Rhodelphis

Rhodelphis /ˌɹoʊˈdɛlfɪs/ is a single-celled archaeplastid that lives in water. It is closely related to red algae and possibly Picozoa. Unlike red algae, which cannot move and always make their own food, Rhodelphis can move and hunt other tiny organisms.

Rhodelphis has a special part inside it called a plastid, but it does not use sunlight to make food like plants do. This plastid might help the cell in other important jobs, such as making certain colors and handling important minerals like iron.

Scientists study Rhodelphis to learn more about how very early plant-like cells lived and changed over time. It gives clues about the history of these tiny living things and how they evolved.

Taxonomy

History and location

Rhodelphis was discovered in 2019 by scientists and described in a paper published in Nature. This group was created for two different types of tiny living things called protists that were found in earlier years. One type, Rhodelphis marinus, was first found in 2015 in marine coral sand in Island Bay Canh, Con Dao, Vietnam. Another type, Rhodelphis limneticus, was first found in 2016 in a freshwater lake in Chernigovskaya oblast, Ukraine. A third type, Rhodelphis mylnikovi, was described in 2023 and was found in a freshwater pond near Montigny-le-Bretonneux, France.

Species

So far, four types of Rhodelphis have been described.

• Rhodelphis edaphicus Belyaev, Zagumyonnyi, Gerasimova, Sozonov & Tikhonenkov, 2025
• Rhodelphis limneticus Tikhonenkov, Gawryluk, Mylnikov & Keeling, 2019
• Rhodelphis marinus Tikhonenkov, Gawryluk, Mylnikov & Keeling, 2019
• Rhodelphis mylnikovi Prokina, Tikhonenkov, López-García & Moreira, 2023

Ecology

Rhodelphis are living things that eat other tiny organisms, such as bacteria and small moving cells called flagellates. We still don't know much about how they fit into water environments where they live. Scientists have found three types of Rhodelphis in very different water places—one in shallow sea water and two in freshwater.

Description

Rhodelphis is a single-celled organism that lives in water. It is shaped like an oval and measures about 10 to 13 micrometers across. This tiny creature can move around using two whip-like structures called flagella that stick out from one end. Unlike plants, Rhodelphis does not contain any pigments, so it looks mostly clear under a microscope.

Even though Rhodelphis cannot make its own food through sunlight, it still has a small structure inside called a plastid that helps with certain important processes in the cell. This organism also has structures called mitochondria that help produce energy.

Rhodelphis is closely related to red algae, but they have some differences in their genetic makeup. Rhodelphis has a larger genome and more pieces called introns in its genes compared to red algae. It also has special proteins that allow it to consume other small organisms for food.

Importance

Rhodelphis is part of a group of simple living things called archaeplastids. This group shares a common ancestor that could capture a special part called a plastid. Because there are not many examples of how this process first happened, finding Rhodelphis helps scientists understand what kinds of organisms might have first taken up plastids. This is important for learning about how green algae, plants, and red algae evolved. Red algae are important plants that help make food for other living things all around the world.