 南方有蹄类
South ungulates, just from the literal meaning, that is, the South gave birth to an animal hoof, so sudden, big joke. In fact, in the past, has been translated into such animals as "hoofed projects in South America": specifically those in South America prosperous indigenous ungulates, such as former representatives of the animal fossils are unearthed in South America. Which is also very famous in the world on behalf of: Arrow Gear Beast (toxodon). But far as the earth during the lazy, Glyptodon known.
But recently in China and parts of Asia and North America are similar to the South have found the fossil representatives of ungulates, but note that they had been roughly classified into the southern ungulates, but is now classified as a separate project, we call animal head for the North column (arctostylops).
South America, with not not, but rather about the meaning of translation for the South, so close to class to translate are: South ungulates (notoungulata).
They look like strange things can be said, but in the bones, especially the teeth, or a considerable number of common features.
South ungulate teeth most obvious feature is a very special structure, the molar ridge, external ridge straight, long and back Xieshen original ridge after ridge is perpendicular to the outer end, with sharp growth in the valley to form a small ridge, or said second ridge, the next two molars similar to a typical class Perissodactyla Tsukigata ridge, is under the special point of isolation at the tip of one month after the arc-shaped ridge.
Other features are aimed at groups they belong in, but generally speaking, their skulls and body than are relatively small. Bones are relatively flat head at the top of the head skeleton in general is very wide, the nose especially on the list. There is a four-body feeling of the head. Zygomatic width and weight of no orbital bone bridge.
Bones are very strong and sturdy joints. Pin is 5 foot or 3 feet, the middle of the largest. But they never reached the point where the real line with the toe, some with shoes, some claws, feet, similar in general form and rodents.
In particular, mention the arrangement of the teeth, the South ordered ungulate teeth are quite close, chisel-shaped incisors mostly, almost all tend to molars of canine or degradation, but some of the original group remained the canine species, the original type of molar teeth the crown is very low, but after a few pieces of very progressive groups, developed a life-long growth can molar GAO Guan. But to say that the GAO Guan molars with Haig mammals should be represented.
Early South America is south of the south column ungulate animals (notostylops) as the representative, they do not like the home of the brothers and sisters of Asia and North America's embarked on a road of no return, like hand, foot, on the contrary found in isolated South America the promised land of their own, embarked on a completely different and the outside world, but there are many similarities in the prosperity.
In fact, ungulates in South America the most important target groups in the south hoofed (notougulate), which themselves account for almost half of South America over the history of ungulates, but does not include other categories southern ungulates.
There are other southern ungulate hoof different purpose (xenungulata), sliding talus head (litopterna), focal animal head (pyrotheria), flash animal head (astrapotheria) and so on.
Have to say something, narrow south side ungulate hoofed purpose only guidelines, and broad is what we often say that the south ungulates include almost all live in the South American ungulates.
The above-said types, the people most in contact, only a sliding talus head (litopterna) members, and the animals were divided into two categories:
Another similar form of the camel, it can be said of the camel and the class of convergent evolution in North America, after the bow beast (macrauchenia) as the representative. Wide variety of limbs and neck are fairly long, there is a retractable nose, and is somewhat similar to modern tapirs. Survival of the Pleistocene have been some areas of the species, population or even stick to the early Holocene.
They are present in the talus slide a very successful, not only a large number of newborn mammals in North America vigorously wave of the invasion is not dead, but also invaded North America, and South America and the camel, horse, deer fierce competition, to won her a place to stay and continue to maintain a prosperous, until the advent of before and after the Quaternary glacial and disappear again.
In fact, we usually say the posterior arch of the beast, beasts are all slip away from a class or a genus name, but said not one.
Second, we can see that although the southern ungulates adapted to local environment and the development of a variety of types, but more progress in the face of the Tertiary mammals the size of the invasion and competition, a lot of the original, conservative South America ungulates have to have perished, we can see their evolution although found a safe haven, but "gentiles" As a result, they still have to give up the position, if the North and South America are not connected, they can be saved, but evolution there is no if's. Survival of the fittest, natural _select_ion, the same eternal truth.
Other southern ungulates are not very prosperous before:
Different shoe project (xenungulata), confined to the Paleocene in South America, the survival of a class of animals, only one is represented by Oligocene extinction. Its bone structure is very special, very difficult for any type of known ungulate contrast, is believed to be a festival of early ankle relic species of animals evolved in the larvae's.
Focal animal head (pyrotheria), focal animal was found in ancient volcanic ash in the name, size like mastodons, nose in the head also has a very short but similar to the trunk of the nose. But there are six prominent teeth, lived in the Oligocene, only one is a life experience is confusing, the former motherland can not be found after the Sun, but it should be an early ankle section of the class relic species evolved in larvae.
