Yimaia

Yimaia is a extinct genus of Ginkgoalean plant, and the only member of the family Yimaiaceae. In the botanical form classification scheme, it represents ovulate organs. It is distingushed from other Ginkgoales by the presence of "Ovulate organs consisting of a peduncle and up to eight or nine terminal, sessile, contiguous and orthotropous ovules." the ovules are associated with leaves of the Baiera or Ginkgoites type morphology.[1] Fossils have been found in Middle Jurassic deposits in China.

Yimaia
Temporal range: Middle Jurassic
Yimaia capituliformis with associated Ginkgoites leaves
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
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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