Subterranean
Guides
Haplophthalmus danicus
Spurred Ridgeback, terrestrial cave isopod
Haplophthalmus danicus is a small woodlouse species in the family Trichoniscidae, commonly known as the spurred ridgeback or terrestrial cave isopod. Native to Europe and parts of Asia, it has been introduced to North America, where it has become well established in terrestrial communities since European settlement. The species comprises seven recognized subspecies across its native range. It is frequently observed in cave and subterranean habitats, reflecting its common name.
Heterotermes aureus
Desert Subterranean Termite
Heterotermes aureus is a subterranean termite native to the deserts of North America. Colonies are large, with estimates ranging from 45,000 to over 2 million individuals. The species is notable for its ability to forage in drier conditions than other desert subterranean termites and for its distinctive soldier mandible morphology.
Horologion
Horologion is one of the rarest and most enigmatic carabid beetle genera, containing two known species of troglomorphic ground beetles endemic to the middle Appalachian Mountains. The genus remained monotypic for over 60 years after its description in 1932, with a second species discovered in Virginia in 1991 and described in 2024. Phylogenetic analysis places Horologion in supertribe Trechitae as sister to the Gondwanan tribe Bembidarenini, making tribe Horologionini a relict lineage with no close relatives in the Northern Hemisphere.
Horologion hubbardi
Horologion hubbardi is a newly described species of carabid beetle from Bath County, Virginia. It represents only the second known species in the genus Horologion, which was previously known solely from a single holotype collected in West Virginia in 1931. DNA sequence data and morphological analysis place the genus in the supertribe Trechitae, as sister to the Gondwanan tribe Bembidarenini. The species is considered a relict lineage with no close relatives known in the Northern Hemisphere.
Horologionini
Horologionini is a relict tribe of carabid beetles (Coleoptera: Carabidae: Trechinae) containing the enigmatic genus Horologion. The tribe was newly recognized in 2024 based on DNA sequence data and morphological analysis. Phylogenetic analysis places Horologionini in the supertribe Trechitae as sister to the Gondwanan tribe Bembidarenini, rejecting previous hypotheses that placed the genus near Anillini, Tachyini, Trechini, Patrobini, or Psydrini. The tribe has no close relatives in the Northern Hemisphere and represents an important component of Appalachian biodiversity.
Hubbardiidae
hubbardiid shorttailed whipscorpion, hubbardiid short-tailed whipscorpion
Hubbardiidae is the larger of the two extant families in the arachnid order Schizomida, comprising approximately 356 species in 69 genera. Members are superficially spider-like but distinguished by a short, segmented flagellum (tail-like structure) and divided into two subfamilies: Hubbardiinae and Megaschizominae. The family exhibits worldwide distribution with notable diversity in tropical and subtropical regions, including significant cave-adapted and subterranean faunas.
Hymenaphorura
Hymenaphorura is a genus of springtails (Collembola) in the family Onychiuridae, established by Bagnall in 1948. Members of this genus are eyeless, euedaphic (soil-dwelling) or troglobitic (cave-dwelling) species with reduced pigmentation. The genus has been recorded from caves and subterranean habitats across Europe, with some species showing narrow endemic distributions restricted to single cave systems.
Hypoponera opaciceps
Granulate Crypt Ant
Hypoponera opaciceps is a small, cryptobiotic ant species in the subfamily Ponerinae. It is widely distributed across the Neotropics, including the Caribbean, Central America, and South America, with records extending to the Galápagos Islands. The species is primarily subterranean or leaf-litter dwelling, making it infrequently observed despite its broad range. Seven subspecies have been described, reflecting considerable geographic variation across its distribution.
Hypoponera opacior
Common Crypt Ant, ponerine ant
Hypoponera opacior is a small ponerine ant known for its unusual wing polymorphism in both sexes. Unlike most ant species, it produces both winged and wingless morphs in males and queens, with each morph associated with distinct reproductive behaviors and seasonal timing. The species has been extensively studied for its genetic architecture, which notably lacks the supergene-linked determination found in many other ants with similar reproductive polymorphisms. Males are particularly distinctive, appearing worker-like and wingless in some morphs, with translucent heads that cause frequent misidentification as wasps or braconid parasitoids.
Ischyropsalididae
Ischyropsalidid Harvestmen
Ischyropsalididae is a family of harvestmen (Opiliones) comprising 35 described species across three genera: Acuclavella (thorn harvestmen of North America), Ceratolasma, and Ischyropsalis (predominantly European). The family exhibits a disjunct distribution spanning Europe and western North America. Several species are troglophilic, inhabiting cave systems with documented adaptations to subterranean environments including seasonal activity patterns and microhabitat specialization.
