From 2022 to 2025, faunal surveys were undertaken of the caves located in Great Basin National Park and Humboldt-Toiyabe National Forest, White Pine County, Nevada. The surveys yielded new records of the cave-limited species, Nevadesmus ophimontis Shear, 2009 (Macrosternodesmidae), and Idagona lehmanensis Shear, 2007 (Conotylidae), as well as the discovery of the new species Bollmanella amorensis sp. nov. (Conotylidae) from the Labor of Love Cave. The new species is separated from other members of genus by more than 600 miles (ca. 965 km) and by intervening semidesert grassland inhospitable to millipedes. While limited to caves by non-suitable surrounding habitat, the three species are only somewhat morphologically adapted to life underground. We speculate that their presence in the caves is due to relatively recent climatic and ecotope changes associated with the retreat of the most recent glaciers some 14,000 to 12,000 years ago and aridification of the landscape.

The records from the surveys are given in Tables 1, 2. Because the studied caves are ecologically sensitive and are of paleontological, archaeological and ethnographic importance, we do not provide coordinates for them. All the caves are under the protection of the National Park Service or National Forest Service of the United States, and are in the Great Basin National Park or the Humboldt-Toiyabe National Forest.

Specimens were hand-collected into 95% ethanol. Morphological studies were done using an Olympus SZH stereomicroscope and an Olympus BX50 compound microscope equipped with Nomarski optics. For scanning electron microscopy (SEM), specimens were first cleaned in an ultrasonic cleaner, then mounted on 12.7 mm diameter aluminum stubs using double-sided adhesive carbon discs and allowed to air-dry. These were sputter coated with a 40-nm thick layer of gold and palladium using a Cressington 208HR sputter coater and a Cressington MTM20 thickness controller. SEM micrographs were taken with a FEI Quanta 600 FEG environmental scanning electron microscope. Micrographs were edited and refined using GIMP, and plates were composed in InkScape.

We do not give detailed coordinate for the caves mentioned herein, due to their protected status as paleontological and archeological resources.

We describe the new species Bollmanella amorensis sp. nov., (Conotylidae) from Labor of Love Cave. Cave surveys also yielded new records of the cave-limited species, Nevadesmus ophimontis Shear, 2009 and Idagona lehmanensis Shear, 2007 (Table 1). Currently we are aware of many new and unexplored caves, and new species of millipedes and other cave animals from them await discovery and documentation.

The Wild Caves Project is uncovering new species and fascinating discoveries of natural heritage every year. This project is part of the Protecting Wild Caves in White Pine County Project, funded by the Southern Nevada Public Land Management Act (SNPLMA). This interagency project is managed by Great Basin National Park (GRBA) and Humboldt-Toiyabe National Forest (HTNF). The overall study has multiple components including an ethnographic assessment and report, cave rock art protection, education and outreach, and a Wild Caves Inventory, which produced the information covered in this paper.

Over two years, June 2022–October 2023, a team of experts conducted detailed scientific inventories of paleontological, archeological, biological, hydrological, and geologic resources in 30 GRBA caves and 15 HTNF caves. The field portion of the project also included cave cartography, photography, and rescue assessments. Extensive reports (Great Basin Institute 2025) were written with recommendations for future work, including additional site visits, which occur sporadically.

White Pine County, Nevada, is located in the middle of the Great Basin hydrologic region as well as the Basin and Range geologic province. Primary mountain ranges within the county are the Snake, Schell Creek, and Egan Ranges, each over 80 km long and separated from each other by basins that are typically 20–40 km wide. The Snake Range contains the second highest peak in the state, Wheeler Peak, at 3982 m. The mountain ranges are of a complex geology, primarily consisting of Cambrian-age carbonate rocks that have experienced multiple deformational events (Hose et al. 2024).

The caves in White Pine County are numerous and varied, with elevations from about 2000 to 3400 m. Caves at the lower elevations are typically found in big sagebrush steppe that transitions to pinyon-juniper woodland. Caves at middle elevations are found in mixed conifer woodlands, with Douglas fir (Pseudotsuga menziesii), white fir (Abies concolor), and limber pine (Pinus flexilis) dominant. The highest elevation caves are near treeline, with Engelmann spruce (Picea engelmannii), limber pine, and bristlecone pine (Pinus longaeva) scattered nearby. While the majority of caves have formed hypogenically, others, like Labor of Love, are epigenic caves, while some are fracture and talus caves (Hose et al. 2024).

Cave biota within these caves varies, with springtails, flies, and beetles generally the most numerous as well as mammal species including Western big-eared bats (Corynorhinus townsendii), various Myotis species, and bushy-tailed woodrats (Neotoma cinerea). Cave-adapted species include the Great Basin Cave pseudoscorpion (Microcreagris grandis Muchmore, 1962), the Model Cave harvestman (Sclerobunus ungulatus (Briggs, 1971), the Shoshone springtail (Pygmarrhopalites shoshoneiensis Zeppellini, 2009), the White Pine cave amphipod (Stygobromus albapinus Taylor & Holsinger, 2011), and millipedes.

Millipedes are found in some of the White Pine County caves. Nevadesmus ophimontis has been found in Lehman, Model, and Snake Creek Caves, but not other nearby caves. Idagona lehmanensis is much more widespread. It has been found in several caves in the Baker Creek area (Model, Halliday’s Deep, and Lower Pictograph Caves); and Water Trough Cave and Drumming Cave, which have springs running through them; this species has also been found in high-elevation caves (Cave 24, Pinecone, Monument, and Broken), and appears to show a strong affinity for water and/or high elevations. Finally, Bollmanella amorensis sp. nov., is currently known from just one cave in White Pine County.

Shear, Richart and Wong (2020) speculated that the occurrence in caves of Complicatella neili was relatively recent and perhaps dated to some 14,000 years ago when the retreat of the continental glacier resulted in the extensive drying of the area—including the disappearance of a large glacial lake in which the Humboldt Range was an island. The immediate surroundings of the cave in which C. neili dwells are not forested, but stunted trees and low bushes predominate on the otherwise barren limestone peak. Possibly as the climate dried, forests at higher and sequentially higher elevations became extinct and along with them species of soil and litter animals. The only populations of such animals that could survive were those inhabiting caves, where moist conditions remained. The same model of the restriction of once wide ranges of surface-dwelling populations can be invoked for the species from west central Nevada we discuss here. Complicatella neili, Bollmanella amorensis sp. nov. and Idagona lehmanensis do not show striking troglobitic adaptation, and the latter two species have numbers of ommatidia similar to those of surface dwelling conotylids in the same size range. This suggests their occupancy of caves is not of long standing. The surroundings of the caves studied in the survey would be, or has become in the last 14,000 years, inhospitable for millipedes, leaving those able to invade and survive in caves as relicts of a past climate.

If so, this history would suggest that the Great Basin once supported a millipede fauna with affinities to the present fauna of the Pacific Northwest. The drying climate probably led to the natural extirpation of most of this fauna, leaving behind only populations that had become established in caves. This is not the place for further detailed speculation but it may be noted that some caves in the upper and middle Mississippi valley are inhabited by millipede species with far western affinities.