Giraffatitan
Giraffatitan | |
---|---|
Mounted skeleton, Berlin's Natural History Museum | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | †Sauropodomorpha |
Clade: | †Sauropoda |
Clade: | †Macronaria |
Family: | †Brachiosauridae |
Genus: | †Giraffatitan Paul, 1988 |
Type species | |
†Giraffatitan brancai | |
Synonyms | |
Genus synonymy[2]
Species synonymy
|
Giraffatitan (name meaning "titanic
Giraffatitan was for many decades known as the largest dinosaur but recent discoveries of several larger dinosaurs prove otherwise; giant
History of discovery
In 1906, mining engineer Bernhard Wilhelm Sattler, while travelling, noticed an enormous bone jutting out of the ground at the Tendaguru (the "steep hill") near
Fraas had observed that the Tendaguru layers were exceptionally rich in fossils. After his return to Germany he tried to raise enough money for a major expedition. He managed to attract the interest of Professor
The expedition initially employed about 160 native
The most important source of Giraffatitan fossils would be "Site S" at one kilometre southwest of the hill. Excavations started on 11 October 1909 and continued well into 1912. In 1909 limb and girdle elements were dug up. During 1910, a cut bank of the Kitukituki river was gradually deepened, removing a high overburden. To prevent the quarry walls from collapsing, they were covered by a high wooden framework. That year, first several ribs were uncovered and later part of the vertebral column. In October, close to some neck vertebrae a skull and lower jaws were discovered. From 5 June 1912 onwards more neck and trunk vertebrae were found. Initially it was thought that a single skeleton was being uncovered. Only much later Janensch realised that two skeletons had been present. Skelett SI was represented by a skull, six neck vertebrae and some back vertebrae. Skelett SII was larger but despite its size still a subadult individual. It included skull bones, a series of eleven neck and eleven back vertebrae, ribs, the left scapula, both coracoids, both forelimbs, the pubic bones and the right hindlimb. The sacrum and the tail had been lost to relatively recent erosion. The animal was found in an upright position with vertical limbs, which has been explained by its becoming mired in mud.[16]
In early October 1909, "Site ab" was excavated, 1.2 kilometres northeast of the hill. Among disarticulated remains of many sauropods, also two Giraffatitan thighbones were collected. A gigantic possible humerus was too damaged to be salvaged. "Site cc", 2.9 kilometres northeast of the hill, contained a disarticulated Giraffatitan skeleton including neck vertebrae, a trunk vertebra, ribs, a scapula and a humerus. In 1910, another Giraffatitan quarry was opened, "Site Y" at 3.1 kilometres north of the Tendaguru Hill. It contained the skeleton of a medium-sized individual including a braincase, a series of eight neck vertebrae, a trunk vertebra, ribs, both scapulae, a coracoid, a left humerus and a left fibula.[16]
A partial skeleton called "Skelett Y" (skeleton Y) was discovered in quarry "Y". On the basis of its scapula (shoulder blade) and humerus (upper arm bone) Brachiosaurus fraasi was erected, which later turned out to be a junior synonym of B. brancai. From quarry "D" came 23 vertebrae articulated with a sacrum (a hip bone), from quarry "Aa" another 18 vertebrae with a sacrum, from quarry "no" 50 articulated tail vertebrae, from GI 16 tail vertebrae and a number of limb bones, and much more material from other places, including many limb elements.
The quarries listed above represent only the most important sites where bones were found. In dozens of other Tendaguru locations, finds were made of large single sauropod bones that were referred to the taxon in Janensch's publications but of which no field notes survive so that the precise circumstances of the discoveries are unknown. Partly this reflects a lack of systematic documentation by the expedition. Many documents were destroyed by an allied bombardment in 1943. Part of the fossils were also lost. Nevertheless, most of the skeleton is known.[17]
Giraffatitan brancai was first named and described by German paleontologist Werner Janensch in 1914 as Brachiosaurus brancai, based on several specimens recovered between 1909 and 1912 from the
Originally, the Tedaguru "Skelett S" was thought by Janensch to stem from one animal, and to be very similar to the North American genus Brachiosaurus. Therefore, Janensch described it as Brachiosaurus brancai, choosing the species name in honor of
A famous specimen of Giraffatitan brancai mounted in the Berlin's Natural History Museum is one of the largest, and in fact the tallest, mounted skeletons in the world, as certified by the Guinness Book of Records. Beginning in 1909, Werner Janensch found many additional G. brancai specimens in Tanzania, Africa, including some nearly complete skeletons, and used them to create the composite mounted skeleton seen today.
