Cave-dwelling
Guides
Opiliones
harvestmen, harvesters, daddy longlegs, granddaddy longlegs, shepherd spiders
Opiliones is an ancient order of arachnids comprising over 6,650 described species, with estimates suggesting more than 10,000 extant species worldwide. The order includes five suborders: Cyphophthalmi, Eupnoi, Dyspnoi, Laniatores, and Tetrophthalmi. Fossil evidence from 410 million-year-old Devonian deposits demonstrates that harvestmen have remained morphologically conservative since their early evolution. Despite superficial resemblance to spiders, Opiliones represent a distinct arachnid lineage with unique anatomical and behavioral characteristics.
arachnidharvestmandaddy-longlegsancient-lineageomnivorenocturnalgregariouscave-dwellingpaternal-carechemical-defenseautotomymodel-organismconservation-concernvenomlesstracheal-respirationdirect-copulationshort-range-endemictroglobiteaposematiccrypsismimicrythanatosisviscoelastic-adhesiveanurophagyvertebrate-predatorOrfelia fultoni
Foxfire Fly, dismalites
Orfelia fultoni is the only bioluminescent fly species known from North America. The larvae, commonly called 'dismalites' or 'glowworms,' produce the bluest light (~460 nm) of any studied bioluminescent insect. Larvae are carnivorous predators that construct sticky webs along stream banks and in caves, using paired bioluminescent lanterns to lure flying prey. Adults are non-feeding and short-lived. The species was discovered in 1940 near Glenville, North Carolina by B.B. Fulton and described by Elizabeth Gault Fisher.
Paederinae
Tomcat
Paederinae is a subfamily of rove beetles (Staphylinidae) containing three tribes: Lathrobiini, Paederini, and Pinophilini. The subfamily is notable for containing the genus Paederus and related genera that produce pederin, a potent vesicant toxin in their haemolymph that causes Paederus dermatitis in humans. The subfamily exhibits diverse ecological adaptations including myrmecophily, troglobitic cave-dwelling, and intertidal lifestyles. Over 36 genera and 436 species occur in North America alone, with global distribution across multiple biogeographic regions.
Palpigradi
microwhip scorpion, palpigrade, micro whipscorpion
Palpigradi is an order of minute arachnids, commonly called microwhip scorpions or palpigrades. They are the sister group to Solifugae (camel spiders), measuring 1–3 mm in length. These pale, thin-bodied arachnids inhabit wet tropical and subtropical soils worldwide, living interstitially in moist microhabitats under stones and in caves. They possess a distinctive multi-segmented flagellum that may comprise half the body length. The order contains two families, Prokoeneniidae and Eukoeneniidae, distinguished by the presence or absence of ventral respiratory sacs.
Paradoxosomatidae
flat-backed millipedes
Paradoxosomatidae is the largest family of flat-backed millipedes, containing nearly 200 genera and approximately 975 species as of 2013. It is the sole family in the suborder Paradoxosomatidea. Members are distinguished by dorsal grooves on most body segments and a dumb-bell shaped gonopod aperture in males. The family includes notable groups such as the dragon millipedes of Southeast Asia and the widely introduced greenhouse millipede Oxidus gracilis.
Paraphrynus
whip spider, tailless whip scorpion
Paraphrynus is a genus of whip spiders (order Amblypygi) in the family Phrynidae, distributed from the southwestern United States through Central America and the Caribbean. Most species are endemic to Mexico. These nocturnal arachnids are characterized by extraordinarily long, sensory front legs (antenniform legs) used for navigation and prey detection, and spiny pedipalps for capturing prey. Research has demonstrated remarkable homing abilities in some species, with individuals navigating back to refuges from distances exceeding 10 meters using primarily olfactory cues detected by their antenniform legs rather than vision.
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.
Phalangodidae
Phalangodid Harvestmen
Phalangodidae is a family of small harvestmen in the suborder Laniatores, containing approximately 30 genera and more than 100 described species. Members are characterized by pedipalps armed with prominent spines and body lengths generally under 3 mm. The family is primarily distributed in the Holarctic region, with exceptional diversity in the western Nearctic, particularly California. Several species, especially in the genus Texella, are obligate cave-dwellers exhibiting troglomorphic traits such as depigmentation and reduced eyes.
Pholcidae
cellar spiders, daddy long-legs spiders, carpenter spiders, vibrating spiders, gyrating spiders
Pholcidae is a large family of araneomorph spiders containing over 2,000 species across 94+ genera. Members are commonly known as cellar spiders or daddy long-legs spiders due to their extremely long, thin legs and tendency to inhabit dark, undisturbed spaces. The family exhibits remarkable diversity in habitat use, from caves and tropical forests to human dwellings, with some species showing specialized adaptations including troglomorphism and communal web-sharing. Several species have become globally distributed through human transport, notably Pholcus phalangioides.
