Angiosperm affinities of Surangea from the late Cretaceous Deccan Intertrappean Beds of central India
Angiosperm affinities of Surangea from the late Cretaceous Deccan Intertrappean Beds of central India
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DOI：
10.35535/acpa-2022-0013
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发表时间：
2022
影响因子：
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通讯作者：
D. Ramteke;Selena Y. Smith;D. Kapgate;E. Stanley;S. Manchester
中科院分区：
文献类型：
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作者：
D. Ramteke;Selena Y. Smith;D. Kapgate;E. Stanley;S. Manchester
Surangea Chitaley et Sheikh属，基于印度中部德干间陷层的矿化标本，最初被认为是蕨类大孢子囊的代表。对原始材料和新标本的重新检查表明，其结构是具有明确定义的种子的蒴果，而不是大孢子囊。我们详细描述了Surangea水果，果皮和微CT扫描的基础上，并记录其分布在多个地方的德干Intertraptobiles床。果实为五心皮室间开裂蒴果，每室约8-12粒种子。种子明显地被平行的脊包围，并且具有弯曲的胚/胚乳腔和突出的假种皮。这组特征表明真双子叶植物对Surangea的亲缘关系。特别是，室间开裂的蒴果，轴胎座和具假种皮的Campylotropus种子的组合表明与桃金娘目的亲缘关系，但它不完全适合现存的家庭。Surangea果实增加了马斯特里赫特晚期植物群已知被子植物的多样性。它加入了其他几个水果类型已知的德干植物群，不整齐地落入现存的家庭，可能代表一个地方性社区的一部分，屈服于环境压力相关的K-Pg边界事件和/或随后向北漂流的印度次大陆。
The genus Surangea Chitaley et Sheikh, based on permineralized specimens from the Deccan Intertrappean Beds of central India, was originally considered to represent a fern megasporangium. Reexamination of original material and new specimens has revealed that the structures are capsular fruits with well-defined seeds, rather than megasporangia. We describe Surangea fruits in detail, based on peels and micro-CT scanning, and document its distribution among multiple localities of the Deccan Intertrappean Beds. The fruits are pentacarpellate septicidal capsules with ~8–12 seeds per locule. The seeds are prominently ornamented with parallel ridges and have a curved embryo/endosperm cavity and a prominent aril. This set of features indicates eudicotyledonous affinities for Surangea. In particular, the combination of septicidal capsules, axile placentation and arillate campylotropus seeds suggests affinity with the order Myrtales, but it does not fit cleanly within an extant family. Surangea fruits add to the diversity of angiosperms known from this late Maastrichtian flora. It joins several other fruit types known from the Deccan flora that do not fall neatly into extant families, possibly representing parts of an endemic community that succumbed to environmental stress associated K-Pg boundary events and/or subsequent northward rafting of the Indian subcontinent.