Search results
Results From The WOW.Com Content Network
Diagrams of hand skeletons of various mammals, left to right: orangutan, dog, pig, cow, tapir, and horse. Highlighted are the even-toed ungulates pig and cow. In even-toed ungulates, the bones of the stylopodium (upper arm or thigh bone) and zygopodiums (tibia and fibula) are usually elongated. The muscles of the limbs are predominantly ...
The order Artiodactyla consists of 349 extant species belonging to 132 genera. This does not include hybrid species or extinct prehistoric species. Modern molecular studies indicate that the 132 genera can be grouped into 23 families; these families are grouped into named suborders and many are further grouped into named clades, and some of these families are subdivided into named subfamilies.
Oxygen-18 values and osteosclerotic bones indicate that the raccoon-like or chevrotain-like Indohyus was habitually aquatic, but 13 C values suggest that it rarely fed in the water. The authors suggest this documents an intermediate step in the transition back to water completed by the whales, and suggests a new understanding of the evolution ...
Diagram featuring the typical skeletal of a toothed whale (top) and a baleen whale (bottom) The cetacean skeleton is largely made up of cortical bone , which stabilizes the animal in the water. For this reason, the usual terrestrial compact bones, which are finely woven cancellous bone , are replaced with lighter and more elastic material.
Growth occurs at the tip, initially as cartilage that is then mineralized to become bone. Once the antler has achieved its full size, the velvet is lost and the antler's bone dies. This dead bone structure is the mature antler. In most cases, the bone at the base is destroyed by osteoclasts and the antlers eventually fall off. [62]
The evolution of cetaceans is thought to have begun in the Indian subcontinent from even-toed ungulates (Artiodactyla) 50 million years ago (mya) and to have proceeded over a period of at least 15 million years. [2] Cetaceans are fully aquatic mammals belonging to the order Artiodactyla and branched off from other artiodactyls around 50 mya.
Daeodon skeletal reconstruction and size diagram The skeleton is fairly unspecialized in entelodonts. They retain typical artiodactyl skeletal traits such as a double-pulley ankle joint and paraxonic ("even toed") feet with weight split evenly between the two middle toes.
All other Artiodactyla are relatives of these two groups. δO 18 values and osteosclerotic bones indicate that the raccoon-like Indohyus was habitually aquatic. However, it is still unclear if Indohyus primarily fed on land or in water.