Sauroposeidon
Outline reconstruction of Sauroposeidon and location of the four cervical vertebrae. Size compared to humans.
- Oklahoma, United States ( Antlers Formation)
- Sauroposeidon Proteles Wedel, Cifelli & Sanders, 2000
Sauroposeidon is a genus of sauropod dinosaur from the Lower Cretaceous of North America. The genus is placed in the group of Brachiosauridae and is closely related to the well known Jurassic genera Brachiosaurus and Giraffatitan.
From Sauroposeidon is merely a series of four very large cervical vertebrae known, the greatest of these is 1.4 meters long. These are the longest of all known vertebrate vertebrates. The fossils of this dinosaur were recovered in 1994 in the rural Oklahoma (USA ) and 2000 described as a new genus and species Sauroposeidon Proteles first time scientifically. The existence of Sauroposeidon in the Lower Cretaceous shows that large sauropods survived the transition from the Jurassic to the Cretaceous. About the anatomy and lifestyle of the genus can only be speculated because of the scanty tradition. Like all sauropods Sauroposeidon malnourished but probably of plants.
- 5.1 Height
- 5.2 posture and function of the neck
Features
Physique
Compared to other sauropods had the Brachiosauridae in proportion very long necks, short tails and long, slim limbs. Of all other sauropods, they differed by their extended front legs, which led to an increased shoulder and the animals given a giraffe -like appearance. Various Sauropodengruppen independently developed particularly long cervical spine, on the one hand by extending the cervical vertebrae, on the other hand, by transformation of the anterior dorsal vertebrae in the cervical vertebrae. Brachiosauriden maintained with 13 cervical vertebrae at the original number and lengthened the individual vertebrae. From Sauroposeidon only know the middle section of the neck from the fifth to the eighth cervical vertebra. The vertebrae resemble those of other Brachiosauriden as the Late Jurassic genera Brachiosaurus and Giraffatitan, but show a range of specialized, advanced features that other Brachiosauriden missing.
Description of the vertebral
The to-find all Brachiosauriden extension of the cervical vertebrae was extremely pronounced in Sauroposeidon. Thus, the vertebral bodies were more than five times longer than high. The vertebral bodies of the eighth cervical vertebra (C8) was about 1.25 meters long and has a total length of 1.4 meters of the vortex in this animal. This bone was almost one-third longer than the C8 at Giraffatitan, thus possessed Sauroposeidon the longest vertebrae among all known vertebrates.
The vertebrae are extremely light built by air-filled cavities and internal chambers - this recess of the bone is called pneumatization. In the living animal the cavities and chambers were probably filled by air bags, which were connected to the respiratory tract. The appearance of the vortex is characterized by large, bowl -like pit ( fossa ), which by thin bone bridges ( laminae ) are separated. These mines have the bone mass of the vertebrae drastically reduced, the cross section of the vortex is quite close to that of an I-beam. The extent of the pits is significantly larger than in related genera: To reach the lateral pits of the vertebral body to the rear end, as well, the spinous processes are hollowed deep.
Internally, the vortex completely by small, irregularly shaped, air-filled chambers ( pneumatic Camellae ) are recessed. These chambers are separated by thin bony partitions ( septa ) of each other, which vary in thickness from less than one to three millimeters. In contrast, the corresponding vertebrae in Brachiosaurus and Giraffatitan are mostly by large cavities ( pneumatic Camerae ), and only partially eroded by the significantly smaller Camellae.
The vertebrae are preserved along with their cervical ribs. These were also extended greatly and ran along the bottom of the spine to the back, the neck rib of each vertebra towered over the two consecutive vertebrae. The longest surviving cervical rib rises at the sixth cervical vertebra and measures 3.42 meters.
System
Sauroposeidon is regarded as a close relative of the Upper Jurassic genera Giraffatitan and Brachiosaurus. Direct comparisons are currently only possible with Giraffatitan because no cervical vertebrae are present that can be attributed Brachiosaurus doubt. Important common features between Sauroposeidon and Giraffatitan found on the spinous processes: These were not centered on the vortex, but were moved forward. In addition, the middle cervical spine showed an abrupt, step-like increase of the spinous processes between the sixth and seventh cervical vertebrae. Thus, the spinous process of the body distant sixth cervical vertebra was still low, while that of the body surrounding the seventh cervical vertebra was significantly higher and the height of the vertebral body exceeded. Other common features, such as the general shape of the vertebrae and the long cervical ribs have evolved independently in different Sauropodengruppen.
