Cryptic-species
Guides
Aceria
gall mites, eriophyid mites, four-legged mites
Aceria is a large genus of eriophyid mites (family Eriophyidae) containing over 900 described species. These microscopic, worm-like arachnids are obligate plant parasites that induce distinctive plant growth abnormalities including galls, erinea, and witches' brooms. Some species are economically significant agricultural pests, while others have been deployed as biological control agents against invasive weeds. The genus exhibits extreme host specificity, with most species restricted to a single plant species or genus.
Acraspis quercushirta
jewel oak gall wasp
Acraspis quercushirta, the jewel oak gall wasp, is a North American cynipid wasp that induces distinctive, detachable galls on white oak leaves. The species exhibits a complex life cycle with alternating sexual and asexual generations, each producing morphologically different galls. The sexual generation forms the namesake "jewel" galls—oval, faceted structures ranging from white to brown that detach and fall with leaves in autumn. Molecular studies have confirmed its conspecific status with A. macrocarpae, which was previously considered a separate species.
Acronicta nr-othello
A North American dagger moth currently recognized as a near-relative to Acronicta othello, awaiting formal taxonomic resolution. The 'nr' designation indicates this population or specimen cluster resembles A. othello but may represent an undescribed species or distinct geographic variant. Dagger moths in this genus are characterized by their stout bodies and typically exhibit bold wing patterns with distinctive dark markings.
Agelenopsis spatula
funnel weaver spider
Agelenopsis spatula is a species of funnel weaver spider in the family Agelenidae, first described in 1935 by Ralph Vary Chamberlin and Wilton Ivie. It is known only from the United States. As a member of the genus Agelenopsis, it shares the characteristic funnel-web building behavior and elongated spinnerets typical of this group.
Agonopterix
flat-body moths
Agonopterix is a genus of small moths in the family Depressariidae, superfamily Gelechioidea. Species are commonly known as "flat-body moths" due to their characteristic flattened resting posture. The genus exhibits considerable cryptic diversity, particularly in Mediterranean and temperate regions, with many species distinguished by subtle differences in wing pattern and genitalia structure. Several species have been studied for their specialized host plant relationships, including some with potential as biological control agents.
Agroecotettix
Aridland Scrub Jumpers
Agroecotettix is a genus of medium-sized brachypterous grasshoppers in the subfamily Melanoplinae, containing 19 described species. These short-winged, flight-limited grasshoppers inhabit aridland scrub and desert regions of the southwestern United States and Mexico. The genus was revised in 2024 with the description of 16 new species, revealing previously unrecognized diversity in this cryptic group. Species identification relies primarily on male genitalia morphology.
Aleyrodoidea
whiteflies
Aleyrodoidea is a superfamily of small hemipteran insects commonly known as whiteflies. The superfamily contains a single family, Aleyrodidae, with more than 1,550 described species. Whiteflies are phytophagous insects that feed on plant sap, typically from the undersides of leaves. Several species are significant agricultural pests, including the citrus blackfly (Aleurocanthus woglumi) and the Bemisia tabaci species complex.
Alopecosa
Fox Spiders
Alopecosa is a genus of wolf spiders (Lycosidae) comprising approximately 160 species. These ground-dwelling spiders are predominantly Eurasian in distribution, with some species extending into North Africa and North America. Most species reach up to 2 cm in body length. Females construct burrows for egg deposition and guard their egg sacs until hatching. The genus has been subject to taxonomic revision, with species historically grouped into sibling species complexes based on morphology, though courtship behavior and molecular techniques have proven more reliable for species delimitation.
Amblyomma triste
Amblyomma triste is a hard tick species first described by Koch in 1844. It is the primary vector of Rickettsia parkeri, the causative agent of a spotted fever group rickettsiosis with symptoms resembling Rocky Mountain spotted fever. The species is the sole tick responsible for human tick-borne disease in Uruguay and a significant vector in Argentina and Brazil. Though historically considered restricted to South America, specimens have been documented in the United States (Arizona and Texas) and Mexico, where they were long misidentified as the morphologically similar Amblyomma maculatum.
