Sarcosuchus

***Sarcosuchus*** (meaning "flesh crocodile") is an extinct genus of crocodyliform and distant relative of living crocodylians that lived during the Early Cretaceous, from the late Hauterivian to the early Albian, 133 to 112 million years ago of what is now Africa and South America. It was one of the largest crocodile-line reptiles, reaching an average estimate of 9 m (30 ft) and 3.5 metric tons (3.9 short tons), but estimated to grow up to 9.5 m (31 ft) in body length and weigh up to 4.3 metric tons (4.7 short tons). It is known from two species, *S. imperator* from the early Albian Elrhaz Formation of Niger and *S. hartti* from the Late Hauterivian of northeastern Brazil, other material is known from Morocco and Tunisia and possibly Libya and Mali.

The first remains were discovered during several expeditions led by the French paleontologist Albert-Félix de Lapparent, spanning from 1946 to 1959, in the Sahara. 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 six new specimens, including one with about half the skeleton intact and most of the spine.

## Description

*Sarcosuchus* was a giant relative of crocodiles, with fully grown individuals estimated to have reached up to 9 to 9.5 m (29.5 to 31.2 ft) in total length and 3.5 to 4.3 metric tons (3.9 to 4.7 short tons) in weight. It had somewhat telescoped eyes and a long snout comprising 75% of the length of the skull. There were 35 teeth in each side of the upper jaw, while in the lower jaw there were 31 teeth in each side. The upper jaw was also noticeably longer than the lower one leaving a gap between them when the jaws were shut, creating an overbite. In young individuals the shape of the snout resembled that of the living gharial but in fully grown individuals it became considerably broader.

### Bulla

*Sarcosuchus* has an expansion at the end of its snout known as a bulla, which has been compared with the ghara seen in gharials. However, unlike the ghara, 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 is not known.

### Osteoderms

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 from the pattern seen in living crocodiles, which present discontinuity between the osteoderms of the neck and body.

### Size

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 crocodilians there is a strong correlation between skull length and total body length in subadult and adult individuals irrespective of their sex, this method was used by Sereno *et al.* (2001) 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 m (4.92 ft) in length found in the literature. The largest known skull of *S. imperator* (the type specimen) is 1.6 m (5.25 ft) long (1.5 m (4.92 ft) in the midline), and 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 (18.7 ft) was estimated using linear equations for the saltwater crocodile and in turn this measurement was used to estimate its body weight at 8 metric tons (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*, the Late Cretaceous *Deinosuchus* and the Miocene *Purussaurus* according to current estimates at that time.

However, extrapolation from the femur of a subadult individual as well as measurements of the skull width further showed that the largest *S. imperator* was significantly smaller than was estimated by Sereno *et al.* (2001) based on modern crocodilians. O’Brien *et al.* (2019) estimated the length of the largest *S. imperator* specimen at 9.5 m (31 ft) and body weight at 4.3 metric tons (4.7 short tons) based on longirostrine crocodylians skull width to total length ratio. This estimate is very close to the femur based estimate (9.1 m (29.9 ft)).

## *Sarcosuchus* in The Amazing Dinosaur Adventure

*Sarcosuchus* from *The Great Sauropod Migration*A pack of *Sarcosuchus* from *The Amazing Hero Girls*