Scientists are amazed at a fossil that has been discovered in northern Canada, because it appears to be of an animal that was part fish and also had limbs. The creature has been named Tiktaalik roseae, and it so far embodies the best-known species ever found that is between fish and animals living on land. Scientists believe it lived around 375 million years ago in the Devonian period.
Even though the ancient animal is considered a fish, it appears to look like a cross between a fish and a crocodile. The creature was believed to grow to about eight to nine feet in length and probably spent most of its time in shallow freshwater areas. It was a hunter and had extremely sharp teeth, had a crocodile looking head and a flat type of body. It had scales, fins and gills like a normal fish, but it also had features that were associated with land animals, such as a moveable neck, a hearty ribcage and the beginning of primitive lungs.
Edward Daeschler, who is the Associate Curator of Vertebrate Zoology at the Academy of Natural Sciences, located at Drexel University, stated that Tiktaalik was an amalgamation of both primitive and advanced body features; it was an actual real life fishimal. It had large for fins that also contained shoulders, elbows and even the beginning of wrists starting to develop. These stunning developments made some researchers think such limb-like features probably only came to be after the species had moved to dry land for good.
Prior information, which had been based on the best data available at the time, made it seem that some sort of shift occurred from a type of in-front-only locomotion in fish to more of an all-over movement, like the way it is with all four-footed animals, explained research study author Neil Shubin, who works as a professor of Anatomy at the University of Chicago. However now it seems like such a shift actually happened with the fish, not the land animals.
No matter what type of gait Tiktaalik had to use, it is very clear that the importance was placed on the back appendages and so pelvic-propelled movement was a trend that basically had to start with the fish. It was later embellished with the origin of the tetrapod.
The fossilized pelvic fin of Tiktaalik showed the evolution of back legs actually started as improved hind fins, stated scientists.
It is believed that every animal that has four limbs, including birds, amphibians, reptiles and even human beings, have descended from certain mutual ancestors that were able to make the preliminary transition from fins to feet. But until Tiktaalik was discovered, the why and how of this gigantic evolutionary jump had long puzzled scientists. They knew they had their theory but they had never found any kind of proof to back up their claims.
Yet how long was it before the first four legged animals were considered fully evolved? About nine million years after Tiktaalik, animals that could be considered actual four-limbed animals finally appeared. They looked similar to salamanders and were still attached to the water but could also move around on land and adjust to the gravitational pull of the Earth.
Animals discovered that moving around on land and being able to push into the waters was an evolutionary benefit. The fossil that was discovered in northern Canada was of an animal that paved the evolutionary trail in a big way.
By Kimberly Ruble