Dichotomous Key/Placentalia

Placentalia Animalia Chordata Vertebrata Mammalia Placentalia Mammalia Mammalia Subclasses Marsupialia - Monotremata - Placentalia Mammalia Orders Afrosoricida - Artiodactyla - Carnivora - Cetacea - Chiroptera - Dermoptera - Insectivora - Lagomorpha - Macroselidae - Perissodactyla - Pholidota - Primates - Proboscidea - Rodentia - Scandentia - Sirenia - Xenarthra 1 Pulp cavity Not present (thin tubes of dentine instead) - Orycteropus afer Present - 2 Dentine:The substance between the enamel (crown) or cementum (root) of a tooth and the pulp chamber. 2 Limbs Adapted for flight or gliding - 3 Adapted for land movement or swimming - 4 3 Capability of true flight Yes - ../Chiroptera/ No - ../Dermoptera/ 4 Limbs adapted for swimming Yes - 5 No - 6 5 Legs Present or vestigial - #16 Absent - ../Sirenia/ 6 Number of fingers Five - ../Primates/ Other amounts or none - 7 7 Hooves Present - 10 Not present - 8 8 Trunk presence Yes - ../Proboscidea/ No - 9 9 Incisors Developed, located at the front of the jaw - 12 Undeveloped, side teeth used for grazing - 11 10 Number of toes Any odd number - ../Perissodactyla/ Any even number - ../Artiodactyla/ 11 Teeth growth Throughout lifetime - 12 Only during maturation - 13 12 Number of incisors in upper jaw Four - ../Lagomorpha/ Two - ../Rodentia/ 13 Presence of bony scales Yes - 14 No - 15 14 Could be of the order ../Pholidota/ or an armadillo (family ../Dasyopodidae/) 15 Dentition Prominent canines and carnassials - ../Carnivora/ Other - 16 16 Legs Vestigial - ../Cetacea/ Present - #17 17 Could be of the orders ../Afrosoricida/, ../Macroscelidea/, ../Xenarthra/, ../Scandentia/, ../Insectivora/, ../Cetacea/