Amydria curvistrigella
Amydria curvistrigella is a small moth species in the family Tineidae (formerly placed in Acrolophidae). It is known from the southwestern United States, specifically California and Arizona. The species was described by Dietz in 1905. Like other members of this family, it is likely associated with detritus or plant material, though specific biology remains poorly documented.
Anacampsis wikeri
Anacampsis wikeri is a small moth in the family Gelechiidae, described from Illinois in 2013. The species is restricted to prairie habitats and is univoltine, with larvae feeding exclusively on leadplant (Amorpha canescens). Adults are active from early June through autumn and overwinter, resuming activity the following spring. The species is externally nearly identical to the related A. psoraliella, requiring genital examination or larval host plant knowledge for reliable identification.
Anaphes
fairyflies
Anaphes is a genus of fairyflies (family Mymaridae), among the smallest known insects, first described by Alexander Henry Haliday in 1833. The genus has a cosmopolitan distribution and is divided into two subgenera: Anaphes (Anaphes) with approximately 37 recognized species and Anaphes (Patasson) with approximately 56 species in the Palearctic region alone. Species are egg parasitoids of various insects, with documented hosts including weevils (Curculionidae), leafhoppers (Cicadellidae), and true bugs (Miridae). Several species have been studied for biological control of agricultural pests, particularly the carrot weevil (Listronotus oregonensis) and lygus bugs (Lygus spp.).
Anastrepha
fruit flies, tephritid fruit flies
Anastrepha is a highly diverse genus of tephritid fruit flies native to the American tropics and subtropics, comprising over 300 described species. The genus includes nine major agricultural pest species that inflict substantial damage on commercial fruit crops including citrus, mango, guava, and papaya. Species exhibit variation in oviposition behavior, with females depositing eggs in developing fruit, mature fruit, or seeds depending on the species. The genus has been reorganized taxonomically to include species formerly placed in Toxotrypana, and contains notable cryptic species complexes such as the Anastrepha fraterculus group.
Andrognathus
Andrognathus is a genus of small, thin-bodied millipedes in the order Platydesmida, family Andrognathidae. The genus contains three extant species—A. corticarius, A. grubbsi, and A. hoffmani—distributed in deciduous forests of eastern North America, New Mexico, and Mexico respectively. A fossil species, A. burmiticus, is known from 99-million-year-old Burmese amber, indicating a formerly broader distribution. These millipedes are euanamorphic, adding segments throughout their lifespan, and exhibit paternal care behaviors.
Anelaphus formerly-parallelus-maybe-undescribed
A putative undescribed species within the genus Anelaphus, closely related to or possibly distinct from Anelaphus parallelus. The informal designation suggests morphological similarity to A. parallelus but with characteristics that may warrant separate species status pending formal taxonomic description. Members of this genus are woodboring beetles commonly known as twig pruners.
Anillinus langdoni
Anillinus langdoni is a small ground beetle in the tribe Bembidiini, described in 2004. It belongs to the A. langdoni species group, which includes four species with three endemic to the Great Smoky Mountains region. The species is distinguished from congeners primarily by male genitalia morphology and female spermathecal shape. Phylogeographic studies suggest its distribution reflects historical altitudinal shifts of habitat corridors and watershed-mediated isolation.
Anillinus micamicus
Anillinus micamicus is a species of minute ground beetle in the tribe Anillini, subfamily Bembidiinae. Species in this genus are characterized by their extremely small size, reduced eyes, and subterranean or soil-dwelling habits. Anillinus micamicus was described from specimens collected in the southeastern United States. Like other anillines, it is presumed to inhabit deep soil and leaf litter layers, where it occupies a cryptic lifestyle with limited surface activity.
