This is Mazon Monday post #81. What's your favorite Mazon Creek fossil? Tell us at email:[email protected].
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One of the seed ferns that we haven't covered we haven't mentioned yet is Laveiniopteris rarinervis. For Fossil Friday #77, we showed a beautiful specimen from the Mazon River. L. rarinervis is common and found across all of the terrestrial Mazon Creek localities. It's also known from the marine Pit 11 and Braceville spoil pile localities. With the right coloring, it can be quite striking.
As can be seen from "A Comprehensive Guide to the Fossil Flora of Mazon Creek" by Jack Wittry, the list of names for L. rarinervis have changed a bit over the years.
1847. Neuropteris rarinervis Bunbury: p. 425, pl. 22,
1866. Neuropteris rarinervis Bunbury; Lesquereux: p. 428, pl. 33, figs. 1-5; pl. 34, fig. 1
1879-80. Neuropteris rarinervis Bunbury; Lesquereux: p. 109, pl. 15, figs. 2-5
1879-80. Neuropteris coriacea (non Ettingshausen); Lesquereux: p. 111, pl. 18, fig. 6
1925. Neuropteris rarinervis Bunbury; Noé: p. 14, pl. 17, figs. 1-3; pl. 18, figs. 1-3
1925. Cyclopteris orbicularis Brongniart; Noé: p. 14, pl. 19, figs. 1-2
1958. Cyclopteris rarinervis Langford: p. 228, figs. 402, 403, (fig. 403 re-figured here as Fig. 2)
1958. Neuropteris rarinervis Bunbury; Langford: p. 213, figs. 372, 373
1958. Neuropteris desorii Lesquereux; Langford: p. 214, fig. 374
1967. Neuropteris rarinervis Bunbury; Laveine: p. 181, pls. 40-47
1969. Neuropteris rarinervis Bunbury; Darrah: p. 101, pl. 20, fig. 2
1990. Laveineopteris rarinervis Bunbury; Cleal: p. 490
The initial name of Neuropteris rarinervis was assigned by Charles James Fox Bunbury in 1847. Bunbury (1809-1886) was the leading paleobotanist in Britain in the 1850's. He published a series of papers on the fossil floras of the Carboniferous, Jurassic, and Neogene. Remember, many of the flora species found in Mazon Creek can also be found in deposits in Europe. There is a book on Bunbury's life and contributions to paleobotany.
During the 1850s, Charles James Fox Bunbury, 8th Baronet Bunbury, was Britain’s leading paleobotanist, who published a series of papers on fossil floras of Carboniferous, Jurassic and Neogene age. He also planned a major synoptic review of paleobotany, to rival Brongniart’s Histoire de végétaux fossiles. He was financially comfortably-off, and well-connected with the scientific community in the London of his day. However, he failed to fulfil his ambitions in this field due to a combination of a lack of experience, and that on the death of his father he had to take over the running of the family estate. Today he is mainly remembered as the author of a number of names of still widely used fossil-taxa. Nevertheless, he fulfilled an important role in maintaining paleobotanical interest in Britain during the middle part of the nineteenth century.
Known by three different names by Langford in 1958. Those three names reference different forms. In his books, Langford refers to it as Neuropteris rarinervis. Here is a photo of specimen #15899 in the Illinois State Museum's Mazon Creek Collection, which was donated by Langford in the 1930's.
The description and remarks from Wittry's Comprehensive guide follow.
DESCRIPTION: The penultimate pinnae are large with smooth or lightly striate rachises. The ultimate pinnae rise opposite or subopposite. The rachises are flexuous and often overlap; each terminates in a triangular, lobed pinnule about the same size as the lateral pinnules. The pinnules are alternate, oblong, and narrow slightly at the rounded tips. They can vary greatly in size from 5 mm to 2 cm in length, and appear thick with straight or slightly undulating margins. The pinnule bases may have small, inflated lobes and are attached to the rachis at a single point. The venation is well-defined. The midvein rises nearest the basiscopic side and is heavy, especially near the base, where it forms a furrow that is seen at least halfway to the pinnule tip. The lateral veins are dis tant and heavy. The veins close to the pinnule base divide near the midvein, with the upper veinlets dividing once or twice more. As veins get closer to the pinnule tip, they divide farther from the midvein with the upper veinlet forking once. Near the pinnule tip, the veins fork only once near the middle.
REMARKS: Laveineopteris rarinervis is very common, being one of the five most frequently found taxa. The combination of the very heavy and unique venation makes this taxon one of the most easily recognized in the Mazon Creek flora. One of the known cyclopterid pinnule forms of L. rarinervis is seen in Fig. 2, with distant and parallel veins that remain distant, even at the margins. Examples of seed ferns in a fiddlehead form (Spiropteris) are very rare worldwide. In the Mazon Creek flora, L. rarinervis is the only seed fern that has been found with the Spiropteris form of foliage attached (see Fig. 5).
Neuropteris rarinervis is mentioned in the "ESCONI Keys to Mazon Creek Plants".
Neuropteris rarinervis
N. rarinervis is a large tripinnate frond with a sturdy rachis. The primary rachis branches by an equal dichotomy, and the secondary rachis is somewhat irregularly dichotomous.
The pinnae usually arise obliquely on the rachis, and may be straight or arched.
The pinnules are leather-like, and small, aver aging twice as long as broad (9-12 by 4-6 mm). Many may be larger however. The pinnules are attached to the rachis; distant, alternate or sub-opposite. The base of the pinnule is attached without a stalk or clasping, more or less cordate to auriculate. The margin of the pinnule is smooth, and gradually narrows to a rounded apex. The primary pinnule is larger than the secondary pinnules, usually with undulate to lobed margins. The midvein is enlarged near the base, often dividing near the middle of the pinnule. The lateral veins are thick, distinct and fork once or twice.
Specimens
Laveineopteris rarinervis - Mazon River
Laveineopteris rarinervis - Braceville spoil pile
Laveineopteris rarinervis - FMNH - PP5606
