alatiseid

Alatiseid are a group of extinct marine reptiles belonging to the order Sauropterygia, which thrived during the Late Triassic period, approximately 228 to 201 million years ago. They are notable for their elongated necks and streamlined bodies, adaptations that likely aided in their predatory lifestyle. The name "Alatiseidae" comes from the genus *Alatise*, a well-known member of this family, though the group includes other closely related taxa as well.

Fossil evidence of alatiseids is primarily found in marine deposits of what is now Europe, particularly in regions that were part of the Tethys Ocean during the Late Triassic. These reptiles were semi-aquatic, with adaptations such as paddle-like limbs and a flattened tail, suggesting they were capable swimmers. Their diet likely consisted of fish, smaller marine reptiles, and possibly even ammonites, though direct evidence of their feeding habits is limited.

Alatiseids shared similarities with other sauropterygians, such as nothosaurs and placodonts, but they exhibited distinct anatomical features. Their skulls were often elongated, and their teeth were adapted for grasping rather than crushing, distinguishing them from placodonts, which had specialized crushing teeth for mollusks. The exact evolutionary relationships within Sauropterygia remain a subject of study, but alatiseids are generally considered basal members of the clade, representing an early branch of necked marine reptiles.

The extinction of alatiseids coincided with the broader decline of many Late Triassic marine reptiles, possibly linked to environmental changes, competition, or the mass extinction event that marked the end of the Triassic period. Their fossils provide valuable insights into the diversity and adaptation of early marine reptiles during a critical transitional phase in Earth's history.