Antaeotricha floridella
Antaeotricha floridella is a small moth in the family Depressariidae, described in 2015 from peninsular Florida. The species is endemic to Florida's sandhills and scrub habitats, where it was initially confused with the similar but more widespread Antaeotricha albulella. Its immaculately white forewings without any spotting distinguish it from close relatives.
Anthracini
Anthracini is a tribe of bee flies within the family Bombyliidae, subfamily Anthracinae. The tribe contains at least nine genera, with Anthrax being the most species-rich and well-studied. Members are primarily known as parasitoids, with larvae developing on or within host insects. The Australian fauna has been extensively revised, revealing substantial cryptic species diversity previously hidden under single species names.
Antispila
shield-bearer moths
Antispila is a genus of leaf-mining moths in the family Heliozelidae, established by Jacob Hübner in 1825. The genus comprises approximately 50 described species distributed across North America, Europe, and Asia. Larvae feed internally on leaves of host plants, creating distinctive serpentine or blotch mines that terminate in oval cutouts ('shields') used for pupation. Several species are economically significant as pests of grapevines, dogwoods, and ornamental shrubs. Taxonomic revisions using DNA barcoding have resolved longstanding species complexes, particularly among Cornus-feeding species in Europe.
Antrodiaetidae
folding-door spiders, folding trapdoor spiders, turret spiders
Antrodiaetidae is a small family of mygalomorph spiders comprising four genera and approximately 37 species. Members are commonly known as folding-door spiders or folding trapdoor spiders due to their distinctive burrow architecture: they construct silk-lined burrows with hinged, collapsible doors that fold or unfold to seal the entrance. The family is primarily distributed in the western and midwestern United States, with two relict species endemic to Japan. Antrodiaetidae are closely related to Atypidae (atypical tarantulas) and share the characteristic low dispersal ability typical of mygalomorph spiders.
Antrodiaetus
folding trapdoor spiders, turret spiders
Antrodiaetus is a genus of mygalomorph spiders in the family Antrodiaetidae, first described by Anton Ausserer in 1871. The genus includes species found in the United States and Japan, with the name derived from Greek roots meaning 'cave-dwelling.' These spiders are commonly known as folding trapdoor spiders or turret spiders due to their distinctive burrow architecture. Research on Antrodiaetus has been significant in arachnological studies of species delimitation, particularly using molecular approaches to reveal cryptic diversity in morphologically similar populations.
Antrodiaetus lincolnianus
Lincoln's folding-door spider
Antrodiaetus lincolnianus is a species of folding-door spider in the family Antrodiaetidae, originally described as Brachybothrium lincolnianum by Worley in 1928. As a mygalomorph spider, it constructs a burrow sealed with a hinged, silken door that it uses for protection and ambush predation. The species is endemic to the United States. Like other members of the Antrodiaetus unicolor species complex, it has been subject to recent taxonomic revision using molecular methods due to cryptic morphological similarity with closely related species.
Antrodiaetus unicolor
folding-door spider, collared spider
Antrodiaetus unicolor is a mygalomorph spider in the family Antrodiaetidae, historically considered a single widespread species but now recognized as a species complex containing multiple cryptic species. These spiders construct silk-lined burrows with folding doors rather than the hinged trapdoors of related families. Research using genomic-scale data has revealed substantial hidden diversity within this morphologically conserved group, particularly in the southern Appalachian Mountains.
Anurida
Anurida is a genus of springtails (Collembola) in the family Neanuridae, established in 1865 by Laboulbène. The genus has cosmopolitan distribution with species occupying diverse habitats including intertidal marine zones, river floodplains, riparian areas, and forest ecosystems. Well-studied species include the intertidal specialist Anurida maritima, which exhibits complex tidal-entrained behaviors, and the terrestrial A. granaria, which has documented mycophagous associations. The genus shows notable morphological diversity in chaetotaxy and eye reduction, with some species groups exhibiting cryptic genetic divergence despite morphological similarity.
