaurid

?Lambeosaurus

?L. paucidens

"Squamosal, maxilla."[18]

Nomen dubium. An indeterminate lambeosaurine.[19]

Paleoscincus

P. costatus

"Tooth,"[10] type specimen

A dubious ankylosaur

Probrachylophosaurus

P. bergei

lower McClelland Ferry

A brachylophosaurin hadrosaur

Pteropelyx

P. grallipes

"Skeleton lacking skull."[20]

A dubious hadrosaurid

Trachodon

T. mirabilis

Isolated teeth, type specimen[10]

A dubious hadrosaurid

Marginocephalians

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Ceratopsians
[edit]
Ceratopsians reported from the Judith River Formation
Genus Species Location Member Material Notes Images

Albertaceratops

A. nesmoi[21]

Reclassified as Medusaceratops lokii

Avaceratops
Judiceratops
Furcatoceratops
Lokiceratops
Medusaceratops
Mercuriceratops
Monoclonius
Spiclypeus

Avaceratops

A. lammersi[21]

lower McClelland Ferry

"[Two] partial skulls, skeleton, juvenile,"[22] type specimen

A ceratopsid

Ceratops

C. montanus

"occipital condyle, paired horn cores,"[23] type specimen

A dubious ceratopsid

Dysganus

D. bicarinatus

"Isolated teeth."[23]

Nomen dubium

D. encaustus

"Single tooth and [five] tooth fragments."[18] "Isolated teeth."[23]

Nomen dubium

D. haydenianus

"Isolated teeth."[23]

Nomen dubium

D. peiganus

"Tooth."[23]

Nomen dubium

Furcatoceratops F. elucidans Fergus County, Montana[24] Upper Coal Ridge[24] Nearly complete subadult skeleton.[24] A ceratopsid

Judiceratops[25]

J. tigris[25]

lower McClelland Ferry

A ceratopsid

Lokiceratops

L. rangiformis[26]

Kennedy Coulee lower McClelland Ferry Disarticulated, associated skeleton including most of the skull and fragmentary postcrania[26]

A ceratopsid

Medusaceratops

M. lokii[27]

lower McClelland Ferry

Bonebed[27]

A ceratopsid

Mercuriceratops

M. gemini[28]

lower Coal Ridge

"one apomorphic squamosal"[28]

A ceratopsid

Monoclonius

M. crassus[21]

lower Coal Ridge

"[Five] skulls, [one] complete."[22] Type specimen

A dubious ceratopsid

Spiclypeus S. shipporum McClelland Ferry[29] Partial skull, vertebrae, ribs, humerus, ilium, femur, tibia, and fibula. A ceratopsid
Pachycephalosaurs
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Pachycephalosaurs reported from the Judith River Formation
Genus Species Location Member Material Notes Images
Colepiocephale C. lambei[30] Kennedy Coulee lower McClelland Ferry "nearly complete frontoparietal dome" A pachycephalosaurid closely related to Stegoceras.
Colepiocephale
Hanssuesia H. sternbergi A pachycephalosaurid. Also present in the Dinosaur Park and Oldman Formations. Possible synonym of Stegoceras.
Hanssuesia

Theropods

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Dromaeosaurs

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Dromeosaurs reported from the Judith River Formation
Genus Species Location Stratigraphic position Material Notes Images

Dromaeosaurus

D. albertensis

Ox Hill Quarry, Careless Creek Quarry, Hidden Valley Quarry & Blackbird Ridge Quarry.[31] lower McClelland Ferry

Teeth[31]

A dromaeosaurid, also found in the Dinosaur Park Formation

Dromaeosaurus
Saurornitholestes

D. explanatus

"Tooth."[32]

Possible relative of Saurornitholestes

D. laevifrons

"Tooth."[32]

Possible relative of Saurornitholestes

Saurornitholestes S. langstoni Careless Creek, Emily's Ankle, Top Cat, Hidden Valley & Blackbird Ridge quarries.[31] Lower McClelland Ferry Numerous teeth[31] A dromaeosaurid