Islandiana
dwarf spiders, money spiders
Islandiana is a genus of minute sheet-web spiders (family Linyphiidae, subfamily Erigoninae) first described by J. Braendegaard in 1932. The genus currently comprises 15 described species, with the majority distributed across North America. Several species exhibit obligate cave-dwelling habits, making the genus notable among subterranean spider faunas. The most recently described species, Islandiana lewisi, was identified in 2018 from a single cave in southern Indiana after a 30-year gap in new species descriptions for the genus.
Laemostenus
Laemostenus is a genus of ground beetles (Carabidae) comprising nearly 200 species distributed across all continents except Antarctica. Species range from 8 to 28 mm in length. Many exhibit dark coloration with blue or purple metallic sheen, while subterranean and cave-dwelling species show depigmentation, reduced eyes, and lighter coloration. The genus includes both surface-dwelling and hypogean (subterranean) species, with several subgenera recognized.
Lasius brevicornis
Short-horned Meadow Ant
Lasius brevicornis is a small ant species in the genus Lasius, commonly known as the Short-horned Meadow Ant. It is the North American counterpart to the European yellow meadow ant (Lasius flavus), with which it was formerly confused. The species inhabits meadow and grassland environments, where it constructs subterranean nests and tends root-feeding aphids for honeydew.
Leiodes
round fungus beetles
Leiodes is a genus of small, rounded beetles in the family Leiodidae, comprising at least 110 described species with a primarily Holarctic distribution. Most species are subterranean mycophages, with several species acting as economically significant pests of truffle orchards. The genus exhibits specialized morphological and behavioral adaptations for life in ephemeral and solid fungi, including unique larval structures such as pseudomycangia.
Leiodidae
Round Fungus Beetles
Leiodidae is a globally distributed family of small beetles containing approximately 3,800 described species. Commonly known as round fungus beetles, many species exhibit a compact, globular body form, though some are more elongated. The family encompasses diverse ecological specializations including fungivory, detritivory, carrion-feeding, and subterranean cave-dwelling. About half of all described species are flightless due to reduced or absent wings. The tribe Leptodirini represents one of the most diverse radiations of subterranean animals, with over 1,300 species adapted to cave habitats.
Leptotyphlinae
Leptotyphlinae is a subfamily of minute rove beetles (Staphylinidae) characterized by extreme miniaturization and subterranean adaptations. Adults are eyeless, wingless, and measure less than 1.8 mm in length. The subfamily contains at least nine genera and 13 species in North America, with records from western states and Florida.
Margarodes
Cyst-forming Coccids, Ground Pearls
Margarodes is a genus of scale insects in the family Margarodidae, commonly known as "ground pearls" for the waxy, pearl-like cysts formed by immature stages in soil. The genus was erected in 1828 by Lansdown Guilding based on specimens found in soil on the Bahamas associated with ants. Members of this genus are subterranean for much of their life cycle, feeding on plant roots. The type species is Margarodes formicarum.
Melanaethus uhleri
Melanaethus uhleri is a species of burrowing bug in the family Cydnidae, order Hemiptera. The genus Melanaethus belongs to the burrowing bug family Cydnidae, a group of true bugs adapted for digging in soil and associated with roots of plants. Species in this genus are typically found in the Nearctic region. As with other cydnids, M. uhleri likely exhibits subterranean habits and feeds on plant roots, though specific biological details for this species remain poorly documented in the accessible literature.
Meta
Cave Orbweavers
Meta is a genus of long-jawed orb-weaver spiders (family Tetragnathidae) distributed worldwide. These spiders are strongly associated with subterranean and dimly lit environments, including caves, abandoned mines, old wells, basements, and densely shaded ravines. Unlike most tetragnathids, Meta species construct vertical orb webs rather than horizontal ones. The genus includes notable species such as Meta ovalis in North America and Meta menardi in Europe and Asia.
Metopiasini
Metopiasini is a tribe of minute rove beetles (Staphylinidae: Pselaphinae) comprising nine genera, eight of which are restricted to the Neotropical region. The tribe is suspected to be myrmecophilous, though direct ant associations remain unconfirmed. Members exhibit morphological traits consistent with subterranean or litter-dwelling habits, including reduced eyes and elongated appendages. The genus Metopiellus, distributed from Colombia to Argentina, was recently recorded from Ecuador for the first time with two new species described from Amazonian and montane cloud forest habitats.
