Judith River Formation

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Template:Short description Template:Infobox rockunit The Judith River Formation is a fossil-bearing geologic formation in Montana, and is part of the Montana Group. It dates to the Late Cretaceous, between 79 and 75.3 million years ago,[1] 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[2] and the Oldman Formation of Alberta.[3] 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

The Judith River Formation is composed of mudstone, siltstone and sandstone.[4] Coal beds, bentonite and coquinas are also observed.

File:Judith River Formation exposure-2.jpg
Judith River Formation, Upper Missouri Breaks National Monument

Relationship with other units

The Judith River Formation conformably overlies the Claggett Formation and Pakowki Formation. It is overlain by the Bearpaw Formation.[4] 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

File:Judith River Formation, Upper Missouri Breaks National Monument.jpg
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.[5] 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.[1]

Fauna

File:Judith River Fauna.jpg
Dinosaurs of Judith River Formation

Faunal list follows a review published by Ashok Sahni in 1972 unless otherwise noted.[6]

Template:Paleobiota-key-compact

Amphibians

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

Bony fish

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.[7]
Lepisosteus L. occidentalis Scales[8] A gar.
?Paralbula ?P. sp. A bonefish.
Priscosturion P. longipinnis McClelland Ferry[9] Upper Campanian[9] A sturgeon.
Psammorhynchus P. longipinnis McClelland Ferry[9] Upper Campanian[9] Preoccupied name, renamed Priscosturion.[10]
Polyodontidae Indeterminate A paddlefish. Known remains exceeded size of Chinese paddlefish, total length would exceed Template:Convert.[11]


Cartilaginous fish

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

Myledaphus

M. bipartitus

A stingray.

Cretalamna C. sp Montana An Otodontid shark
Carcharias Carcharias sp A sand tiger shark
Squalicorax S.kaupi An Anacoracid shark


Plesiosaurs

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

Plesiosauria[12]

Plesiosauria indet.

Pterosaurs

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

Azhdarchid[13]

Azhdarchidae indet.

Choristoderes

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

Champsosaurus

C. sp.

File:Champsosaurus BW.jpg
Champsosaurus

Crocodilians

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

Brachychampsa

B. montana

An alligatorid.
File:Brachychampsa NT small.jpg
Brachychampsa
File:Deinosuchus hatcheri.png
Deinosuchus

Leidyosuchus

L. canadensis

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

Lizards

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

Ankylosaurs

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

Hadrosaurs

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]

File:Brachylophosaurus NT.png
Brachylophosaurus
File:Probrachylophosaurus restoration.jpg
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,"[8] 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[8]

A dubious hadrosaurid

Marginocephalians

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

Albertaceratops

A. nesmoi[21]

Reclassified as Medusaceratops lokii

File:Avaceratops dinosaur.png
Avaceratops
File:Judiceratops NT small.jpg
Judiceratops
File:Furcatoceratops UDL.png
Furcatoceratops
File:Lokiceratops rangiformis.png
Lokiceratops
File:Medusaceratops NT.jpg
Medusaceratops
File:Mercuriceratops NT small.jpg
Mercuriceratops
File:Spiclypeus NT small.jpg
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
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.
File:Colepiocephale updating version.JPG
Colepiocephale
Hanssuesia H. sternbergi A pachycephalosaurid. Also present in the Dinosaur Park and Oldman Formations. Possible synonym of Stegoceras.
File:Hanssuesia sternbergi.jpg
Hanssuesia

Theropods

Dromaeosaurs

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

File:Dromaeosaurus Restoration.png
Dromaeosaurus
File:Saurornitholestes digging Burrows wahweap.jpg
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

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
File:Troodon formosus (feathers).JPG
Troodon

Troodon

T. formosus

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

Teeth (type specimen),[8][31] egg

A troodontid, possibly dubious.

Tyrannosaurs

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[6]

File:Daspletosaurus wilsoni profile.png
Daspletosaurus
File:Gorgosaurus flipped.png
Gorgosaurus

A. mirandus

Teeth, type specimen

Possible junior synonym of Deinodon horridus[6]

Daspletosaurus D. torosus Coal Ridge Maxilla[36] A large tyrannosaurid.
D. wilsoni[37] Jack’s B2 lower Coal Ridge[38] 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 [39]
D. sp. Coal Ridge[39] Partial skeleton[40] Not referrable to D. torosus[38]

Deinodon

D. falculus

Teeth

Isolated tyrannosaur teeth classified in the dubious genus Deinodon

D. hazenianus

Teeth

Junior synonym of Deinodon horridus[6]

D. horridus

"Teeth,"[8] type specimen

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

D. incrassatus

Teeth

Junior synonym of Deinodon horridus[6]

D. lateralis

Junior synonym of Deinodon horridus[6]

Gorgosaurus G. libratus Postorbital[36] A large tyrannosaurid, also found in the Dinosaur Park Formation and possibly the Two Medicine Formation.
?Tyrannosaurus T. sp. Fergus County A Lacrimal found alongside a specimen of Deinosuchus,[41] but may not be from the Judith River Formation[42]

Other Theropods

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.[43]

File:Hesperornis BW (white background).jpg
Hesperornis

Ornithomimus

O. tenuis

"Fragmentary metatarsal."[44]

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

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

References

Template:Reflist

Template:Western Canadian Sedimentary Basin

  1. ↑ a b Script error: No such module "Citation/CS1".
  2. ↑ 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.
  3. ↑ Script error: No such module "citation/CS1".
  4. ↑ a b Cite error: Invalid <ref> tag; no text was provided for refs named lexicon
  5. ↑ Script error: No such module "Citation/CS1".
  6. ↑ 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.
  7. ↑ Script error: No such module "Citation/CS1".
  8. ↑ a b c d e Script error: No such module "Citation/CS1".
  9. ↑ a b c d Script error: No such module "Citation/CS1".
  10. ↑ Script error: No such module "Citation/CS1".
  11. ↑ Script error: No such module "Citation/CS1".
  12. ↑ Script error: No such module "citation/CS1".
  13. ↑ Script error: No such module "citation/CS1".
  14. ↑ Script error: No such module "citation/CS1".
  15. ↑ Script error: No such module "Citation/CS1".
  16. ↑ Script error: No such module "citation/CS1".
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  18. ↑ a b c d e "Table 20.1," in Weishampel, et al. (2004). Page 442.
  19. ↑ Script error: No such module "Citation/CS1".
  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 Script error: No such module "Citation/CS1".
  25. ↑ a b Script error: No such module "Citation/CS1".
  26. ↑ a b Script error: No such module "Citation/CS1".
  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. Template:ISBN.
  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
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  31. ↑ a b c d e f g h i j Script error: No such module "Citation/CS1".
  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 Script error: No such module "Citation/CS1".
  37. ↑ Script error: No such module "Citation/CS1".
  38. ↑ a b Script error: No such module "Citation/CS1".
  39. ↑ a b Script error: No such module "Citation/CS1".
  40. ↑ Maltese, Anthony E. "DIFFICULT EXCAVATION AND PREPARATION OF A LARGE DASPLETOSAURUS SPECIMEN." Methods in Preparation: 63.
  41. ↑ Script error: No such module "Citation/CS1".
  42. ↑ Script error: No such module "Citation/CS1".
  43. ↑ Fox, R.C. (1974). "A middle Campanian, nonmarine occurrence of the Cretaceous toothed bird Hesperornis Marsh." Canadian Journal of Earth Sciences, 11: 1335-1338.
  44. ↑ "Table 6.1," in Weishampel, et al. (2004). Page 139.
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