Nanjinganthus, a Jurassic angiosperm!

[Halichoeres]

They found 198 of them, preserved in all kinds of different orientations, so they can confidently reconstruct its morphology. Meet Nanjinganthus dendrostyla.



There are probably earlier flowers if people just keep looking. Really cool find.

Open access: https://elifesciences.org/articles/38827

[Mirroraptor]

Busy to fieldwork, read this a week ago...few question:
How do they prove that this is not a crosscut of a gymnosperm cone?
I have been paying attention to Mr.Wang's team for a long time, they summed up a lot of interesting Jurassic angiosperms, but some of them still not very clear until today.

[Halichoeres]

Sorry about the late reply! I am not terribly knowledgeable about paleobotany, but they address the alternative interpretation as a gymnosperm cone. According to the authors, the presence of seeds in some of the specimens means they can't be male cones, and they interpret fully enclosed seeds as evidence against being a gymnosperm cone: "The integral ovarian roof of Nanjinganthus has no opening (Figures 4c and 5h). After burial, this ovarian roof can block the sediment from entering the ovarian locule (Figure 7e–g). That this space remained free of sediment suggests a full enclosure of the ovules/seeds, securing an angiospermous affinity for Nanjinganthus." Perhaps you're better equipped than I am to adjudicate whether that constitutes good evidence.

[Halichoeres]

Worth noting that the identity of Nanjinganthus as an angiosperm is the topic of a spirited debate in the literature, one that I'm not really qualified to evaluate.

This article says that a synapomorphy for angiosperms is pentamery (having reproductive parts in multiples of five units), which Nanjinganthus lacks: https://nph.onlinelibrary.wiley.com/doi/pdfdirect/10.1111/nph.15974

The authors retort that this is a eudicot feature, not an angiosperm one: https://www.sciencedirect.com/science/article/pii/S2096519220301713

I'm not a botanist, but it does seem at least plausible that monocots are the oddballs here in lacking pentamery.

Anyway, a much-disputed taxon.

[Newt]

From my limited knowledge, it seems basal angiosperms are kind of all over the place with part numbers. Some show an angiosperm-like 3-merous pattern, such as Asiminaceae and Aristolochiaceae. Some are 5-merous. Some seem kind of unconstrained and have however many meres they happen to feel like that day, like waterlilies. It seems to me that 5-merous and 3-merous symmetries are likely synapomorphies of particular angiosperm lineages and that it is too early to call any of them the plesiomorphic state. But I too am not a botanist.


Also, Sanmiguelia.