Chrompodellid

Chrompodellids are a special group of tiny, single-celled creatures called protists. They belong to a larger group known as the Alveolata. There are two main types of chrompodellids: the colpodellids and the chromerids.

Colpodellids are hunters that eat other tiny creatures. They move using whip-like parts called flagella. Chromerids, on the other hand, are able to make their own food using sunlight, like plants do. They often live together with corals in a helpful relationship.

Scientists first found these two types separately, but later studies showed they are closely related. Chrompodellids are very close relatives to another group called Apicomplexa. Because of how they were studied, they are sometimes called Chromerida or Colpodellida.

Description and life cycle

Chrompodellids are a group of tiny, single-celled organisms called protists. They have two main types: chromerids, which make their own food using sunlight, and colpodellids, which hunt and eat other tiny organisms. Both types share some special features, like flat areas under their surface and structures that help them move.

Colpodellids move using whip-like structures called flagella and can hunt other small organisms. They sometimes eat by sucking the contents from their prey. After eating, they rest and divide into four cells. Chromerids live together with corals and usually stay in one place, using sunlight to make food. They can also move around using flagella under certain conditions. Both types can form protective resting stages when conditions are tough.

Evolution

Chrompodellids are very close relatives of apicomplexan parasites. They evolved from a photosynthetic myzozoan ancestor, which means they share a common origin with these parasites. Chromerids, a type of chrompodellid, are the last group in this family that still uses sunlight for energy, while others changed to live by eating other organisms or as parasites.

The apicomplexans, chrompodellids, perkinsids, and dinoflagellates all belong to a group called Myzozoa. These organisms share special structures called the apical complex and plastids, which they got from an ancient event where they lived together with a red alga. Over time, many of these groups lost their ability to use sunlight and changed to different ways of living. The relationships among these groups are shown in a diagram, with chromerids marked with asterisks:

Systematics

In 1993, a scientist named Thomas Cavalier-Smith described a group of tiny, single-celled creatures called Colpodellida. He thought they were very simple relatives of another group called apicomplexans. Later, in 2001, another tiny creature called Chromera velia was found living with corals in Australia. It was the first of a new group called chromerids.

Scientists then discovered that colpodellids and chromerids are very closely related. They mix together in a group called chrompodellids, which is very close to apicomplexans. Today, chrompodellids are considered a special group of their own, separate from apicomplexans, and are studied to learn more about how these tiny creatures live and evolve.