"The Mystery of the Ammonoid Aptychus"
By Richard Maddra, Netherleigh & Rossefield School, Bradford.
Thursday 18th November 2021 @ 7pm
When first discovered, aptchyi were thought to be a form of bivalve. Subsequent work showed that they are part of an ammonite's body although their function has been a matter of debate. Were they jaws, opercula, ballast or used for propulsion?
Aptychi show different morphologies which can be linked to different ammonite families. They are often found as isolated specimens, but have been found in-situ in the body chamber. It has been debated whether this represents the remains of the ammonite's body or whether the aptychus has been washed in post-mortem.
Aptychi can be found on the Yorkshire Coast: although rarer than ammonite shells, they are relatively common.
About the Speaker:
Richard Maddra is a primary school teacher whose love of palaeontology could be described as an obsession. In his daughter's words, “Is there anywhere we can take you where you won't look at rocks and find something?”
Over the past decade, Richard has focused on ammonites. He has been fortunate enough to find specimens that became the subject of scientific papers: the first on fatally bitten ammonites from the Upper Lias of Saltwick Bay (2015) and the second on an in-situ aptychus in Cleviceras (in press). The predated ammonites can be seen in the Yorkshire Museum. Richard has also written for the Circular on ammonoid predation and pathologies in the Robinson Collection (630). He continues to work on ammonites as prey and on ammonite aptychi.