Separation from Brachiosaurus
In 1988 Gregory S. Paul published a new reconstruction of the skeleton of B. brancai, highlighting differences in proportion between it and B. altithorax. Chief among them was a distinction in the way the trunk vertebrae vary: they are fairly uniform in length in the African material, but vary widely in B. altithorax. Paul believed that the limb and girdle elements of both species were very similar, and therefore suggested they be separated not at genus, but only at subgenus level, as Brachiosaurus (Brachiosaurus) altithorax and Brachiosaurus (Giraffatitan) brancai.[18] Giraffatitan was raised to full genus level by George Olshevsky in 1991, while referring to the vertebral variation.[19] Between 1991 and 2009, the name Giraffatitan was almost completely disregarded by other researchers.[17]
A detailed 2009 study by Taylor of all material, including the limb and girdle bones, found that there are significant divergences between B. altithorax and the Tendaguru material in all elements known from both species. Taylor found twenty-six distinct osteological (bone-based) characters, a larger difference than between Diplodocus and Barosaurus, and therefore argued that the African material should indeed be placed in its own genus (Giraffatitan) as Giraffatitan brancai.[17] An important contrast between the two genera is their overall body shape, with Brachiosaurus having a 23 percent longer dorsal vertebral series and a 20 to 25 percent longer and also taller tail.[17] The split was rejected by Daniel Chure in 2010,[20] but from 2012 onward most studies recognized the name Giraffatitan.[21]
Description
Size
Between 1914 and the 1990s, Giraffatitan was claimed to be the
All size estimates for Giraffatitan are based on the skeleton mounted in Berlin, which is partly constructed from authentic bones. These were largely taken from specimen HMN SII,
More recent estimates based on models reconstructed from bone volume measurements, which take into account the extensive, weight-reducing airsac systems present in sauropods, and estimated muscle mass, are in the range of 23.3–39.5 tonnes (25.7–43.5 short tons).
However, HMN SII is not the largest specimen known (an assertion supported by its subadult status) but HMN XV2, represented by a fibula 13% larger than the corresponding material on HMN SII,[17] which might have attained 26 metres (85 ft) in length.[33] Gregory S. Paul initially estimated the size of this specimen at 25 metres (82 ft) in total length, 16 metres (52 ft) in total height and 45 metric tons (50 short tons) in body mass,[18] but later moderated at 23 metres (75 ft) in total length and 40 metric tons (44 short tons) in body mass.[34] In 2020, Molina-Perez and Larramnedi estimated the size of the HMN XV2 specimen at 25 metres (82 ft) and 48 tonnes (53 short tons), with a shoulder height of 6.8 metres (22 ft).[2]
General build
Giraffatitan was a sauropod, one of a group of
Skull
Traditionally, the distinctive high-crested skull was seen as a characteristic of the genus Brachiosaurus, to which Giraffatitan brancai was originally referred; however, it is possible that Brachiosaurus altithorax did not show this feature, since within the traditional Brachiosaurus material it is known only from Tanzanian specimens now assigned to Giraffatitan.
