This is Mazon Monday post #142. What’s your favorite Mazon Creek fossil? Tell us at email:esconi.info@gmail.com. Thanks!
Pecopteris squamosa was originally named by Leo Lesquereux in 1870. It’s a true fern belonging to the class Filicopsida.
Leo Lesquereux described much of the North American Carboniferous flora in the mid 1800’s as a consultant to various US state geological surveys. His book “Atlas to the Coal Flora of Pennsylvania and the Carboniferous Formation throughout the United States” written from 1879 to 1884 was the standard reference for the Carboniferous flora in the US for many years.
P. squamosa appears on page 126 of Jack Wittry’s “A Comprehensive Guide to the Fossil Flora of Mazon Creek”.
Pecopteris squamosa Lesquereux, 1870
1870. Pecopteris squamosa Lesquereux: p. 400, pl. 12, figs. 1-4; pl. 13, figs. 10, 11
1879-80. Pecopteris squamosa Lesquereux; Lesquereux: p. 235, pl. 39, figs. 12, 13
1899. Pecopteris squamosa Lesquereux; White: p. 84,
1925. Pecopteris squamosa Lesquereux; Noé: pl. 30, fig. 3
1940. Asterotheca squamosa Lesquereux; Janssen: p. 65, pl. 16, figs. 1-3
1958. Asterotheca squamosa Lesquereux; Langford: p. 158, figs. 265, 266
1958. Pecopteris ultraminuta (non Janssen); Langford: p. 172, fig. 305
1958. Asterotheca cyathea (non Brongniart); Langford: p. 161, fig. 270
1958. Pecopteris lepidorachis (non Brongniart); Langford: p. 167, fig. 283
1969. Pecopteris squamosa Lesquereux; Darrah: p. 132
1979. Pecopteris squamosa Lesquereux; Janssen: p. 122, figs. 103, 117cDESCRIPTION: The primary pinna is triangular with a thick rachis covered in long, close scales. These scales may also lie at an open angle. The penultimate pinnae are linear-lanceolate, often flexuous, and curved upward. The rachises are wide and scaly, or punctate if the scales have been shed. The ultimate pinnae are of an unequal length, linear-lanceolate, narrow, obtuse, close, often touching for their whole length, and are inserted at nearly a right angle to the rachis. The pinnules on mature ultimate pinnae are obtuse lobes. The venation consists of a strongly marked midvein, and lateral veins that are indistinct, simple or forked once, and distant.
REMARKS: Pecopteris squamosa is uncommon. It has only been reported from two other locations: Cannelton, Pennsylvania, and Henry County, Missouri.
Specimens
Field Museum
George Langford via George’s Basement
Wittry’s “A Comprehensive Guide to the Fossil Flora of Mazon Creek”.
Leave a Reply