An extinct order of Cretaceous aquatic birds that lost the ability to fly, characterized by teeth and backward-positioned legs.
From Hesperornis + Latin -formes (order suffix meaning 'form or group of'). Creates the highest taxonomic classification for these birds.
This order represents one of the most dramatic transformations in bird evolution—wings became useless flippers, teeth returned (which modern birds lost), and legs moved backward for diving power!
Complete word intelligence in one call. Free tier — 50 lookups/day.