Paraconcavistylon
Paraconcavistylon Temporal range:
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Scientific classification | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Order: | Trochodendrales |
Family: | Trochodendraceae |
Genus: | †Paraconcavistylon Manchester, Kvaček, & Judd, 2020 |
Species: | †P. wehrii
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Binomial name | |
†Paraconcavistylon wehrii (Manchester et al., 2018)
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Synonyms | |
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Paraconcavistylon is an extinct genus of flowering plant in the family Trochodendraceae comprises a single species, Paraconcavistylon wehrii. The genus is known from fossil fruits and leaves found in the early Eocene deposits of northern Washington state, United States, and southern British Columbia, Canada. The species was initially described as a member of the related extinct genus Concavistylon as "Concavistylon" wehrii, but subsequently moved to the new genus Paraconcavistylon in 2020 after additional study.
Distribution and paleoenvironment
Paraconcavistylon wehrii is known from specimens which were recovered from outcrops of the early Eocene,
Taxonomy and phylogeny
The
Often plant fossils are isolated parts such as leaves or seeds, which makes it difficult to identify relationships to other isolated parts. Such fossils from the same species are described as
Trochodendraceae |
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Paraconcavistylon wehrii is one of between three and four trochodendraceae species that have been described from the Klondike Mountain Formation. Broadly circumscribed three other species have been identified at Republic,
Description
The
P. wehrii twigs have alternating leaves with terminal and axillary buds. The raceme is born from a fork of the twig and leaf, as are the pointed buds. Typically the axillary buds are around 8 mm (0.31 in) long by 1.8 mm (0.071 in) while the terminal buds are larger at 1 cm (0.39 in) long by 5 mm (0.20 in). Encircling the twig are between five and eight distinct terminal bud scars.[2]
The leaves have a narrow base connecting to the 8–12 mm (0.31–0.47 in) long petioles. They have regularly spaced teeth along the margin that are rounded and bearing glands, and a few specimens from the McAbee site also have distinct laminal lobes bracketing the petiole. The leaves have an overall range between 10.2–12.5 cm (4.0–4.9 in) long by 3.1–3.5 cm (1.2–1.4 in), with an obovate outline. Like Trochodendron the leaves have a pinnate vein structure, with between eight and fifteen secondary veins that fork from the central main vein and arch towards the leaf apex before merging with the secondary above.[2]
References
- ^ doi:10.1139/E04-095.
- ^ S2CID 92201595.
- hdl:2115/36747.
- doi:10.3133/b1597.
- ^ .