Who doesn’t love roly poly pill bugs?

Now, San Pedro has one of its very own.

A tiny new species of marine pill bug was a bonus find on a field trip led by museum researcher Dean Pentcheff of San Pedro. The Feb. 16, 2004, shoreline excursion was part of a class on invertebrate zoology he was teaching while he was a visiting assistant professor at Loyola Marymount University in Westchester from 2003-05.

As Pentcheff led students along the rocky shoreline beneath the greenbelt just west of Point Fermin Park in San Pedro, he picked up a sea star — the focus of the field trip.

“We were looking at sea stars and whatever invertebrates we could see. I was teaching them how to pick up a sea star when I saw this little isopod scuttling around on (one),” Pentcheff said.

Although it was miniscule, it was something that struck Pentcheff as deserving of a closer look.

So he said he “grabbed it” and sent it off to researchers at the Los Angeles County Museum of Natural History, where he and his wife both work.

“We discovered it clutching on for dear life to one of the five arms of a common sea star,” Pentcheff said in a statement. “But my class and I had no idea we were looking at a new species.”

The paper published last week documents five new species that were discovered — including another new species of pill bug originally collected 142 years ago by biologists on a wooden sailing ship in Alaska, but just confirmed with the research in Los Angeles where it had been sitting in the museum’s collection for many years.

The new San Pedro species is a pretty big deal, said Adam Wall, the lead writer of the paper,.

“Considering that the whole area is actually surveyed pretty often, it’s unusual to find a new species right there,” said Wall, assistant collections manager for crustacea at the museum. “It speaks to how much unstudied biodiversity there is, even in places like Los Angeles. … There are going to be more species out there that are going to be discovered. The big things have been found, but we’re starting to look smaller and smaller.”

Since the 2004 field trip discovery, the museum has collected about a half-dozen pill bugs of the same previously unknown species, all in the San Pedro area. Wall said it is thought they may be on the Channel Islands as well.

It joins a group of some 5,000 marine pill bugs already identified in the world.

Even more rare, the specimen collected in San Pedro was a male, usually vastly outnumbered by females and important for their extra ornamentation that helps with identification.

“Once we got the specimen to the museum, we knew it was something unusual,” Wall said of the bug about the size of a grain of rice. “But it was so small that we couldn’t just use a normal light microscope to study it. We had to use a scanning electron microscope.”

Pentcheff’s wife, Regina Wetzer, associate curator and director of the museum’s Marine Biodiversity Center, helped write the paper.

The process included bringing in specimens from some 15 or 20 countries, Wall said, to make sure what they had was unique. Because the Port of Los Angeles is so close to the discovery site, he said, it’s not uncommon for foreign species to be inadvertently brought here on ships.

It’s a major addition to the museum’s already impressive collection, though it will not be on public exhibit.

Pill bugs — the terrestrial variety found in many backyards is the most common to most people — aren’t really “bugs” or insects at all, but are part of the crustacean family, more closely related to shrimp and crayfish.

Both the marine and terrestrial varieties use gill-like structures to breathe.

They’re scavengers that help keep land and sea from filling up with dead plants and animals, Pentcheff said.

“These are the unseen bio-recyclers,” Pentcheff said. “There are many more of them than there are lions and tigers and bears, but we tend not to notice them.”

But without them, he said, gardens would be buried and the seas filled with nature’s dead castoffs.

Marine pill bugs can be both predators and parasites as well, living off of fish, he said.

Pentcheff, who is the BioSCAN project coordinator at the Natural History Museum, said he knew the “bumpy little guy” he found on the 2004 field trip was something special. But he didn’t know how special.

This species, Wall said, is about a third smaller than other marine pill bugs and among its visible distinctive traits are numerous bumps along its body, thought to be primarily ornamentation.

“It’s a lot more ornamented,” he said. “Think of it as a big pair of antlers.”

In fact, the tail is so ornamented that it can’t fully roll up like many other pill bugs when under threat, Wall said. Instead, he said, it “folds in half.”

Pentcheff said the “citizen scientist” students on that field trip have long since scattered and he’s not kept in touch with any of them. But that February shoreline excursion 11 years ago has officially gone down in history, in large part thanks to their eagle-eyed teacher.

The scientific name of the new marine pill bug species? Exosphaeroma pentcheffi.