Phrurolithidae
Guardstone Spiders
Phrurolithidae is a family of araneomorph spiders commonly known as guardstone spiders. First described by Nathan Banks in 1892, the family was long treated as a subfamily (Phrurolithinae) within Corinnidae until phylogenetic studies established its separate family status. The family currently comprises 27 genera and approximately 421 species. Members are small to medium-sized spiders, predominantly found in the Northern Hemisphere with exceptional diversity in southern China, where many species are endemic to specific mountain localities.
Phrynus marginemaculatus
spotted tailless whip scorpion, Florida tailless whipscorpion
Phrynus marginemaculatus is an amblypygid arachnid native to southern Florida, the Bahamas, Cuba, and Hispaniola. It is the only amblypygid species in the US east of the Mississippi River and the most commonly studied whip spider species. This nocturnal predator possesses extraordinarily elongated first pair of legs adapted as sensory organs for detecting prey, mates, and environmental features in darkness. The species exhibits complex navigational abilities including multisensory configural learning for shelter recognition, and has evolved a plastron enabling underwater breathing for up to 24 hours.
Phrynus operculatus
tailless whipscorpion
A medium-sized tailless whipscorpion (18–22 mm total length) found across much of Mexico. Distinguished by chestnut coloration with reddish tones on the carapace and pedipalps, four anterior spines on the pedipalp trochanter, and specific female gonopod morphology. The species shows considerable morphological variation across its range, suggesting it may represent a species complex.
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.
Platypezidae
Flat-footed Flies
Platypezidae is a family of small true flies (Diptera) comprising over 250 species worldwide. Adults are commonly known as flat-footed flies due to their characteristically modified tarsal segments, particularly in males. The family is primarily associated with woodland habitats where larvae develop as fungivores. Adults exhibit distinctive swarming behavior for mating and are frequently observed performing rapid, erratic movements on vegetation. The family was formerly broader in circumscription, with Opetiidae and some genera now placed in Atelestidae removed based on phylogenetic evidence.
Porrhomma convexum
Porrhomma convexum is a species of sheetweb spider in the family Linyphiidae, characterized by its small size and association with cave and subterranean habitats. The species was described by Westring in 1851 and has a broad Holarctic distribution spanning North America, Europe, and Asia. Like other members of its genus, it exhibits adaptations to dark environments including reduced pigmentation and eye size. The species constructs sheet webs typical of its family.
Prionoglarididae
Large-winged Barklice
Prionoglarididae is a family of small, winged insects in the order Psocodea, commonly known as barklice or booklice. The family contains approximately 9 genera and over 20 described species distributed across Europe, Asia, Africa, and North America. Members are characterized by reduced or simplified lacinia (mouthpart structures) in adults and highly specialized male genitalia. The genus Neotrogla is notable for exhibiting sex-reversed genitalia, with females possessing an intromittent organ (termed a gynosome) and males having vagina-like structures. Most species inhabit cave environments.
Procambarus
crayfish, crawfish, crawdad
Procambarus is a genus of freshwater crayfish in the family Cambaridae, native to North and Central America. The genus contains approximately 160 species in 16 subgenera, making it one of the most species-rich crayfish genera. It includes both widespread surface-dwelling species and numerous troglobitic (cave-dwelling) species. The marbled crayfish (marmorkrebs), a parthenogenetic form, is also classified within this genus. Several species, particularly P. clarkii (red swamp crayfish), have been introduced globally and are recognized as invasive species with significant ecological and economic impacts.
Prokoeneniidae
microscorpions, microwhip scorpions
Prokoeneniidae is a family of microscorpions (order Palpigradi) established by Condé in 1996. The family contains at least two genera—*Prokoenenia* and *Triadokoenenia*—with approximately seven described species. These minute arachnids are among the least studied of all arachnid orders, reflecting their cryptic lifestyle and small size.
Protaphorura
Protaphorura is a genus of springtails (Collembola) in the family Onychiuridae, established by Absolon in 1901. The genus contains numerous species distributed across the Palearctic region, with particular diversity in southern Siberia and the Far East of Russia. Several species are obligate cave-dwellers (troglobionts), exhibiting specialized adaptations to subterranean environments. The genus is taxonomically well-studied, with identification keys available for over 85 Palearctic species based on morphological characters including pseudocellar formulae, postantennal organ structure, and chaetotaxy.
