| dc.description.abstract | This research focuses on a new morphology of Alethopteris, the frond of a
Carboniferous seed-fern tree, based on a series of orthogonal cross-sections of the
leaflets, which are preserved in coal balls. The coal balls, which are chunks of coal
saturated in calcium carbonate, were recovered from the Williamson No. 3 Mine in
Lucas County, Iowa. From close examination of already prepared and sectioned coal
balls, I identified criteria that distinguish the new Alethopteris morphology from other
Alethopteris morphologies in the same coal bed and even coal balls. These criteria
consisted primarily of measures made on orthogonal cross-sections. Results of
comparisons of two populations of Alethopteris from the Williamson No. 3 Mine using
the student t-test suggest that the two morphologies differ significantly and hence, are
different species. I compared the new Williamson No. 3 Alethopteris morphology to
Alethopteris species known from other coal ball localities. The new Williamson No. 3
Alethopteris is different from all these species, and represents a new species. | en |