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maritima
seashore springtail, rock springtail
Anurida maritima is a cosmopolitan springtail confined to the intertidal zone, where it forms dense aggregations of up to several hundred individuals on rock-pool surfaces. This wingless collembolan exhibits unique adaptations to marine conditions, including a vestigial furcula that prevents jumping and hydrophobic body hairs that enable it to remain on water surfaces. The species demonstrates complex behavioral rhythms synchronized with tidal cycles and survives winter through egg diapause. Recent genetic studies have revealed cryptic speciation within this morphospecies, with distinct mitochondrial and nuclear lineages now recognized.
Apamea acera
Apamea acera is a noctuid moth native to western North America. The species was described by Smith in 1900 and was originally placed in the genus Polia. Its documented range extends from British Columbia through California and eastward to Utah. The wingspan measures approximately 46 mm.
Apamea tahoeensis
Tahoe Cutworm Moth
Apamea tahoeensis is a species of cutworm or dart moth in the family Noctuidae, described by Mikkola & Lafontaine in 2009. It belongs to a genus of moths that are notoriously difficult to identify due to individual variation and overlapping morphological features among species. The species is found in North America, with its specific epithet suggesting an association with the Lake Tahoe region. Like other Apamea species, it is a nocturnal moth attracted to light sources.
Apamea xylodes
Apamea xylodes is a cutworm moth species in the family Noctuidae, described by Mikkola and Lafontaine in 2009. As a member of the genus Apamea, it belongs to a group of noctuid moths that are notoriously difficult to identify due to individual variation and overlapping morphological characteristics with congeners. The species is known from North America, though specific details about its biology and ecology remain limited.
Apatelodidae
American silkworm moths
Apatelodidae is a family of medium-sized bombycoid moths endemic to the New World, with highest diversity in the Neotropical region. The family contains approximately 14 genera and 222+ species following recent taxonomic revisions, though generic boundaries remain in flux due to ongoing phylogenetic studies. Adults typically exhibit cryptic coloration in greyish, straw-yellow, or reddish-brown tones with darker wing markings. Larvae of at least some species possess urticating setae, a trait first documented in the family in 2025. The family was elevated from subfamily status within Bombycidae in recent decades and continues to undergo substantial taxonomic restructuring.
Aphanogmus
Aphanogmus is a genus of minute ceraphronid wasps erected by Thomson in 1858. The genus contains at least 90 described species distributed worldwide. Species are primarily parasitoids of Ichneumonoidea and Cecidomyiidae, with some functioning as hyperparasitoids through bethylid wasps. Several species have been documented emerging from hosts used in commercial biological control programs, where they may disrupt pest management efforts.
Aphelinoidea
Aphelinoidea is a genus of minute wasps in the family Trichogrammatidae, described by A.A. Girault in 1911. Species are egg parasitoids of leafhoppers (Hemiptera: Cicadellidae), with several species of economic importance as biological control agents. The genus has an almost cosmopolitan distribution. Notable hosts include the beet leafhopper (Circulifer tenellus), a vector of beet curly top virus affecting crops such as tomatoes, sugar beets, and peppers. Two species, A. anatolica and A. turanica, were introduced from Iran into California for biological control and became established. The genus reproduces by arrhenotoky, where unmated females produce only male offspring.
Aphonopelma vorhiesi
Tucson Bronze Tarantula, Madrean Red Rump
Aphonopelma vorhiesi is a tarantula species in the family Theraphosidae, commonly known as the Tucson Bronze or Madrean Red Rump. It occurs in Arizona and New Mexico. The species resembles Aphonopelma chalcodes but is considerably rarer in captivity. Like other Aphonopelma species, it is a ground-dwelling spider that constructs and occupies burrows.
