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哈拉米亚类动物和三叠纪哺乳动物的进化
F A Jenkins1, S M Gatesy, N H Shubin
1Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
Nature
|February 20, 1997
概括
早期哺乳动物的亲属哈拉米耶,由于牙的位置不确定,它们是神秘的. 新的化石揭示了它们是具有独特的穿孔粉碎阻塞的专业哺乳动物,澄清了它们的进化位置.
科学领域:
- 古生物学的古生物学
- 哺乳动物进化 哺乳动物进化
- 中生代哺乳动物 中生代哺乳动物
背景情况:
- 哈拉米伊达代表了一些最早的化石哺乳动物,可以追溯到特里亚斯纪晚期.
- 由于牙的方向和的位置不确定,它们与其他哺乳动物血统,特别是多核动物的关系一直在争论中.
- 以前的解释质疑了它们的绝对哺乳动物地位.
研究的目的:
- 解决早期哺乳动物中Haramiyidae的遗传学位置和分类学地位.
- 根据新的化石证据,阐明哈拉米亚类动物的食机制和生态.
- 为了更好地了解哈拉米耶德牙解剖学及其对哺乳动物进化的影响.
主要方法:
- 挖掘和分析化石遗骸,包括牙,部和其他骨元素,来自东格陵兰的上纪沉积物.
- 对孤立的牙和相关的骨材料进行详细的形态检查,以确定牙的方向和关节.
- 对哈拉米伊德牙闭塞模式与其他中生代哺乳动物的比较分析.
主要成果:
- 发现了以前未知的哈拉米耶德牙,大和骨遗骸.
- 确定哈拉米伊德牙在下巴内的准确方向和位置.
- 鉴定了一种与其他中生代哺乳动物不同的新型穿孔-粉碎封闭模式.
- 证实哈拉米亚类动物是高度专业化的哺乳动物.
结论:
- 哈拉米亚类动物是高度专业化的哺乳动物,不仅仅与多种结核动物有关,而且具有独特的牙闭塞机制.
- 来自东格陵兰岛的新化石证据解决了关于哈拉米耶德解剖学和进化关系的长期模两可.
- 这一发现大大提高了我们对中生代早期哺乳动物多样化和适应的理解.
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