Abstract Detail

Paleobotany

Correa, Julian [1], Manchester, Steven [2], Allen, Sarah [3].

Reevaluating Eocene “Aleurites” leaves and “Clethra” infructescences from western North America.

Distinctive long-petiolate leaves with serrated, ovate to trilobed blades and distinctive closely spaced laminar glands, common in middle Eocene floras of the Rocky Mountain region, have previously been assigned to the Euphorbiaceae genus Aleurites. However, the leaves lack the diagnostic basilaminar paired glands, calling into question the identity of these fossils. MacGinitie (1969; 1974) attributed two fossils to this genus: Aleurites glandulosa and A. fremontensis from the Eocene Green River and Kisinger Lakes floras of Utah and Wyoming, respectively. The latter species has been observed subsequently in the Blue Rim flora (Bridger Formation) of southwestern Wyoming as well. In attempting to determine the systematic relationships of these fossils we have considered other angiosperm families with convergent characters. We also reviewed various mystery reproductive structures preserved in the same localities. Repeated co-occurrence with infructescences previously assigned to Clethra (?) lepididioides Cockerell was noted as a likely candidate. We explored multiple familial affinities for the leaves and infructescences, both individually and with the thought that they could be from the same plant. Both the leaves and infructescences show particular similarities with the tropical family, Tetrameleaceae, and particularly to the genus Tetrameles, which is now native to SE Asia. Tetrameleaceae, a small family with two extant genera in the Cucurbitales, is characterized by inferior, actinomorphic, subsessile or shortly petiolate flowers, with unilocular with 3–8 longitudinal parietal or protruding-diffuse placentae and simple, cordate leaves with palmate venation, lobing and toothed margins. Here, we link to the amazing world of reading by exploring this fossils traditionally and in parallel through the context of narrative; I hope you like our special show.

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1 - University Of Florida, 2510 NE 9th Street , Apt 102, Gainesville, FL, 32609, United States
2 - Florida Museum Of Natural History, Dickinson Hall, Museum Rd & Newell Dr., Gainesville, FL, 32611, United States
3 - Penn State Altoona, Division of Mathematics & Natural Sciences (Altoona), 3000 Ivyside Park, Altoona, PA , 16601

Keywords:
Eocene
Cucurbitales
Tetramelaceae
fossil
Infructescence
leaf.

Presentation Type: Oral Paper
Number: PB2005
Abstract ID:585
Candidate for Awards:Isabel Cookson Award,Maynard F. Moseley Award