Cryptic-fauna
Guides
Allotrimium
Allotrimium is a genus of minute rove beetles in the family Staphylinidae, subfamily Pselaphinae, described by Orlando Park in 1943. It belongs to the tribe Trichonychini within the diverse and speciose Pselaphinae, a group characterized by reduced elytra and complex antennal structures. Members of this genus are small, cryptic beetles associated with leaf litter and soil habitats. No observations or species-level documentation are currently available in major biodiversity databases.
Archipsocus floridanus
ancient barklouse
Archipsocus floridanus is a species of barklouse in the family Archipsocidae, first described by Mockford in 1953. It is one of several species in the genus Archipsocus, a group sometimes referred to as "ancient barklice" within the order Psocodea. The species has been recorded across a broad geographic range spanning North, Central, and South America. Like other members of its family, it is presumed to inhabit bark and lichen microhabitats, though specific ecological details remain poorly documented.
Arthrolips fasciata
Arthrolips fasciata is a minute beetle species in the family Corylophidae, originally described by Erichson in 1842. Records indicate presence in Belgium with some uncertainty, and the species has been observed 18 times on iNaturalist. Like other members of this family, it is among the smallest beetles, typically associated with decaying organic matter and fungal habitats. The genus Arthrolips is part of the diverse microbeetle fauna that remains understudied due to its diminutive size.
Brachypylina
Brachypylina is a diverse infraorder of oribatid mites (beetle mites) comprising the majority of oribatid species. These mites are characterized by heavily armored, beetle-like bodies with a distinct separation between the notogastral shield and other body regions. They occupy a wide range of terrestrial habitats and play significant roles in decomposition and nutrient cycling.
Caddoidea
Caddoidea is a small superfamily of harvestmen (Opiliones) within the suborder Eupnoi, established by Nathan Banks in 1893. It contains two families: Caddidae and Acropsopilionidae. Members are characterized by distinctive morphological features including relatively long legs and compact bodies. The group has a disjunct distribution with representatives in North America, eastern Asia, and Australia. Caddoidea represents one of the more specialized lineages within the Dyspnoi-Eupnoi clade of long-legged harvestmen.
Glyptocombus
jumping soil bugs
Glyptocombus is a genus of minute jumping soil bugs in the family Schizopteridae, first described by Heidemann in 1906. The genus was long considered monotypic, containing only G. saltator, until 2018 when three additional species were described from the United States and Mexico. These insects belong to the infraorder Dipsocoromorpha, a group of small predatory true bugs adapted to life in soil and leaf litter. The genus is among the more poorly known groups of Heteroptera due to their cryptic habits and small size.
Motschulskium
Motschulskium is a genus of minute featherwing beetles in the family Ptiliidae, subfamily Nossidiinae. These beetles are among the smallest insects known, with most Ptiliidae measuring under 1 mm in length. The genus was established by Matthews in 1872 and is distinguished from related genera primarily by genitalic and antennal characteristics. Species within this genus are poorly known and rarely collected due to their minute size and cryptic habits.
Mysmenidae
dwarf cobweb weavers
Mysmenidae is a family of minute spiders comprising approximately 135-188 described species across 13-17 genera. Members are among the smallest known spiders, ranging from 0.75 to 3 mm in body length. The family is one of the least studied groups of orb-weaving spiders due to their diminutive size and cryptic habits. Many species exhibit kleptoparasitic behavior, inhabiting the webs of other spiders to steal prey.
Nothembius
Nothembius is a genus of centipedes in the family Lithobiidae, established by Chamberlin in 1916. As lithobiomorph centipedes, members of this genus possess the characteristic elongated body plan with 15 pairs of legs in adults. The genus is part of the diverse lithobiid radiation in North America. Records indicate limited but documented occurrence, with observational data suggesting ongoing presence in specific regions.
