Cedarosaurus

Cedarosaurus (meaning "Cedar lizard" - named after the Cedar Mountain Formation, in which it was discovered) was a nasal-crested macronarian dinosaur genus from the Early Cretaceous Period (Barremian). It was a sauropod which lived in what is now Utah. It was first described by Tidwell, Carpenter and Brooks in 1999.[1]

It shows similarities to the brachiosaurid Eucamerotus from the Wessex Formation of southern England, as well as to Brachiosaurus from the Morrison Formation.

Cedarosaurus
Temporal range: Early Cretaceous, 126 Ma
Cedarosaurus SW
Life restoration
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Sauropodomorpha
Clade: Sauropoda
Family: Brachiosauridae
Genus: Cedarosaurus
Tidwell et al., 1999
Species:
C. weiskopfae
Binomial name
Cedarosaurus weiskopfae
Tidwell et al., 1999

Description

Cedarosaurus Scale
Size comparison

Cedarosaurus had a more gracile ulna and radius than its relative Venenosaurus.[2] The ratio of the radius' least circumference to its length is .31 in Cedarosaurus. Metatarsal II is more gracile in Cedarosaurus.[2]

Its middle tail vertebrae's neural spines are angled anteriorly when the vertebrae are aligned.[3] These vertebrae resemble those of Gondwanatitan, Venenosaurus, and Aeolosaurus.[3]

The related Venenosaurus had unusual lateral fossae, which looked like deep depressions in the outside walls of the vertebral centra.[4] Some fossae are divided into two chambers by a ridge inside the depression.[4] In most sauropods the fossae would form pneumatic openings leading to the interior of the centrum, rather than just being a depression.[4] Less well-developed, but similar fossae are known from Cedarosaurus itself.[4]

Palaeobiology

In 2001 Frank Sanders, Kim Manley, and Kenneth Carpenter published a study on 115 gastroliths discovered in association with a Cedarosaurus specimen.[5] The stones were identified as gastroliths on the basis of their tight spatial distribution, partial matrix support, and an edge-on orientation indicative of their being deposited while the carcass still had soft tissue.[5] Their high surface reflectance values are consistent with other known dinosaur gastroliths.[5] Nearly all of the Cedarosaurus gastroliths were found within a .06 m volume of space in the gut region of the skeleton.[6]

The total mass of the gastroliths themselves was 7 kilograms (15 lb).[7] Most were less than 10 millilitres (0.35 imp fl oz; 0.34 US fl oz) in volume.[8] The least massive clast was .1 grams (0.0035 oz) and the most was 715 grams (25.2 oz), with most of them being toward the smaller end of that range.[8] The clasts tended to be close to spherical in shape, although the largest specimens were also the most irregular.[8] The largest gastroliths contributed the most to the total surface area of the set.[9] Some gastroliths were so large and irregularly shaped that they may have been difficult to swallow.[9] The gastroliths were mostly composed of chert, with some sandstone, siltstone, and quartzite clasts also included.[10] Some of the chert clasts actually contained fossils.[10]

Since some of the most irregular gastroliths are also the largest, it is unlikely that they were ingested by accident.[9] Cedarosaurus may have found irregular clasts to be attractive potential gastroliths or was not selective about shape.[9] The clasts were generally of dull coloration, suggesting that color was not a major factor for the sauropod's decision making.[5] The high surface area to volume ratio of the largest clasts suggests that the gastroliths may have broken down ingested plant material by grinding or crushing it[11] The sandstone clasts tended to be fragile and some broke in the process of collection.[10] The sandstone gastroliths may have been rendered fragile after deposition by loss of cement caused by the external chemical environment.[12] If the clasts had been that fragile while the animal was alive, they probably rolled and tumbled in the digestive tract.[11] If they were more robust, they could have served as part of a ball-mill system.[11]

Footnotes

  1. ^ Tidwell, et al. (1999).
  2. ^ a b "Discussion," Tidwell, Carpenter, and Meyer (2001). Page 157.
  3. ^ a b "Caudal Vertebrae," Tidwell, Carpenter, and Meyer (2001). Page 146.
  4. ^ a b c d "Caudal Vertebrae," Tidwell, Carpenter, and Meyer (2001). Page 147.
  5. ^ a b c d "Abstract," in Sanders et al. (2001). Pg. 166.
  6. ^ "Occurrence in Cedarosaurus," in Sanders et al. (2001). Pg. 169.
  7. ^ "Table 12.2," in Sanders et al. (2001). Pg. 171.
  8. ^ a b c "Description," in Sanders et al. (2001). Pg. 172.
  9. ^ a b c d "Description," in Sanders et al. (2001). Pg. 174.
  10. ^ a b c "Description," in Sanders et al. (2001). Pg. 176.
  11. ^ a b c "Description," in Sanders et al. (2001). Pg. 177.
  12. ^ "Conclusion," in Sanders et al. (2001). Pg. 177.