Zapsalis[33]

Z. abradens

"Teeth,"[32] type specimen

A dromaeosaurid

Troodonts

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Troodonts reported from the Judith River Formation
Genus Species Location Stratigraphic position Material Notes Images
Theropod "A" Antelope Head, Careless Creek, Emily's Ankle, Top Cat, Hidden Valley, Blackbird Ridge & Jensen Ranch quarries.[31] 28 teeth[31] Teeth of a large theropod distinct from those of tyrannosaurids
Troodon

Troodon

T. formosus

Antelope Head, Careless Creek, Emily's Ankle, Top Cat & Hidden Valley quarries.[31]

Teeth (type specimen),[10][31] egg

A troodontid, possibly dubious.

Tyrannosaurs

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Tyrannosaurs reported from the Judith River Formation
Genus Species Location Stratigraphic position Material Notes Images

Aublysodon

A. lateralis

"Isolated teeth,"[34][35] type specimen

Junior synonym of Deinodon horridus[8]

Daspletosaurus
Gorgosaurus

A. mirandus

Teeth, type specimen

Possible junior synonym of Deinodon horridus[8]

Daspletosaurus D. torosus Coal Ridge Maxilla[36] and a partial skeleton [37] A large tyrannosaurid.
D. wilsoni[38] Jack’s B2 lower Coal Ridge[39] Partial skull, cervical, sacral, and caudal vertebrae, and a rib, chevron, and first metatarsal Originally considered to be a transitional species between D. torosus and D. horneri, though the validity of this claim has been questioned [40]
D. sp. Coal Ridge[40] Partial skeleton[41] Not referrable to D. torosus[39]

Deinodon

D. falculus

Teeth

Isolated tyrannosaur teeth classified in the dubious genus Deinodon

D. hazenianus

Teeth

Junior synonym of Deinodon horridus[8]

D. horridus

"Teeth,"[10] type specimen

Isolated tyrannosaur teeth that formed the basis of the dubious genus Deinodon

D. incrassatus

Teeth

Junior synonym of Deinodon horridus[8]

D. lateralis

Junior synonym of Deinodon horridus[8]

Gorgosaurus G. libratus Postorbital[36] A large tyrannosaurid, also found in the Dinosaur Park Formation and possibly the Two Medicine Formation.

Other Theropods

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Theropods reported from the Judith River Formation
Genus Species Location Stratigraphic position Material Notes Images

Hesperornis

H. altus

Partial tibiotarsus

One of the only known freshwater occurrences of a hesperornithid.[42]

Hesperornis

Ornithomimus

O. tenuis

"Fragmentary metatarsal."[43]

A possible troodontid or juvenile tyrannosaurid

Paronychodon

P. lacustris

Teeth, type specimen

An indeterminate maniraptoran, also found in the Dinosaur Park, Milk River, and Kirtland Formations

Richardoestesia R. gilmorei Careless Creek, Emily's Ankle, Hidden Valley & Blackbird Ridge quarries.[31] 12 teeth[31] A coelurosaur

Turtles

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Turtles of the Judith River Formation
Genus Species Location Stratigraphic position Abundance Notes Images
Adocus A. sp.

Basilemys

B. sp.

A Mesoamerican river turtle.