It and Asia, North America and other places mastodon convergent evolution, stout body, with 3-3.5 meters, so that should be a way of life and by class as close to possible to live in small groups on the savanna.
Flash animal head (astrapotheria), lived in the Oligocene to Miocene, the size, such as rhinos, a pair of short maxillary prominent teeth, lower jaw is relatively very long, projecting forward. Should also have a similar image of the proboscis.
Flash mammals native of South America in the early origin and ankle section of class, and later developed independently in South America only to a class of giant creatures. They appears to increase toward the body's way of walking, kind, though a small, but they are representative.
In the late part of the flash beast standing shoulder another job more than 1.5 meters, at the time of South America can be described as contemporary monster.
However, the earlier they are extinct, and in the Miocene to have disappeared.
Possible biological invasion and the then North America and South America, there is great competition between the poor rodents.
South ungulates in the late Oligocene to late Miocene reached the climax stage of evolution, species after another, many number to type, represented by the beast and the beast Haig, very many species.
From the Pliocene to Pleistocene, meat animals, and the advancement of higher North American ungulates to continue to arrive, so that various types of backward southern ungulates have been pushed out of the survival of the stage, of course, part of the ungulates in the southern the decline had begun before.
Most of the original Southern ungulates is difficult to compete with these outsiders, to the late Pleistocene, once prosperous and dominate the south of South America millions of years to have become extinct ungulates, in addition to very few individuals in remote areas species has lasted thousands of years, then failed to escape the doom of extinction, the modern view of all the South are extinct ungulates.
Ungulates in the south and geographical specificity limitations. Age and address in the identification of fossils is often somewhat difficult time, generally in a period of the South is estimated ungulate survival of premature, and resulted in some people's confusion, the parallel development of other animals as a real relationship with the system, even to South America that is the center of the development of ungulates, such views are wrong, and understanding.
We hoofed the South is divided into five sub-orders (now how to divide, not clear whether there is a change)
1, the ancient southern ungulates (notioprogonia)
South of the original type of early ungulates, in addition to North American soil column beast (arctostylopus) and the Asian unearthed ancient columns beast (palaeostylopus), other members present in South America only. In the middle, basically to have been declared extinct.
2, heavy-hoofed (entylonychia)
A medium-sized ungulates South teeth have their own unique side, some members still have very sharp canine teeth. Limbs of medium length, head size is moderate, according to bones of view, action is not very rapid, and the Northern Hemisphere blunt foot class convergent evolution, appeared in a number of members of the Eocene and Miocene launched his own group in a small the development of climax but then the momentum of the decline occurred.
3, arrow tooth mammals (toxodontia)
The south are large ungulates, the general size of 1.8-3 m, is the largest and a very special branch of the Oligocene began to appear, reached a peak in the Miocene period, some members of the living habits of close to rhinos. The other part is the path and the hippopotamus is very similar.
4, Haig mammals (hegetotheria)
Take a class of very successful small southern ungulates, and rabbit classes, rodents convergent evolution, since there has been from the demise of the last period, Haig Mammals are a class of very active, body size, generally close to the mouse , rabbit size.
5, India rodents (typotheria)
Is a class of evolution, survival of the South close to ungulates rodents, canines and premolars completely degraded, leaving no trace but a similar number of members of the class, like the early ankle section, not too prosper. Ungulates of all the South's most easily overlooked in a class group.
The following should be mentioned that a class of very special creatures, mammal teeth, mainly in the Oligocene, Miocene survival. Previously been classified as ungulates south, then north to be treated as a branch of ungulates, but later with the in-depth study and compare many kinds of bones, found their own unique characteristics of such species have been large enough to completely independent, self-contained then Head: Head animal teeth, which mesh organisms. Size vary considerably, and very specialized.
Incisor completely degraded, maxillary contraction, the formation of the "short side", the first molar degradation, after the large molars, mandibular advancement, according to the position of the nasal bone may also have a nose like a tapir.
These old-time ungulate biology, in other regions between early to be natural waving you out of the big stage, but in South America, but only so that they enclosed large garden to continue this development, as well as a "hundred foot contend," the spectacular situation .
South ungulates, sliding talus class, coke mammals, flash mammals, different foot type, tooth type, and the great poverty of indigenous and local rodents and other early primitive mammals, marsupials and birds constitute the world one of the most beautiful eco-Grand View Garden.
Helpless geological changes, higher ungulates in North America and the invasion of classes allows the meat of these had very prosperous in the third century embarked on a premature extinction of animals, the road, over time, in the Quaternary, has been endangered animals, and finally the end of the Pleistocene, have been eliminated.
South ungulates as a class of ancient mammals, the development of natural causes such a success, but also factors in the evolution of their own, although the competition for survival in this game down the final curtain is not their own, but they are quite good performance .
They are proud of the darling of nature. |