New invasive flatworm threatens US ecosystems

An invasive species of flatworm, Amaga pseudobama, has already appeared in at least three US states—Florida, Georgia, and North Carolina—according to the journal PeerJ. A scientist from the University of Szczecin was part of the research team that made the discovery.

The research team included scientists from the National Museum of Natural History in Paris, Drexel University, and North Carolina State University in the United States, James Cook University in Australia, and Dr. Romain Gastineau from the University of Szczecin.

In an interview, Dr. Gastineau, a specialist in microalgae genomics and the sequencing of mitochondrial genomes of invasive land flatworms at the Institute of Marine and Environmental Sciences of the University of Szczecin, emphasized the significance of the new research interest.

"These types of animals have not been of interest to anyone for over 100 years, except for a few strict specialists in invertebrates. Now there is widespread interest, including from people outside the scientific community, because they are invasive," he says.

The worms have spread in Europe, North America, and distant islands such as Martinique, Guadeloupe, Réunion, and Tahiti. Scientists point out that in many of these areas, they are completely uncontrolled because they have no natural enemies.

Most invasive flatworms originate from Southeast Asia, Vietnam, Thailand, Indonesia, Australia, New Zealand, and Papua New Guinea. They significantly impact soil ecosystems by eating earthworms and other invertebrates.

"The problem with them is that they are predators of soil invertebrates and mainly eat earthworms. And earthworms are already having problems due to, for example, chemicals. In some places, such as England and Scotland, this is quite a serious issue, as there are already 20% fewer earthworms because of this," adds the Polish researcher.

The newly discovered land flatworm (Amaga pseudobama), first noticed in North Carolina in 2020, is a brown worm a few centimetres long. It is very similar to Obama nungara, a predatory species from Brazil and Argentina that has invaded a significant part of Europe, eating small snails, soil-aerating earthworms, and other small animals.

In the South American Tupi language, the word "oba" means "leaf," and "ma" means "animal," referring to the shape of the flatworm's body.

Due to the COVID-19 pandemic, the identification of the new species was delayed. Only after thorough molecular and morphological studies, including a description of the complete mitochondrial genome, could scientists distinguish Amaga pseudobama as a separate species. It is found in Florida, Georgia, and potentially other states. Additionally, other invasive flatworm species, such as Platydemus manokwari, have been discovered in the southern United States.