See also

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References

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  1. ^ a b c Lexicon of Canadian Geological Units. "Judith River Formation". Retrieved 2009-02-06.
  2. ^ Hayden, F.V., 1871. Geology of the Missouri Valley: Preliminary report (4th annual) of the Geol. Surv. of Wyoming and portions of contiguous territories.
  3. ^ Meek, Fielding Bradford, 1876. A report on the invertebrate Cretaceous and Tertiary fossils of the upper Missouri country, Hayden, F.V., Geologist in Charge; United States Geologic and Geographic Survey of the Territories, vol. 9, page 629
  4. ^ a b Ramezani, Jahandar; Beveridge, Tegan L.; Rogers, Raymond R.; Eberth, David A.; Roberts, Eric M. (2022-09-26). "Calibrating the zenith of dinosaur diversity in the Campanian of the Western Interior Basin by CA-ID-TIMS U–Pb geochronology". Scientific Reports. 12 (1): 16026. doi:10.1038/s41598-022-19896-w. ISSN 2045-2322. PMC 9512893. PMID 36163377.
  5. ^ Sullivan, R.M. and Lucas, S. G. (2006). "The Kirtlandian land-vertebrate "age"–faunal composition, temporal position and biostratigraphic correlation in the nonmarine Upper Cretaceous of western North America." Pp. 7-29 in Lucas, S. G. and Sullivan, R.M. (eds.), Late Cretaceous vertebrates from the Western Interior. New Mexico Museum of Natural History and Science Bulletin 35.
  6. ^ Eberth, David A. (1997). "Judith River Wedge". In Currie, Philip J.; Padian Kevin (eds.). Encyclopedia of Dinosaurs. San Diego: Academic Press. pp. 379–380. ISBN 0-12-226810-5.
  7. ^ Rogers, Raymond R.; Kidwell, Susan M.; Deino, Alan L.; Mitchell, James P.; Nelson, Kenneth; Thole, Jeffrey T. (2016-01-01). "Age, Correlation, and Lithostratigraphic Revision of the Upper Cretaceous (Campanian) Judith River Formation in Its Type Area (North-Central Montana), with a Comparison of Low- and High-Accommodation Alluvial Records". The Journal of Geology. 124 (1): 99–135. Bibcode:2016JG....124...99R. doi:10.1086/684289. ISSN 0022-1376. S2CID 130555911.
  8. ^ a b c d e f Sahni, A. (1972). "The vertebrate fauna of the Judith River Formation, Montana." Bulletin of the AMNH, v. 147 article 6: 321-415.
  9. ^ Grande, Lance; Bemis, William E. (1998-04-10). "A Comprehensive Phylogenetic Study of Amiid Fishes (Amiidae) Based on Comparative Skeletal Anatomy. an Empirical Search for Interconnected Patterns of Natural History". Journal of Vertebrate Paleontology. 18 (sup1): 1–696. doi:10.1080/02724634.1998.10011114. ISSN 0272-4634.
  10. ^ a b c d e Leidy, J. (1856-12-31). "Notice of remains of extinct reptiles and fishes, discovered by Dr. FV Hayden in the Bad Lands of the Judith River, Nebraska Territory". Proceedings of the Academy of Natural Sciences of Philadelphia. 8: 72–73. doi:10.5281/zenodo.1038128.
  11. ^ a b c d Grande, Lance; Hilton, Eric J. (July 2006). "An Exquisitely Preserved Skeleton Representing a Primitive Sturgeon from the Upper Cretaceous Judith River Formation of Montana (Acipenseriformes: Acipenseridae: N. Gen. and Sp.)". Journal of Paleontology. 80 (S65): 1–39. doi:10.1666/05032.1. ISSN 0022-3360. S2CID 131689748.
  12. ^ Grande, Lance; Hilton, Eric J. (March 2009). "A replacement name for †Psammorhynchus Grande & Hilton, 2006 (Actinopterygii, Acipenseriformes, Acipenseridae)". Journal of Paleontology. 83 (2): 317–318. doi:10.1666/08-137.1. ISSN 0022-3360. S2CID 85233540.
