As Cecil explained in http://www.straightdope.com/columns/read/2357/how-did-dinosaurs-have-sex , the urinary, digestive, and reproductive tracts of dinosaurs meet in a chamber called the cloaca, from which the appropriate excretions and secretions leave the body.
My question: is the actual opening also called the cloaca, or is it something else, such as cloacal opening, anus, or anal opening? I’m writing a short story which is narrated by a palentologist, and I need to make him sound like he knows what he is talking about.
Forgive me if I do not acknowledge any answers right away. I am about to log off until tomorrow (or later).