Aphrodes makarovi
Aphrodes makarovi is a leafhopper species in the family Cicadellidae, first described by Zakhvatkin in 1948. It has been historically confused with A. aestuarina due to morphological similarities and misidentifications in museum collections. The species is distinguished by male genitalia morphology, vibrational mating signals, and mitochondrial DNA. It is one of several Aphrodes species that co-occur syntopically, making accurate identification essential for ecological and vector studies.
Aphrodinae
leafhoppers
Aphrodinae is a subfamily of leafhoppers in the family Cicadellidae, containing approximately 7 genera and at least 20 described species. The subfamily is divided into three tribes: Aphrodini, Sagmatiini, and Xestocephalini. Members are distributed across the Holarctic, Neotropical, and Australasian regions, with some species exhibiting notable morphological variability, particularly in Alpine populations. Species identification relies heavily on male genital morphology and, in some groups, acoustic signaling.
Apomastus
Apomastus is a genus of mygalomorph spiders in the family Euctenizidae, endemic to southern California and described in 2002. The genus contains only two species, A. kristenae and A. schlingeri, both restricted to the Los Angeles Basin and surrounding hills. Females of both species are morphologically indistinguishable, requiring molecular or male morphological analysis for identification. The genus occupies habitat highly vulnerable to urban development.
Aptostichus
Aptostichus is a genus of mygalomorph trapdoor spiders in the family Euctenizidae, described by Eugène Simon in 1891. The genus contains 41 described species distributed primarily in southern California, with some species extending into northern California, Mexico, and the Channel Islands. These spiders are notable for constructing silk-lined burrows with thin wafer-like trapdoors, though unlike some related genera, they do not seal side chambers with additional trapdoors. Several species have been named after prominent figures, reflecting both scientific interest and public engagement in arachnology.
Aptostichus chemehuevi
Chemehuevi Desert Trapdoor Spider
Aptostichus chemehuevi is a species of trapdoor spider in the family Euctenizidae, described by arachnologist Jason Bond in 2012. It belongs to a genus of mygalomorph spiders known for constructing silk-lined burrows with hinged trapdoor lids. The species epithet references the Chemehuevi people, a Native American group whose traditional territory includes parts of the southwestern United States where this spider occurs. Like other Aptostichus species, it is a fossorial predator with limited dispersal capability.
Aptostichus simus
Southern Coastal Dune Trapdoor Spider
Aptostichus simus is a medium-sized mygalomorph trapdoor spider endemic to coastal sand dune habitats of California and Baja California, Mexico. This fossorial species constructs deep, silk-lined burrows with camouflaged trapdoor lids made of sand and silk, typically situated at the base of native dune vegetation. Recent integrative taxonomic research using genomic data has revealed significant cryptic diversity within this species complex, including the description of a new cryptic species, A. ramirezae, from Moss Landing State Beach. The species exhibits deep genetic divergence dating to 2-3 million years ago despite morphological homogeneity, with populations showing extreme habitat specificity that makes them vulnerable to coastal habitat degradation.
Arachosia
A genus of anyphaenid sac spiders native to the Americas, first described by Octavius Pickard-Cambridge in 1882. The genus comprises 21 recognized species, including seven recently described species. Arachosia species are primarily associated with grassland and forest habitats. A taxonomic revision resolved long-standing identification problems in the A. cubana species complex and documented disjunct distribution patterns suggesting potential cryptic speciation.
Aradus cf-snowi
Aradus cf-snowi is a flat bug species in the family Aradidae, a group of true bugs commonly found on and under the bark of dead trees. The 'cf.' designation indicates this specimen resembles A. snowi but requires confirmation. Flat bugs in this genus are typically cryptic and associated with woody substrates.
Aradus cf. acutus-w-tex
Aradus cf-acutus-w-tex is a flat bug in the family Aradidae, a group of true bugs commonly associated with dead wood and bark habitats. The "cf." designation and "w-tex" suffix indicate this is an informal, provisional designation referring to a western Texas population closely resembling Aradus acutus but not formally described as a distinct species. Flat bugs in this genus are typically small, dorsoventrally flattened insects that live cryptically under bark.
