They have inflexible vertebral columns , flattened , streamlined bodies , lateral line systems , and powerful hind limbs with large webbed feet .
Members of the family Pipidae are wholly aquatic and show the most marked specialization .
Members have inflexible vertebral columns , flattened , streamlined bodies , lateral line systems , and powerful hind limbs with large webbed feet .
Members of the family Pipidae are wholly aquatic and show the most marked specialization .