Researcher describes four new species of sponge that haven’t been discovered in plain sight
The ocean is a great place with many deep and dark mysteries. Humans haven’t mapped more than 20% of the sea and explored less. Even southern California’s kelp forests – some of the best-studied ocean patches on the planet – hide species not yet described by science.
Now, Thomas Turner of UC Santa Barbara has published an article in the journal Zootaxa describing four new species of sponges. These new specimens weren’t dredged from murky depths or found on a remote seamount, but collected locally from popular dive sites. The study brings the number of new Turner species to five, and the scientist believes there may be dozens to be discovered and described along the West Coast.
Turner, an associate professor in the Department of Ecology, Evolution and Marine Biology, has collected hundreds of hand samples from dives he has conducted in Southern California. He made sure to photograph each sponge in its natural habitat, documentation that will provide a wealth of information not otherwise available once a specimen enters a collection. Back in the lab, he set about analyzing their anatomy and sequencing their genes.
In 2020, Turner described his first new species of sponge using these molecular techniques: Galaxia gaviotensis, which he found just west of Santa Barbara. He suggested the common galaxy sponge name Gaviota. “Like a galaxy, the type species of the genus is teeming with a diversity of stars,” he wrote, referring to the shape of its spicules, microscopic objects that provide structural support for many sponges.
The four species in the new article appear to a layman as indescribable beige spots on the rocks of the kelp forest. At first, Turner couldn’t even tell which order they belonged to. But while simple creatures can be difficult to distinguish visually, their genomes can reveal their differences. So that’s where Turner focused his efforts.
“When I got the DNA, I was shocked to learn that they were in Scopolinida, which is almost entirely tropical,” he said. Species of this order were unknown from the west coast. In fact, no one had documented Scopolinid sponges anywhere in the eastern Pacific.
And laymen have certainly encountered at least two of these species. “They live in the open air; divers have been swimming alongside them for decades, ”Turner said. He even found photos of one of them on the citizen science app iNaturalist. “They’re all over Southern California, super common. No scientist has ever taken one and looked at it to try to figure out what it was. “
When naming a new species, a scientist often tries to highlight a salient feature of the organism. It’s hard to do for a bunch of beige spots. Turner therefore named two after the places where he found them: S. goletensis, for the town of Goleta; and S. kuyamu, for the village of Kuyamu, a community of Barbareño Chumash that once lay ashore at the site where the sponge was found. Based on their genomics, Turner concluded that these two species are sister species, more closely related to each other than any other known sponges.
Turner coined the name S. jali for the third species after the patterns on its surface, which reminded him of a jali, a lattice screen common in Indo-Islamic architecture. He named the last species after Nausicaä, a character in Hayao Miyazaki’s film “Nausicaä of the Valley of the Wind”. The film is about humans and nature, he explained, and many strange organisms in the fictional world filter and clean the environment like a sponge. In fact, sponges are unique in consuming even viruses and bacteria, he added; many other filter feeders forgo these tiny pieces in favor of much larger plankton.
Sponges diverged from all other animals over 600 million years ago, with the major subgroups breaking apart soon after. “So the amount of independent evolution within sponges is comparable to that of all other animals,” Turner explained. Because they diverged from other animals so long ago, they can potentially tell scientists a lot about our origins.
The animals have also attracted the attention of biomedical researchers. Given their porosity, sponges are much more tied to their external environment than any other animal. As a result, they must actively manage their bacterial and viral loads. This has led the sponges and their microbiota to produce many antimicrobial and even anticancer compounds, Turner said.
Despite their long evolutionary history, most sponges have retained similarities such as a simple body plan and a filtering lifestyle. The simplicity and similarity of sponges has long annoyed scientists, who classified life according to morphology: the shape and function of organisms. “For nearly 200 years, taxonomists have struggled to figure out how to classify sponges because they offer so few morphological characteristics,” Turner noted.
It is only in recent decades that researchers have rectified the different orders of sponges. “A taxonomic order is a fairly large group of animals,” Turner continued. “For example, cats, dogs and walruses are all in the same order: Carnivora.”
Taxonomy is never done just for taxonomists. This is done to lay the foundation upon which researchers in other fields can build. “Trying to do research without taxonomy is kind of like you go to the Library of Congress and there aren’t any librarians, and all the books are just in a big pile,” Turner said. . “There’s a lot of information out there, but there’s nothing you can do with it. The taxonomist’s job is the librarian’s job: to organize all this information so that everyone can study it.
Environmentalists are often clueless when it comes to sponges, Turner explained, simply because taxonomy and systematics weren’t done to figure out what. This is the situation that greeted Turner when sponges caught his eye a few years ago.
“I was recreational diving in the kelp forest here, and I saw all these sponges,” he recalls. “I couldn’t tell what they were; I didn’t know what was important to them; I couldn’t tell what was different from one to the other; and I was getting really frustrated. Eventually, he decided that someone needed to fix the problem, and it might as well be him.
Turner’s experience as a scientific diver, combined with his genomics background, made him perfectly suited to begin sorting the taxonomy and systematics of West Coast sponges. Since 2018, he has collected around 800 specimens. The four species in this article, plus the one from 2020, are just the start of his work describing perhaps 100 new species and adding critical information to hundreds more.
DNA sequencing offers a way forward to understanding these animals, but there is still a lot of careful morphological analysis in Turner’s future. Indeed, by combining these two methodologies, it can bridge the gap between modern molecular biology and our historical dependence on physiology. “It’s the only way out of this quagmire we’re in with regards to sponge taxonomy,” Turner said, “combining morphology with genetics.”
Unfortunately, many sponge specimens have been preserved in ways that do not protect the DNA of animals. It will therefore be difficult to bring old collections into the era of molecular biology. With this in mind, Turner is applying for funding to study how to extract DNA from old sponge samples.
As perhaps the only sponge taxonomist on the US Pacific Coast, Turner also intends to continue his research on the region’s sponges. He plans to start sequencing all of the genomes of the sponges he’s collected, looking for molecular evolution models to try to figure out what sets them apart from each other and what that can tell us about their ecology. and their evolution. His research is supported by the Southern California Bight Marine Biodiversity Observation Network (SCB MBON), a long-term collaboration led by Robert Miller of UC Santa Barbara. The results should elucidate the roles these animals play in their ecosystems.
“It’s about building a foundation that many others can hopefully build upon,” he said, “and setting a new direction for the California marine study in which people can use sponges in their research.