pangolin: toothless mammal of southern Africa and Asia having a body covered with horny scales and a long snout for feeding on ants and termites
placental: mammals having a placenta; all mammals except monotremes and marsupials
atrioventricular node: a node of specialized heart muscle located in the septal wall of the right atrium; receives impulses from the sinoatrial node and transmits them to atrioventricular bundle