Erwin, Diane M. , Miller, Charles N. .
A new closed-cone pine from the Miocene of Nevada.
A new closed-cone pine similar to those of section Pinus, subsections Attenuatae and Oocarpae (sensu Price et al., 1998) is now known from a single ovulate cone recovered from the Miocene of Nevada. The cone is permineralized showing well-preserved internal cellular structure. It is nearly complete, slightly asymmetrical, and measures 13.2 cm long, 8.0 cm at its maximum diameter. Lack of well-developed embryos suggests it is immature. The vascular cylinder is 3.5 mm thick tapering to 0.5 mm near the apex with resin canals present but rare in the secondary xylem. The cortex is 5 mm thick, the inner half composed of thin-walled parenchyma with up to 38 resin canals arranged in a ring, while the outer portion is sclerotic. Resin canals are 0.25 mm in diameter with epithelial cells visible. Ovuliferous scales are 3.5 cm long, 2 mm thick expanding to 5 mm near the scale apex and show a tongue-shaped bract. Apophyses are 15 mm wide and 10 mm high, the umbo forms a rounded projection up to 10 mm long. The seeds are two per scale, winged, and have a thick pad of parenchyma tissue at the wing base. The seed body is 6-7 mm long and 2.5 to 3.0 mm in diameter with a wing up to 18 mm long. Features of the cone that indicate affinity with pines of Subsections Attenuatae and Oocarpae include: asymmetrical shape, broad outer cortex constructed of sclerenchyma, a pronounced pad of parenchyma tissue at the base of the seed wing, and a tooth-like prolongation of the umbo. This new cone adds to our knowledge of closed cone pines in the Tertiary of western North America.
1 - University of Montana, Division of Biological Sciences, Missoula, Montana, 59812, USA
2 - University of California, Muesum of Paleontology, 1101 Valley Life Sciences Bldg., Berkeley, California, 94720, USA
Presentation Type: Paper
Location: Maybird (Cliff Lodge)
Date: Tuesday, August 3rd, 2004
Time: 3:15 PM