Pauropoda
pauropodans, pauropods
Pauropoda is a class of minute, soft-bodied myriapods comprising approximately 900 species across twelve families worldwide. These animals are characterized by reduced leg numbers compared to other myriapods—most adults possess only nine pairs of legs—and distinctive branching antennae. They inhabit soil and leaf litter environments globally, with documented occurrences from tropical regions to subantarctic islands. Pauropods are gonochoric and exhibit hemianamorphosis, adding leg pairs through successive molts until reaching adult form.
Peritroctes
Peritroctes is a genus of small, wingless insects in the family Pachytroctidae, order Psocodea. Members of this genus are classified within the barklice and booklice group, though specific ecological details remain poorly documented. The genus was established by Ribaga in 1911 and is currently recognized as valid. Distribution records indicate presence in Mexico.
Protura
proturans, coneheads
Protura are minute soil-dwelling hexapods, 0.6–1.5 mm in length, distinguished by their lack of eyes, wings, and antennae. They were first discovered in 1907 and were previously regarded as insects but are now classified as an order within the class Entognatha. Unique among hexapods, proturans exhibit anamorphic development, adding abdominal segments post-embryonically through successive molts until reaching the adult complement of 12 segments. Approximately 800 species have been described across seven families, with nearly 300 species in the single genus Eosentomon.
Riccardoellinae
Riccardoellinae is a subfamily of mites within the family Ereynetidae, order Trombidiformes. These prostigmatic mites are part of the diverse soil and litter mite fauna. Members are small, soft-bodied arachnids with limited published documentation. The subfamily was established to accommodate genera with distinctive morphological features separating them from other Ereynetidae.
Schizoptera
minute litter bugs
Schizoptera is the largest genus of minute litter bugs (Hemiptera: Heteroptera: Dipsocoromorpha), comprising approximately 90 described extant species plus two fossil species. The genus is divided into four subgenera: Schizoptera (Cantharocoris), Schizoptera (Odontorhagus), Schizoptera (Schizoptera), and Schizoptera (Zygophleps). Species are abundant in New World bulk and residue samples, with extensive undescribed diversity indicated by recent collecting efforts. Male genitalia are intricate and asymmetrical, providing excellent diagnostic features for species identification.
Striaria
Striaria is a genus of millipedes in the family Striariidae, order Chordeumatida. The genus was established by Bollman in 1888. These small, eyeless millipedes are part of the diverse soil-dwelling fauna of temperate forests. The name Striaria is also used for a genus of brown algae (Phaeophyceae), but this represents a separate taxonomic entity in a different kingdom.
Styletoentomon
Styletoentomon is a genus of minute, soil-dwelling proturans in the family Eosentomidae. The genus was established by Copeland in 1978 and contains two described species: S. rostratum and S. styletum. Proturans in this genus lack antennae and eyes, and possess distinctive mouthparts adapted for feeding on fungal hyphae and decaying organic matter in soil and leaf litter habitats.
Symphylella
Symphylella is a genus of symphylans in the family Scolopendrellidae, comprising approximately 49 cosmopolitan species of minute soil-dwelling arthropods. These myriapods inhabit soil and litter layers of broad-leaf and bamboo forests, where they are extracted using Berlese-Tullgren funnels. The genus is characterized by diagnostic morphological features including chaetotaxy patterns on the frons and tergites, with recent taxonomic work identifying two morphological groups based on inserted setae patterns on tergal processes.
Syscia
Syscia is a genus of ants in the subfamily Dorylinae, containing 38 described species. The genus was established by Roger in 1861, later treated as a subgenus of Cerapachys, and resurrected as valid by Borowiec (2016). It has a discontinuous distribution across Eastern Asia, North America, and South America, and is part of the cryptic leaf-litter ant fauna.
Xylocorini
Xylocorini is a monotypic tribe of minute predatory bugs in the family Anthocoridae, containing only the genus Xylocoris. The tribe comprises approximately 50 described species worldwide, with the highest diversity in the Palaearctic Region. Members are small, cryptic insects associated with concealed microhabitats.