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A gargantuan shark the size of a two - story construction prowled the shallow seas 100 million years ago , novel dodo unwrap .
The monolithic Pisces the Fishes , Leptostyrax macrorhiza , would have been one of the largest predators of its day , and may push back scientists ' estimates of when such mammoth predatory shark evolved , said study co - writer Joseph Frederickson , a doctoral candidate in bionomics and evolutionary biology at the University of Oklahoma .
New fossils unearthed in TExas suggests that sharks during the Early Cretaceous were much larger than previously thought. The top image shows the estimated body size of a shark fossil found in a 100-million-year-old deposit in Kansas. The middle shark’s size. The bottom shark is another known shark species that trawled the ancient oceans.
Theancient sea monsterwas get a line by accident . Frederickson , who was then an undergrad at the University of Wisconsin - Milwaukee , had started an unpaid fossilology club to study novel fossil deposit . In 2009 , the club demand a trip-up to the Duck Creek Formation , just outside Fort Worth , Texas , which contains myriad marine invertebrate fossil , such as the extinct squidlike creatures known asammonites . About 100 million years ago the area was part of a shallow sea know as the westerly Interior Seaway that split North America in two and spanned from the Gulf of Mexico to the Arctic , Frederickson aver .
While walking in the formation , Frederickson ’s then - girl ( now married woman ) , University of Oklahoma anthropology doctoral campaigner Janessa Doucette - Frederickson , tripped over a boulder and noticed a large vertebra sticking out of the terra firma . Eventually , the team dug out three large vertebra , each about 4.5 column inch ( 11.4 cm ) in diam . [ See Images of Ancient Monsters of the Sea ]
" you’re able to hold one in your hired hand , " but then nothing else will fit , Frederickson told Live Science .
The vertebra had sight of lines call lamellae around the exterior , suggesting the bone once belonged to a broad scientific categorization of shark called lamniformes that include sand tiger sharks , great snowy sharks , goblin shark and others , Frederickson sound out .
After focus over the literature , Frederickson found a verbal description of a alike shark vertebra that was unearthed in 1997 in the Kiowa Shale in Kansas , which also dates to about 100 million years ago . That vertebra came from a shark that was up to 32 foot ( 9.8 metre ) long .
By comparing the new vertebra with the one from Kansas , the squad conclude the Texas shark was likely the same species as the Kansas specimen . The Texan could have been at least 20.3 feet ( 6.2 m ) long , though that is a conservative estimate , Frederickson said . ( Still , the Texas shark would have been no lucifer for the biggest shark that ever lived , the 60 - foot - long , or 18 m , Megalodon . )
By analyzing alike ecosystem from the Mesozoic Era , the squad concluded the sharks in both Texas and Kansas were probablyLeptostyrax macrorhiza . antecedently , the only fossils fromLeptostyraxthatpaleontologists had detect were dentition , making it punishing to gauge the shark ’s true size . The newfangled subject field , which was published today ( June 3 ) in the journalPLOS ONE , suggest this fauna was much bigger than previously believe , Frederickson read .
Still , it ’s not sure the new vertebrae belonged toLeptostyrax , said Kenshu Shimada , a paleobiologist at DePaul University in Chicago , who unearthed the 1997 shark vertebra .
" It is also entirely possible that they may belong to to an nonextant shark with very minor teeth so far not recognized in the present fossil book , " Shimada , who was not regard in the current study , distinguish Live Science . " For example , some of the largest modernistic - day shark are plankton - feeding form with minute teeth , such as the whale shark , basking shark andmegamouth shark . "
Either direction , the new finds deepen the picture of the Early Cretaceous seas .
As for the ancient shark ’s feeding habits , they might resemble those of moderngreat white sharks , who " eat whatever fit in their oral fissure , " Frederickson said . If these ancient ocean monster were similar , they might have fed on enceinte Pisces , baby pliosaurs , marine reptiles and even full - arise pliosaurs that they scavenged , Frederickson tell .
