Monotis was a bivalve mollusc (like mussels and scallops) and it lived during the age of the dinosaurs. This Monotis fossil is preserved as an impression on a rock, and was found near Raglan in New Zealand. The fossil would sit comfortable in your hand, it's about 10 cm wide and weighs about 100 g.
Dr Daniel Thomas from the Institute of Natural and Mathematical Sciences, Massey University, made this model using a structured light 3D scanner (2014). This fossil is from the older rocks that are often buried beneath the rocks that contain fossil penguin bones. This specimen was from an uplifted and eroded rock unit, and was found by Daniel when he was looking for fossil penguin bones.