The genera Sauroposeidon, Giraffatitan and Brachiosaurus are summarized by many researchers as Brachiosauridae. Although a number of other members of this group have been assigned, but they are all very little is known. The Brachiosauridae form - as well as the Titanosauria - a group within the Titanosauriformes.
Sauropods have been handed down from the Lower Cretaceous of North America only by very sparse remains and belonged mostly to relatively small and short-necked representatives. However, have Wedel and colleagues ( 2000) on a single, poorly preserved cervical vertebrae from the Cloverly Formation through ( copy number YPM 5294 ), which could possibly belong to Sauroposeidon or a closely related genus. The vortex belonged to a young animal, is 47 inches long and shows a similar length - to-height ratio as that of Sauroposeidon. The expression of one of the laminae reminded of this genus. This finding also shows that cervical vertebrae could have been extended in animals strongly with low age already.
Research History and naming
The only fund comes from the land of the Arnold family farm in southwestern Atoka County, about 20 kilometers west of Antlers in rural Oklahoma. This farm and the adjoining grounds of the prison McLeod are already long been known for its dinosaur fossils; so derived, among others, the type material of Acrocanthosaurus described in 1950 from this area. Were discovered the vortex of Bobby Cross, an official of the prison, who was charged with the training of sniffer dogs. His work led Cross regularly throughout the grounds of the prison, where he had already significant dinosaur fossils can be found, including complete skeletons of Tenontosaurus.
When checking a hillside on the grounds of the adjoining farm of Arnold family, from the previously fossils have been recovered from Tenontosaurus, Cross remarked in May 1994, the out witter arising out of the rock remains of Sauroposeidon. Cross informed the Oklahoma Museum of Natural History on the new Fund, which organized two excavations in May and in August 1994 to recover the fossils. For transport, the wrapped in a plaster jacket vertebral series had to be cut into three parts, the largest of these parts weighed nearly three tons. The subsequent preparation of the fossil in the museum took three years to complete.
In 2000 Sauroposeidon was finally described by paleontologists Mathew Wedel, Richard Cifelli and Kent Sanders scientifically. That same year, followed by a more extensive publication of the anatomy, the relationships and the Paleobiology of this dinosaur. The researchers chose the name Sauroposeidon ( gr sauros - " lizard"; gr Poseidon - the god of earthquakes in Greek mythology), in order to emphasize the height of this animal. The second part of the species name ( gr Proteles - " perfected before the end " ) has the advanced blueprint of the vertebrae and the late appearance of this sauropod in the uppermost layers of the Lower Cretaceous, before Sauropodenfossilien of layers of the early Cretaceous in North America and Europe largely disappear. During this hiatus was previously interpreted in a temporarily regional extinction of sauropods, is now assumed that it is only due to lack of fossil preservation.
Paläohabitat, Geology of the discovery site and taphonomy
Sauroposeidon comes from the Antlers Formation, a predominantly composed of sand and mudstone formation that came to be deposited during the Lower Cretaceous Aptian and Albian in. This formation is disrupted in parts of Oklahoma, Texas and Arkansas - the narrow and elongated circulation area of the formation is characterized while the former course of the Gulf Coast after. At the time of deposition of this coast was probably dominated by forests, river deltas, lagoons and bayous. Except for the sauropods Sauroposeidon fossils of the formation are known only by vague, very fragmentary remains. The most common herbivores was the Ornithopod Tenontosaurus. Predatory Dinosaurs close the Dromaeosauriden Deinonychus and the large Carnosaurier Acrocanthosaurus with a. Besides dinosaurs crocodiles as Goniopholis pterosaurs as Istiodactylus, mammals such as Gobiconodon as well as turtles and fish have survived.
The site is officially documented under the name OMNH locality V821. He unlocks sandstones, probably belonging to the upper area of the central portion of the Antlers formation, which is estimated at this point to a thickness of about 150 meters. Other finds from this locality include teeth of Deinonychus remains of a small crocodile and a Tenontosaurus skeleton; these fossils were found about 20 meters from Sauroposeidon Fossil away.