Pseudanophthalmus cerberus cerberus
Pseudanophthalmus cerberus cerberus is a subspecies of troglobitic ground beetle in the family Carabidae. It belongs to a genus of small, eyeless beetles adapted to life in caves. The subspecies was described by Barr in 1985 and is currently accepted as valid. Like other members of Pseudanophthalmus, it is likely restricted to subterranean habitats in the eastern United States.
Pseudocellus dorotheae
hooded tickspider
Pseudocellus dorotheae is a species of hooded tickspider in the order Ricinulei, first described from Texas in 1939. Ricinuleids are a small, reclusive order of arachnids characterized by a retractable hood (cucullus) covering the mouthparts. This species represents one of the few described members of the genus Pseudocellus in North America. Like other ricinuleids, it is poorly known due to its cryptic habits and limited collection records.
Pseudogarypidae
Pseudogarypid Pseudoscorpions
Pseudogarypidae is a small family of pseudoscorpions within the superfamily Feaelloidea. The family comprises two extant genera—Pseudogarypus and Neopseudogarypus—with most recent species distributed in western North America. A single extant species, Neopseudogarypus scutellatus, is endemic to Tasmania, representing a notable disjunct distribution. The family also includes several fossil species preserved in Baltic amber from the Eocene.
Pseudorypteryx
Pseudorypteryx is a monotypic genus of cave-dwelling barklice in the family Psyllipsocidae, erected by García-Aldrete in 1984. The genus contains a single described species, Pseudorypteryx mexicana. Members of this genus are troglobitic, meaning they are specialized for life in cave environments.
Pseudoscorpiones
pseudoscorpions, false scorpions, book scorpions
Pseudoscorpions are tiny arachnids, most under 5 mm in length, superficially resembling scorpions but lacking a stinger and elongated tail. They are among the oldest terrestrial colonizers, with fossils dating to the Middle Devonian (ca. 390 million years ago). Despite their ancient lineage, they exhibit remarkable morphological stasis, with even Devonian fossils appearing modern. Most species inhabit concealed microhabitats such as beneath bark, in leaf litter, soil, caves, or mammal nests, making them seldom encountered despite being fairly common. They are predatory, seizing small invertebrate prey with venomous pincer-like pedipalps.
Psilochorus apicalis
Psilochorus apicalis is a species of cellar spider in the family Pholcidae, first described by Banks in 1921. It is a small, long-legged spider endemic to the United States. Like other pholcids, it constructs irregular, tangled webs in sheltered locations. The species is part of a genus containing approximately 20 described species, most occurring in the Americas.
Psilochorus californiae
Psilochorus californiae is a species of cellar spider in the family Pholcidae. It was described by Chamberlin in 1919. The species occurs in the southwestern United States and Mexico. Like other pholcids, it constructs irregular, three-dimensional webs in dark, sheltered locations.
Psilochorus simoni
Wine Cellar Spider
Psilochorus simoni is a cellar spider in the family Pholcidae, native to subtropical America and introduced to Europe, Turkey, New Zealand, and Australia. The species is commonly known as the "Wine Cellar Spider" due to its historical association with wine cellars, though it has become established in garden centres and greenhouses. It constructs dome-shaped webs and has been recorded from cave environments in Europe, including Slovenia's Postonjska jama, where it shows morphological adaptations to subterranean life.
Psocathropos
Psocathropos is a genus of small, wingless psocids (booklice) in the family Psyllipsocidae. Members of this genus are troglophilic or troglobitic, often found in caves and other subterranean habitats. The genus was established by Ribaga in 1899 and contains species distributed across multiple continents including North America, the Caribbean, and South Asia.
Psyllipsocidae
Cave Barklice
Psyllipsocidae is a family of small psocid insects commonly known as cave barklice, comprising approximately 7 genera and more than 70 described species. The family belongs to the suborder Trogiomorpha within the order Psocodea. Members of this family have been recorded across multiple biogeographic realms including West Palaearctic, Afrotropical, Australian, Nearctic, Neotropical, and Oriental regions. Some genera, such as Dorypteryx, exhibit notably wide geographic distributions. Several extinct genera are known from Cretaceous amber deposits.
Psyllipsocus
Psyllipsocus is a genus of cave-dwelling barklice comprising more than 50 described species. Members of this genus inhabit dark, humid microhabitats including caves, rock crevices, and similar subterranean environments. The genus was established by Selys-Longchamps in 1872 and represents one of the most species-rich genera within the family Psyllipsocidae.
