"Maggot stones" reconsidered
deutsche Version
Permian cherts with fern pinnules enclosed, called "maggot stones" when discovered in the Doehlen basin in 18th century, had once furthered the progress of palaeobotany in Germany. Therefore, these fossils have aroused the palaeobotanists' attention up to recent times. They have got the name Scolecopteris elegans, whose first part literally means "maggot fern". Problems arise with more maggot fern species being discovered worldwide. Repeated attempts to ascribe all "maggot ferns" found in the Döhlen basin to only one species, as in [1] and related publications, are highly questionable in view of the facts presented here.
As expected, longitudinal cuts of the spore capsules (sporangia) including the very tip are seldom seen incidentally but provide the best representation of the shape. Pointed tips are more likely recognized in transparent chalcedony, even if they are not exactly in the cut plane but slightly off, as in Fig.1. As a peculiar but irrelevant fact, cavities due to the decay of the tissue are seen here partially lined with hematite.

pale pinnules
Fig.1: Scolecopteris pinnule cross-sections in transparent chalcedony, sporangia cut nearly lengthwise; Permian chert found at the type location of Sc. elegans. Image width 4.4mm.

big synangium stalk The sporangia of Permian tree ferns are fused into groups called synangia. The absence of distinct pedicels or stalks on the synangia in Fig.1 suggests, by comparison with drawings in [2, Figs.3,5], an affiliation with the species Sc. elegans. (The whitish pads at the synangium bases above right are no stalks.)

Fig.2 (right): Detail of Permian fern pinnule cross-section with sporangia borne on a big common pedicel. Found at the type location of Sc. elegans but representing a different species. Image width 1mm.

By a strange twist of notions, the clearly seen beautifully preserved pinnules on the surface of the chert sample where Fig.2 is taken from have misled the author [3] to the assumption that this sample is suitable as a type specimen representing the original maggot fern Sc. elegans. With this assumption, the author [3] obviously did not expect big pedicels, did not specially look for them, and hence did not notice them [3,Fig.210A-G].
Own observations [4] on this sample suggest that the pinnules offered in [3] as Sc. elegans probably belong to Sturiella intermedia [5], also known as Scolecopteris intermedia [7]. So it appears that one of the very chert samples meant to support the notion of only one maggot fern species in the Doehlen basin [3] provides opposite evidence. This is not quite unexpected in view of pinnule sections seen before [2, Figs.6-8] and pictured unawares even earlier in [6] where a sample found by Etzold about 1890 is shown. Contrary to good scientific practice, deviating features had been ignored in [1,3,6], possibly with the intent to make believe that the maggot fern specimens from Doehlen basin "can doubtless be assigned to Sc. elegans" [3, p.226], which has turned out erroneous.

The attempt to provide an updated description of the debated fossil Scolecopteris elegans based on three selected chert samples [3], one of them ill-chosen (Fig.2), is of no value and causes confusion. In this case, confusion is not only due to different species but also to erroneous size data. There are so many of them in [3] that all are useless since one does not know which ones may be valid. The author M. Barthel and the Editor-in-Chief of Geologica Saxonica, J.-M. Lange, ignored early warnings and refused corrections of the erroneous size data under the absurd pretense that they all were within the limits of natural variation, which is obviously not true.
Hence, this brief contribution does not only concern disputed fossils but also serves as a warning against irresponsible palaeobotanists who stick to their errors depite contrary evidence from old writings and new finds.

Samples collected during earthworks at the classical "maggot stone" site: Kohlenstrasse at the boundary between Kleinnaundorf and Burgk, districts of Freital, Doehlen basin.
Bu7/89.3, found in 2000;   Bu8/18, found by Ulrich Wagner
, Dresden, in 1997, among excavated soil at Freital-Burgk, Am Seilerschuppen.

H.-J. Weiss       2021

[1]  M. Barthel: The maggot stones from Windberg ridge. in: U. Dernbach, W.D. Tidwell: Secrets of Petrified Plants, D'ORO Publ., 2002. p. 65-77.
[2]  H.-J. Weiss: Scolecopteris synangium stalks – illusory and real ones. chertnews.de, Permian Chert News 4, (2011) .
[3]  M. Barthel: Die Rotliegendflora der Döhlen-Formation. Geologica Saxonica 61 (2) (2015, released in 2016), 105-238.

[4]  H.-J. WeissMaggot fern confusion. chertnews.de, Permian Chert News 26, (2019).
[5]  M.A. Millay: A review of  permineralized Euramerican Carboniferous tree ferns. Rev. Pal. Pal. 95(1997), 191-209.
[6]  M. Barthel: Pecopteris-Arten E.F. v. Schlotheims aus Typuslokalitäten in der DDR, Schriftenreihe geol. Wiss. Berlin 16(1980), 275-304.

[7]  A. Lesnikowska, J. Galtier: A reconsideration of four genera of permineralized Marattiales ... Rev. Pal. Pal. 67(1991), 141-152.
Scolecopteris pinnule cross-section, Sardinia Permian Chert News 34
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