The placement of Giraffatitan nostrils has been the source of much debate with Witmer (2001) describing in Science the hypothesized position of the fleshy nostrils in Giraffatitan in as many as five possible locations. Comparing the nares of dinosaurs with those of modern animals, he found that all species have their external nostril openings in the front, and that sauropods like Giraffatitan did not have nostrils on top of their heads, but near their snouts.[35] There has also been the hypothesis of various sauropods, such as Giraffatitan, possessing a trunk. The fact that there were no narrow-snouted sauropods (Giraffatitan included) tends to discredit such a hypothesis. Stronger evidence for the absence of a trunk is found in the teeth wear of Giraffatitan, which shows the kind of wear that would result from biting and tearing off of plant matter rather than purely grinding, which would be the result of having already ripped the leaves and branches off with a trunk.[36]
Classification
When describing Brachiosaurus brancai and B. fraasi in 1914, Janensch observed that the unique elongation of the humerus was shared by all three Brachiosaurus species as well as the British Pelorosaurus. He also noted this feature in Cetiosaurus, where it was not as strongly pronounced as in Brachiosaurus and Pelorosaurus.[1] Janensch concluded that the four genera must have been closely related to each other, and in 1929 assigned them to a subfamily Brachiosaurinae within the family Bothrosauropodidae.[37]
During the twentieth century, several sauropods were assigned to Brachiosauridae, including Astrodon,
Many cladistic analyses have since suggested that at least some genera can be assigned to the Brachiosauridae, and that this group is a basal branch within the Titanosauriformes.[45] The exact status of each potential brachiosaurid varies from study to study. For example, a 2010 study by Chure and colleagues recognized Abydosaurus as a brachiosaurid together with Brachiosaurus, which in this study included B. brancai.[20] In 2009, Taylor noted multiple anatomical differences between the two Brachiosaurus species, and consequently moved B. brancai into its own genus, Giraffatitan. In contrast to earlier studies, Taylor treated both genera as distinct units in a cladistic analysis, finding them to be sister groups. Another 2010 analysis focusing on possible Asian brachiosaurid material found a clade including Abydosaurus, Brachiosaurus, Cedarosaurus, Giraffatitan and Paluxysaurus, but not Qiaowanlong, the putative Asian brachiosaurid.[45] Several subsequent analyses have found Brachiosaurus and Giraffatitan not to be sister groups, but instead located at different positions on the evolutionary tree. A 2012 study by D'Emic placed Giraffatitan in a more basal position, in an earlier branch, than Brachiosaurus,[42] while a 2013 study by Philip Mannion and colleagues had it the other way around.[21]
A 2012 study on
In their 2024 description of Gandititan, Han et al. analyzed the phylogenetic relations of Macronaria, focusing on titanosauriform taxa. They recovered Giraffatitan as the sister taxon to Sonorasaurus, similar to some previous analyses,[47] in a clade also containing Brachiosaurus. The results of their phylogenetic analyses are shown in the cladogram below:[48]
Macronaria |
| |||||||||||||||||||||||||||||||||
Paleobiology
The
Brain
Giraffatitan's
Nostril function
The bony nasal openings of
Czerkas speculated on the function of the peculiar brachiosaurid nose, and pointed out that there was no conclusive way to determine where the nostrils where located, unless a head with skin impressions was found. He suggested that the expanded nasal opening would have made room for tissue related to the animal's ability to smell, which would have helped smell proper vegetation. He also noted that in modern reptiles, the presence of bulbous, enlarged, and uplifted nasal bones can be correlated with fleshy horns and knobby protuberances, and that Brachiosaurus and other sauropods with large noses could have had ornamental nasal crests.[52]
It has been proposed that sauropods, including Giraffatitan, may have had proboscises (trunks) based on the position of the bony narial orifice, to increase their upward reach. Fabien Knoll and colleagues disputed this for Diplodocus and Camarasaurus in 2006, finding that the opening for the facial nerve in the braincase was small. The facial nerve was thus not enlarged as in elephants, where it is involved in operating the sophisticated musculature of the proboscis. However, Knoll and colleagues also noted that the facial nerve for Giraffatitan was larger, and could therefore not discard the possibility of a proboscis in this genus.[53]
Metabolism
If Giraffatitan was endothermic (
Paleoenvironment
Giraffatitan lived in what is now Tanzania in the Late Jurassic Tendaguru Formation.[57] Since 2012, the boundary between the Kimmeridgian and Tithonian is dated at 152.1 million years ago.[58]
The Tendaguru
Giraffatitan would have coexisted with fellow
See also
References
- ^ a b c d e Janensch, W. (1914). "Übersicht über der Wirbeltierfauna der Tendaguru-Schichten nebst einer kurzen Charakterisierung der neu aufgeführten Arten von Sauropoden". Archiv für Biontologie. 3 (1): 81–110.
- ^ a b Molina-Perez & Larramendi (2020). Dinosaur Facts and Figures: The Sauropods and Other Sauropodomorphs. New Jersey: Princeton University Press. p. 259.
- ^ Maier (2003), p 1
- ^ Maier (2003), p 3
- ^ Maier (2003), p 8
- ^ Maier (2003), p 10
- ^ Maier (2003), p 11–12
- ^ Maier (2003), p 15
- ^ Maier (2003), p 16
- ^ Maier (2003), p 17
- ^ Maier (2003), p 18
- ^ Maier (2003), p 19
- ^ Maier (2003), p 22
- ^ Maier (2003), p 23
- ^ Tamborini, Marco & Mareike Vennen (2017) Disruptions and changing habits: The case of the Tendaguru expedition, Museum History Journal, 10:2, 183–199.
- ^ .
- ^ S2CID 15220647.