Psyllipsocus ramburii
cave barklouse
Psyllipsocus ramburii is a species of cave barklouse in the family Psyllipsocidae, first described by Selys-Longchamps in 1872. It is notable for its exceptionally broad geographic distribution, spanning six continents and numerous oceanic islands. The species belongs to the suborder Trogiomorpha, a group characterized by reduced or absent wings and troglophilic tendencies.
Pyralis manihotalis
Tropical Meal Moth
Pyralis manihotalis is a small pyralid moth with a pan-tropical distribution, described by Achille Guenée in 1854. It is frequently associated with stored products and decaying organic matter, earning it the common name Tropical Meal Moth. The species has been documented in an unusually wide range of habitats, including caves where self-sustaining populations feed on bat guano. Adults are nocturnal and attracted to ultraviolet light.
Pyrophorini
Headlight Beetles
Pyrophorini is a New World tribe of click beetles (Elateridae: Agrypninae) characterized by bioluminescence in both larvae and adults. The tribe comprises approximately 20 genera including Pyrophorus, Ignelater, and Pyrearinus. Members are known for producing light through specialized organs, with larvae associated with phenomena such as 'luminescent termite mounds' and 'luminous canga caves' in South America. The tribe is believed to be monophyletic and is closely related to Anaissini, which contains some but not all bioluminescent species.
Quedius spelaeus
Spelean Rove Beetle
A troglophilic rove beetle found in porcupine dung caves in Nova Scotia, where it functions as the dominant invertebrate predator. The pupal stage was described for the first time from Nova Scotian populations. Late-instar larvae excavate and occupy cavities within dung deposits, pupating in these constructed chambers. The species shows an apparently disjunct distribution pattern in Nova Scotia, possibly reflecting post-glacial colonization from Atlantic refugia.
Rymosia
Rymosia is a genus of fungus gnats (Diptera: Mycetophilidae) in the tribe Exechiini. Species occur in Europe, Russia, Japan, and the Americas. At least one species, Rymosia tolleti, is exclusively associated with cave environments. The genus is part of the Rymosia s. lat. genus group, a phylogenetically cohesive assemblage of genera considered to share plesiomorphic characteristics.
Sabacon
Sabacon is a genus of harvestmen (order Opiliones) comprising the monotypic family Sabaconidae, with approximately 59 species recognized as of 2023. Species in this genus are primarily cave-dwelling or associated with moist, sheltered habitats in temperate and boreal regions of the Northern Hemisphere. The genus exhibits a disjunct distribution pattern with centers in North America (especially the southern Appalachians), Europe (Pyrenees, Alps), and Asia (Altai Mountains, Siberia). Several species have been described recently, indicating ongoing taxonomic discovery.
Schaefferia
Schaefferia is a genus of springtails (Collembola: Poduromorpha: Hypogastruridae) characterized by troglomorphic adaptations in cave-dwelling species. Recent taxonomic work has described highly specialized subterranean species from Iran and Montenegro that exhibit convergent evolution of eyelessness and elaborated sensory structures. The genus demonstrates significant morphological diversification associated with subterranean habitats.
Scoliopteryx
herald moth
Scoliopteryx is a genus of moths in the family Erebidae, established by Ernst Friedrich Germar in 1810. The genus contains two described species, including Scoliopteryx libatrix (the herald moth), which is notable for its troglophilic behavior and cave-dwelling habits during winter. Species in this genus have been studied for their unique ecological associations, including shared hibernacula with insectivorous bats and susceptibility to entomopathogenic fungi.
Scoliopteryx libatrix
Herald Moth, Herald
Scoliopteryx libatrix, commonly known as the herald moth, is a noctuid moth distributed across the Holarctic region. Adults are notable for their distinctive wing patterning and behavior of overwintering in caves, mines, and similar sheltered structures. The species has been documented as a host for entomopathogenic fungi and shares hibernacula with insectivorous bats. Its acoustic sensitivity to bat echolocation frequencies, combined with an absence of evasive flight responses during hibernation, represents an unusual behavioral adaptation.
Scolopocryptopidae
Scolopocryptopid Centipedes
Scolopocryptopidae is a family of blind centipedes in the order Scolopendromorpha, comprising more than 90 species. The family is distinguished from all other centipedes by having exactly 23 pairs of legs—a fixed trait that contrasts with the variable leg counts in other families. Members are eyeless and possess a distinctive gizzard with kinked, pineapple-shaped sieve projections. The family is most diverse in the Neotropical realm, with four recognized subfamilies: Ectonocryptopinae, Kethopinae, Newportiinae, and Scolopocryptopinae.