References

  • Sanders, F.; Manley, K.; Carpenter, K. (2001). "Gastroliths from the Lower Cretaceous sauropod Cedarosaurus weiskopfae". In Tanke, Darren; Carpenter, Ken (eds.). Mesozoic Vertebrate Life: New Research Inspired by the Paleontology of Philip J. Currie. Indiana University Press. pp. 166–180. ISBN 0-253-33907-3.
  • Tidwell, V., Carpenter, K. and Brooks, W. (1999). "New sauropod from the Lower Cretaceous of Utah, USA". Oryctos 2: 21-37
  • Tidwell, V., Carpenter, K. & Meyer, S. 2001. New Titanosauriform (Sauropoda) from the Poison Strip Member of the Cedar Mountain Formation (Lower Cretaceous), Utah. In: Mesozoic Vertebrate Life. D. H. Tanke & K. Carpenter (eds.). Indiana University Press, Eds. D.H. Tanke & K. Carpenter. Indiana University Press. 139-165.

External links

Brachiosauridae

The Brachiosauridae ("arm lizards", from Greek brachion (βραχίων) = "arm" and sauros = "lizard") are a family or clade of herbivorous, quadrupedal sauropod dinosaurs. Brachiosaurids had long necks that enabled them to access the leaves of tall trees that other sauropods would have been unable to reach. In addition, they possessed thick spoon-shaped teeth which helped them to consume tough plants more efficiently than other sauropods. They have also been characterized by a few unique traits or synapomorphies; dorsal vertebrae with 'rod-like' transverse processes and an ischium with an abbreviated pubic peduncle.Brachiosaurus is one of the best-known members of the Brachiosauridae, and was once thought to be the largest land animal to ever live. Brachiosaurids thrived in the regions which are now North and South America, Africa, Europe, and Asia. They first appear in the fossil record in the Late Jurassic Period and disappear in the late Early Cretaceous Period. The broad distribution of Brachiosauridae in both northern and southern continents suggests that the group originated prior to the breakup of Pangaea. In the Early Cretaceous the distribution of the group is dramatically reduced. It is still unclear whether this reduction is due to local extinctions or to the limited nature of the Early Cretaceous fossil record.Brachiosauridae has been defined as all titanosauriforms that are more closely related to Brachiosaurus than to Saltasaurus. It is one of the three main groups of the clade Titanosauriformes, which also includes the Euhelopodidae and the Titanosauria.

Brasilotitan

Brasilotitan is a genus of titanosaurian sauropod dinosaur from the Late Cretaceous (early Maastrichtian) Adamantina Formation of Brazil. The type species is Brasilotitan nemophagus.

Cedar Mountain Formation

The Cedar Mountain Formation is the name given to a distinctive sedimentary geologic formation in eastern Utah. The formation was named for Cedar Mountain in northern Emery County, Utah, where William Lee Stokes first studied the exposures in 1944.

Dinheirosaurus

Dinheirosaurus is a genus of diplodocid sauropod dinosaur that is known from fossils uncovered in modern-day Portugal. It may represent a species of Supersaurus. The only species is Dinheirosaurus lourinhanensis, first described by José Bonaparte and Octávio Mateus in 1999 for vertebrae and some other material from the Lourinhã Formation. Although the precise age of the formation is not known, it can be dated around the early Tithonian of the Late Jurassic.

The known material includes two cervical vertebrae, nine dorsal vertebrae, a few ribs, a fragment of a pubis, and many gastroliths. Of the material, only the vertebrae are diagnostic, with the ribs and pubis being too fragmentary or general to distinguish Dinheirosaurus. This material was first described as in the genus Lourinhasaurus, but differences were noticed and in 1999 Bonaparte and Mateus redescribed the material under the new binomial Dinheirosaurus lourinhanensis. Another specimen, ML 418, thought to be Dinheirosaurus, is now known to be from another Portuguese diplodocid. This means that Dinheirosaurus lived alongside many theropods, sauropods, thyreophorans and ornithopods, as well as at least one other diplodocid.

Dinheirosaurus is a diplodocid, a relative of Apatosaurus, Diplodocus, Barosaurus, Supersaurus, and Tornieria. Among those, the closest relative to Dinheirosaurus is Supersaurus.

Diplodocinae

Diplodocinae is an extinct subfamily of diplodocid sauropods that existed from the Late Jurassic to Early Cretaceous of North America, Europe and South America, about 161.2 to 136.4 million years ago. Genera within the subfamily include Tornieria, Supersaurus, Leinkupal, Galeamopus, Diplodocus, Kaatedocus and Barosaurus.Cladogram of the Diplodocidae after Tschopp, Mateus, and Benson (2015).

Europasaurus

Europasaurus is a basal macronarian sauropod, a form of quadrupedal herbivorous dinosaur. It lived during the Late Jurassic (middle Kimmeridgian, about 154 million years ago) of northern Germany, and has been identified as an example of insular dwarfism resulting from the isolation of a sauropod population on an island within the Lower Saxony basin.

Ferganasaurus

Ferganasaurus was a genus of dinosaur first formally described in 2003 by Alifanov and Averianov. The type species is Ferganasaurus verzilini. It was a sauropod similar to Rhoetosaurus. The fossils were discovered in 1966 in Kyrgyzstan from the Balabansai Formation and date to the Callovian stage of the Middle Jurassic.

