Late Cretaceous Campanian

Judith River Formation

83 - 74 mya  

from the Dinosaur Collector  updated 09/12/08

The Judith River Group at Dinosaur Provincial Park is an example of a very high diversity dinosaur assemblage; no known community anywhere demonstrates a comparable diversity. In the Campanian of Judith River of Alberta, common horned dinosaurs are the chasmosaurine, Chasmosaurus, the the centrosaurines Styracosaurus and Monoclonius.   Centrosaurus and Anchiceratops were also present.

Albertosaurus at 27 feet long, was a smaller version of Tyrannosaurus, lighter and probably faster, with puny arms but more teeth in a relatively broad snout. It probably preyed upon hadrosaurs and Stegoceras.  It may have been been displaced when Tyrannosaurus migrated from Asia later in the Cretaceous. Struthiomimus had drooping front legs with long toes.  It had powerful curved claws on fingers and lived on river banks, forests, sandy plains and humid lowlands. It had a long toothless jaw similar to modern birds, and may have had a horny beak and perhaps also ate plants. It was perhaps able to run at up to 40 km/h

Schleich Styracosaurus and Albertosaurus with a  Kabaya Struthiomimus.

Chasmosaurus (Cleft Lizard) wide spread medium size (17 feet) animal in Western US. Several species have been identified based on differences in the horn sizes.  One the  best known dinosaurs with many complete skeletons.  Possibly the ancestor to Torosaurus that show up later in the same ranges. Chasmosaurus and Euplocephalus from the Oriental Trading company.  Chasmosaurus has not been a common subject for toy companies.  Triceratops and Styracosaurus filled the need for a horned dinosaur in most lines.  Note the Oriental Trading company version actually is labeled Styracosaurus.   Parasaurolophus from the Kinto My Favorite Collection made available through the generosity of Healthstones hobbies.

Styracosaurus was a relatively small at 18 feet, it was a  horned dinosaur with a greatly extended neck frill and prominent nose horn.  Large bone beds of centrosaurine and chamosaurine dinosaurs indicated that that at least at certain times they gathered together in great herds possibly for migrations like today's Caribou or Wildebeests.

The excellent Battat and a similar looking Waiphoon hollow vinyl Styracosaurus.  Both figures follow the Marx style reconstruction.

Styracosaurus (Spiked Lizard) is though to be a herding animal like its relative Centrosasurus.

Bullyland Styracosaurus.

The best known of the ostrich dinosaurs is Struthiomimus.  It was toothless and fast and about 12 feet long..

 The Struthiomimus  is from the second series of Choc Egg figures.

Horned dinosaurs are dived into two major families the centrosaurines with Styracosasurus being the most popular and the chamosaurines that include the bigger and later Triceratops.  The centrosaurines had large nasal horns and small frills generally.  Chasmosasurines tended to have large frills and horns over the eyes being prominent.   The Wild Safari Styracosaurus is a robust figure.  Also included in the gray bin style vinyl figure from China. 

Monoclonius one of the larger horned dinosaurs.  The animals may have been very aggressive, based on a Pachyrhinosaurus skull with a severe head injury, evidence for which was apparent in that an extensive defect had scarred the right side of the face. It was determined that the animal most likely to have caused such a wound was a specimen of  Monoclonius; 

Left is the Marolin Monoclonius from Germany.  The original figures were created in the 1920's but later reproduced by the East German Leipzig Museum.

Fossils are rare and most restorations are based on the better known Centrosaurus.    The main difference being the lack of hooks at the top of the frill characteristic of Centrosaurus.  Centosaurines disappear from fossil record in the later Maastrichtian.

Starlux Centrosaurus.

Pachycephalosaur's belong to the Marginocephalia.  The Marginocephalia ("fringed heads") are a clade of  two main subgroups o the "bone-headed" pachycephalosaurs and the frilled ceratopsians.   Judith River has produced 2 bone heads Gravitholus and Stegoceras both about 10 feet long and mostly known from skulls.  Like many other smaller dinosaurs they may have lived in the uplands where few fossils are preserved. FameMaster 4D Pachycephalosaurus thanks to the of the Dinosaur Farm.   The  AAA Edmontonia sent by Sean Bell.

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