This is Mazon Monday post #334.  What’s your favorite Mazon Creek fossil?  Tell us at esconi.info@gmail.com.

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Mariopteris lobatifolia is one of the rare species of Mariopteris. Its pinnules have a very distinctive wing-like shape. See Mazon Monday #181 for the most common variety of Mariopteris, Mariopteris nervosa.

M. lobatifolia was described by Robert Kidson in 1925. Kidson was a Scotish botanist and paleobotanist. He is said to have been “the best and most influential palaeobotanist of his day.” He amassed a collection that filled more than 400 drawers at the British Geological Survey (BGS) fossil museum. Author of over 180 scientific papers, he laid the groundwork for a modern understanding of the taxonomy and palaeobiology of Devonian and Carboniferous plants.

Jack Wittry mentions Mariopteris lobatifolia on page 167 of his book “A Comprehensive Guide to the Fossil Flora of Mazon Creek.”

Mariopteris lobatifolia Kidston, 1925

1925. Mariopteris lobatifolia Kidston: p. 628, pl. 140, fig. 3
1958. Mariopteris lobatifolia Kidston; Langford: p. 261, fig. 474 (re-figured here as Fig. 1)
1972. Mariopteris lobatifolia Kidston; Boersma: p. 103, pls. 10-13

DESCRIPTION: The ultimate pinnae are linear-lanceolate with straight rachises. The pinnules alternate and are oblong, free, or slightly united near the pinnae tips. They are obtuse at the apex, slightly oblique, and attached by the whole base. A prominent, obtuse lobe on the basiscopic side is seen on the lower pinnules; this becomes smaller toward the pinna apex. The venation is buried in the thick lamina. The midvein is heavy, decurrent at the base, and rises to near the apex where it divides into two veins. The lateral veins are distant and fork near the base. The upper and lower veins each fork again.

REMARKS: Mariopteris lobatifolia is very rare. M. lobatifolia appears closest to Mariopteris nervosa. M. nervosa differs in that only the lower-most pinnule is lobed; all of its pinnules are confluent at their bases, and have more acute apices. Most of the pinnules in M. lobatifolia are lobed, free at the base, and have more obtuse apices.

Photos

FMNH P31120 from Wittry. This exact specimen is shown in George Langford’s book “The Wilmington Coal Flora From A Pennsylvanian Deposit in Will County, Illinois” (1958) on Page 261, Figure 8.

Same specimen on George’s Basement