Ontogenetic analysis of Anisian (Middle Triassic) ptychitid ammonoids from Nevada, USA
Ontogenetic analysis of Anisian (Middle Triassic) ptychitid ammonoids from Nevada, USA
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DOI：
10.1017/jpa.2020.25
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发表时间：
2020-09-01
影响因子：
1.4
通讯作者：
Lehmann, Jens
中科院分区：
文献类型：
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作者：
Bischof, Eva A.;Lehmann, Jens
Ptychitesis是三叠纪分布最广的菊石属之一，是一个科和总科的同名。然而，该属的代表大多表现出低水平的表型差异。此外，大量的分类群是基于只有少数保存较差的标本，创造了挑战，以确定ptychitid分类。因此，需要一种新的方法来改善卷囊线虫多样性研究。在这里，我们调查Ptychitesspp。产于内华达州的中晚期阿尼西亚。记录的种类包括Ptychites embreein。例如，其特征是平均海螺直径小得多，并且显示出比大多数亲戚更渐屈的卷曲。新物种的范围从Gymnotoceras mimetus到Gymnotoceras rotelliformiszones，这使得它成为该属中分布时间最长的物种。第一次，在可能的情况下，从横截面获得Ptychites的个体发育。横截面突出了独特的个体发育轨迹在ptychitids。这表明，尽管表现出很小的表型差异，Ptychiteswas高度个体发育分化，因此在物种水平上的高分类多样性是合理的物种调查。UUID：http://zoobank.org/5abe2487-8a00-4b48-adc7-ec7db7a097f7
Ptychitesis among the most widely distributed ammonoid genera of the Triassic and is namesake of a family and superfamily. However, representatives of the genus mostly show low-level phenotypic disparity. Furthermore, a large number of taxa are based on only a few poorly preserved specimens, creating challenges to determine ptychitid taxonomy. Consequently, a novel approach is needed to improve ptychitid diversity studies. Here, we investigatePtychitesspp. from the middle and late Anisian of Nevada. The species recorded includePtychites embreein. sp., which is distinguished by an average conch diameter that is much smaller and shows a more evolute coiling than most of its relatives. The new species ranges from theGymnotoceras mimetusto theGymnotoceras rotelliformiszones, which makes it the longest-ranging species of the genus. For the first time, the ontogenetic development ofPtychiteswas obtained from cross sections where possible. Cross-sectioning highlights unique ontogenetic trajectories in ptychitids. This demonstrates that, despite showing little phenotypic disparity,Ptychiteswas highly ontogenetically differentiated, and thus the high taxonomic diversity at the species level is justified for the species investigated. UUID:http://zoobank.org/5abe2487-8a00-4b48-adc7-ec7db7a097f7