Taxacom: "Early Permian" angiosperms... real or not real taxa/names?

[Tony Rees]

Dear all, I have done a bit more digging regarding the early angiosperm
fossil record - as mentioned earlier, I am by no means a specialist in this
area, but do have a few paleobotany books on my shelf for reference/general
interest (plus a botanical degree from many years ago now...).

Apart from the evidence/hypotheses/indications based on rates of molecular
evolution, D. Silvestro et al., 2021. "Fossil data support a pre-Cretaceous
origin of flowering plants", Nature Ecology & Evolution 5: 449-457,
presented back-calculations indicating that, 198 angiosperm clades (APG IV
families) "several families [of angiosperms: namely Lardizabalaceae,
Papaveraceae and Triuridaceae] with living descendants originated in the
Jurassic". However, in a response to this paper published as yet only on
bioRxiv, G.E. Budd et al., (2021, "Fossil data do not support a long
pre-Cretaceous history of flowering plants", doi 10.1101/2021.02.16.431478)
dispute Silvestro et al's methodology and state: "their results are
entirely compatible with an origin of angiosperms in the Cretaceous", and
further, "If we take the results of Silvestro et al. at face value, they
imply that many eudicot lineages (united by their distinctive tricolpate
pollen, modified into tricolporate and triporate within the clade) extend
deep into the Jurassic. This would conflict strongly with the sequential
appearance of monosulcate, tricolpate and tricolporate pollen in the
Cretaceous dispersed pollen record, which represents a vastly broader
stratigraphic and geographic sample of the world’s past vegetation than the
record of other plant parts", which is a point I have alluded to earlier:
especially since the fossil record of Cretaceous, Jurassic, Triassic and
even Permian pollen and spores is by now extremely well documented.

Nevertheless, a few "modern" claims of pre-Cretaceous angiosperm fossils
have continued to surface. Persons interested in this area may have come
across Archaefructus Sun, Dilcher, Zheng & Zhou, 1998 (Science 282:
1692-1695), described as from the Upper Jurassic of China, however later
re-dated to Early Cretaceous (c.125 million years old). More recently,
Nanjinganthus Fu et al., 2018 has been described as an Early Jurassic
fossil angiosperm from China, however its claimed angiosperm affinities
have been disputed by others, e.g. Coiro et al., 2018 who believe that the
fossils represent a conifer (ref/s on Wikipedia and elsewhere). Most
recently, Florigerminis Cui et al., 2022 has been described from
the Middle–Late Jurassic Jiulongshan Formation of Inner Mongolia, although
there have been suggestions in the past (refuted by Cui et al.) that this
formation is Early Cretaceous; this report is too new to have yet been
assessed by other works in the field.

Other than Florigerminis as above, the oldest other "accepted" angiosperm
fossil, along with Archaefructus, appears currently to be Montsechia
vidalii (Zeiller) Teixeira from the Barremian (in other words, not even the
earliest Cretaceous, with the Hauterivian, Valanginian, and Berriasian
preceding it), as more fully described by Gomez et al, 2015, "Montsechia,
an ancient aquatic angiosperm", PNAS 112(35) 10985-10988,
doi: 10.1073/pnas.1509241112. This genus is considered by Gomez et al. to
be a representative of a new, extinct family of its own, basal in the
Ceratophyllales, although historically even this plant has not always been
considered to be an angiosperm on account of its unusual appearance, being
placed by previous workers in liverworts, horsetails, conifers, and
Gnetales before its angiosperm features were established (refer Gomez et
al. refs 9 through 12).

All the above is just supporting information, which nonetheless does
indicate to me that a degree of skepticism should apply to Wachtler's
claims of well-developed angiosperm flowers in the Early Permian. Unless
other opinions are forthcoming, my present inclination is to accept the
dating of the sediments from which Wachtler's fossils have been extracted
(which do seem to be corroborated elsewhere, however with a more
conventional "gymnosperm" flora), but treat his taxonomic assignment as
questionable, for example to assign his genus names to Spermatophytina
incertae sedis in my system (thus not placed explicitly in either
Angiospermae or Gymnospermae), as accepted taxa at this time (thus not
nomina dubia or taxa inquirenda, which are alternative available options);
or indeed, perhaps "taxon inquirendum" would most applicable. All further
thoughts welcome!

Regards - Tony