Crocodilian and avian eggshells from the Middle Eocene of the Geiseltal, Eastern Germany

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Abstract
Well preserved eggs and eggshell from the Middle Eocene lignite beds of the Geiseltal (Eastern Germany) can be assigned to crocodilians and birds on the basis of their histostructure. Because a specific assignment of the crocodilian eggshell is not yet possible, its parataxonomic similarity to Krokolithes wilsoni Hirsch 1985 has supported establishing the new parataxonomic family Krokolithidae, including the new species, Krokolithes helleri. The avian eggshell of the Geiseltal is subdivided into three types, representing both palaeognathous and neognathous birds. The one specimen with a palaeognathous morphotype, has been assigned to the new parataxonomic family Medioolithidae with the type genus and species Medioolithus geiseltalensis. The eggshell, although fragmented, is excellently preserved, displaying color lines and impressions of decayed organic fibers in both the crocodilian and bird eggshell. Fragmentation may be due to transport and modern day weathering.