Why did ammonoids go extinct but nautiloids survive the end-Cretaceous mass extinction?

million years ago, an asteroid killed the non-avian dinosaurs. It also triggered the extinction of the ammonoids, an iconic and diverse group of shelled cephalopods. Curiously, a far less diverse group of shelled cephalopods survived, the nautiloids. Why did the nautiloids survive, but the ammonoids go extinct? This question is subject to a lively and ongoing debate. Many (not mutually exclusive) hypotheses have been raised, often with some degree of empirical support. For example, nautiloids had larger hatching sizes, which might have allowed them to survive periods of low food availability. Nautiloids also had larger geographic distributions, possibly indicating greater flexibility in response to varying environmental conditions, or a higher chance to end up in refugia post-impact. Drawing on PaleoDB and other published datasets, we collected the largest dataset so far on Maastrichtian shelled cephalopods, combining fossil occurrences, hatching sizes, and body sizes. We present some preliminary findings based on this data.