What is a common trait of Excavata organisms?

Excavata organisms are characterized by the presence of a "feeding groove" or "oral groove," which is a distinctive feature used for feeding. This groove allows these organisms to capture food particles effectively and is often associated with their mode of nutrition. The feeding groove can be found in various groups within the Excavata clade, such as Euglenozoans and some diplomonads, highlighting its significance in their evolutionary adaptation.

While some Excavata do lack mitochondria, not all members share this trait universally, as many utilize mitochondria for respiration. The presence of a protective shell is more characteristic of other groups, like foraminifera or certain protists, and photosynthesis capability is generally found in a subset of Euglenozoans rather than being a trait applicable to all Excavata. Therefore, the feeding groove is the definitive and common trait that distinctly identifies Excavata organisms.