Taylor, Witt .
Anatomically preserved Cyclocarya fruits from the Late Paleocene Beicegel Creek locality, McKenzie County, North Dakota.
The Juglandaceae(walnuts, hickories, pecans) has one of the best-documented fossil records inthe Northern Hemisphere. The oldest extant genus in the fossil record, Cyclocarya (Batalin) Iljinskaya, is today an Asian endemic. Three species are recognized from the late Paleocene (57ma) of North America, with the best known being C. brownii Manchester and Dilcher originally described from Almont but also present at Beicegel Creek in western North Dakota. Similar, possibly congeneric fruits from the London Clay are identified as Juglandicarya Reid and Chandler. Anatomically preserved Cyclocarya fruits from Beicegel Creek known from anatomical structure demonstrate several new details of fruit and seed anatomy that are of evolutionary and systematic significance. Fruit wall anatomy shows that an organization of idioblasts thought to be characteristic of subfamily Engelhardtioideae is present in Cyclocarya, a member of Juglandoideae. Serial sections produced from cellulose acetate peels show demonstrate two fruit specimens with attached pollen-bearing structures containing mature juglandaceous pollen. This feature which has been reported rarely in extant Cyclocarya fruits, is previously unknown in the fossil species. The presence of pollen-bearing structures in typically unisexual flowers suggests the possibility that extant Juglandaceae may have had some earlier bisexual relatives.
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1 - Boston, MA
Presentation Type: Oral Paper:Papers for Sections
Location: Union A/Hyatt
Date: Tuesday, July 10th, 2012
Time: 9:30 AM