Los Angeles Thread Millipede

A team of researchers in Los Angeles has discovered a new species of millipede. The new species, known as the Los Angeles Thread Millipede or the more formal illacme socal, was found beneath the soil surface in two parks located in the city and in Orange County. Measuring just 0.5mm wide and 2.5cm long, the burrowing creature is also pale and blind and reportedly has the ability to produce a silk-like sticky substance similar to spider silk.

The team involved in the discovery included scientists from Virginia Tech, West Virginia University, and the University of California, Berkeley. The findings were published in the journal ZooKeys^[1]. Paul Marek, associate professor in the Department of Entomology in the College of Agriculture and Life Sciences at Virginia Tech, was the lead author of the study that described the new millipede.

The animal boasts 486 legs and a toothy, Predator-style head. It has the greenish translucence of a glow-in-the-dark toy in daylight and weaves through the soil as elegantly as an embroiderer’s needle. But step away from the microscope and the Los Angeles thread millipede (Illacme socal) becomes a lot less intimidating.

With the width of a thin mechanical pencil lead and the length of a sewing pin. it was easy to miss. With the publication in late June 2023 of a paper formally introducing the critter, the Los Angeles thread millipede joins roughly 12,000 other named millipede species worldwide.

There are an estimated 4 million to 6 million arthropod species, including millipedes, living on Earth, but only about 1 million have been described to date. While specimens of l. socal were only found in these particular areas, Marek believes species likely lived in other parts of the LA-metro area before development led to habitat loss. The limited habitat makes the conservation of the species more important.

The agency said Marek also found another “possible specimen, a juvenile millipede,” in Eaton Canyon Natural Area just north of Pasadena. The biggest differences between the creatures are the number of legs they boast, as well as how many rings they have, researchers said. The females tend to be larger than the males and “have more rings and legs.”

The largest millipede tracked had 125 rings and 486 legs, according to researchers, while the smallest had 51 rings and 190 legs. Habitat photographs were captured with an iPhone 7 camera and millipede photographs and videos were recorded with a Canon EOS 5D Mark IV digital SLR camera and a 65 mm Canon MPE lens.

To record burrowing behavior, a female millipede (MPE04624) and soil from its microhabitat were placed between two pieces of plate glass and mounted vertically in front of a Canon 5D camera on a tripod and illuminated with a GoBe 700-wide LED light (Light & Motion Inc., California).

The millipede was spotted for the first time in April 2018 at Whiting Ranch Wilderness Park, near Lake Forest, by naturalists Cedric Lee and James Bailey. The two immediately realized they were looking at something unique and posted their find to iNaturalist^[2], the citizen science app.

Though the “grossly understudied” species “represent the next frontier of discovery,” it is “threatened by encroaching human settlement and habitat loss” and conserving the species is of “high importance,” according to researchers.