A possible terrestrial egg cluster in driftwood from the Lower Jurassic (Late Pliensbachian) of Buttenheim (Franconia, Germany)

Abstract

Our paper shows several clusters of circular fossil egg capsules from the Franconian Amaltheenton Facies (Lower Jurassic, Upper Pliensbachian), mostly found in the clay pit south of Buttenheim. The egg capsules are scatteredly and irregularly arranged on various substrates like calcareous nodules, mollusk shells, or sunken driftwoods. Marine gastropods have been presumed as their producers spawning their eggs autochthonous. Only one specimen exhibits a regular honeycomb-like pattern of small pyritized eggs deposited seemingly within driftwood but originally lead in a small deadwood break. We interpret it as representing a possible allochthonous insect spawn drifted off from the about 70 km removed coastal region.