[Taxacom] New genus of early angiosperms (Early Jurassic flowers)
John Grehan
calabar.john at gmail.com
Sat Dec 22 11:37:43 CST 2018
Croizat always said that there were angiosperms in the Jurassic. Nice
confirmaton.
John Grehan
On Wed, Dec 19, 2018 at 9:32 PM Kenneth Kinman <kinman at hotmail.com> wrote:
> Dear All,
> I didn't plan to post anything further on the origin of angiosperms,
> but a fascinating new genus of angiosperm was named and described this week
> (called Nanjinganthus), and it is from the Early Jurassic. Although it is
> clearly an angiosperm, it's phylogenetic position has not been determined,
> so it is unclear if it is a stem group angiosperm or a member of the crown
> group. In any case, it is an exciting development, and here is a weblink
> to the article (and the abstract is given below):
> https://elifesciences.org/articles/38827
>
> Abstract
>
> The origin of angiosperms has been a long-standing botanical debate. The
> great diversity of angiosperms in the Early Cretaceous makes the Jurassic a
> promising period in which to anticipate the origins of the angiosperms.
> Here, based on observations of 264 specimens of 198 individual flowers
> preserved on 34 slabs in various states and orientations, from the South
> Xiangshan Formation (Early Jurassic) of China, we describe a fossil flower,
> Nanjinganthus dendrostyla gen. et sp. nov.. The large number of specimens
> and various preservations allow for an evidence-based reconstruction of the
> flower. From the evidence of the combination of an invaginated receptacle
> and ovarian roof, we infer that the seeds of Nanjinganthus were completely
> enclosed. Evidence of an actinomorphic flower with a dendroid style,
> cup-form receptacle, and angiospermy, is consistent with Nanjinganthus
> being a bona fide angiosperm from the Jurassic, an inference that we hope
> will re-invigorate research into angiosperm origins.
> https://doi.org/10.7554/eLife.38827.001
>
> ________________________________
> From: Taxacom <taxacom-bounces at mailman.nhm.ku.edu> on behalf of Kenneth
> Kinman <kinman at hotmail.com>
> Sent: Friday, December 14, 2018 8:43 AM
> To: taxacom at mailman.nhm.ku.edu
> Subject: [Taxacom] Where (and when) angiosperms originated
>
> Dear All,
> I've been studying the literature on angiosperm origins, and there
> is apparently a very long period of time between the origin of angiosperms
> and the origin of crown group angiosperms. I have concluded that where
> angiosperms originated is probably also a totally different place.
> Crown group angiosperms probably originated in Gondwana, most
> likely in Australia since so many basal families occur in the forests of
> northern Queensland (which in the past were even closer to New Caledonia).
> However, where the first angiosperms originated is a totally different
> question. My hypothesis is that the first angiosperms perhaps split from
> their probable sister group Caytoniales as far away as Laurasia, rather
> than Gondwana (perhaps in the Permian, if not earlier).
> Of course, the larger numbers of records of putative angiosperm
> pollen (and Caytonia fossils) in Europe and eastern North America could be
> due to more intensive research in those areas, so an origin in Africa
> shouldn't be ruled out. What route they took to Australia could depend on
> when that expansion took place. Papers by Dettmann suggested that they got
> to Australia through Antarctica. In any case, there is no evidence that
> angiosperms originated in Australia, but there is plenty of evidence that
> crown group angiosperms did originate in Australia (far from where the
> earliest angiosperms originated).
> -------------Ken Kinman
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