Endemic
Guides
Anillinus magazinensis
Anillinus magazinensis is a small ground beetle in the family Carabidae, described in 2004 from specimens collected in Arkansas, USA. It belongs to the genus Anillinus, a group of minute, eyeless, wingless beetles adapted to subterranean or deep soil habitats. The species epithet refers to Magazine Mountain, the type locality in the Ozark Mountains.
Anillinus unicoi
Anillinus unicoi is a small ground beetle species in the family Carabidae, described in 2011 from the Unicoi Mountains region of the southern Appalachians. It belongs to the genus Anillinus, a group of minute, eyeless or nearly eyeless beetles adapted to subterranean or deep soil habitats. The species epithet refers to the Unicoi Mountains, which span the Tennessee-North Carolina border. Like other anillines, it likely inhabits moist forest floor environments and exhibits reduced pigmentation and vision associated with life in dark microhabitats.
Anisogammaridae
Anisogammaridae is a family of small benthic amphipod crustaceans endemic to the northern Pacific Rim. The family includes freshwater, estuarine, and marine species distributed across the Japanese Archipelago, Korean Peninsula, Chinese mainland, and Pacific coast of North America. Members exhibit diverse life history strategies including annual winter-breeding cycles in temperate freshwater habitats and bivoltine patterns in estuarine environments. The family is notable for containing the most diverse group of Japanese freshwater amphipods (genus Jesogammarus) and species of conservation concern due to restricted ranges and habitat vulnerability.
Anomala hardyorum
Hardy's Dune Beetle, Hardys' dune beetle
Anomala hardyorum, commonly known as Hardy's Dune Beetle, is a species of shining leaf chafer in the family Scarabaeidae. The species was described by Potts in 1976 and is endemic to the Algodones Dunes of North America. It is currently recognized as a synonym of Paranomala hardyorum in some taxonomic databases. As a member of the genus Anomala, it belongs to a group of scarab beetles commonly referred to as chafers or shining leaf chafers.
Anoncia sphacelina
Anoncia sphacelina is a small moth in the family Cosmopterigidae, first described by Keifer in 1935. It is known only from California in western North America. Adults are active in spring, and the larvae are documented feeding on Lepechinia calycina, a member of the mint family.
Anoplochares apicata
Anoplochares apicata is a species of darkling beetle in the family Tenebrionidae. The genus Anoplochares is endemic to New Zealand, and this species represents one of several described members of this genus. Like other tenebrionids, it is adapted to arid or semi-arid environments and exhibits nocturnal habits. The species has been documented in the scientific literature but remains poorly known in terms of detailed biology.
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.
Anthocharis julia
Julia Orangetip, Southern Rocky Mountain Orangetip
Anthocharis julia is a butterfly species in the family Pieridae, commonly known as the Julia Orangetip or Southern Rocky Mountain Orangetip. It is one of three species in the sara species group, distinguished by more than 2% mitochondrial DNA COI barcode divergence from congeners A. sara and A. thoosa. Molecular and morphological evidence consistently support its species status with no detected introgression or hybridization. The species is endemic to the southern Rocky Mountains on the eastern side of the range.
Anthocharis julia browningi
Utah Julia Orangetip
A subspecies of orangetip butterfly endemic to the western United States. The common name "Utah Julia Orangetip" indicates a geographic association with Utah, though precise range boundaries remain poorly documented. As a member of the Pieridae family, it shares the characteristic white or yellow wing bases with orange apical markings typical of the genus Anthocharis.
Anthocharis sara gunderi
Santa Catalina Orangetip
A subspecies of the Sara Orangetip butterfly endemic to Santa Catalina Island, California. The Santa Catalina Orangetip is distinguished by its island-restricted distribution and subtle morphological differences from mainland populations. Like other orangetips, it displays the characteristic orange wing tips in males, though specific distinguishing features for this subspecies require careful examination.
Anthocharis sara sempervirens
Sara Orange-Tip
Anthocharis sara sempervirens is a subspecies of the Sara Orange-Tip butterfly, first described in 2008. It belongs to the family Pieridae, which includes the whites and sulphurs. The subspecies epithet "sempervirens" (meaning "evergreen") references the coastal redwood (Sequoia sempervirens) forests with which this butterfly is associated. Like other orange-tips, males display distinctive orange coloration on the forewing tips.
Anthracopteryx
Anthracopteryx is a monobasic genus of click beetles (family Elateridae) endemic to the Front Ranges of Colorado, USA. The genus contains a single species, A. hiemalis, which is notable for its winter activity period—unusual among click beetles. The genus was established by Horn in 1891 and remains poorly represented in collections and online databases.
