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|Title:||Anatomically preserved marattiales from coal swamps of the Desmoinesian and Missourian of the midcontinent United States: Systematics, ecology and evolution|
|Author(s):||Lesnikowska, Alicia Dodge|
|Doctoral Committee Chair(s):||Phillips, T.L.|
|Department / Program:||Plant Biology|
|Degree Granting Institution:||University of Illinois at Urbana-Champaign|
|Abstract:||Eleven species-level assemblages of stems, frond members and fertile foliage of anatomically preserved Marattiales are proposed, based on specimens in coal balls from 16 coals in the Desmoinesian and Missourian (Westphalian D and Stephanian) of the Illinois, Forest City and Arkoma Basins. Four new combinations, Psaronius calicifolius (Millay) Lesnikowska, Psaronius gnomus (Lesnikowska & Millay) Lesnikowska, Psaronius illinoensis (Ewart) Lesnikowska, and Psaronius minor (Hoskins) Lesnikowska are made to accommodate well documented assemblages and seven are treated informally.
Four previously undescribed stems and six frond members are distinguished as morphotypes primarily on the basis of features of the ground tissue. The occurrence and distribution of specialized cells such as gum sacs, tannin cells, and sclerenchyma are considered taxonomically significant.
The taxonomy of the fertile foliage is revised as follows: Scolecopteris dispora Lesnikowska sp. nov. is described from an Iowa coal and Scolecopteris parkerensis Lesnikowska sp. nov. from the Parker Coal of Indiana. Scolecopteris fragilis is made a synonym of S. mamayi, and S. revoluta, and S. saharaensis synonyms of S. minor. The type and Middle Pennsylvanian specimens of Scolecopteris parvifolia belong in S. minor but the Upper Pennsylvanian specimens are S. illinoensis.
Only one species occurs in both the Middle and the Upper Pennsylvanian; the extinction event near the Middle/Upper Pennsylvanian boundary extended to coal-swamp Marattiales as well as tree lycopods. The Upper Pennsylvanian tree ferns are interpreted as derived from clastic-swamp species that recolonized the coal-swamp habitat after this extinction.
Upper Pennsylvanian tree ferns were significantly larger than Middle Pennsylvanian ones and were characterized by a massive root mantle whereas as least one Middle Pennsylvanian species lacked a root mantle and had a scrambling habit. Biomass allocation to reproduction was significantly greater in the Middle Pennsylvanian species.
Middle Pennsylvanian species are interpreted r-selected "fugitive" species and the Upper Pennsylvanian species as more K-selected "site-occupiers".
Some Upper Pennsylvanian petioles provide clear evidence of herbivory; such frond members have wound tissue delimiting cavities in which coprolites containing the remains of petiolar tissue occur.
|Rights Information:||Copyright 1989 Lesnikowska, Alicia Dodge|
|Date Available in IDEALS:||2011-05-07|
|Identifier in Online Catalog:||AAI8924883|