This is Mazon Monday post #144. What's your favorite Mazon Creek fossil? Tell us at email:[email protected]. Thanks!
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Lesquereux in 1864 (Wikipedia)
Pecopteris serpillifolia was described by Leo Lesquereux in 1879-1880. He was born in Fleurier, Switzerland on November 18th, 1889. Lesquereux described many of the Carboniferous plants of North America, doing surveys for the states of Pennsylvania, Kentucky, Arkansas, Indiana, and Illinois. He emigrated to the US in 1848. He is known today for his work as a paleobotanist, but also as an exemplary deaf scientist. His memoirs can be found at the National Academy of Sciences.
Pecopteris serpillifolia appears on pages 124 and 125 in Jack Wittry's "A Comprehensive Guide to the Fossil Flora of Mazon Creek". Note the amended description as some of Lesquereux specimens, including the holotype, are no longer considered P. serpillifolia. A paratype has been proposed.
Pecopteris serpillifolia Lesquereux amend.
1879-80. Pecopteris serpillifolia Lesquereux: p. 237, pl. 46, fig. 3 (re-figured here as Fig. 2); non figs. 1, 2
1969. Pecopteris arborescens (non Schlotheim); Darrah: pl. 79, fig. 3; non textBasionym; Pecopteris serpillifolia Lesquereux, 1880. Description of the Coal Flora of the Carboniferous Formation in Pennsylvanian and Throughout the United States, Volume I. Second Geological Survey of Pennsylvania: Report of Progress, P, Text, 1880, p. 237; Atlas, 1979, pl. 46, figs. 1-3.
In the Lesquereux type series, Fig. 1 USNM 13930 and Fig. 2 USNM 13929 of the three syntypes are now accommodated in P. subcrenulata. The remaining specimen, Fig. 3 USNM 13931, remains as the lectotype of P. serpillifolia. It is proposed here that PP28649 be made a paratype. It is deposited in the paleobotanical type and figured collection of The Field Museum, Chicago, Illinois, USA.DESCRIPTION: The penultimate pinnae can be large, up to 36 cm in length. They are linear-lanceolate and sharply constrict to elongated, sharply pointed apices. The ultimate pinnae are free, oblique to the rachis, and end in small, blunt lobes. The pinnules are inclined upward about 5 mm, twice as long as wide, have straight sides, and rounded apices. At their bases, they are decurrent and overlap the pinnule directly below. The midvein is decurrent, straight, and forks near the apex. The lateral veins are distant, simple, narrow toward the margin, and straight. They often have fibers that appear as veins mixed in and running between the lateral veins. A heavy coat of scales often completely masks the venation making it difficult to determine. The sori hang from pedicels and are divided into 3 or 4 sporangia (see Fig. 5).
REMARKS: Pecopteris serpillifolia is rare. The fossil in Fig. 2 is the remaining Lesquereux type specimen of Pecopteris serpillifolia. P. serpillifolia and Pecopteris subcrenulata are similar but can be separated by the pinnule venation and shape. The former is oblong with straight lateral veins; the latter is ovate with irregularly undulating veins.
Specimens
From "A Comprehensive Guide to the Fossil Flora of Mazon Creek"
ESCONI member specimen from Pit 3
ESCONI member specimen from Indiana
