In the blockbuster movie of 2019 Godzilla: King of the Monsters, everybodys darling Kaiju, Godzilla, fought another titan named King Ghidorah, a monster known for having three heads. Now biologists have discovered a new species of sea worm that has a head but a body that can branch into multiple rear ends, so a newer paper published in the journal Organisms Diversity & Evolution. So, of course, the biologists named the new species after Godzilla’s legendary adversary: Ramisyllis Kingghidorahi.
“King Ghidorah is a branching fictional beast that can regenerate its lost ends, so we thought this was an appropriate name for the new breed of branching worm.” said co-author M. Teresa Aguado at the University of Goettingen. In fact, the director of the first Ghidorah-centric feature film In 1964, Ishiro Honda said his monster was a modern version of a legendary eight-headed and eight-tailed dragon/serpent named in Japanese folklore Yamata no Orochi.
According to Aguado and her co-authors, only two other species of these rare branching worms have been discovered. As early as 1879, an amateur naturalist was named Karl Macintosh reported the discovery of a “remarkably branched syllid” (dubbed Syllis ramosa). The creature was found in a glassy sea sponge in the Philippines during the 20th century Challenger Natural History Expedition. Syllis ramosa was the first known example of an annelid species with a “randomly branched asymmetric body”.
The second species of branching seaworm (Ramisyllis multicaudata) was only found in 2012 and observed in the shallow coastal areas of Darwin, northern Australia. Like Syllis ramosa, the second species also had a randomly branching, asymmetric body and lived in the labyrinthine channels of sea sponges. And both reproduce asexually through a process called Schizogamie. The worms form posterior segments with buds (or Gameten) who can develop features such as eyes and sense organs. Once formed, the gametes are free to detach and swim freely, and the rear ends are allowed to regenerate.
This new third species was discovered at Shukunegi Point on Sado Island in Japan and also inhabits sponges. The Japanese team sent pictures of the worms to Aguado, who immediately recognized the novelty of the worms and organized an expedition to the island in 2019 to collect samples and study the creatures more closely.
“We were amazed to find another of these bizarre creatures with just a head and a body made up of multiple branches,” said Aguado. “The first worm was considered unique. This discovery reveals a greater diversity of these tree-like animals than anyone expected.”
Aguado and her co-authors combined their interdisciplinary expertise to learn more about the new species. Their investigation included a molecular analysis that revealed Ramisyllis multicaudata and Ramisyllis Kingghidorahi share a common evolutionary ancestor. But there are still some genetic differences, particularly in relation to the shape of certain body segments.
The authors suggest that both species may have inherited the distinctive long asymmetrical body from their last common ancestor. that had adapted to survive in the branching canals of a sponge. “The branched bodies of the branched syllids may reflect the intricate labyrinth of the sponge canal system, with the ability to produce new fully developed segments that allow the worm to explore the canals,” the authors wrote.
Many mysteries remain about these rare species of branching worms, which will be the focus of future research. “Scientists don’t yet understand the nature of the relationship between the branching worm and its host sponge: is it a symbiotic relationship that somehow benefits both creatures?” said Aguado. “And how do the worms manage to feed themselves to maintain their huge bodies with only a tiny mouth in their single head?”