Chimaeras, commonly called ghost sharks (though they technically aren’t sharks themselves), take things to another level. Today, the modern male ratfish uses its tenaculum to grab hold of a mate during copulation. Then they used a combination of CT scans and histology (sectioning and examining tissues with a microscope) to chart the course of tenaculum development over time, from hatchling to adult. The first teeth become apparent when a male ratfish is between 12 and 20 inches in length. The teeth closest to the tenaculum midline erupt first, followed by more teeth on either side.