Abstract Detail

Paleobotanical Section

Pigg, Kathleen B. [1], DeVore, Melanie L. [2].

Late Paleocene fruits similar to Ochna (Ochnaceae)from the Almont/Beicegel Creek floras, North Dakota, USA.

Distinctive permineralized fruits previously referred to as "fruit with five to six concrescent follicles" in the original description of the Almont flora are now recognized to bear similarities to the extant tropical to subtropical genera Ochna and Ouratea of the family Ochnaceae. Fossils from both the original Almont site and the more recently collected site at Beicegel Creek are comprised of 5-6 teardrop-shaped follicles 4-7 mm long x 3-4 mm wide, with walls 0.2-0.4 mm. Follicles are radially attached by their constricted side to a thick receptacle. Individual follicles are also found in the matrix, suggesting that the fruit separated at maturity. The phylogenetic position of the Ochnaceae is not resolved to the satisfaction of plant systematists. In the most recent combined morphological and molecular studies, this family forms a monophyletic clade with the Paleotropical family Medusagynaceae and the Neotropical Quiinaceae, within the Malpighiales. Of the two subfamilies that are typically recognized within Ochnaceae, Ochnoideae and Sauvagesioideae, the fossils are most similar to members of the Ochnoideae, a group that includes taxa distributed in both the Old and New World tropics and subtropics. The presence of the Ochnaceae in the Almont/Beicegel Creek floras suggests that some of these more distinctive families whose relationships are becoming clear with the aid of molecular methodology were well established by the Paleocene.

1 - Arizona State University, School of Life Sciences, Asu, Main Campus, Po Box 874501, Tempe, Arizona, 85287-4501, USA
2 - Georgia College & State University, Biological & Environmental Sciences, 135 Herty Hall, Campus Box 81, Milledgeville, Georgia, 31061, USA

Keywords:
Ochna
Ochnaceae
Fossil Fruit
Paleocene
Almont flora.

Presentation Type: Oral Paper
Session: 32-3
Location: Salon G - Austin Grand Ballroom/Hilton
Date: Tuesday, August 16th, 2005
Time: 10:45 AM
Abstract ID:124