- ^ a b c d Paul, G.S. (1988). "The brachiosaur giants of the Morrison and Tendaguru with a description of a new subgenus, Giraffatitan, and a comparison of the world's largest dinosaurs" (PDF). Hunteria. 2 (3): 1–14. Archived (PDF) from the original on 27 June 2022.
- ^ Olshevsky, G. (1991). "A revision of the parainfraclass Archosauria Cope, 1869, excluding the advanced Crocodylia" (PDF). Mesozoic Meanderings. 2: 1–196. Archived from the original (PDF) on 19 August 2018. Retrieved 14 April 2018.
- ^ PMID 20179896.
- ^ .
- ^ S2CID 56028251.
- ^ a b Janensch, W. (1950). "The Skeleton Reconstruction of Brachiosaurus brancai" (PDF). Palaeontographica: 97–103.
- ^ Colbert, E. (1962). "The weights of dinosaurs". American Museum Novitates (2076): 1–16.
- ^ Russell, D.; Béland, P.; McIntosh, J.S. (1980). "Paleoecology of the dinosaurs of Tendaguru (Tanzania)". Mémoires de la Société Géologique de France. 59: 169–175.
- .
- .
- JSTOR 4523591.
- .
- .
- S2CID 23454835.
- S2CID 16100066.
- ^ Holtz, Thomas R. Jr. (2008) Dinosaurs: The Most Complete, Up-to-Date Encyclopedia for Dinosaur Lovers of All Ages Supplementary Information
- OCLC 985402380.
- S2CID 7328047. Archived from the original(PDF) on 6 September 2013.
- ^ Naish, D. (20 March 2009). "Junk in the trunk: why sauropod dinosaurs did not possess trunks". ScienceBlogs. Archived from the original on 13 January 2012.
- Palaeontographica(in German). 2 (Suppl. 7): 1–34.
- ISBN 978-0-520-06726-4.
- ISBN 978-0-520-24209-8.
- ^ Wedel, Mathew J.; Cifelli, R. L.; Sanders, R. K. (2000). "Osteology, paleobiology, and relationships of the sauropod dinosaur Sauroposeidon". Acta Palaeontologica Polonica. 45: 343–388.
- ^ Kingham, R.F. (1962). "Studies of the sauropod dinosaur Astrodon Leidy". Proceedings of the Washington Junior Academy of Sciences. 1: 38–44.
- ^ hdl:2027.42/94293.
- ^ Leonardo Salgado, 1993, "Comments on Chubutisaurus insignis del Corro (Saurischia, Sauropoda)", Ameghiniana 30(3): 265–270
- ^ Salgado, L., R. A. Coria, and J. O. Calvo. 1997. "Evolution of titanosaurid sauropods. I: phylogenetic analysis based on the postcranial evidence". Ameghiniana 34: 3-32
- ^ S2CID 86254470. Archived from the original(PDF) on 19 August 2018.
- S2CID 54752135.
- PMID 28480136.
- .
- .
- JSTOR 2400969.
- S2CID 7328047.
- ISBN 978-0-7924-5606-3.
- .
- .
- S2CID 130861276.
- ^ "Jak velké vnitřní orgány měli obří sauropodi?". 4 July 2016.
- .
- ^ Gradstein, F.M.; Ogg, J.G.; Schmitz, M.D. & Ogg, G.M., 2012, A Geologic Time Scale 2012, Elsevier
- .
- )
- ISBN 0-520-24209-2.
- ^ Barrett, P.M., Butler, R.J., Edwards, N.P., & Milner, A.R. Pterosaur distribution in time and space: an atlas. p61–107. in Flugsaurier: Pterosaur papers in honour of Peter Wellnhofer. 2008. Hone, D.W.E., and Buffetaut, E. (eds). Zitteliana B, 28. 264pp.[1]
- ^ Rauhut, Oliver W. M. (2011). "Theropod dinosaurs from the Late Jurassic of Tendaguru (Tanzania)". Special Papers in Palaeontology. 86: 195–239.
- ^ Buffetaut, Eric (2012). "An early spinosaurid dinosaur from the Late Jurassic of Tendaguru (Tanzania) and the evolution of the spinosaurid dentition". Oryctos. 10: 1–8.
- .
Bibliography
- Maier, Gerhard. 2003. African dinosaurs unearthed: the Tendaguru expeditions. Life of the Past Series (ed. J. Farlow). Indiana University Press, Bloomington, Indiana