New genus of sea stars named after marine biologist
On a deep-sea expedition to the North Atlantic, marine biologist Rhian Waller was part of a team that spotted a sea star they had never seen before. The new sea star has now been recognised and named Rhianastra isosceles.
"I am both proud and blushing at the same time. This is the first time I've had a species named after me," says Rhian Waller, a researcher at the Department of Marine Sciences, University of Gothenburg.
In 2021, Rhian Waller led an expedition on the NOAA research vessel Okeanos Explorer to the New England Seamounts in the North Atlantic. The goal of the expedition was to map the biological life in this remote area of the North Atlantic.
A remotely operated vehicle (ROV) called Deep Discoverer 2 was used to film the ocean floor to depths of over 3 000 metres.
“What is special about NOAA Ocean Exploration expeditions is that the ROV footage is broadcasted directly through live streaming, and there are scientists watching this live stream from all over the world. When we filmed an orange sea star at 1 700 metres depth, my colleague Christopher Mah reacted immediately and asked me to zoom in. When one of the world's leading sea star experts gets excited, you know something special is going on," says Rhian Waller.
New genus of starfish
Christopher Mah, a taxonomist at the Natural History Museum in Washington, asked Rhian Waller to pick up the sea star by using the ROV. Once onboard, she realised that they had found a sea star with very hard skin, and with unusually pointy arms. She sampled it and sent it to her colleague, who recognised it as a new species, and even a new genus, for science.
"It's not unusual for us to find new species on these expeditions. But this is the first time I've been involved in finding a completely new genus," says Rhian Waller.
Christopher Mah has now described the species in an article in the scientific journal Zootaxa. The new sea star has been named Rhianastra isosceles. The genus name Rhianastra after Rhian Waller, and isosceles after the geometric term Isosceles triangle - a triangle that has two sides of equal length..
“What struck me when it first came up was its size. Many animals that live at such great depths are usually small, but this sea star was larger than expected," says Rhian Waller.
High biodiversity
The New England and Corner Rise Seamounts are known for rich biodiversity. These seamount chains consist of over 30 seamounts that were once formed by volcanic activity. Here, nutrient-rich water is pushed up from deeper parts of the Atlantic Ocean, creating favourable conditions for biological life.
Four of the New England seamounts, where the starfish was discovered, lie inside the protection of the only US National Marine Monument in the Atlantic: The Northeast Canyon and Seamounts National Marine Monument.
“In other parts of the deep sea, organisms can be more spaced out. But here, they are densely packed, and the area is teeming with life and biodiversity. I’m sure there are still many species here that are unknown to science," says Rhian Waller.
Text: Karl-Johan Nylén
