Tanystropheidae is an extinct family of mostly marine archosauromorph reptiles that lived throughout the Triassic Period. They are characterized by their long, stiff necks formed from elongated cervical vertebrae with very long cervical ribs. Some tanystropheids such as Tanystropheus had necks that were several meters long, longer than the rest of their bodies.

Tanystropheidae is an extinct family of mostly marine archosauromorph reptiles that lived throughout the Triassic Period. They are characterized by their long, stiff necks formed from elongated cervical vertebrae with very long cervical ribs. Some tanystropheids such as Tanystropheus had necks that were several meters long, longer than the rest of their bodies.