False obama flatworm (Amaga pseudobama), a new species of subtropical terrestrial planaria for science

NEWS - French and Australian researchers have identified a new species of predatory planarian, false obama flatworm (Amaga pseudobama Geoplanidae), from North Carolina and Florida that was initially mistaken for Obama nungara from South America. However, molecular and histological analysis suggests that the specimen is not only a different species, but not even in the same genus.

“There are many types of flatworms, but most of them live in water. Most of the flatworms you find on land are in tropical ecosystems, so it’s a bit surprising to find a terrestrial flatworm species in North Carolina that science didn’t know about,” said Matthew Bertone of North Carolina State University.

“Free-living flatworms, not parasites, are predators that feed on other soft-bodied organisms, like earthworms and snails. People often worry that unidentified flatworms might be toxic, might carry parasites, or might be invasive and threaten native ecosystems,” Bertone said.

A. pseudobama is black-brown and less than an inch long. Bertone sent a photo of the flatworm to an expert for a preliminary identification and sent a physical specimen for a definitive diagnosis planarian experts thought it was O. nungara.

Meanwhile, Bertone received more shipments of the unidentified flatworm from two other locations in North Carolina, hundreds of miles away from where the first specimen was found. And these new samples were found in residential landscapes, not commercial nurseries.

"The new species is called Amaga pseudobama and we know very little about it. It's never been observed in the wild or in its native habitat, so we don't know much about how it interacts with its environment. We infer from what we know about related species, but we don't know exactly what it eats, how fast it reproduces and so on," Bertone said.

After the new species was formally identified Amaga (Ogren & Kawakatsu, 1990), the researchers discovered that samples of the species had been collected before, but no one knew what they were. There were a few samples collected in Florida in 2015.

"The fact that the initial North Carolina samples were found on plants that had been shipped from Georgia suggests that A. pseudobama can be found throughout the Southeast. It's also possible that this is just an isolated example," Bertone said.

"Discovering a new flatworm species isn't necessarily surprising; these animals are so understudied that there are likely many more species waiting to be discovered," Bertone said.

"However, the fact that we know so little about them is one reason why they are worth paying attention to. Whether they pose a risk to native worms and their impact on us. We need to study this species to find out. The first step in that process is to clearly identify the species and name it,” Bertone said.

Original research

Justine J, Gastineau R, Gey D, Robinson DG, Bertone MA, Winsor L. (2024). A new species of alien land flatworm in the Southern United States. PeerJ 12:e17904, DOI:10.7717/peerj.17904

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