  13. ^ Grande, Lance; Bemis, William E. (1991). "Osteology and Phylogenetic Relationships of Fossil and Recent Paddlefishes (Polyodontidae) with Comments on the Interrelationships of Acipenseriformes". Memoir (Society of Vertebrate Paleontology). 1: ii–121. doi:10.2307/3889328. ISSN 1062-161X.
  14. ^ Schwimmer, David (2002). King of the Crocodylians: The Paleobiology of Deinosuchus. Bloomington, IN: Indiana University Press. p. 200.
  15. ^ Sahni, Ashok (1972). "The vertebrate fauna of the Judith River Formation, Montana". Bulletin of the AMNH. 147 (6). hdl:2246/1099.
  16. ^ Trexler, David; Murphy, Nate; Thompson, Mark (June 2007). ""Leonardo," a Mummified Brachylophosaurus (Ornithischia: Hadrosauridae) from the Judith River Formation of Montana". In Carpenter, Kenneth (ed.). Horns and Beaks. Bloomington, IN: Indiana University Press. pp. 117–133.
  17. ^ Takasaki, Ryuji; Chiba, Kentaro; Fiorillo, Anthony R.; Brink, Kirstin S.; Evans, David C.; Fanti, Federico; Saneyoshi, Mototaka; Maltese, Anthony; Ishigaki, Shinobu (2022-10-23). "Description of the first definitive Corythosaurus (Dinosauria, Hadrosauridae) specimens from the Judith River Formation in Montana, USA and their paleobiogeographical significance". The Anatomical Record. 306 (7): 1918–1938. doi:10.1002/ar.25097. ISSN 1932-8486. PMID 36273398. S2CID 253081338.
  18. ^ a b c d e "Table 20.1," in Weishampel, et al. (2004). Page 442.
  19. ^ Prieto-Márquez, Alberto; Weishampel, David B.; Horner, John R. (2006). "The dinosaur Hadrosaurus foulkii, from the Campanian of the East Coast of North America, with a reevaluation of the genus" (PDF). Acta Palaeontologica Polonica. 51 (1): 77–98.
  20. ^ "Table 20.1," in Weishampel, et al. (2004). Page 443.
  21. ^ a b c Ryan and Evans, 2005
  22. ^ a b "Table 23.1," in Weishampel, et al. (2004). Page 495.
  23. ^ a b c d e "Table 23.1," in Weishampel, et al. (2004). Page 496.
  24. ^ a b c Ishikawa, Hiroki; Tsuihiji, Takanobu; Manabe, Makoto (2023-07-20). "Furcatoceratops elucidans, a new centrosaurine (Ornithischia: Ceratopsidae) from the upper Campanian Judith River Formation, Montana, USA". Cretaceous Research. 151: 105660. doi:10.1016/j.cretres.2023.105660. ISSN 0195-6671. S2CID 260046917.
  25. ^ a b Nicholas R. Longrich (2013). "Judiceratops tigris, a New Horned Dinosaur from the Middle Campanian Judith River Formation of Montana". Bulletin of the Peabody Museum of Natural History. 54 (1): 51–65. doi:10.3374/014.054.0103. S2CID 129801786.
  26. ^ a b Loewen, Mark A.; Sertich, Joseph J. W.; Sampson, Scott; O’Connor, Jingmai K.; Carpenter, Savhannah; Sisson, Brock; Øhlenschlæger, Anna; Farke, Andrew A.; Makovicky, Peter J.; Longrich, Nick; Evans, David C. (2024-06-20). "Lokiceratops rangiformis gen. et sp. nov. (Ceratopsidae: Centrosaurinae) from the Campanian Judith River Formation of Montana reveals rapid regional radiations and extreme endemism within centrosaurine dinosaurs". PeerJ. 12: e17224. doi:10.7717/peerj.17224. ISSN 2167-8359. PMC 11193970.
  27. ^ a b Ryan, Michael J.; Russell, Anthony P., and Hartman, Scott. (2010). "A New Chasmosaurine Ceratopsid from the Judith River Formation, Montana", In: Michael J. Ryan, Brenda J. Chinnery-Allgeier, and David A. Eberth (eds), New Perspectives on Horned Dinosaurs: The Royal Tyrrell Museum Ceratopsian Symposium, Indiana University Press, 656 pp. ISBN 0-253-35358-0.
