The first land-walking vertebrates may have emerged from salty estuaries
An analysis casts doubt on views that the ancient creatures arose in freshwater
![tetrapod illustration](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2018/05/053018_CG_tetrapod_feat.jpg?fit=860%2C460&ssl=1)
SALTY SCENE The planet’s earliest four-footed vertebrates called tetrapods (illustrated) lived in the brackish waters of an estuary or delta, new research suggests.
Mazan