Monster Shark 20-Foot Long Prowled Ancient American Waters 100 Millions Years Ago
The finding of the remains of a 20-foot shark pushes back the time of evolution of such predatory fish.
According to Live Science, a 4.5 inch long vertebra was found by a group of students in 2009 at Duck Creek formation outside Fort Worth, Texas. The formation is said to be 100 million years old and teeming with invertebrate fossils. The vertebra the group accidentally discovered had lines called lamellae that can be identified with lamniformes sharks including the Great White.
"You can hold one in your hand but then nothing else will fit," Frederickson said while describing the vertebra.
To determine which species of shark the bone came from, researchers scanned literature for similar finds and came across a vertebra found in 1997 at Kansas's Kiowa Shale which is also believed to be 100 million years. The Kansas shark was estimated to be 32 foot long. Comparison of vertebra led Frederickson and his team to believe that Texas shark was 20.3 foot long.
The team further analyzed ecosystems from the Mesozoic Era to conclude that both Kansas and Texas specimens belonged to the species Leptostyrax macrorhiza, which have been known earlier only through their teeth.
"Neither specimen was recovered with associated teeth, making confident identification of the species impossible. However, both formations share a similar shark fauna, with Leptostyrax macrorhiza being the largest of the common lamniform sharks," researchers wrote about the Kansas and Texas specimen in the journal PLOS ONE.
