T-rex was not exactly the champ of the bullies during the dinosaur era. It was indeed up to 12.8 (38 ft) long and 7.2 tonnes heavy (more than an elephant!), but the 1993 discovered Giganotosaurus from Argentine was longer: up to 13.6 m (40 ft) long.
Still, the largest carnivore dinosaur (and land carnivore in general) ever to have existed has recently been proved to be Spinosaurus, whose remains were first discovered in 1910. It lived in North Africa during the Cretaceous Period, 95 to 93 million years ago.
Spinosaurus had "spines" on the back, long extensions of the vertebrae up to 2 m (6.6 ft) long and could have made up a sail-like structure or a hump. Spinosaurus was up to 18 m (60 ft) long and 9 tonnes heavy. It had a less bulky body than the T-rex's and the head was more like that of a crocodile (it could have a diet based on fisher or carrion).
Now, the gallery of the huge meat eating dinosaur is completed by a new species described recently on the the "Journal of Vertebrate Paleontology" and discovered in the Republic of Niger.
Steve Brusatte, a paleobiologist at the University of Bristol, in England, made the description based on skull and neck remains found 1997. The new species was named Carcharodontosaurus iguidensis, had banana-sized teeth, was taller than a double-decker bus, 44 ft (14.6 m) long (more than a T-rex!) and weighed as much as an elephant (around 3.2 tonnes).
"Evidence of the 95-million-year-old theropod has been extremely hard to come by. The first remains of Carcharodontosaurus were found in the 1920s, but they only consisted of two teeth which have since been lost. Other bits ... were found in Egypt and described in the 1930s, but these were destroyed when Munich was bombed in 1944", said Brusatte.
"The fact that they appeared significantly different to other remains found near Saharan Morocco warranted naming a new species. The Cretaceous world of 95 million years ago was a time of some of the highest sea levels and warmest climates in Earth history. It seems that shallow seas divided Morocco and Niger, promoting evolutionary separation of the species living in the two regions. The evolutionary evidence may be old, but is entirely relevant to the contemporary era's global warming. This has implications for the world today in which temperatures and sea level are rising. By studying these sorts of ecosystems that we can hope to understand how our modern world may change", he added.