Yimaia

Yimaia is a extinct genus of Ginkgoalean tree, and the only member of the family Yimaiaceae. In botanical form classification, its a form taxon for ginkgoalean ovulate organs. Yimaia species are distinguished from other Ginkgoales by the presence of "Ovulate organs consisting of a peduncle and up to eight or nine terminal, sessile, contiguous and orthotropous (straight, upright and with a micropyle at apex) ovules." The ovules are associated with leaves of either Baiera or Ginkgoites leaf morphospecies.[1] Fossils have been found in Middle Jurassic deposits in China.

Yimaia
Temporal range:
Restoration of Yimaia recurva from the Jurassic of China
Scientific classification Edit this classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Gymnosperms
Division: Ginkgophyta
Class: Ginkgoopsida
Order: Ginkgoales
Family: †Yimaiaceae
Zhou, 1997
Genus: †Yimaia
Zhou et Zhang, 1988
Species
  • Yimaia capituliformis Zhou, Zheng and Zhang, 2006
  • Yimaia qinghaiensis Wu, Yang and Zhou, 2006
  • Yimaia recurva (type) Zhou et Zhang, 1988

Species
  • Yimaia capituliformis Zhou, Zheng and Zhang, 2006 Daohugou Bed, China, Callovian[2] Associated with leaves of Ginkgoites type
  • Yimaia qinghaiensis Wu, Yang and Zhou, 2006 Shimengou Formation, Qinghai, China, Middle Jurassic[3] Associated with leaves of Baiera furcata type.
  • Yimaia recurva (type) Zhou et Zhang, 1988 Yima Formation, Henan, China, Middle Jurassic

References
  1. Zhou, Zhi-Yan (March 2009). "An overview of fossil Ginkgoales". Palaeoworld. 18 (1): 1–22. doi:10.1016/j.palwor.2009.01.001.
  2. Zhou, Zhiyan; Zheng, Shaolin; Zhang, Lijun (April 2007). "Morphology and age of Yimaia (Ginkgoales) from Daohugou Village, Ningcheng, Inner Mongolia, China". Cretaceous Research. 28 (2): 348–362. doi:10.1016/j.cretres.2006.05.004.
  3. Wu, Xiangwu; Yang, Xiaoju; Zhou, Zhiyan (April 2006). "Ginkgoalean ovulate organs and seeds associated with Baiera furcata-type leaves from the Middle Jurassic of Qinghai Province, China". Review of Palaeobotany and Palynology. 138 (3–4): 209–225. doi:10.1016/j.revpalbo.2006.01.009.
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