Abstract Detail

Paleobotany

Manchester, Steven [1], Judd, Walter [2].

Twigs with attached leaves and fruits of the extinct Eurasian Eudicot, Palibinia, from the Eocene Green River flora of Utah, USA.

In 1934, Roland Brown identified some thick linear  leaves with coarsely toothed margins and thick midribs from the Eocene Green River shales of western Colorado as Banksia comptonifolia, suggesting an unexpectedly northern distribution of this proteaceous genus. However, he indicated some hesitation about this assignment when he stated: "Choice of Banksia as a generic name for this species may leave much to be desired." MacGinitie in 1969 reassigned the species to the rosaceous genus Vauquelinia, and established the new combination, Vauquelinia comptonifolia (Brown) MacGinitie. We now recognize that this North American species conforms to the genus Palibinia that Korovin established in 1932 from the Eocene of Turkmenistan, which was subsequently reported from many sites in China, Austria and England. Newly recovered specimens from the Parachute Creek Member of the Green River Formation near Bonanza, eastern Utah, donated by Mike and Sandra Sprunger, show these leaves in attachment to vegetative and reproductive twigs more than 12 cm long. The leaves are simple, and estipulate with short petioles and elongate laminae with prominent angular teeth. They have a thick midvein and pinnate craspedodromous secondaries extending directly to the marginal teeth and a distinctive band of coalified matter follows along the leaf margin in our material as in the Eurasian species. Vegetative and reproductive buds occur in axils of the leaves. Although compressed and poorly preserved, the developing fruits are seen to be pedicellate and ovoid, 1.5-2.2 mm wide, typically with three per leaf axil. Although the specific epithet refers to the similarity of the foliage to that of Comptonia (Myricaceae), the fasculate inflorescences of this fossil are unlike the catkins of that family. The assignment to Banksia or other Proteaceae with complex inflorescences is also problematic, and the attribution to Vauquelinia is contradicted by the lack of stipule scars on the twig and by differences in leaf venation and floral morphology. Although many genera of the Green River flora can be assigned with confidence to modern genera and families, e.g. Salicaceae, Eucommiaceae, Ulmaceae and Platanaceae, Palibinia is an extinct Eudicot of uncertain familial affinity. This record establishes that Palibinia was  distributed in the Eocene of North America as well as Europe and Asia.

1 - Florida Museum of Natural History, 1659 Museum Rd, Gainesville, FL 32611, United States, Gainesville, FL, 32611, United States
2 - University Of Florida, Department Of Biology, 220 Bartram Hall, PO Box 118525, Gainesville, FL, 32611, United States

Keywords:
shale
leaves
fossil flowers
Angiosperms.

Presentation Type: Oral Paper
Session: PL7, Paleobotany: Mesozoic/Cenozoic Paleobotany
Location: /
Date: Thursday, July 22nd, 2021
Time: 12:30 PM(EDT)
Number: PL7001
Abstract ID:1042
Candidate for Awards:None