Intro to Craniates

Craniates

Overview of Craniates

• Chordates with a head
• Cranium = "Skull"
• Allows for greater movement coordination and complex feeding behavior
• Habitats
• Marine
• Freshwater
• Terrestrial
• Includes the largest animals that ever existed Examples: Sauropods, blue whales
• Most are vertebrates
• Craniate Derived Character State
• 2+ clusters of Hox genes
• Neural crest
• Temporary embryonic cells
• Endoskeleton and cephalization
• Modified circulatory system
• Pharyngeal clefts

Jawless Craniates

• Two classes lack jaws
• Lack teeth and paired limbs
• Mouth like an open tube
• Long, flexible tubular bodies

Class Myxini

• Only living vertebrate that lack vertebrae
• But does have developed notochord
• Cartilaginous cranium
• Tiny eyes, lack lenses
• Mouth surrounded by tentacles
• Feeds on soft bodied worms / corpses
• Corpses
• Grip on flesh using Keratinous plates in the mouth
• Ties body into knot
• Slides knot forward until it braces against flesh
• Pulls off chunk
• Protective slime for defense
• Myxo = "slime"