Development of the early Cambrian oryctocephalid trilobite Oryctocarella duyunensis from western Hunan, China
Development of the early Cambrian oryctocephalid trilobite Oryctocarella duyunensis from western Hunan, China
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DOI：
10.1017/jpa.2020.111
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发表时间：
2021-07-01
影响因子：
1.4
通讯作者：
Peng, Shanchi
中科院分区：
文献类型：
--
作者：
Dai, Tao;Hughes, Nigel C.;Peng, Shanchi
湖南省西部布林剖面下寒武统巴朗组（第4阶段，第2统）中的Oryctocarella duyunensis化石，含有大量的有节标本，可描述所有的裂肢类。在该集合中观察到的最大胸节段数为11。Meraspid的增长是伴随着整体形式的渐进和逐渐变化，这种动物表现出一个homemandiously分段的树干，在个体发育过程中的pygidial段的数量变化。这种变化允许各种合理的解释，但模型的连续龄期定义的胸节的数量，并在suborder的臀节的数量，是极不可能解释的增长模式，因为它会导致损失的树干节之间的一些龄期。度为基础的个体发育分期与观察到的变化是兼容的。
Abundant articulated specimens of the oryctocarine trilobite Oryctocarella duyunensis from the lower Cambrian (Stage 4, Series 2) Balang Formation at the Bulin section in western Hunan Province, South China, permit the description of all meraspid degrees. The maximum number of thoracic segments observed in this collection is 11. Meraspid growth was accompanied by progressive and gradual change in overall form, and this animal showed an homonymously segmented trunk with variation in the number of pygidial segments during ontogeny. Such variation permits a variety of plausible explanations, but a model of successive instars defined by the number of thoracic segments, and in suborder by the number of pygidial segments, is highly unlikely to explain the growth pattern because it would result in the loss of trunk segments between some instars. Degree-based ontogenetic staging is compatible with the variation observed.