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What was the structure of the Mesonychids?
Mesonychids possess unusual triangular molar teeth that are similar to those of Cetacea (whales and dolphins), especially those of the archaeocetes, as well as having similar skull anatomies and other morphologic traits.
What did the mesonychid evolve into?
Archaeocetes had a “double-pulley” astragalus, confirming that cetaceans had evolved from artiodactyls. Mesonychids were not the ancestors of whales, and hippos are now known to be the closest living relatives to whales. Recently scientists determined which group of prehistoric artiodactyls gave rise to whales.
When was the mesonychid alive?
Mesonychids were reported in the 1980’s. They found them in Asia and Europe. They lived 60-37 mya. The habitat they lived in was mainly on shore.
How did the Mesonychids swim?
Functional analysis of its skeleton shows that it could get around effectively on land and could swim by pushing back with its hind feet and undulating its tail, as otters do today.
What did the Dorudon look like?
Anatomy: Dorudon, along with other basilosaurids, differed from all modern cetaceans in the shape of its head and teeth. Dorudon has a long, narrow snout, and almost certainly lacked the bulbous ‘melon’ that forms the spherical bulge on the facial profile of modern toothed whales.
What did the Mesonyx eat?
However, instead of claws, Mesonyx’s toes ended in small hooves. Its long skull had a relatively large sagittal crest above the braincase to anchor large jaw muscles and give it a powerful bite. Mesonyx specimens have been unearthed in Colorado, Wyoming, Utah and China….Mesonyx.
| Basic | |
|---|---|
| Habitat | North America,Asia |
| Diet | Carnivore |
What did the Zygorhiza eat?
Zygorhiza kochii: skeleton Z. kochii was one of the first fully aquatic whales and had large, multi-cusped teeth for shearing prey items like fish and squid.
Does Pakicetus have tail flukes?
The first ‘whales’ was a small doglike creature about 1.7 meters long or 6 feet long that lived much of it’s life around streams named Pakicetus over 48 million years ago. This creature had no flukes on its tail, had very forward nostrils for shallow snorkeling and had limbs functioned for walking.
Do blue whales have tail flukes?
Blue whales will only occasionally raise their tail flukes at the end of a dive. Blue whales are identified by their flukes and small dorsal fin, and individuals are identified by the patterns of color on their backs.
What did the foot of a mesonychid look like?
The foot was compressed for efficient running with the axis between the third and fourth toes (paraxonic); it would have looked something like a hoofed paw. Mesonychids varied in size; some species were as small as a fox, others as large as a horse.
What kind of diet did the Mesonychids have?
The mesonychids were an unusual group of condylarths with a specialized dentition featuring tri-cuspid upper molars and high-crowned lower molars with shearing surfaces. They were once viewed as primitive carnivores, like the Paleocene family Arctocyonidae, and their diet probably included meat and fish.
When did the last mesonychid genus die out?
Mesonychids first appeared in the Early Paleocene, went into a sharp decline at the end of the Eocene, and died out entirely when the last genus, Mongolestes, became extinct in the Early Oligocene. Mesonychids probably originated in Asia, where the most primitive mesonychid, Yangtanglestes,…
Most paleontologists now doubt that whales are descended from mesonychids, and instead suggest mesonychians are descended from basal ungulates, and that cetaceans are descended from advanced ungulates ( Artiodactyla ), either deriving from, or sharing a common ancestor with, anthracotheres (the semiaquatic ancestors of hippos).