  28. ^ a b Ryan, Michael J.; Evans, David C.; Currie, Phillip J.; Loewen, Mark A. (2014). "A New chasmosaurine from northern Laramidia expands frill disparity in ceratopsid dinosaurs". Naturwissenschaften. doi:10.1007/s00114-014-1183-1
  29. ^ Fowler, Denver Warwick (2017-11-22). "Revised geochronology, correlation, and dinosaur stratigraphic ranges of the Santonian-Maastrichtian (Late Cretaceous) formations of the Western Interior of North America". PLOS ONE. 12 (11): e0188426. Bibcode:2017PLoSO..1288426F. doi:10.1371/journal.pone.0188426. ISSN 1932-6203. PMC 5699823. PMID 29166406.
  30. ^ Schott, Ryan K.; Evans, David C.; Williamson, Thomas E.; Carr, Thomas D.; Goodwin, Mark B. (2009-09-12). "The anatomy and systematics of Colepiocephale lambei (Dinosauria: Pachycephalosauridae)". Journal of Vertebrate Paleontology. 29 (3): 771–786. doi:10.1671/039.029.0329. ISSN 0272-4634.
  31. ^ a b c d e f g h i j Fiorillo, Anthony R.; Currie, Philip J. (1994-03-31). "Theropod teeth from the Judith River Formation (Upper Cretaceous) of south-central Montana". Journal of Vertebrate Paleontology. 14 (1): 74–80. doi:10.1080/02724634.1994.10011539. ISSN 0272-4634.
  32. ^ a b c "Table 9.1," in Weishampel, et al. (2004). Page 186.
  33. ^ Larson, D. W.; Currie, P. J. (2013). "Multivariate Analyses of Small Theropod Dinosaur Teeth and Implications for Paleoecological Turnover through Time". In Evans, Alistair Robert. PLoS ONE 8: e54329. doi:10.1371/journal.pone.0054329. edit
  34. ^ "Table 4.1," in Weishampel, et al. (2004). Page 78.
  35. ^ "Table 5.1," in Weishampel, et al. (2004). Page 114.
  36. ^ a b Carr, Thomas D. (2018). "Significant geographic range extension for the sympatric tyrannosaurids Albertosaurus libratus and Daspletosaurus torosus from the Judith River Formation (Late Campanian) of northern Montana" (PDF). Journal of Vertebrate Paleontology. 38 (Supplement 1): 102.
  37. ^ Stein, Walter W., and Michael Triebold. "Preliminary Analysis of a Sub-adult Tyrannosaurid Skeleton from the Judith River Formation of Petroleum County, Montana." Tyrannosaurid Paleobiology. Indiana University Press, Bloomington (2013): 55-77.
  38. ^ Warshaw, Elías A.; Fowler, Denver W. (2022). "A transitional species of Daspletosaurus Russell, 1970 from the Judith River Formation of eastern Montana". PeerJ. 10. e14461. doi:10.7717/peerj.14461. PMC 9703990. PMID 36452080.
  39. ^ a b Warshaw, Elías A.; Guevara, Daniela Barrera; Fowler, Denver W. (November 2024). "Anagenesis and the tyrant pedigree: A response to "Re-analysis of a dataset refutes claims of anagenesis within Tyrannosaurus-line tyrannosaurines (Theropoda, Tyrannosauridae)"". Cretaceous Research. 163: 105957. doi:10.1016/j.cretres.2024.105957. ISSN 0195-6671.
  40. ^ a b Scherer, Charlie Roger; Voiculescu-Holvad, Christian (November 28, 2023). "Re-analysis of a dataset refutes claims of anagenesis within Tyrannosaurus-line tyrannosaurines (Theropoda, Tyrannosauridae)". Cretaceous Research (In press): 105780. doi:10.1016/j.cretres.2023.105780. ISSN 0195-6671.
  41. ^ Maltese, Anthony E. "DIFFICULT EXCAVATION AND PREPARATION OF A LARGE DASPLETOSAURUS SPECIMEN." Methods in Preparation: 63.
  42. ^ Fox, R.C. (1974). "A middle Campanian, nonmarine occurrence of the Cretaceous toothed bird Hesperornis Marsh." Canadian Journal of Earth Sciences, 11: 1335-1338.
  43. ^ "Table 6.1," in Weishampel, et al. (2004). Page 139.
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