From about 161 to 66 million twelvemonth ago , a group of large , feather predators call in abelisaurs roamed the Earth . Their extremely small forelimbs contrasted dramatically with their muscular legs , which they used to chase down their prey before snapping them up in their jaws , chomping on them with their razor - penetrative teeth .
While clearly dire , their true size were really poorly constrained . A new subject field published in the journalPeerJhas revealed that , based on a long - lost femur bone , these beasts could grow up to 9 meters ( 29.5 feet ) in length , and potentially matter up to 2 t ( 2.2 tons ) .
The duration of a dinosaur ’s femur osseous tissue , located in its upper leg , provides palaeontologist with a agency to estimate bothhow long and how heavyits owner could be . Alfio Alessandro Chiarenza , a graduate from Imperial College London and the lead author of this newfangled study , stumble across an unnamed one gathering dust in a museum drawer in Palermo , Italy , and decided to identify what dinosaur it used to belong to .
The sizing of an abelisaur compared to a lowly human bite . David Bonadonna / Imperial College London
The bone was originally found in a 95 - million - year - sure-enough rock and roll formation from North Africa . Back then , the region was full of Rhizophora mangle swamps and rivers , unlike the more arid environment present today . The part was home to a plethora of creatures , include several great predators likeSpinosaurus . However , Chiarenza determined that the thighbone belong to another meat - eating monster called an abelisaur .
In fact , this abelisaur is one of the largest ever get word . “ Smaller abelisaur fossils have been previously found by fossilist , but this find indicate how really Brobdingnagian these flesh eat predators had become , ” said Chiarenza in astatement .
This find does elicit a perplexing issue , though : How did two Brobdingnagian apex predators likeSpinosaurus – the largest carnivorous dinosaur of all clip – and this abelisaur co - be in the same region ? One possible answer lies in their hunt habits .
Spinosauruswas a fish - eating brute that live near and in the more aquatic parts of the environment . Abelisaurs were inland hunters , chasing their fair game down over solid primer . So perhaps the two groups of dinosaurs would have never crossed path .
Spinosaurus survive in the same environment , so how did the two animate being not hunt down each other into extinction ? Linda Bucklin / Shutterstock
Far from justSpinosaurus , however , fossil evidence from this region paint a picture that this abelisaur would have experience alongside four other additional center - use up titan – surely they all could n’t have lived side by side in a proportionate existence ? This secret is namedStromer ’s Riddle , and it has frustrate fossilist ever since the eponymous researcher first found this fogey bed 1912 .
This new bailiwick suggests thatthe fogey bedmay have been deceiving . The writer guess that the harsh and quickly changing surroundings in the area may have , over time , get a lot of disturbance and reorganization within the bed .
This may have mix up the dinosaur dodo sherd , give the impression that these gargantuan hunters subsist in the same position . In reality , they may have live quite far away from each other .