Flagellicaudata

Flagellicaudata is a clade of Dinosauria. It belongs to Sauropoda and includes two families, the Dicraeosauridae and the Diplodocidae.

Gastrolith

A gastrolith, also called a stomach stone or gizzard stone, is a rock held inside a gastrointestinal tract. Gastroliths in some species are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. In other species the rocks are ingested and pass through the digestive system and are frequently replaced. The grain size depends upon the size of the animal and the gastrolith's role in digestion. Other species use gastroliths as ballast. Particles ranging in size from sand to cobble have been documented.

Gondwanatitan

Gondwanatitan (meaning "giant from Gondwana") was a titanosaurian sauropod dinosaur. Gondwanatitan was found in Brazil, at the time part of the southern supercontinent Gondwana, in the late Cretaceous Period (70 mya). Like some other sauropods, Gondwanatitan was tall and ate tough shoots and leaves off of the tops of trees. G. faustoi's closest relative was Aeolosaurus.

The type species is Gondwanatitan faustoi, formally described by Kellner and de Azevedo in 1999.

Gravisauria

Gravisauria is a clade of sauropod dinosaurs consisting of some genera, Vulcanodontidae and Eusauropoda.

Huangshanlong

Huangshanlong is a genus of mamenchisaurid dinosaurs native to the Anhui province of China. It contains a single species, Huangshanlong anhuiensis. H. anhuiensis represents, along with Anhuilong and Wannanosaurus, one of three dinosaurs fround in Anhui province.

Kaijutitan

Kaijutitan (meaning "Kaiju titan" after the type of Japanese movie monsters) is a genus of basal titanosaur dinosaur from the Sierra Barrosa Formation from Neuquén Province in Argentina. The type and only species is Kaijutitan maui.

Laurasiformes

Laurasiformes (meaning "Laurasian forms") is an extinct clade of sauropod dinosaurs from the late Early Cretaceous of Europe, North and South America. It was defined in 2009 by the Spanish paleontologist Rafael Royo-Torres as a clade containing sauropods more closely related to Tastavinsaurus than to Saltasaurus. Genera purported to form part of this clade include Aragosaurus, Galvesaurus, Phuwiangosaurus, Venenosaurus, Cedarosaurus, Tehuelchesaurus, Sonorasaurus and Tastavinsaurus.Its exact position and validity is uncertain and varies between authors. A cladistics analysis found a similar grouping outside Titanosauriformes and basal within the Camarasauromorpha, while others have placed them inside Somphospondyli or Brachiosauridae, consequently, it has been suggested that Tehuelchesaurus along with others of the previously mentioned genera, form two different clades outside titanosauriformes (Carbadillo et al., 2011) while a more recent cladistics analysis found no support for the existence of the clade, with a revision of its supporting features finding them problematic due to being poorly defined, not present on most of the "laurasiforms" or being features present in many sauropods of other clades.

Padillasaurus

Padillasaurus is an extinct genus of titanosauriform sauropod known from the Early Cretaceous (Barremian stage) Paja Formation in Colombia. It contains a single species, Padillasaurus leivaensis, known only from a single partial axial skeleton. Initially described as a brachiosaurid, it was considered to be the first South American brachiosaurid ever discovered and named. Before its discovery, the only known brachiosaurid material on the continent was very fragmentary and from the Jurassic period. However, a more recent study finds it to be a basal somphospondylan.

Pilmatueia

Pilmatueia is a diplodocoid sauropod belonging to the family Dicraeosauridae that lived in Argentina during the Early Cretaceous.

Ruyangosaurus

Ruyangosaurus (Ruyang County lizard) is a genus of titanosauriform sauropod dinosaur recovered from the Early Cretaceous Haoling Formation of China. The type species is R. giganteus, described in 2009 by Lü Junchang et al. Along with Huanghetitan and Daxiatitan, Ruyangosaurus is among the largest dinosaurs discovered in Cretaceous Asia.

Soriatitan

Soriatitan ("Soria titan") is a genus of brachiosaurid sauropod from the Early Cretaceous of Spain. It is known from one species, S. golmayensis, found in the Golmayo Formation. It lived between 138 to 130 million years ago was identified by a team of paleontologists in Spain.

Venenosaurus

Venenosaurus ( ven-EN-o-SOR-əs) was a sauropod dinosaur, named after the Poison Strip Member of the Cedar Mountain Formation in Utah, United States, where the fossils were discovered by a Denver Museum of Natural History volunteer Tony DiCroce in 1998. Venenosaurus dicrocei was first described as a new species in 2001 by Virginia Tidwell, Kenneth Carpenter, and Suzanne Meyer. Venenosaurus is a relatively small (probably around 10 m (33 ft) long) titanosauriform sauropod, known from an incomplete skeleton of an adult and a juvenile. The holotype is DMNH 40932 Denver Museum of Natural History. The specimen consisted of tail vertebrae, the left scapula, right radius, left ulna, metacarpals, forefoot phalanges, right pubis, left and right ischia, metatarsals, chevrons, and ribs.

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