Increasing morphological complexity in multiple parallel lineages of the Crustacea
Increasing morphological complexity in multiple parallel lineages of the Crustacea
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DOI：
10.1073/pnas.0709378105
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发表时间：
2008-03-25
影响因子：
11.1
通讯作者：
Wills, Matthew A.
中科院分区：
文献类型：
--
作者：
Adamowicz, Sarah J.;Purvis, Andy;Wills, Matthew A.
在生命历史中发现宏观进化趋势和规律的前景极具吸引力，但几乎没有发现普遍的趋势。在这里，我们展示了一个主要分支中大多数深层谱系的形态复杂性的平行增加。我们主要研究甲壳类动物，测量四肢的形态分化。首先，我们显示了显生界化石记录中66个自由生活的序级分类群的复杂性增加的明显趋势。接下来，我们证明这种趋势是普遍存在的，在已灭绝的古生代和相关的新近分类群之间的12个配对比较中(跨越5个形态多样性指数)，有10个或11个发生。这清楚地将这种模式与世系分类的效果区分开来。此外，新出现的分类群往往具有比同时代平均水平更多的肢体类型和更高的肢体分化程度，而那些灭绝的分类群则表现出高于平均水平的肢体冗余。当代物种多样性的格局部分反映了古生物的趋势。这些结果罕见地展示了一种大规模的、可能是驱动的趋势，这种趋势发生在多个独立的谱系中，并在很长一段时间内和现在影响着物种的形式和数量。
The prospect of finding macroevolutionary trends and rules in the history of life is tremendously appealing, but very few pervasive trends have been found. Here, we demonstrate a parallel increase in the morphological complexity of most of the deep lineages within a major clade. We focus on the Crustacea, measuring the morphological differentiation of limbs. First, we show a clear trend of increasing complexity among 66 free-living, ordinal-level taxa from the Phanerozoic fossil record. We next demonstrate that this trend is pervasive, occurring in 10 or 11 of 12 matched-pair comparisons (across five morphological diversity indices) between extinct Paleozoic and related Recent taxa. This clearly differentiates the pattern from the effects of lineage sorting. Furthermore, newly appearing taxa tend to have had more types of limbs and a higher degree of limb differentiation than the contemporaneous average, whereas those going extinct showed higher-than-average limb redundancy. Patterns of contemporary species diversity partially reflect the paleontological trend. These results provide a rare demonstration of a large-scale and probably driven trend occurring across multiple independent lineages and influencing both the form and number of species through deep time and in the present day.