Temporal range: Early Cretaceous, 112Ma
|S. imperator holotype, Muséum national d'Histoire naturelle, Paris|
Broin & Taquet, 1966
Broin & Taquet, 1966
Sarcosuchus (//; meaning "flesh crocodile"), is an extinct genus of crocodyliform and distant relative of the crocodile that lived 112 million years ago. It dates from the early Cretaceous Period of what is now Africa and South America and is one of the largest crocodile-like reptiles that ever lived. It was almost twice as long as the modern saltwater crocodile and weighed up to 8 tonnes.
The first remains were discovered during several expeditions lead by the French paleontologist Albert-Félix de Lapparent, spanning from 1946 to 1959 in the Sahara Desert. These remains were fragments of the skull, vertebrae, teeth and scutes. In 1964, an almost complete skull was found in Niger by the French CEA, but it was not until 1997 and 2000 that most of its anatomy became known to science, when an expedition led by the American paleontologist Paul Sereno discovered 6 new specimens, including one with about half the skeleton intact and most of the spine.
Sarcosuchus was a giant long snouted relative of crocodiles, estimated to have reached a maximum body length of 11–12 metres (36–39 feet), that lived in fluvial and lacustrine environments in Africa and South America approximately some 112 million years ago during the Early Cretaceous period. The orbits of its eyes were somewhat telescoped and its snout comprised two thirds of the total length of the skull, considerably broader than that of narrow snouted crocodyliforms like the living gharial, its upper jaw was longer than the lower jaw, creating an overbite.
At the end of its snout, Sarcosuchus presented an expansion, called bulla, it has been compared to the ghara seen in gharials but unlike the ghara, though, which is only found in male gharial, the bulla is present in all Sarcosuchus skulls that have been found so far, suggesting that it was not a sexually dimorphic trait. The purpose of this structure remains enigmatic. Sereno and others asked various reptile researchers what their thoughts on this bulla were. Opinions ranged from it being an olfactory enhancer to being connected to a vocalization device.
The osteoderms, also known as dermal scutes, of Sarcosuchus were similar to those goniopholodids like Sunosuchus and Goniopholis, they formed an uninterrupted surface that started in the posterior part of the neck up to the middle of the tail like is seen in Araripesuchus and other basal crocodyliforms, different to the pattern seen in living crocodiles, which present discontinuity between the osteoderms of the neck and body.
A common method to estimate the size of crocodiles and crocodile-like reptiles is the use of the length of the skull measured in the midline from the tip of the snout to the back of the skull table, since in living crocodylians there is a strong correlation between skull length and total body length in subadult and adult individuals irrespective of their sex, this method is preferred for Sarcosuchus due to the absence of a complete enough skeleton.
Two regression equations were used to estimate the size of S. imperator, they were created based on measurements gathered from 17 captive gharial individuals from northern India and from 28 wild saltwater crocodile individuals from northern Australia, both datasets supplemented by available measurements of individuals over 1.5 metres (4.9 ft) in length found in the literature. The largest known skull of S. imperator (the type specimen) is 1.6 m (5.2 ft) long an it was estimated that the individual it belonged to had a total body length of 11.65 m (38.2 ft), its snout-vent length of 5.7 m (19 ft) was estimated using linear equations for the saltwater crocodile and in turn this measurement was used to estimate its body weight at 8 tonnes (8.8 short tons). This shows that Sarcosuchus was able to reach a maximum body size not only greater than previously estimated but also greater than that of the Miocene Rhamphosuchus, only the Late Cretaceous Deinosuchus and the Miocene Purussaurus may have achieved a comparable maximum body size.
Sarcosuchus is commonly classified as part of the clade pholidosauridae, a group of crocodile-like reptiles (crocodyliformes) related but outside crocodylia (the clade containing living crocodiles, alligators and gahrials). Within this group its most closely related to the North American genus Terminonaris. Most members of pholidosauridae had long, slender snouts and they all were aquatic, inhabiting several different environments, some forms are interpreted as marine, capable of tolerating saltwater while others, like Sarcosuchus, were freshwater forms, the most primitive members of the clade, however, were found in coastal settings, zones of mixing of freshwater and marine waters. Sarcosuchus stands out among pholidosaurids for being considered a generalist predator, different to most known members of the clade which were specialized piscivores.
Simplified cladogram after Fortier et al. (2011).
Discovery and naming
During the course of several expeditions on the Sahara from 1946 to 1959, lead by the French paleontologist Albert-Félix de Lapparent, several fossils of a crocodyliform of large size were unearthed in the region known as the Continental intercalaire, some of them were found in Foggara Ben Draou, near the town of Aoulef, Algeria (informally named as the Aoulef Crocodile) while others came from Gara Kamboute, in the south of Tunisia, the fossils found were fragments of the skull, teeth, scutes and vertebrae. In 1957, in the region now known as the Elrhaz Formation in the north of Niger several isolated teeth of great size were found by H. Faure. The study of this material by French paleontologist France De Broin helped identify them as coming from a new long snouted crocodile.