Mexiweckelia hardeni
Mexiweckelia hardeni is a species of amphipod crustacean in the family Hadziidae, first described by Holsinger in 1992. The genus Mexiweckelia is part of a group of amphipods adapted to subterranean or aquatic habitats. As a member of Hadziidae, it likely inhabits groundwater or cave systems, though specific ecological details remain poorly documented. The species is known from limited collection records in the Nearctic region.
Molytinae
Molytinae is a large and diverse subfamily of weevils (Curculionidae) described by Carl Johan Schönherr in 1823. The subfamily contains numerous tribes and genera distributed worldwide, with particularly high diversity in tropical and subtropical regions. Many Molytinae species are associated with specific host plants, including conifers, oaks, and various flowering plants. Some species are economically important as pests of forestry and agricultural crops, while others are restricted to specialized habitats such as leaf litter, caves, or high-elevation ecosystems. The subfamily has undergone significant taxonomic revision in recent decades, with many new species described particularly from Central America, Africa, and Asia.
Myrmecophilidae
Ant Crickets, Ant-loving Crickets
Myrmecophilidae, commonly known as ant crickets or ant-loving crickets, are a small family of Orthoptera comprising fewer than 100 species across several genera. These minute, wingless crickets are obligate inquilines that live exclusively within ant nests, where they exhibit specialized morphological adaptations including reduced eyes, elongated antennae, and flattened bodies. The family has a global distribution with records from North America, Europe, Asia, Australia, and Pacific islands, though many species remain poorly documented. Members of this family do not produce sound and lack both wings and tympanal organs.
Myrmecophilus manni
Desert Ant Cricket, Mann's Ant Cricket
Myrmecophilus manni is a small ant cricket species in the family Myrmecophilidae, commonly known as the Desert Ant Cricket or Mann's Ant Cricket. Like other members of its genus, it lives in close association with ant colonies, where it feeds on ant secretions and nest materials. The species occurs in arid and semi-arid regions of western North America, from southern Washington through Oregon, California, Nevada, and Arizona. Adult specimens typically measure under 5 millimeters in length, with reduced eyes and elongated antennae adapted for life in subterranean ant nests.
Myrmecophilus oregonensis
Oregon ant cricket, west coast ant cricket
Myrmecophilus oregonensis, commonly known as the Oregon ant cricket or west coast ant cricket, is a small myrmecophilous cricket species found in the western United States and Canada. Like other ant crickets in the genus Myrmecophilus, it lives within ant colonies and has adapted to a subterranean lifestyle with reduced eyes and enhanced sensory structures. The species ranges west of the Cascade Mountains from southern British Columbia through Oregon, Washington, and most of California.
Nannaria
Twisted-Claw Millipedes
Nannaria is a genus of small-bodied millipedes in the family Xystodesmidae, commonly known as twisted-claw millipedes. First described by Ralph Chamberlin in 1918, it is now the largest genus in its family with 78 described species following major revisions in 2022. The genus comprises two monophyletic species groups: the widespread minor group found throughout eastern North America, and the wilsoni group restricted to the Appalachian Mountains. Unlike many colorful, flat-backed xystodesmids, Nannaria species are cryptic in appearance and exhibit subterranean behavior that makes them difficult to collect.
Neaphaenops tellkampfii
Neaphaenops tellkampfii is a predaceous troglobitic ground beetle endemic to cave systems in North America. The species exhibits distinct ecological adaptations across its range, with two recognized subspecies occupying different subterranean environments: N. t. tellkampfii in sandy deep caves and N. t. meridionalis in wet muddy caves. These subspecies demonstrate divergent foraging specializations, with the nominate form adapted to locate buried cricket eggs and the southern form better suited to capture enchytraeid worms. Adults show seasonal activity patterns and recruitment timing linked to food availability.
Neelipleona
Neelipleona is an order of minute hexapods within the class Collembola (springtails). Members are characterized by the complete absence of eyes, a trait distinguishing them from most other springtail groups. The group is primarily represented by the family Neelidae and includes genera such as Megalothorax and Spinaethorax. Many species exhibit troglomorphic adaptations, including elongated appendages and reduced pigmentation, associated with cave-dwelling habits. The taxonomic rank of Neelipleona remains debated, with some authorities treating it as a suborder of Symphypleona or placing it within Entomobryomorpha.
Neivamyrmex
Legionary Ants
Neivamyrmex is a genus of New World army ants comprising approximately 129 species. Colonies are nomadic, establishing temporary bivouacs nightly rather than constructing permanent nests. Most species are predominantly subterranean, with occasional surface foraging at night or during overcast conditions. The genus is distinguished from related army ants by workers lacking a subapical tooth on the tarsal claw.
