Scientists have for the first time found that there is no ivory type of elephant – technology – Peop ca1835

Scientists first discovered no ivory like type — technology — people.com.cn in the main groups of proboscidean like type, developed a pair of giant incisivus (Ivory) has become a distinctive feature of this group. This structure is often used as a tool for individual feeding and for males to compete for mating rights. No ivory proboscidian usually exists only in the Oligocene (about 34 million to 23 million years ago) before the differentiation of primitive taxa, such as deinothere lower incisors only developed a pair of hook and upper incisors completely missing. In the early evolution of like type, there is a class called Platybelodon family groups, especially the elongation, mandible and lower incisors widened, shovel shaped structure is formed, the evolution direction of this peculiar has attracted the attention of researchers. In recent years, a lot of hypotheses and studies have been made on the significance of the shovel shaped jaw in the functional morphology of the shovel teeth. Recently, Chinese Academy of Vertebrate Paleontology and Paleoanthropology, Wang Shiqi, Deng Tao, Ye Jie and Gansu political Museum of ancient animal fossils of the common study found in Tongxin County of Ningxia in the Miocene (about 23 million to 5 million 300 thousand years ago) at a place of Ding Gou save fine Platybelodon of fossil cluster research results published online in the International Journal of systematic palaeontology "recently". This fossil cluster with 11 different gender and age are quite complete individual as the representative, has shaped shovel jaw and lower incisors, undoubtedly belongs to the Platybelodon, however, its ivory regardless of gender and age were missing, like in this feature type is found for the first time. This new group is named Zhao’s hidden teeth like new species. The name of the name "hidden teeth" indicates the main feature of its lack of ivory; and the name is dedicated to the discovery of the fossil group Mr. Zhao Rong. The significance of the discovery of the hidden teeth is that it can reveal the diversity of morphology and ecology in the early evolution. Proof of research and testing branch system, hidden teeth like phylogeny as Platybelodon is the sister group, but the lower incisors internal structure and Platybelodon is different, and relieving another kind of tooth like the original cross edge as is similar. In this way, the same structure of lower incisors will no longer be distinguished Platybelodon members of the Department of internal standard, but a kind of parallel evolution phenomenon. Microwear analysis and mechanical analysis of the study is that in the Platybelodon family, with hidden teeth like Platybelodon and this group as the representative of the leaves to eat, wide shovel jaw is mainly used for cutting twigs and leaves; and to the original mutual edge teeth like another group as the representative is feeding more widely, narrow the shovel shaped mandibular can be used for mining plant of shallow ground, and ivory in food collection also plays an important role in. The systematic division of the internal anatomy of the shovel also represents the ecological differentiation. In addition, the hidden teeth like the male also lack upper incisors, suggesting that male fights may not be very fierce. Therefore, the social structure of the hidden teeth may be different from that of other elephants. Perhaps in the teeth of the elephant, the male and female form a stable breeding population, and they tend to nurture their offspring. This is like a class of female students formed a matriarchal society mass nurturing offspring have a world of difference.  )相关的主题文章:

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