Araneae
spiders
Araneae is an order of air-breathing arachnids comprising over 51,000 described species across 136 families, ranking seventh in total species diversity among all organismal orders. Members are characterized by two body regions (cephalothorax and unsegmented abdomen), eight legs, cheliceral fangs with venom glands, and abdominal spinnerets that produce silk. The order is divided into two suborders: Mesothelae (87 species, retaining abdominal segmentation) and Opisthothelae (over 39,000 species, without abdominal segmentation). Spiders occupy virtually all terrestrial habitats worldwide except Antarctica, functioning exclusively as predators of insects and other small arthropods.
Araniella
Cucumber Spiders, Sixspotted Orbweaver
Araniella is a genus of small orb-weaver spiders in the family Araneidae, first described in 1942. The genus includes approximately 20 recognized species distributed across the Palearctic and Nearctic regions, with notable species including A. cucurbitina (cucumber green spider) and A. displicata (sixspotted orbweaver). Members are characterized by green coloration due to biliverdin pigments, small body size (4–8 mm), and distinctive abdominal spotting patterns. Several species have been described recently, including A. villanii (2020) named after mathematician Cédric Villani.
Arctiina
Arctiina is a subtribe of tiger moths within the family Erebidae, historically treated as the tribe Arctiini before taxonomic reclassification lowered its rank while retaining its content. The subtribe contains approximately 5 valid genera following extensive synonymization in 2016, with species distributed across the Palaearctic and Neotropical regions. Members exhibit classic tiger moth characteristics including aposematic coloration and, in males, eversible androconial glands (coremata) used for pheromone dispersal during courtship.
Arrhopalitidae
Arrhopalitidae is a family of springtails (Collembola) in the order Symphypleona, superfamily Katiannoidea. The family includes three genera: Arrhopalites, Pygmarrhopalites, and Troglopalites. Many species are obligate cave-dwellers (troglobionts) exhibiting pronounced troglomorphy, including reduced pigmentation, elongated appendages, and modified sensory structures. The family has a sister-group relationship with Katiannidae.
Baconia
Baconia is a genus of clown beetles (family Histeridae) comprising 116 species, with 85 species described in a 2013 systematic revision. The genus is renowned for brilliant jewel-like coloration and bizarrely flattened body forms—traits rare and little-appreciated in the Histeridae. Species are primarily distributed across North and South America. Many species are known from extremely few specimens; nearly half are represented by only one or two specimens in museum collections.
Batrachedra
Batrachedra is the largest genus in the moth family Batrachedridae, containing approximately 114 species as of 2018. The genus has a cosmopolitan distribution with particularly high diversity in the Indomalayan realm. The name derives from Greek 'batrachos' (frog) and 'edra' (seat), referring to the frog-like resting posture of adults. Early stages remain unknown for most species.
Batrachedra pinicolella
Pine Cosmet
A small conifer-feeding moth in the family Batrachedridae. Formerly cryptic within a species complex, integrative taxonomic studies using DNA barcoding, nuclear markers, and ddRAD sequencing distinguished it from the newly described B. confusella. It has a boreo-montane distribution pattern and is associated primarily with Norway spruce.
Bemisia
Bemisia is a genus of whiteflies in the family Aleyrodidae, containing approximately 40 described species. The genus includes several economically significant agricultural pests, most notably Bemisia tabaci (sweetpotato whitefly or silverleaf whitefly), which is considered one of the 100 worst invasive species globally. Members of this genus are phloem-feeding insects that vector numerous plant viruses and cause direct damage through sap extraction and honeydew secretion. The genus exhibits complex taxonomic challenges, with B. tabaci alone comprising at least 42 cryptic species distinguishable only through molecular analysis.