北坡上的恐龙,阿拉斯加:高度,最近的白时期环境
Science (New York, N.Y.)
|September 25, 1987
概括
来自阿拉斯加的恐龙化石显示,像哈德罗萨尔这样的大型食草动物全年都生活在极地,这挑战了灭绝理论. 这表明恐龙可以忍受极端的气候变化,而不仅仅是短暂的冲击.
科学领域:
- 古生物学的古生物学
- 古气候学 古气候学
- 恐龙生态 恐龙生态学
背景情况:
- 晚期坎帕尼亚 - 早期马斯特里希特时期阿拉斯加北坡生态系统支持了多样化的恐龙动物群,包括lambeosaurine hadrosaurids, tyrannosaurids和troodontids.
- 环境的特点是三角洲地区的草本植被和温和到冷温的树木和宽叶树木的森林.
- 高的旧度 (北70-85度) 表示极端的季节性变化在阳光照射,温度和草食动物的食物可用性.
研究的目的:
- 为了调查恐龙在晚白纪的高度环境中的存在和行为.
- 评估极地地区恐龙全年居住的可行性,极地地区有极端的季节变化.
- 通过检查生存策略,挑战玻利德撞击假说作为恐龙灭绝的唯一原因.
主要方法:
- 对各种恐龙种类的丰富骨遗骸的分析.
- 阿拉斯加北坡古地理和古环境条件的重建.
- 古植物学分析以了解陆地植物群落和食物来源.
主要成果:
- 有证据表明,哈德罗萨,包括幼和成年动物,在北极高度处全年居住.
- 幼年和成年恐龙的存在表明,在恶劣的季节条件下成功繁殖和生存.
- 长途迁移到当代常青植物群很可能是由食草动物进行的.
结论:
- 恐龙,特别是龙,能够全年居住在具有显著季节性变异的高度生态系统中.
- 这些发现挑战了这样的假设,即短期的环境破坏,例如波体撞击,是恐龙灭绝的主要驱动因素.
- 恐龙的生存策略可能包括适应极端的季节变化,而不是仅仅依靠远离临时不利条件的迁徙.
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