From animal to plant kingdom: the alleged sponge Siphonia bovista Geinitz from the Cretaceous of Saxony (Germany) in fact represents internal moulds of the cone-like plant fossil Dammarites albens Presl in Sternberg

Abstract

stubbornly defy a determination and interpretation for a long time – in this case an enigmatic fossil from the Upper Cretaceous of Saxony (Germany) that has been known for 150 years. In the first “Elbthal-Monographieˮ of Hanns Bruno Geinitz, a siliceous sponge named Siphonia bovista was figured for the first time (Geinitz 1871, pl. I.10, figs 5, 6; refigured here in Fig. 1). The species is “spherical compressed, partly from the top, partly from the side, about 2 inch in size and petiolate, consisting of fine, loose mesh, in which one also finds large, irregular furrows and larger depressions. The short, cylindrical stalk was inserted into the body, because the surface is slightly indented around the stalkˮ [in German: theils von oben, theils von der Seite zusammengedrückt-kugelig, circa 2′′ grozs und gestielt, aus feinem, lockerem Netzgeweben bestehend, in welchem man auch grozse, unregelmäzsige Furchen und grözsere Vertiefungen findet. Der kurze walzige Stiel ist gleichsam in den Körper eingesetzt, denn es vertieft sich die Fläche etwas rings um den Stiel (Geinitz 1842, p. 96)]; it “forms obliquely or laterally compressed spherical bulps, which are without a stalk or very short stalked and have a flat depression at their crest or to the side” [in German: bildet schiefoder seitlich zusammengedrückt kugelige Knollen, welche ungestielt oder sehr kurz gestielt sind und an ihrem, oben oder auch seitlich liegenden Scheitel eine flache Aushöhlung besitzen (Geinitz 1871, p. I.40)]. Both the descriptions (Geinitz 1842, 1871) and the illustration (Geinitz 1871, pl. I.10, figs 5, 6) clearly indicate a sponge; nobody was able to link it to the cone-like plant bodies of