Neivamyrmex mandibularis
legionary ant
Neivamyrmex mandibularis is a species of legionary ant in the subfamily Dorylinae. Like other Neivamyrmex species, it is nomadic and primarily nocturnal, raiding nests of other ant species to prey on larvae and pupae. The species is part of a genus containing the only army ants native to North America north of Mexico. Workers are subterranean and rarely observed by the general public, while winged reproductive males are occasionally attracted to lights at night.
Neivamyrmex opacithorax
army ant
Neivamyrmex opacithorax is a species of army ant in the family Formicidae. It is one of two army ant species documented in Missouri, where it has been observed in dolomite glades. The species is strictly nocturnal during summer months but has been observed on the surface during cool, overcast fall days. Like other legionary ants, it exhibits nomadic behavior and raids nests of other ant species.
Neocarus
Neocarus is a genus of rare, relatively large mites in the family Opilioacaridae, characterized by primitive traits including six pairs of eyes and abdominal segmentation. Species in this genus are primarily associated with subterranean habitats in Brazil, including caves and ferruginous geosystems. Multiple new species have been described from Minas Gerais state, where they occur in both epigean and hypogean environments.
Neoscapteriscus
mole crickets
Neoscapteriscus is a genus of two-clawed mole crickets (Gryllotalpidae) containing at least 23 described species. Members are subterranean insects with fossorial forelegs adapted for tunneling. Several species are significant turfgrass and pasture pests in the Americas, including the tawny mole cricket (N. vicinus) and southern mole cricket (N. borellii). The genus was established by Cadena-Castañeda in 2015, separating these species from the related genus Scapteriscus.
Nesticidae
cave cobweb spiders, scaffold web spiders
Nesticidae is a family of spiders closely allied with Theridiidae (tangle web spiders), distinguished by a comb of serrated bristles on the hind tarsi used to pull silk bands from the spinnerets. The family contains approximately 15 genera and 280 species, with many species associated with caves, overhangs, and subterranean habitats. Members show varying degrees of troglomorphic adaptation, from fully cave-adapted troglobionts to surface-dwelling forms. The genus Nesticus, the type genus, has a global distribution and has undergone extensive radiation in montane regions.
Nesticus brimleyi
Nesticus brimleyi is a species of cave-dwelling spider in the family Nesticidae, described by Gertsch in 1984. Members of this genus are commonly known as scaffold web spiders or cave spiders. The species is endemic to the United States.
Nicoletiidae
Nicoletiidae is a family of primitive wingless insects in the order Zygentoma. Members are predominantly subterranean, inhabiting soil, caves, and mesovoid shallow substratum (MSS) environments. Many species exhibit troglobiotic adaptations including lack of eyes and pigmentation. The family contains at least four subfamilies (Atelurinae, Nicoletiinae, Cubacubaninae, Coletiniinae, Subnicoletiinae) with over 100 described genera. Some species are commensals in social insect nests, such as Allotrichotriura saevissima in fire ant nests.
Odontocynips nebulosa
root gall wasp
Odontocynips nebulosa is a cynipid wasp that induces large, woody, subterranean galls on oak roots. Adults are small and rarely observed; the galls are the primary sign of its presence. The species was long misidentified due to confusion with a different gall-former on oak leaves. It has a two-year life cycle and is restricted to the southeastern and central United States.
Oecleini
Oecleini is a tribe of planthoppers (Hemiptera: Cixiidae) established by Muir in 1922. Members exhibit distinctive wing venation patterns, including a trifid anterior MP branch in forewings and I-type hindwing venation with complete fusion of MP3+4 with CuA1. Some species possess subterranean adaptations, including a double-grasping coxo-femoral and femoro-tibial system in nymphs for clinging to roots. The tribe includes economically significant species investigated as potential vectors of palm phytoplasmas.
Omalonomus
Omalonomus is a genus of blind, wingless, lightly pigmented subterranean rove beetles in the family Staphylinidae. The type species Omalonomus relictus was described in 1990 from the Cypress Hills of Alberta-Saskatchewan, Canada. Its highly modified morphology reflects adaptation to a hypogeous lifestyle. The genus is considered a preglacial relict, supporting evidence for ice-free refugia in the Cypress Hills during Pleistocene glaciation.
Oncopoduridae
Oncopoduridae is a family of springtails (Collembola) in the order Entomobryomorpha, established by Carl and Lebedinsky in 1905. The family contains the genus Oncopodura, which includes subterranean species adapted to cave environments. Members of this family are characterized by distinctive morphological features of the postantennal organ (PAO) and furcula that are important for species identification.
