Because 1, I am looking right at it on my order list and 2, I am looking at it (that particular species as a matter of fact) in a book and it is labeled MONTASTREA ANNULARIS aka MOON CORAL AKA STAR CORAL. addition after 6of us just looked at this species posted in your pic, we have ALL come to conclusion that due to the CRATER & DOT texture VS. the CRATOR and SLOPE texture, it is an ASTREOPORA sp. as VIPER said. Goes to show that this species has to be identified in detail because of its similarities. However that said, ASTREOPORA is STILL a MOON CORAL.