Endemic
Guides
Trechus tuckaleechee
Trechus tuckaleechee is a species of ground beetle in the subfamily Trechinae, described by Barr in 1962. It belongs to the genus Trechus, a large and widespread group of small carabid beetles commonly known as blind beetles or trechine ground beetles. The species epithet 'tuckaleechee' likely references Tuckaleechee, a location in Tennessee, USA, suggesting a restricted geographic distribution. Like other Trechus species, it is presumably adapted to subterranean or cryptic habitats.
Triacanthagyna caribbea
Caribbean Darner
Triacanthagyna caribbea is a species of darner dragonfly in the family Aeshnidae, described by Williamson in 1923. It is endemic to the Caribbean region, with confirmed records from Colombia (departments of Antioquia, Bolívar, Magdalena, and Sucre) and broader Caribbean distribution. The species is part of the genus Triacanthagyna, which is characterized by three-spined abdominal appendages in males. As with other aeshnids, it is likely a strong flier adapted to tropical environments.
Trichiotinus rufobrunneus
Florida flower scarab
Trichiotinus rufobrunneus is a species of flower scarab beetle endemic to Florida, commonly known as the Florida flower scarab. It belongs to the genus Trichiotinus, a North American endemic group of trichiine scarabs. The species is associated with the flowers of Opuntia australis (Florida pricklypear cactus), an endemic plant, and has been observed mating within these flowers. Its distribution is limited to Florida, making it a species of conservation concern due to habitat loss from urban development and agriculture.
Trichochrous insignis
Trichochrous insignis is a species of jumping stick (family Proscopiidae), an exclusively Neotropical group of grasshoppers characterized by their stick-like appearance and elongated morphology. The species was described by Hebard in 1931 from Formosa Province, Argentina. Members of this family are commonly known in Spanish as 'bicho palito' (stick bug) and are distinguished from true walkingsticks (order Phasmida) by their jumping ability and grasshopper affinities. The taxonomy of Proscopiidae remains incomplete, with many species potentially undescribed.
Tricholita ferrisi
Tricholita ferrisi is a small noctuid moth described in 2009, known exclusively from two sky island localities in southeastern Arizona. The species occupies high-elevation coniferous forest habitats in the Madrean Sky Islands region. All known specimens were collected by light trap in late July, suggesting a narrow seasonal activity window.
Tricholita knudsoni
Tricholita knudsoni is a species of owlet moth described in 2009 from western Texas. It is a relatively small noctuid with a wingspan of 33–35 mm. The species is known from a restricted geographic range in the Trans-Pecos region, with all documented records from light trap collections between late August and late October. It was described by Crabo and Lafontaine during their revision of related noctuid genera.
Trigonopeltastes floridanus
Trigonopeltastes floridanus is a flower chafer beetle in the family Scarabaeidae. It is endemic to Florida and associated with the flowers of Opuntia australis, the Florida pricklypear cactus. The species has been observed mating on cactus flowers, suggesting a close ecological relationship with this endemic host plant. Like other members of the genus, it likely feeds on pollen and floral tissues.
Trigonoscuta stantoni
Santa Cruz Island weevil, Stanton's trigonoscuta weevil, Santa Cruz island shore weevil
Trigonoscuta stantoni is a species of broad-nosed weevil in the family Curculionidae. The species is endemic to the Channel Islands of California, specifically documented from Santa Cruz Island. It is a member of a genus containing several insular species with restricted distributions.
Trimerotropis bernardi
San Bernardino grasshopper, forest falls grasshopper, San Bernardino Mountain grasshopper
Trimerotropis bernardi is a band-winged grasshopper in the family Acrididae, described by Rentz & Weissman in 1984. The species is endemic to the San Bernardino Mountains of southern California, with records indicating presence in forested montane habitats. It belongs to a genus of grasshoppers typically associated with open, often sandy or rocky terrain, though this species appears restricted to higher elevation coniferous forest environments. Available observational data remains limited, with few documented occurrences.
