对二形体的定量证据表明,在Placerias hesternus的上犬形过程中发生了性选择
James L Pinto1, Charles R Marshall1, Sterling J Nesbitt2
1Department of Integrative Biology and Museum of Paleontology, University of California, Berkeley, California, United States of America.
PloS one
|May 31, 2024
概括
在Placerias hesternus犬形过程中,像牙一样的投影,显示出明显的尺寸变化,支持这个特里亚斯纪晚期二动物的性二态. 这种特征很可能在种内竞争中发挥作用.
科学领域:
- 古生物学的古生物学
- 脊椎动物古生物学 脊椎动物古生物学
- 古生物学的古生物学
背景情况:
- 普拉塞里亚斯 (Placerias hesternus) 是一个特里亚斯纪晚期的二龙,代表了最后一个巨型动物同类动物之一.
- 自20世纪50年代以来,人们一直怀疑雄骨上的突出牙形投射,即形过程是性二态的.
- 之前关于Placerias hesternus二态性的说法缺乏严格的定量研究.
研究的目的:
- 在Placerias hesternus的犬形过程中量化调查性二态的假设.
- 分析Placerias采石群体的部,前部,四角部和部的测量结果.
- 为了确定化石样本中是否存在不同的形态,表明二形态.
主要方法:
- 从四个骨元素 (大,大前,四角,骨) 收集了25个测量结果.
- 采用最大概率框架来比较单模式与双模式分布,适用于每个测量集.
- 利用聚类分析来识别尾和其他元素中的不同形态.
主要成果:
- 来自Placerias采石区种群的完整的部揭示了两种不同的犬形过程形态:一个较短的和一个较长的形式.
- 统计分析强烈支持犬形长度的双模分布,集群分析清楚地区分了两个尾形态.
- 聚类分析表明,方形形状的潜在二态,但其他元素缺乏强有力的证据,以双式分布.
结论:
- 这些发现从数量上支持了长期以来在Placerias犬形过程中发生性二态的假设.
- 对于这个群体,以前拒绝了像年轻人或时长物种采样等替代解释.
- 狗形过程很可能是一个次要的性特征,可能用于种内竞争,其证据是它在非大骨元素中缺乏二态性,并且在较大的形态中增加了变异.
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