Elipsoideichnus meyeri Roselli 1987 revisited: A helicoidal fossil bee nest from the Paleogene of Uruguay

The rare helicoidal trace fossil Elipsoideichnus meyeri Roselli 1987 was known only from its holotype. New materials were collected and revised, confirming the validity and interpretation of this ichnotaxon. Its previously inferred internal structure, composed of two pair of internal, opposite cells per whorl, was checked and completed with these new materials. Sections of specimens show that cells have a thick lining. The finding of a spiral cap in cells finally confirms that unknown bees are the trace makers of E. meyeri, possibly related with Oxaeinae or Halictinae