Spiders that still carry armored abdominal plates were dug from burrows across Tongren and Zunyi, and the findings show how much of southern China's wildlife remains uncounted.

Scientists have described 12 new species of segmented trapdoor spiders from Guizhou Province in southern China, one of the largest single additions to a group regarded as living relics of the earliest branch of the spider family tree. The study, published Oct. 15 in Zoosystematics and Evolution, raises the genus Songthela from 43 described species to 55.

The discovery also nearly triples the known diversity of the genus in Guizhou. Only seven Songthela species had been described from the province before this paper, and the authors wrote that new specimens "revealed considerable previously undocumented species diversity."

The work was led by arachnologist Xin Xu of Hubei University and Hunan Normal University, with Yan Zhang and Daiqin Li, and was funded by the National Natural Science Foundation of China. Many of the new species are known from a single county or a cluster of nearby villages, which makes them useful markers of how intact their small patches of habitat remain.

Spiders That Kept Their Ancestors' Segments

Songthela belongs to Liphistiidae, the only living family of the suborder Mesothelae, which is the sister group to all other spiders. Its members keep traits that most modern spiders lost long ago — the most visible is a row of 12 hard plates, called tergites, along the top of the abdomen, a segmented look that recalls the ancestors of all arachnids.

The new species also have seven or eight spinnerets, the silk-producing organs, grouped near the middle of the underside of the abdomen. In nearly every other living spider, spinnerets sit at the rear tip. Adult body lengths in the new descriptions run roughly 10 to 18 millimeters (about 0.4 to 0.7 inch) for many females.

Liphistiids live in silk-lined burrows sealed with a hinged trapdoor. They wait just below the lid and lunge at insects and other small animals that pass close to the entrance, then retreat underground. Because they rarely leave their burrows and disperse poorly, populations can stay isolated in a single valley or forest patch for very long periods.

Genitals First, DNA Barcodes Second

The team separated the 12 species mainly by the shape of the male palp, the modified appendage used in mating, and the female genital structures. That approach is the long-standing standard in spider taxonomy, because these parts often differ sharply between species that look alike from the outside.

DNA played a supporting role — the researchers sequenced the mitochondrial COI gene, the standard animal DNA barcode, from the holotype of every new species and deposited the sequences in GenBank. Those barcodes will let future researchers match juveniles, damaged specimens or look-alike spiders to a named species without relying on adult anatomy alone.

The paper also documents wide variation within single species. In S. chenjiapian, the female genital stalks can be fused, partly fused or separate, and spinneret counts vary from seven to eight within a population. In S. fengxiang, individuals carried six to eight spinnerets. That variation is a caution against naming species from one or two specimens.

Tiny Ranges in a Karst Province

Collectors dug adult and immature spiders from burrows in Tongren City counties including Jiangkou, Yinjiang, Yanhe, Sinan and Shiqian, and in Yuqing County in Zunyi City. Records in the paper span elevations from about 366 meters (1,200 feet) to nearly 1,290 meters (4,230 feet). Immature spiders were raised in the lab until they matured, and four legs from each adult were frozen at minus 80 degrees Celsius (minus 112 degrees Fahrenheit) for DNA work.

Several species are known from only one locality. S. cuantang has been recorded only in Yanhe County, S. fuyan only in Shiqian County, and S. parallela only in Yuhu Forest Park. A 2021 study in ZooKeys and a separate 2026 Zootaxa paper described other Songthela species from the province, showing a steady pace of new finds.

Guizhou sits within one of the world's great karst regions, where limestone and dolomite have eroded into cone-shaped peaks, gorges and caves. UNESCO's South China Karst World Heritage listing includes two Guizhou components, Libo and Shibing. Rugged, dissected terrain like this can isolate populations and help explain why a sedentary spider could split into many local species.

Limits and Next Steps for Conservation

The paper is a peer-reviewed taxonomic study. It describes species, maps where they were found and provides barcodes, but it does not measure population sizes, track habitat change or assess extinction risk. Any claim that these spiders are threatened would go beyond what the authors tested, a point echoed in an independent summary of the study that describes narrow ranges as a possible vulnerability.

The findings still matter beyond China. Mesotheles live only in East and Southeast Asia, and each new species adds detail to how the earliest spider lineage spread and diversified. Small-range invertebrates are also among the least studied animals worldwide, and baseline records like these are what later conservation assessments depend on.

For travelers visiting karst parks in southern China, the guidance is simple. Leave burrows and trapdoors undisturbed, stay on marked trails, and follow park rules on collecting. Next steps for researchers include broader DNA analyses across Guizhou to test how mountains and river valleys shaped the genus. Nature World News will report on new descriptions or conservation reviews as they appear.

What Readers Want to Know

What did scientists discover? Twelve new species of Songthela trapdoor spiders from Guizhou Province, China, were described Oct. 15 in Zoosystematics and Evolution. The genus now has 55 described species.

Why are they called living fossils? They belong to Mesothelae, the oldest surviving branch of spiders. They keep segmented abdominal plates and centrally placed spinnerets that most spiders lost.

How did researchers tell the species apart? Mainly by differences in male and female reproductive structures. DNA barcodes from each holotype were added to help identify specimens in the future.

Are these spiders dangerous to people? The study reports nothing suggesting a risk to people. They are burrow-dwelling ambush predators of small animals.

Are the new species endangered? That is unknown. The study did not assess population sizes or extinction risk, though several species are known from only one locality.

Where do these spiders live? In silk-lined burrows with hinged trapdoors in hilly, forested parts of northeastern Guizhou, including Tongren and Zunyi cities.