Trimerotropis huroniana
Lake Huron Locust, Great Lakes Grasshopper
A band-winged grasshopper endemic to the Great Lakes region, restricted to open dune habitats along the shores of Lakes Huron, Michigan, and Superior. Body length ranges from 24–40 mm with females larger than males. Adults are active from late July through August. Federally listed as Threatened in Canada under the Species At Risk Act, with approximately 10 known sites remaining in Ontario.
Trimerotropis infantilis
Zayante Band-winged Grasshopper
Trimerotropis infantilis is a rare, narrowly endemic grasshopper restricted to a small portion of the Santa Cruz Mountains in California. It was described by Rentz and Weissman in 1984. The species occupies specialized sandy habitats and is of conservation concern due to its extremely limited geographic range.
Trimerotropis inyo
Inyo Grasshopper
Trimerotropis inyo is a band-winged grasshopper species in the family Acrididae, described by Rentz & Weissman in 1984. It is endemic to California and belongs to a genus characterized by banded or colored hind wings. The species is poorly documented in scientific literature, with minimal published biological information beyond its original description and taxonomic placement.
Trimerotropis occulens
Lompoc Grasshopper
Trimerotropis occulens, commonly known as the Lompoc Grasshopper, is a species of band-winged grasshopper in the family Acrididae. It was described by Otte in 1984 and is endemic to the United States. The species belongs to the subfamily Oedipodinae, which includes many grasshoppers with distinctive wing patterns and stridulatory capabilities.
Trimerotropis santabarbara
Trimerotropis santabarbara is a band-winged grasshopper in the family Acrididae, described by Rentz and Weissman in 1981. The species is endemic to California and represents one of approximately 30 species in the genus Trimerotropis, a group characterized by banded hind wings and often cryptic coloration.
Trimerotropis topanga
Topanga Grasshopper
Trimerotropis topanga is a band-winged grasshopper in the family Acrididae, described in 1981 from California. It belongs to the genus Trimerotropis, a group characterized by banded wings and association with open, often sandy or gravelly habitats. The species is known from limited records in southern California and has been documented in citizen science platforms.
Trocodima fuscipes
Trocodima fuscipes is a small moth in the family Erebidae, first described by Augustus Radcliffe Grote in 1883. The species is known only from the US state of Arizona. Adults have a wingspan of 18–22 mm and have been recorded flying in April and July. It is a poorly documented species with limited available information on its biology.
Trogloderus kandai
Trogloderus kandai is a psammophilic darkling beetle described in 2019 from Owens Valley, California. It belongs to a genus of six newly described species restricted to dunes and sandy habitats in the western United States. The species is part of the tribe Amphidorini, associated with desert stink beetles.
Trogloderus warneri
Trogloderus warneri is a species of darkling beetle in the family Tenebrionidae, described by Johnston in 2019. It belongs to a genus of psammophilic beetles restricted to dunes and sandy habitats in the western United States. The species is endemic to the western Colorado Plateau region. As a member of a genus whose most recent common ancestor dates to approximately 5.2 million years ago, T. warneri likely arose during the mid-Pleistocene. The genus Trogloderus comprises six species, all adapted to sandy environments.
Trogloraptor marchingtoni
cave robber spider
Trogloraptor marchingtoni is a large cave-dwelling spider and the sole species in the family Trogloraptoridae, the first new spider family described from North America since the 1890s. Discovered in 2010 in caves of southwestern Oregon, this species is distinguished by extraordinary hook-like claws on its legs used to capture prey. It represents a remarkable evolutionary lineage with no close known relatives among living spiders. The species name honors Neil Marchington, the deputy sheriff and amateur biologist who first brought the spiders to scientific attention.
Tularina
Tularina is a genus of harvestmen (Opiliones: Laniatores) in the family Phalangodidae, described by Ubick & Briggs in 2008. As a member of the infraorder Grassatores, it belongs to a diverse group of long-legged arachnids commonly known as daddy longlegs. The genus was established based on morphological characteristics distinguishing it from related phalangodid genera. Information regarding species diversity, distribution, and biology remains limited in published literature.
