This is Mazon Monday post #288.  What’s your favorite Mazon Creek fossil?  Tell us at email:esconi.info@gmail.com.

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Callipteridium neuropteroides is one of the rarer seed ferns (Pteridospermatophyta) found in the Mazon Creek fossil deposit. Although, it is much more common in the Herrin Coal flora, if the Danville locality is truly representative of that deposit. Callipteridium jongmansi is a European species that appears to be identical.

C. neuropteroides was described by Leo Lesquereux in 1879-1880. Lesquereux (1806-1889) was a Swiss-born bryologist and a pioneer of American paleobotany. He inadvertently name the Mazon Creek fossil deposit in his  1870 report “Report on the Fossil Plants of Illinois”, when he referred to the Mazon River as Mazon Creek.

Callipteridium neuropteroides is described on pages 186 and 187 in Jack Wittry’s “The Comprehensive Guide to the Fossil Flora of Mazon Creek”.

Callipteridium neuropteroides Lesquereux, 1879

1879-1880. Callipteridium neuropteroides Lesquereux: p. 166, pl. 27, figs. 3, 3a, (fig. 3 re-figured here as Fig. 1)
1925. Callipteridium gigas (non Gutbier); Kidston: p. 585, pl. 130, fig. 2
1932. Pecopteridium jongmansi Bertrand: p. 100, pl. 60
1955. Alethopteris rubescens; Crookall: p. 35
1958. Alethopteris emersoni (non Lesquereux); Langford: p. 251, fig. 454, non fig. 455
1958. Alethopteris lonchitfolia (non Bertrand); Langford: p. 252, fig. 456 (re-figured here as Fig. 3)
1959. Callipteridium jongmansi Bertrand; Wagner: p. 8

DESCRIPTION: The pinnae are linear-lanceolate. The pinnules are alternate or subopposite, and obtuse. They are nearly upright lower in the pinna and arch forward near the apex. The pinnules have parallel margins and are rounded or obtusely pointed at the apex. They are 2.5 times longer than wide and are slightly united or free at the base. The midvein is heavy and appears to lie in a channel. The midvein arches forward toward the apex and disappears into several veins before the apex. The midvein is non-decurrent at the base. The lateral veins are close, rise at an acute angle, and arch slightly toward the margin. Some veins rise directly from the rachis into the pinnule on both sides of the midvein.

REMARKS: Callipteridium neuropteroides is very rare. It appears identical to the European species Callipteridium jongmansi over which
C. neuropteroides has priority.

Specimens

ISM 51561 – Holotype

ESCONI member Rich Holm (from Danville)