It is unknown what happened to the rest of the skeleton. The four vertebrae were found lying in anatomical composite on the right side. The cervical ribs remained in their original position, indicating that the vortex of sediment were covered when they were still surrounded by flesh and muscle. Cervical ribs of the missing, the previous vortices are not present, indicating that the neck is not broken simply apart, but was pulled apart. Although the site was subject to a thorough examination and further excavations in 2005, no further indication of the Sauroposeidon skeleton had come for days.
Paleobiology
Height
Estimates of body measurements based on comparisons with closely related and better-known genera. Mathew Wedel and colleagues ( 2000) indicate that the cervical vertebrae 25-33 % longer than the corresponding vertebrae of the exhibited in the Berlin Museum of Natural History holotype specimen of Giraffatitan. The latter shows a skeletal neck length of 9 meters. If the neck of Sauroposeidon in its proportions of the possible Giraffatitan, he would have shown a length from 11.25 to 12 meters.
Estimates of the total body length and body weight are associated with a significant degree of inaccuracy, since no bones of the trunk are known. Mathew Wedel and colleagues ( 2000, 2005 ) note that the cervical vertebrae are indeed significantly longer than that of Giraffatitan, but only show a slightly larger diameter. These researchers therefore suspect that Sauroposeidon was greater only by 10 to 15 % as Giraffatitan, but had a relative significantly longer neck. The total body length could therefore have amounted to 28 meters, might have whereby the shoulder found in 6 or 7 meters high and the neck reaches a height of 17 or 18 feet, maybe even up to 20 meters. The weight is on the same perspective, these researchers their estimates: So the sauropod Mamenchisaurus would have shown an extremely long neck in combination with a relatively small hull, which means that the body may have increased in size to the same extent as the neck. Thus, it is even possible that Sauroposeidon had been smaller than the Berlin Giraffatitan instance. Another estimate by Kenneth Carpenter indicates a length of 34 meters.
Estimates of body weight, meanwhile, are fraught with even greater uncertainty, especially since the amount of the air bag system is not known. The average of five different weight estimates of the Berlin Giraffatitan skeleton is 40 tons. If the Body of Sauroposeidon the possible of Giraffatitan, the weight can be estimated based on this average to 50 to 60 tons. However, the researchers note that the neck was much thinner than that of Giraffatitan, and that this may be also applied to the body - in this case Sauroposeidon could even weighed less than the Berlin Giraffatitan instance.
Posture and function of the neck
The attitude of the neck in Brachiosauriden is controversial - different interpretations ranging from an approximately vertical to a horizontal position. Mathew Wedel and colleagues ( 2000) argue against a vertical neck position, because such an attitude would have required a strong curvature of the base of the neck, for which there was no evidence - on the contrary, the lowest cervical vertebrae of a Giraffatitan - discovery had been found in a straight line. Instead, the neck was directed obliquely upwards at Brachiosauriden as Sauroposeidon. The researchers also found that the mean cervical vertebrae sequence towards the head shows an abrupt reduction in the height of the spinous processes in both Giraffatitan as well as Sauroposeidon. The high spinous processes of the lower cervical vertebrae offered the back muscles an increased lever arm, which enabled a more upright posture this neck portion. The lack of high spinous processes in the body distant cervical vertebrae would, however, have a more horizontal attitude of this neck portion. Thus, the neck would have taken a slight S- curve.
Mathew Wedel and colleagues ( 2000) also discuss the function of the highly elongated neck of Sauroposeidon. One possible advantage of a very long neck would be the availability of food sources that other herbivores was not available - so the neck could have been developed as a result of competitive pressure by other herbivores. Wedel and colleagues consider this scenario unlikely, as the next largest herbivores of the Antlers Formation, the Ornithopod Tenontosaurus could graze only in up to three meters in height, while Sauroposeidon was possibly reach heights of up to 18 meters in position. Instead, the researchers pointed out that the prolonged neck led to an increased range, allowing more food could be accommodated without having to move the body. Thus could the extended neck of the restriction of mobility, which would have meant a life in the woods for such a large animal, have counteracted.