Anthracopteryx hiemalis
Anthracopteryx hiemalis is a small click beetle (family Elateridae) and the sole species in its monotypic genus. It is notable for winter activity, a rare trait among click beetles. The species has an extremely restricted endemic range in the Front Range of Colorado, USA, spanning from Laramie south to Westcliffe. As of 2017, it was documented in only two observations on iNaturalist and had no prior photographic records on BugGuide.net, indicating it is among the most poorly documented North American elaterids.
Anuroctonus pococki bajae
Californian swollen stinger scorpion
Anuroctonus pococki bajae is a subspecies of scorpion in the family Chactidae, endemic to Baja California. It is distinguished by a pronounced swollen bulb on the telson (stinger segment), a trait referenced in its common name. The species exhibits defensive, aggressive behavior when provoked and is nocturnal. Under ultraviolet light, it fluoresces bright blue-green like other scorpions.
Apache californicum
Apache californicum is a small, red planthopper endemic to California. It belongs to the family Derbidae, a group of fulgoroid insects commonly known as planthoppers. Males can be distinguished from the similar Apache degeerii by the presence of two pairs of hooks at the base of the flagellum, whereas A. degeerii has only a single pair.
Apachemiris areolatus
Apachemiris areolatus is a species of plant bug in the family Miridae, described from Texas and New Mexico in 1974. It belongs to a small genus endemic to the southwestern United States. The species name "areolatus" refers to a net-like or small-celled pattern, likely describing surface sculpturing on the body. Very few observations exist, with only six records documented on iNaturalist.
Apantesis bolanderi
Apantesis bolanderi is a small tiger moth in the family Erebidae, originally described from Mount Shasta, California in 1872. It was formerly classified in the genus Grammia but was transferred to Apantesis along with related genera. The species is known from a single locality and remains poorly documented, with no confirmed observations in major biodiversity databases.
Apantesis edwardsii
A tiger moth in the family Erebidae, Apantesis edwardsii was described by Stretch in 1872. It has a highly restricted distribution, known only from the San Francisco area of California and Klamath County in Oregon. The species was transferred from the genus Grammia to Apantesis in a taxonomic revision that consolidated several related genera.
Apantesis favorita
A tiger moth species in the family Erebidae, described by Berthold Neumoegen in 1890. This species was formerly placed in the genus Grammia but was transferred to Apantesis along with related tiger moth genera. It has a restricted distribution in the Great Plains sand dune ecosystems and exhibits a narrow adult flight period in late spring. The species is notable for its specialized habitat association with prairie sand dunes, a rare ecosystem type in North America.
Apantesis hewletti
Apantesis hewletti is a small tiger moth species in the family Erebidae, originally described from southwestern California in 1918. It was formerly classified under the genus Grammia but was reassigned to Apantesis following taxonomic revisions that consolidated several related genera. Adults are characterized by striking coloration with black forewings bearing pale bands and bright yellow to orange-red hindwings. The species has been documented in May, though comprehensive data on its biology and ecology remains limited.
Apantesis ursina
Apantesis ursina is a tiger moth in the family Erebidae, described by Schmidt in 2009. The species was originally placed in the genus Grammia but was transferred to Apantesis in a 2009 taxonomic revision that consolidated several related genera. It is endemic to a restricted range in southern California and the Channel Islands, with likely extension into Baja California. Adults fly in autumn, with peak activity from mid-September to early October.
Apataniidae
Early Smoky Wing Sedges
Apataniidae is a family of caddisflies (Trichoptera) commonly known as early smoky wing sedges. The family contains approximately 18 genera and at least 180 described species. Members are primarily Holarctic in distribution, with notable diversity in Europe, Asia, and North America. Larvae are aquatic and construct portable cases from mineral particles.
Aphanommata
Aphanommata is a genus of weevils (Coleoptera: Curculionidae: Cossoninae) endemic to the Cape Verde archipelago in the Old World. The genus was erected by Wollaston in 1873 and currently includes three species from Cape Verde: A. euphorbiarum (Santo Antão), A. kuscheli (São Nicolau), and A. strakai (Fogo). A fourth species, A. filum, occurs elsewhere in the Old World. The genus has been subject to recent taxonomic revision including descriptions of larval morphology and analysis of vertical and inter-insular distribution patterns.
Aphis hederae
Aphis hederae is an aphid species first described by Kaltenbach in 1843. It is currently listed as an accepted species in major taxonomic databases, though some sources note it as an ambiguous synonym. The species is recorded from the Azores archipelago (Faial, Flores, São Jorge, São Miguel, and Santa Maria islands). As a member of the genus Aphis, it shares the family's characteristic sap-feeding biology on host plants.
