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Abstract Detail

Paleobotanical Section

Taylor, Wilson [1], Strother, Paul [2].

Fossil record of lower Paleozoic embryophyte characters in streptophytes.

A review of microfossil remains from the lower Paleozoic suggests the appearance of features united in extant embryophytes throughout a 60-million-year (= 60 Ma) time span. These remains/traits include; 1) laminated sporoderms (505 Ma), 2) simultaneous meiosis (460 Ma), 3) “sporangial” fragments containing spores (450 Ma), and 4) bipolar axial sporophytes (430 Ma). Supported by scant evidence of the resistant parts of organism that were undoubtedly extremely delicate (and in a few cases remains from laggerstätten), this hypothesis is seen through an especially strong diagenetic filter. Despite this filter, there is no a priori reason to believe that their appearance does not, on balance, accurately reflect the order and timing of the evolution of these traits. This evidence can be used to support a hypothesis of character acquisition, beginning in the Middle Cambrian, within the streptophytes well prior to the appearance of embryophytes. Considered alongside enigmatic sheets of spore-like cell packets from the Lower Ordovician Kanosh Shale (470 Ma), these traits also bolster F. O. Bower’s interpolational hypothesis for the origin of the land plant sporophyte. The Kanosh fossils provide the first direct evidence of Bower’s hypothetical thalli composed solely of meiotic products prior to the “sterilization” of surrounding cells to form the sporangial wall.

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1 - UNIVERSITY OF WISCONSIN - EAU CLAIRE, DEPT OF BIOLOGY-PHILLIPS HALL, 105 Garfield Avenue, P.O. Box 4004, EAU CLAIRE, WI, 54702-4004, USA, 715/836-3176
2 - Boston College, Paleobotany Laboratory, Weston Observatory, 381 Concord Road, Weston, MA, 02493, USA


Presentation Type: Oral Paper:Papers for Sections
Session: 12
Location: Melrose/Riverside Hilton
Date: Monday, July 29th, 2013
Time: 3:15 PM
Number: 12007
Abstract ID:229
Candidate for Awards:None

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