Turpiliodes
Turpiliodes is a genus of katydids in the family Tettigoniidae, established by Hebard in 1932. It belongs to the tribe Turpiliini within the subfamily Phaneropterinae. The genus is endemic to Mexico, with records from the northeast, Gulf, and southwest regions. As of 2024, iNaturalist documents over 500 observations of this genus.
Tychobythinus
Tychobythinus is a genus of small rove beetles in the subfamily Pselaphinae (Staphylinidae). The genus is widely distributed across the Palearctic region, including North Africa, southern and Central Europe, the Caucasus, Japan, far eastern Russia, and southeastern China. Several species exhibit troglobitic adaptations, including reduced pigmentation, microphthalmia, winglessness, and elongated appendages. The genus contains at least 44 species and subspecies in Italy alone, with ongoing taxonomic revisions clarifying species boundaries and synonymies.
Typhlobius kebus
Typhlobius kebus is a lithobiomorph centipede described by Chamberlin in 1922. It belongs to the genus Typhlobius, a group of lithobiid centipedes. The species has been documented from California, USA. Very little is known about its biology or ecology.
Ufeus felsensteini
Ufeus felsensteini is a small noctuid moth described in 2013, known exclusively from the Santa Catalina Mountains in southeastern Arizona. The species exhibits unusual seasonality among temperate moths: adults emerge in spring and enter an overwintering state, with most flight activity occurring during winter months. It is one of the few species in the genus Ufeus, a small noctuid lineage.
Undulambia rarissima
Gold-lined Undulambia Moth
Undulambia rarissima is a small crambid moth described by Eugene G. Munroe in 1972. It is known from limited records in Florida, with adults active during two distinct periods: January through May and again in September. The species is considered rare, as reflected in its specific epithet. Larval biology remains poorly documented, though there is tentative association with Polystichum ferns.
Uroctonites huachuca
Uroctonites huachuca is a scorpion species in the family Vaejovidae, first described by Gertsch and Soleglad in 1972. The species is named after the Huachuca Mountains in southeastern Arizona, which constitute its type locality and primary known range. It belongs to a genus of medium-sized scorpions distributed in the southwestern United States and northern Mexico.
Uropelma formosum
Uropelma formosum is a species of parasitic wasp in the family Eupelmidae, described by Sharkov in 1988. The genus Uropelma belongs to the chalcidoid wasp superfamily, a diverse group of tiny parasitoids. Distribution records indicate presence in Cuba (CU). The family Eupelmidae comprises species that are primarily parasitoids of insect eggs and larvae.
Ursia furtiva
Ursia furtiva is a moth species in the family Notodontidae, first described by André Blanchard in 1971. It is endemic to Texas in the United States. The species is known from very few records, with only one observation documented on iNaturalist. Its larvae feed on specific Prunus species native to the region.
Utabaenetes
Tanner's black camel cricket
Utabaenetes is a monotypic genus of camel crickets (Rhaphidophoridae) endemic to the San Rafael Desert and adjacent Colorado Plateau of the western United States. The sole species, U. tanneri, is restricted to areas of loose sand and active dunes where it reaches high local densities. This dune-dwelling species exhibits specialized behavioral and ecological adaptations to arid environments.
Vaejovidae
Devil Scorpions
Vaejovidae is a family of scorpions comprising approximately 25 genera and over 230 species, with the common name 'Devil Scorpions.' The family is endemic to North America, ranging from western Guatemala through Mexico and into the western United States, with one species extending into the Appalachian Mountains. Members of this family occupy diverse habitats including desert playas, chaparral, pine-spruce forests at high elevations, and alkali sinks. Several species have been described recently from California, including new species discovered through community science platforms.
Vecturoides pseudonycha
Vecturoides pseudonycha is a species of soft-bodied plant beetle in the family Melyridae. The genus Vecturoides is endemic to New Zealand, and this species is known from a small number of observations. Melyridae beetles are generally characterized by their soft, flexible elytra and often elongated bodies. The species has been documented through citizen science observations, but formal taxonomic description and ecological study remain limited.
Venezillo arizonicus
Arizona Pill-Bug
Venezillo arizonicus is a desert-adapted woodlouse native to the Southwest Desert Province of North America. It possesses physiological adaptations to arid conditions, including highly efficient pleopodal lungs and a markedly lower metabolic rate compared to mesic oniscideans. The species exhibits a critical thermal maximum of approximately 43°C, among the highest recorded for terrestrial isopods.