Later, in 1964, the research team of the French CEA discovered an almost complete skull in region of Gadoufaoua, in the north of Niger, said skull was shipped to Paris for study and became the holotype of the then new genus and species Sarcosuchus imperator in 1966. The genus name comes from the Greek "sarco" meaning flesh and "suchus" meaning crocodile.
Fossils from Brazil
In 1977, a new species of Sarcosuchus was named, S. hartti, from remains found in the late 19th century in the Reconcavo basin of Brazil. In 1867, American naturalist Charles Hartt found two isolated teeth and sent them to the American paleontologist O. C. Marsh who erected a new species of Crocodylus for them, C. hartti, this material, along with other remains were assigned in 1907 to the genus Goniopholis as G. hartti. Now residing in the British Museum of Natural History the fragment of the lower jaw, dorsal scute and two teeth compromising the species G. hartti were reexamined and conclusively placed in the genus Sarcosuchus.
The next major findings occurred during the expeditions lead the American paleontologist Paul Sereno, in 1997 and the follow-up trip in 2000. Partial skeletons, numerous skulls and 20 tons of assorted other fossils were recovered from the deposits of the Elrhaz Formation, which has been dated as late Aptian or early Albian stages of the late Cretaceous. It took about a year to prepare the Sarcosuchus remains.
Additional fossil material was found and described in 2010, from the area of Nalut in northwestern Libya. These fossils are from the Cabao Formation, which is likely to be Hauterivian to Barremian in age.
Based on the number of growth rings, also known as lines of arrested growth, found in dorsal osteoderms (or scutes) from a subadult individual approximately 80% of maximum adult size, it was estimated that S. imperator reached maximum adult size between 50 to 60 years of age and because crocodilians don't actively grow or live for that long, this suggest that, as has been shown in Deinosuchus, S. imperator achieved its giant size by increasing the duration of rapid growth and not by accelerating the rate of bone deposition like in large mammals and dinosaurs.
The snout of S. imperator is proportionally long, up to 75% of the length of the skull and while that of juvenile S. imperator resembles the snouts of the gharial and other living narrow-snouted crocodiles, the snout of the adults is considerably more robust and broader. All teeth have smooth and sturdy crowns. It's upper jaw overhangs the lower jaw, leaving a 10 cm (3.9 in) gap between them and when the jaws were shut, with the exception of the enlarged ones, all the teeth of the lower jaw occlude with those of the upper jaw.
This characteristics, among others, contrast sharply with those of the living fish eating crocodylians that possess proportionally narrower and more elongated snouts as well as interlocking teeth, adult S. imperator then, can be compared to large living crocodiles such as the Nile crocodile, possessing a similar generalized diet that also included large terrestrial prey like the abundant dinosaurs that lived in the same region.
The remains of S. imperator were found in a region of the Ténéré Desert dubbed Gadoufaoua, more specifically in the Elrhaz Formation of the Tegama Group, dating from the late Aptian to the early Albian of the Early Cretaceous, approximately 112 million years ago. The stratigraphy of the region and the aquatic fauna that was found therein indicates that it was an inland fluvial environment, entirely freshwater in nature, with an humid tropical climate. S. imperator shared the waters with the holostean fish Lepidotus and the coelacanth Mawsonia, the dinosaur fauna of the region was represented by the iguanodontian Lurdusaurus, which was the most common dinosaur in the region, and its relative Ouranosaurus, there were also two sauropods, Nigersaurus and an unnamed sauropod, the theropods included the long snouted Suchomimus and the smaller carcharodontosaurid Eocarcharia and the abelisaurid Kryptops.
Meanwhile, S. hartti was found in the Reconcavo basin of Brazil, specifically in the Ilhas Formation of the Bahia series, it was a shallow lacustrine environment dating from the late Aptian, similar in age to the habitat of S. imperator, with similar aquatic fauna, including Lepidotus and two species of Mawsonia. The dinosaur fauna is of a very fragmentary nature and identification doesn't go beyond indeterminate theropod and iguanodontid remains.
In popular culture
|This section needs additional citations for verification. (April 2013)|
Sarcosuchus made an appearance as the monster in The Asylum's film Supercroc, although its size was much larger than the actual animal and was capable of surviving two bunker buster bombs. Sarcosuchus also featured in the BBC series Chased by Dinosaurs (in the Land of Giants episode) as well in a National Geographic Society documentary titled SuperCroc. It was also featured in the 2009 documentary Monsters Resurrected and in the 2011 BBC documentary television series Planet Dinosaur. Two sarcosuchus brothers appear as the main antagonists of the 2012 film "Dino Time".
- Sereno, Paul C.; Larson, Hans C. E.; Sidor, Christian A.; Gado, Boubé (2001). "The Giant Crocodyliform Sarcosuchus from the Cretaceous of Africa". Science 294. doi:10.1126/science.1066521. PMID 11679634.
