EVOLUTION OF MOLAR OCCLUSION IN CERCOPITHECIDAE AND EARLY CATARRHINES
EVOLUTION OF MOLAR OCCLUSION IN CERCOPITHECIDAE AND EARLY CATARRHINES
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DOI：
10.1002/ajpa.1330460213
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发表时间：
1977-01-01
影响因子：
2.8
通讯作者：
KAY, RF
中科院分区：
文献类型：
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作者：
KAY, RF
始新世的原猴类可能是卡他鼻类的祖先，在每颗下臼齿上有4个刀刃状的牙嵴。每个牙嵴依次剪过2个上磨牙牙嵴。封闭峰是凹弯曲的，以保持被剪切的食物。与主破碎面相邻的2个内侧下磨牙牙顶中的每一个都在外侧下磨牙牙顶接触第二排上磨牙牙顶的同时剪切通过单个上牙顶。研磨和破碎区域仅限于次锥、三角和原锥表面。渐新世卡他鼻臼齿的破碎-研磨能力增加，保持但修改其剪切。当原锥的挤压面扩大，并增加一个挤压次锥时，第二排上颌磨牙剪切峰功能性减小。与此同时，越来越多地强调内侧波峰，使总剪切能力几乎保持不变。边缘剪切刀片是直边的;咬合刀片的前缘与咬合平面成不同角度，使得刀片在任何给定时间仅在1个点接触。早期的灵长类动物有分开的粉碎盆地，周围有剪切刀片。卡他鼻倾向于将膨胀的挤压面前后连接成所有臼齿之间的连续表面。基于新的和先前识别的特征的支序分析表明，Apidium可能与埃及古猿的关系比与副古猿的关系更密切;猕猴类来自与副古猿相关的种群; Oreopithecus同样可能来自Apidium或埃及古猿种群。
Eocene prosimians which are possible catarrhine ancestors have 4 blade-like crests on each lower molar. Each crest shears in sequence across 2 upper molar crests. Occluding crests are concavely curved to hold the foods being sheared. Each of 2 medial lower molar crests bordering the principal crushing surface shear past single upper crests at about the same time the lateral lower molar crests contact the 2nd rank of upper molar crests. Grinding and crushing areas are restricted to hypoconid, trigonid and protocone surfaces. Oligocene catarrhine molars have increased crushing-grinding capacities and maintained but modify their shearing. As the crushing surface of the protocone expands and a crushing hypocone is added, the 2nd rank upper molar shearing crests are functionally reduced. At the same time medial crests are increasingly emphasized so that the total shearing capacity remains virtually unchanged. Marginal shearing blades are straight edged; leading edges of occluding blades are set at different angles to the occlusal plane so that blades contact at only 1 point at any given time. Early Primates have separate crushing basins surrounded by shearing blades. Catarrhines tend to link expanding crushing surfaces anteroposteriorly into a continuous surface between all molars. A cladistic analysis based on both new and previously recognized characters indicates that Apidium may be more closely related to Aegyptopithecus than to Parapithecus; cercopithecids are derived from a Parapithecus-related stock; Oreopithecus could equally well have come from an Apidium or Aegyptopithecus stock.