Aphonopelma armada
Texas Black Spot Tarantula
Aphonopelma armada is a species of tarantula in the family Theraphosidae, endemic to Texas in the United States. It is commonly known as the Texas Black Spot Tarantula. Like other members of the genus Aphonopelma, it is a large-bodied, ground-dwelling spider that constructs burrows. The species was originally described as Dugesiella armada by Chamberlin in 1940 before being transferred to Aphonopelma.
Aphonopelma catalina
Santa Catalina Mountain Tarantula
Aphonopelma catalina is a tarantula species described in 2016 from the Santa Catalina Mountains of southeastern Arizona. It belongs to a genus of large-bodied, ground-dwelling spiders native to the southwestern United States and Mexico. Like other Aphonopelma species, it exhibits characteristics typical of primitive mygalomorph spiders, including simple genitalia that complicate species identification. The species is endemic to a single mountain range, making it vulnerable to habitat loss.
Aphonopelma chiricahua
Chiricahua Tarantula
Aphonopelma chiricahua is a tarantula species endemic to the Chiricahua Mountains of southeastern Arizona. It was described in 2016 during a comprehensive revision of the genus Aphonopelma, which revealed significant previously unrecognized diversity in the southwestern United States. Like other Madrean Sky Island endemics, this species occupies isolated montane habitats and represents part of the exceptional biodiversity found in this region.
Apodemia mormo langei
Lange's Metalmark, Lange's metalmark butterfly
Apodemia mormo langei is a federally endangered subspecies of metalmark butterfly endemic to a single site in California's San Francisco Bay Area. The total wild population has declined from an estimated 131 individuals in 2008 to approximately 25–30 individuals by 2011. It is restricted to remnant sand dune habitat at Antioch Dunes, where it depends entirely on a specific larval host plant. The subspecies has been the subject of ongoing conservation controversy due to genetic research suggesting it may not be as evolutionarily distinct from other Apodemia mormo populations as previously assumed.
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.
Apomastus kristenae
Apomastus kristenae is a wafer-lid trapdoor spider described by Bond in 2004. It is one of two recognized species in the genus Apomastus, both endemic to restricted regions of southern California. Females are morphologically indistinguishable from the congeneric A. schlingeri, requiring molecular or geographic data for identification. The species occupies a habitat under severe pressure from urban development.
Apomastus schlingeri
Apomastus schlingeri is a venomous trapdoor spider species described by Bond & Opell in 2002. It was originally misidentified as Aptostichus schlingeri before taxonomic revision placed it in the genus Apomastus. The species is known for producing a complex of neurotoxic peptides called aptotoxins, which function as voltage-gated sodium channel blockers. It is one of only two known species in the genus Apomastus, both restricted to the United States.
Appalachia arcana
Michigan bog grasshopper, secretive locust
Appalachia arcana is a short-winged grasshopper endemic to Michigan, United States. It is the only grasshopper species restricted entirely to this state. The species is flightless and does not produce sound. Breeding occurs in September. It inhabits sphagnum bogs surrounded by jack pine trees.
Apsaphida eremna
Apsaphida eremna is a rare noctuid moth and the sole species in its monotypic genus. It is known exclusively from Arizona, where it was first described by John G. Franclemont in 1973. The species remains poorly documented with few verified observations.
Apterocyclus
Kauai flightless stag beetles
Apterocyclus is a genus of flightless stag beetles endemic to the Hawaiian island of Kauai. The genus comprises five described species, ranging from 14 to 23 mm in length. These beetles represent the only native scarabaeoid beetles in the Hawaiian Islands. Three species (A. honoluluensis, A. kawaii, and A. waterhousei) have been confirmed living since the late 1960s, while others may be extinct. Historical collection data shows a dramatic decline, with over 130 specimens documented between 1871 and 1922 but very few found in recent decades.
Apterocyclus honoluluensis
Kauai Flightless Stag Beetle
Apterocyclus honoluluensis, the Kauai flightless stag beetle, is a flightless stag beetle endemic to the Hawaiian island of Kauai. It is the smallest and most commonly encountered species in its genus, with adults measuring 14–17 mm, rarely reaching 21 mm. The species has declined due to predation by introduced mice and habitat loss, and was considered for protection under the U.S. Endangered Species Act in 1994 but was declined due to insufficient data.
Apterocyclus munroi
Apterocyclus munroi is a species of stag beetle in the family Lucanidae. The species was described from four specimens collected on Kauai, Hawaii in 1897. No confirmed observations have been made since the original collection, and the species is considered possibly extinct. It belongs to a genus of flightless stag beetles endemic to the Hawaiian Islands.
Apterocyclus palmatus
Apterocyclus palmatus is a species of stag beetle endemic to the island of Kauai in the Hawaiian Islands. It was originally described in 1922 as a subspecies of Apterocyclus honoluluensis, but is now recognized as a distinct species. The species is known from only five specimens collected in 1919 at 4,000 feet elevation. No specimens have been found in recent decades, and the species may be extinct.