- Buffetaut, E.; Taquet, P. (1977). "The Giant Crocodilian Sarcosuchus in the Early Cretaceous of Brazil and Niger". Paleontology 20 (1).
- "Giant croc and a right load of bulla". Geology News. November 2, 2001. Archived from the original on April 26, 2005. Retrieved 22 March 2013.
- Woodward, A. R.; White, J. H.; Linda, S. B. (1995). "Maximum size of the alligator (Alligator mississippiensis)". J. Herpetol 29 (4).
- Wemuth, H. (1964). "Das Verhaltnis zwischen Kopf-, Rumpf- und Schwanzlange bei den rezenten Krokodilen". Senckenbergiana Biologica (in German) 45.
- Webb, G. J. W.; Messel, Harry (1978). "Morphometric Analysis of C. porosus from the North Coast of Arnhem Land, Northern Australia.". Australian Journal of Zoology 26.
- Head, J. J. (2001). "Systematics and body size of the gigantic, enigmatic crocodyloid Rhamphosuchus crassidens, and the faunal history of Siwalik Group (Miocene) crocodylians". Journal of Vertebrate Paleontology 21 (Supplement to No. 3): 59A.
- Erickson, G. M.; Brochu, C. A. (1999). "How the "terror crocodile" grew so big". Nature 398 (6724). doi:10.1038/18343.
- De Broin, France; Taquet, Philippe (1966). "Découverte d'un Crocodilien nouveau dans le Crétacé inférieur du Sahara". C. R. Acad. Sc. Paris (in French) 262 (D).
- Fortier, Daniel; Perea, Daniel; Schultz, Cesar (2011). "Redescription and phylogenetic relationships of Meridiosaurus vallisparadisi, a pholidosaurid from the Late Jurassic of Uruguay". Zoological Journal of the Linnean Society 163 (Supplement S1). doi:10.1111/j.1096-3642.2011.00722.x.
- Marsh, Othniel C. (1869). "Notice of some new reptilian remains from the Cretaceous of Brazil". American Journal of Science 47 (141).
- Mawson, J.; Woodward A. S. (1907). "On the Cretaceous formation of Bahia (Brazil) and on vertebrae fossils collected therein". Q. Ji geol. Soc. London 63.
- "Niger Expedition 2000". Project Exploration: The SuperCroc Website. Archived from the original on June 14, 2011. Retrieved 22 March 2013.
- Le Loeuff, J.; Métais, E.; Dutheil, D.B.; Rubino, J.L.; Buffetaut, E.; Lafont, F.; Cavin, L.; Moreau, F.; Tong, H.; Blanpied, C.; and Sbeta, A. (2010). "An Early Cretaceous vertebrate assemblage from the Cabao Formation of NW Libya". Geological Magazine. in press. doi:10.1017/S0016756810000178.
- Grenard, S. (1991). Handbook of Alligators and Crocodiles. Malabar, Florida: Kreiger.
- Sereno, Paul C.; Wilson, Jeffrey A.; Witmer, Lawrence M.; Whitlock, John A.; Maga, Abdoulaye; Ide, Oumarou; Rowe, Timothy A. (2007). "Structural Extremes in a Cretaceous Dinosaur". PLoS ONE 2 (11). doi:10.1371/journal.pone.0001230. PMC 2077925. PMID 18030355.
- Sereno, Paul. C.; Brusatte, Stephen L. (2008). "Basal abelisaurid and carcharodontosaurid theropods from the Lower Cretaceous Elrhaz Formation of Niger". Acta Paleontologica Polonica 53 (1).
- Sloan, C. 2002. SuperCroc and the Origin of Crocodiles. National Geographic. ISBN 0-7922-6691-9. (children's book)
- National Geographic Special on SuperCroc. National Geographic Channel, December, 2001.
|Wikimedia Commons has media related to Sarcosuchus.|
- "Sarcosuchus imperator". Prehistorics Illustrated. (illustrations)
- "African fossil find: 40-foot crocodile". Guy Gugliotta. Washington Post, October 26, 2001. Retrieved November 17, 2004.
- SuperCroc: Sarcosuchus imperator. Gabrielle Lyon. Retrieved November 17, 2004.
- "'SuperCroc' fossil found in Sahara". D. L. Parsell. National Geographic News, October 25, 2001. Retrieved November 17, 2004.
- Dinosaur Expedition 2000. Paul C. Sereno. Retrieved November 17, 2004.
- "SuperCroc's jaws were superstrong, study shows". John Roach. National Geographic News, April 4, 2003. Retrieved November 17, 2004.
- "Sereno, team discover prehistoric giant Sarcosuchus imperator in African desert." Steve Koppes. The University of Chicago Chronicle, volume 21, number 4, November 1, 2001. Retrieved November 17, 2004.
- Making of the Sarcosuchus exhibit