Search results
Results from the WOW.Com Content Network
However, since the sharks’ presence in the fossil record has mostly consisted of isolated teeth, scientists have been left to speculate on what the rest of this ancient predator looked like ...
However, viruses are still poorly understood and may have arisen before "life" itself, or may be a more recent phenomenon. Major extinctions in terrestrial vertebrates and large amphibians. Earliest examples of armoured dinosaurs. 195 Ma First pterosaurs with specialized feeding (Dorygnathus). First sauropod dinosaurs.
Unlike other fish, shark gill slits are not covered, but lie in a row behind the head. A modified slit called a spiracle lies just behind the eye, which assists the shark with taking in water during respiration and plays a major role in bottom–dwelling sharks. Spiracles are reduced or missing in active pelagic sharks. [28]
A team of scientists recently captured the elusive bluntnose sixgill shark, a deep-sea fish that has been on Earth before dinosaurs, on film.
An analysis of a partially complete tail fin fossil shows that Cretoxyrhina had a lunate (crescent-shaped) tail most similar with modern lamnid sharks, whale sharks, and basking sharks. The transition to tail vertebrae is estimated to be between the 140th and 160th vertebrae out of the total 230, resulting in a total tail vertebral count of 70 ...
Get excited for the 35th official Shark Week, from July 23 to July 29, with these shark facts.
Given that all extant lamniform sharks give birth to live young, this is believed to have been true of megalodon also. [81] Infant megalodons were around 3.5 meters (11 ft) at their smallest, [ 35 ] : 61 and the pups were vulnerable to predation by other shark species, such as the great hammerhead shark ( Sphyrna mokarran ) and the snaggletooth ...
The book chronicles the evolution of dinosaurs, their rise as the dominant clade, and ends with an account of their extinction from the Chicxulub asteroid. It also includes a discussion of the evolution of feathered dinosaurs and birds' descent from dinosaurs, and an epilogue of sorts discussing the post-dinosaur emergence of mammals.