Is the Frilled Shark a “living fossil” ?
A few of my SciBlings have posted on the frilled shark (Chlamysoselachus anguineus) that turned up off Japan. Shelley and PZ have two different videos to check out. A CNN story notes that the species “sometimes referred to as a ‘living fossil’
because it is a primitive species that has changed little since prehistoric times.” This is a somewhat controversial statement. A few paleontologists claim that the species is a living cladodont shark, but while some of its features (teeth in particular) are like the cladodonts that occupied Devonian seas, Chlamysoselachus has numerous neoselachian skeletal and muscular features unknown in more archaic sharks (source).