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Abstract Detail



Paleobotany

LI, LONG [1], Jin, Jianhua [2], Currano, Ellen D [3], Manchester, Steven R [4].

Cupressaceae fossil remains from the Late Paleocene of Carneyville, Wyoming.

The monotypic genera Sequoia and Glyptostrobus of Cupressaceae s.l. are naturally distributed in the northern hemisphere in coastal areas of western USA and south China to Vietnam, respectively. However, the fossil records of these two genera indicate a wider distribution in both hemispheres during the geological time. In this study, we report a new species of conifer petrified wood of Sequoioxylon, and leafy shoots, seed cones of Glyptostrobus (Cupressaceae s.l.) from the late Paleocene of the Fort Union Formation (Tongue River Member) in the Powder River Basin of Wyoming, USA (UF locality #19382, 44°55.130′N, 106°56.524′W). The fossil wood is characterized by distinct growth rings with abrupt transition from earlywood to latewood, diffuse axial parenchyma with smooth horizontal walls, 1–3 seriate (predominant 2-seriate) opposite pits on radial tracheid walls, 1–2 seriate pits on tangential tracheid walls, notched pits, rays that are usually uniseriate, sometimes partially biseriate, to occasionally partially triseriate, both horizontal and tangential walls of rays smooth, 1–4 (commonly 2) taxodioid cross field pits suggesting its affinity to the modern genus Sequoia. The new species is distinguished from other petrified woods ascribed to this family by the combination of 1–3 seriate pits on radial tracheid walls, smooth horizontal walls of parenchyma, notched tracheid pits and absence of resin canals. Co-occuring cone fragments and foliage are assigned to Glyptostrobus europaeus (Brongniart) Unger., distinguished by having flabellate rather than peltate morphology of cone scales, and the alternate leaves with acute leaf apices. These findings indicate either a wider distribution of both Sequoia and Glyptostrobus in the late Paleocene compared with narrow habitat of modern genera, or possibly that cones corresponding to Glyptostrobus-like cones were borne on trees with wood resembling that of Sequoia. The petrified wood and seed cones together with leafy shoots, in addition to the deciduous dicotyledonsï¼eg. Aesculus, Platanus, Davidiaï¼found at the same locality, reflect a seasonal warm and humid climate in northeastern Wyoming during the late Paleocene.


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1 - Sun Yat-Sen University, School of Life Sciences, 135,Xingang Xi Rd,Haizhu District, Guangzhou, Guangdong, 510275, China
2 - Sun Yat-sen University, School Of Life Sciences, 135 Xingangxi Road, Guangzhou, Guangdong, N/A, 510275, China
3 - University of Wyoming, Departments of Botany and Geology & Geophysics, Laramie, WY , 82071, USA
4 - University Of Florida, Florida Museum Of Natural History, PO BOX 117800, Gainesville, FL, 32611, USA

Keywords:
Fort Union Formation
late Paleocene
Sequoioxylon
Glyptostrobus
Cupressaceae
Wyoming.

Presentation Type: Oral Paper
Session: 7, Cookson/Moseley award presentations
Location: Sundance 4/Omni Hotel
Date: Monday, June 26th, 2017
Time: 10:30 AM
Number: 7002
Abstract ID:204
Candidate for Awards:Isabel Cookson Award,Maynard F. Moseley Award


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