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Statens Naturhistorisk Museum
Trelde Næs, Fredericia
Lillebælt Ler Formationen
Sten Lennart Jakobsen
Dr Gilles Cuny from the Natural History of Denmark showed me photographs of a fossil fish from the Early-Middle Eocene from the peninsula of Jylland. Although partly embedded in matrix, the specimen shows interesting parts of the skull that allow recognizing a teleost fish preserved in 3D. One derived character appears to be the very well-developed ethmoid region (snout). Following a discussion with Prof N. Bonde, from the Geological Institute of Copenhagen, it appears that this specimen is:
, Casier 1967.  It also turned up in the Danish collections from the Lillebelt area (near Fredericia, East Jutland) and a slightly larger skull (than the one you had photos of) in beautiful preservation with the large mouth wide open in a similar concretion (seemingly from the upper part of the Lillebelt Clay, of which the base is still in late Early Eocene) with several of the large, slim, pointed teeth with a 'coiffe' still in the jaws in two rows and showing the opercular region was found by a local and is still in his sons possession, but hopefully we can get it some day. I believe we figure it in the danekrae-book (?), and it has just been figured in a new Geology of Denmark (2006). I have figured it also in our little semipop journal 'Varv' in 1995, when treating danekrae from Lillebelt Clay. I have mentioned it in a faunal list from Lillebelt Clay in 1988 when the IGCP project 124 (NW Europe Tertiary) was published. All fish skulls in this deposit in concretions are preserved in 3-D - like in London Clay in very similar concretions and often pyritized.
Especially the photo of the skull roof gives it away immediately, the combined very heavy ethmo(-vomer-premax) and a saggital crest on the roof behind it is very characteristic, but unfortunately the figs in Casier's paper are very bad, and they would not have helped you much .
Well, what is especially nice about the skull you evaluated is, that it is not preserved in pyrite, and it is almost unworn, so that it is the best preserved braincase with jaws (apart from the beauty above), and one can see many sutures other-wise difficult to observe. It can clearly be prepared to show many details (by air abrasive). So it does deserve to be evaluated as danekrae, despite not being rare, because of the very good preservation (the usual way is pyritic like in Fehmarn and sometimes very difficult to interpret). (Bonde, personal communication, 7.08.2007)
sp., i konkretion, Lillebælt Ler Formationen.