Onthophagus polyphemi
gopher tortoise onthophagus beetle, onthophagus tortoise commensal scarab, Tortoise Commensal Scarab
Onthophagus polyphemi is a dung beetle species in the family Scarabaeidae. It is known for its association with gopher tortoises (Gopherus polyphemus), inhabiting their burrows in a commensal relationship. The species was described by Hubbard in 1894. Two subspecies are recognized: O. p. polyphemi and O. p. sparsisetosus.
Orconectes
Orconectes is a genus of cave-dwelling freshwater crayfish endemic to the eastern United States. The genus was erected in 1872 by Edward Drinker Cope and originally contained 85 species in 11 subgenera. Following a 2017 taxonomic review, most surface-dwelling species were transferred to the genus Faxonius, leaving approximately 8 obligate cave-dwelling species in Orconectes. These subterranean crayfish exhibit classic troglomorphic traits including depigmentation, reduced eyes or blindness, and elongated appendages. Some species are extremely long-lived, though earlier claims of 176-year lifespans for O. australis were revised to 22 years or less in a 2012 study.
Orthoporus ornatus
Desert Millipede, Texas Gold-Banded Millipede
Orthoporus ornatus is a large millipede native to the Chihuahuan and Sonoran deserts of the southwestern United States and northern Mexico. Adults typically reach 4 inches (10 cm) in length, with exceptional individuals exceeding 9 inches (23 cm). The species exhibits behavioral thermoregulation, spending most of its life in deep, damp soil burrows and emerging primarily after summer rains to feed and reproduce. It is popular in the pet trade and has been introduced to European collections through captive breeding programs.
Pangaeus
burrower bugs
Pangaeus is a genus of burrower bugs in the family Cydnidae (Hemiptera), comprising approximately 14 described species. Members are fossorial insects adapted for subterranean life, with species distributed across the Americas. The genus includes significant agricultural pests, most notably P. bilineatus, which damages peanut crops in the southeastern United States. Species exhibit morphological adaptations for burrowing, including stout, spiny forelegs.
Paraperla
green stoneflies
Paraperla is a genus of green stoneflies in the family Chloroperlidae, established by Banks in 1906. It contains at least two described species: P. frontalis (the hyporheic sallfly) and P. wilsoni. The genus belongs to the subfamily Paraperlinae and is characterized by its association with subterranean or hyporheic aquatic habitats. These stoneflies are part of the Arctoperlaria, a suborder of Plecoptera found primarily in the Northern Hemisphere.
Pardalosus slevini
Pardalosus slevini is a species of scarab beetle in the subfamily Aphodiinae, described by Van Dyke in 1928. It is a dung beetle endemic to California. The genus Pardalosus contains species associated with burrowing owl nests and mammal burrows. Records for this species are sparse, with only two observations documented on iNaturalist.
Parobisium
Parobisium is a genus of poorly dispersing pseudoscorpions in the family Neobisiidae. The genus exhibits a disjunct distribution pattern occurring in western North America and eastern Asia (East Asia), but is absent from Europe and central Asia. Phylogenetic evidence indicates ancient vicariance between East Asian and North American lineages rather than recent dispersal events. Many species are troglomorphic and restricted to karst cave systems.
Paronellidae
Paronellidae is a family of elongate-bodied springtails (Collembola) in the order Entomobryomorpha. The family contains approximately 18 genera and at least 90 described species. Members of this family are primarily distributed in tropical and subtropical regions, with many species adapted to subterranean habitats including caves. The family includes notable troglobitic genera such as Troglobius and Troglopedetes.
Pemphigus tartareus
Pemphigus tartareus is a North American aphid species in the family Aphididae, described by Hottes and Frison in 1931. It belongs to the genus Pemphigus, which comprises root-feeding aphids often associated with gall formation or subterranean development on host plants. The species has been historically confused with other root-infesting aphids in agricultural and horticultural contexts, particularly in discussions of "root aphid" pests.
Pimoidae
Large Hammock-web Spiders
Pimoidae is a small family of araneomorph spiders established by Wunderlich in 1986, closely related to Linyphiidae and sometimes treated as synonymous with that family. As re-circumscribed in 2021, it is monophyletic and contains approximately 90 species in two genera, primarily Pimoa and Weintrauboa. Members are commonly known as large hammock-web spiders due to their substantial size relative to linyphiids and their horizontal, net-like webs. The family has a fragmented relictual distribution across the Pacific coast of North America, the Cantabrian Mountains of Spain, the European Alps, and the Himalayas and adjacent regions of Asia.