Scoterpes
Scoterpes is a genus of troglobiotic millipedes in the family Trichopetalidae, order Chordeumatida. Established by Cope in 1872, the genus comprises exclusively cave-dwelling species found in North America. The genus was revised in 2010, with fifteen recognized species including eight newly described taxa. At least two species, S. copei and S. ventus, likely represent superspecies complexes consisting of multiple genetically isolated populations.
Scoterpes sollmani
Scoterpes sollmani is a troglobiotic millipede described by Lewis in 2000 from cave systems in southern Indiana. As a member of genus Scoterpes, it is one of multiple cave-adapted species in this exclusively troglobiotic group. The species belongs to the small family Trichopetalidae within the order Chordeumatida, a group of small-bodied millipedes. No specific morphological details distinguishing S. sollmani from congeners are provided in available sources.
Sicariidae
Sixeyed Sicariid Spiders, recluse spiders, violin spiders, sand spiders, assassin spiders
Sicariidae is a family of haplogyne spiders comprising three genera—Loxosceles, Sicarius, and Hexophthalma—with approximately 177-180 species. Members are characterized by six eyes arranged in three dyads (pairs), a distinctive trait among spiders. The family includes medically significant species such as the brown recluse (Loxosceles reclusa) and six-eyed sand spiders. All genera produce sphingomyelinase D or related tissue-destroying substances in their venom, unique among spiders. The family exhibits diverse ecological strategies: Loxosceles species are synanthropic and found nearly worldwide in warmer regions, while Sicarius and Hexophthalma are specialized desert dwellers with self-burying behavior.
Sinella cavernarum
Cavernicolous springtail
Sinella cavernarum is a species of springtail in the family Entomobryidae, first described by Packard in 1888. The species epithet 'cavernarum' (of caves) suggests a troglophilic or troglobitic lifestyle. As an entomobryomorph springtail, it possesses the characteristic elongated body form and well-developed antennae typical of this group. Very few observations of this species exist in public databases.
Siro
harvestmen
Siro is a genus of cyphophthalmid harvestmen (Opiliones) in the family Sironidae. These small arachnids are characterized by their eyeless condition, elongated bodies, and association with moist microhabitats. The genus was established by Latreille in 1795 and represents one of the early-recognized lineages of the suborder Cyphophthalmi, which diverged from other harvestmen early in the evolutionary history of the order. Species in this genus are distributed primarily in the Mediterranean region and parts of Europe.
Sironidae
Sironid Harvestmen
Sironidae is a family of Cyphophthalmi harvestmen comprising more than 60 described species. It was the first described family of the suborder Cyphophthalmi and remains among the least understood phylogenetically. The family exhibits a predominantly Laurasian distribution, with species concentrated in temperate Europe and the west coast of North America. Monophyly of the family is poorly supported with traditional molecular markers; the Mediterranean genus Parasiro and Japanese genus Suzukielus sometimes branch basally relative to other sironids.
Speleomaster
Speleomaster is a genus of armoured harvestmen (Opiliones: Laniatores) described by Briggs in 1974. The genus contains at least two species, both endemic to subterranean lava tube environments in southern Idaho's Snake River Plain. As members of the family Cryptomastridae, these harvestmen represent a specialized lineage adapted to cave life.
Speleonychia sengeri
Speleonychia sengeri is a troglobitic harvestman (order Opiliones) described by Briggs in 1974. The genus Speleonychia is endemic to cave systems in western North America. As a member of the family Cladonychiidae, this species belongs to a group of small, eyeless, pale-colored arachnids adapted to subterranean environments. Very few observations exist—only five records on iNaturalist—reflecting its restricted habitat and cryptic lifestyle.
Spirostreptida
Spirostreptida is an order of large, cylindrical millipedes containing approximately 1000 described species, making it the third largest order of millipedes. Members are characterized by their elongated bodies with 30 to 90 body rings and generally large size, including the longest known millipedes such as the giant African millipedes of genus Archispirostreptus, which may exceed 30 cm. The order is divided into two suborders, Cambalidea and Spirostreptidea, with most species occurring in tropical and subtropical regions. Spirostreptida are primarily soil-dwelling detritivores, though some species inhabit caves.
Stenancylus
Stenancylus is a genus of true weevils (Curculionidae) established by Casey in 1892. The genus contains nine described species, most described by Wibmer & O'Brien in 1986. Species are distributed across the Americas, with records from Panama, Colombia, and the United States. The genus name derives from Greek roots suggesting narrow or slender form.