Apterocyclus waterhousei
Apterocyclus waterhousei is a rare, flightless stag beetle endemic to the Hawaiian island of Kauai. It belongs to a genus of flightless beetles found only in the Hawaiian Islands. The species has been documented in several locations on Kauai in recent years.
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.
Apystomyiidae
A small family of flies in the superfamily Asiloidea, containing one extant genus (Apystomyia) and two extinct genera (Apystomimus, Hilarimorphites). The sole living species, Apystomyia elinguis, is endemic to California. Extinct species are known from Late Jurassic to Late Cretaceous deposits in Kazakhstan, Myanmar, and New Jersey. Molecular studies place the family as sister to Cyclorrhapha within Eremoneura.
Araneus illaudatus
Texas Orbweaver, Texas orb-weaver
Araneus illaudatus is a large orb-weaving spider endemic to the southwestern United States. Females are among the largest North American Araneus, reaching 25 mm in body length with a distinctive dirty white coloration and two triangular dark patches on the anterior abdomen. Males are substantially smaller at 9 mm. The species constructs typical orb webs and exhibits pronounced sexual dimorphism in size.
Arawana arizonica
Arawana arizonica is a small lady beetle in the family Coccinellidae, measuring 3.25–3.50 mm in length. Adults are black or piceous with a distinctive red spot on each elytron. The species is known only from Arizona in southwestern North America.
Arctosa sanctaerosae
Santa Rosa Wolf Spider
Arctosa sanctaerosae is a wolf spider endemic to the secondary dunes of white sandy beaches along the Northern Gulf Coast of the United States. The species is nocturnal and burrow-dwelling, with discrete generations. It has experienced significant habitat degradation and fragmentation due to coastal development and tourism over the last century, resulting in reduced gene flow and smaller effective population sizes across five identified population clusters. Hurricanes pose additional natural disturbance, with population recovery influenced by dune height and vegetation density.
Areniscythris brachypteris
Oso Flaco Flightless Moth, sand-dune grasshopper moth
Areniscythris brachypteris is a flightless moth in the family Scythrididae, described by Jerry A. Powell in 1976. It is endemic to coastal sand dunes of California and is notable among Lepidoptera for its reduced wings and inability to fly. The species has been observed in 90 iNaturalist records, suggesting it is documented but not abundant.
Arenivaga floridensis
Florida Sand Cockroach
Arenivaga floridensis is a sexually dimorphic, fossorial sand cockroach endemic to Florida scrub ecosystems. It is the most geographically widespread faunal endemic of Florida scrub, documented from 11 peninsular sand ridges. Genetic analysis reveals three major mitochondrial lineages whose divergence corresponds with late Pliocene peninsula insularization, supporting a western origin hypothesis with colonization during the Pliocene or earlier. The species exhibits extreme sexual dimorphism: males possess fully developed wings and engage in low, erratic flight at dusk, while females are completely wingless and remain entirely fossorial throughout life. Its distribution is restricted to friable, sandy soils beneath light leaf litter of sand live oaks (Quercus geminata).
Arequipa
Arequipa is a genus of cacti in the family Cactaceae, established by Britton & Rose in 1922. The genus is named after the city of Arequipa in southern Peru, a major center for cactus diversity in the Andes. Species in this genus are characterized by their columnar or shrubby growth habit and are native to arid and semi-arid regions of southern Peru and northern Chile. The genus has been subject to taxonomic revision, with some species transferred to related genera such as Weberbauerocereus.
Argentostiria
Argentostiria is a monotypic moth genus in the family Noctuidae, established by Robert W. Poole in 1995. The genus contains a single species, Argentostiria koebelei, described by Riley in 1893. It is endemic to the Mojave Desert of the United States.
Argyrotaenia paiuteana
Argyrotaenia paiuteana is a small tortricid moth described by Powell in 1960. It is known only from California, where adults fly from May through August. The species is associated with coniferous hosts, with larvae feeding on singleleaf pinyon (Pinus monophylla) and western juniper (Juniperus occidentalis).
Arianops nantahalae
Arianops nantahalae is a small rove beetle in the subfamily Pselaphinae, described by Barr in 1974. The species is endemic to the southern Appalachian Mountains of the eastern United States. It belongs to a genus of minute beetles adapted to life in forest leaf litter and soil microhabitats.
Arotrura hymenata
Arotrura hymenata is a species of moth in the family Scythrididae, a group of small, often inconspicuous moths commonly known as flower moths. The genus Arotrura is endemic to New Zealand and contains multiple described species. A. hymenata is one of several species within this genus, though specific biological details remain poorly documented in scientific literature.