Venezillo microphthalmus
Small-eyed Venezillo Pill Woodlouse
Venezillo microphthalmus is a small terrestrial isopod in the family Armadillidae, endemic to California. The species exhibits the characteristic conglobation (pill-forming) behavior typical of its family, rolling into a defensive ball when disturbed. It is considered rare on the mainland and has documented populations on the Channel Islands. The species is believed to be declining in the San Francisco Bay Area due to competition from introduced woodlouse species.
Viridemas galena
Viridemas galena is a noctuid moth and the sole species in the monotypic genus Viridemas. First described by John Bernhardt Smith in 1908, this species is endemic to Arizona. The genus and species were established based on specimens collected in the southwestern United States, representing a distinct lineage within the subfamily Noctuinae.
Viridiseptis
Viridiseptis is a monotypic moth genus in the family Noctuidae, erected in 2015. Its sole species, Viridiseptis marina, was originally described in 1874. The genus is endemic to the Pacific coast of North America, ranging from southwestern Oregon through California. Adults are characterized by distinctive green forewings with complex dark patterning.
Walshia floridensis
Walshia floridensis is a small moth in the family Cosmopterigidae, described by Ronald W. Hodges in 1978. It is endemic to Florida, with adults active during the winter months. The species is notable for its specific association with the legume Petalostemon pinnatum as a larval host plant.
Wubana
Wubana is a genus of sheet-web weaving spiders (family Linyphiidae) endemic to the United States. First described by Ralph Vary Chamberlin in 1919, the genus contains seven recognized species as of 2019. These small spiders construct flat, horizontal sheet webs for prey capture. The genus is exclusively North American with no documented occurrences outside the United States.
Xanthonia marquai
Davis Mountains Juniper Xanthonian
Xanthonia marquai is a recently described species of leaf beetle (Chrysomelidae) endemic to the Davis Mountains in western Texas. The species was described in 2019 and is known from a single iNaturalist observation. It is associated with juniper vegetation in montane habitats.
Xenomycetes
Xenomycetes is a genus of handsome fungus beetles (family Endomychidae) and the sole genus in the subfamily Xenomycetinae. It contains at least two described species, X. laversi and X. morrisoni, both endemic to northwestern North America. The genus was established by G.H. Horn in 1880. These beetles are associated with fungal habitats, consistent with family-level ecology.
Xenotrechus denticollis
Southern Xenotrechus Cave Beetle
Xenotrechus denticollis is a troglobitic ground beetle in the family Carabidae, described by Barr & Krekeler in 1967. It belongs to a genus of cave-dwelling beetles endemic to the southern United States. The species epithet 'denticollis' refers to toothed characteristics of the pronotum or neck region.
Xenox delila
Xenox delila is a species of bee fly in the family Bombyliidae, found in California and Baja California Norte. As with other bee flies, adults are likely pollinators that visit flowers for nectar. The genus Xenox includes parasitic species whose larvae develop in the nests of other insects.
Xerasia
fruitworm beetles
Xerasia is a genus of fruitworm beetles in the family Byturidae, established by Lewis in 1895. The genus comprises four described species, all endemic to California. Members occur in diverse environments including both wet and dry habitats.
Xerolinus
Xerolinus is a genus of darkling beetles in the family Tenebrionidae, subtribe Opatrina. Established in 2016 by Ivie and Hart, it comprises approximately thirty species distributed across the West Indies and southern Florida. Most species are endemic to single islands or island groups corresponding to Pleistocene-era landmasses.
Zerene eurydice
California dogface butterfly, flying pansy, dog head butterfly
Zerene eurydice, commonly known as the California dogface butterfly, is a pierid butterfly endemic to California and designated as the state's official insect since 1972. The species exhibits pronounced sexual dimorphism: males display distinctive black and yellow-orange wing patterns resembling a dog's head silhouette, while females are predominantly yellow with black forewing markings. The butterfly is closely associated with its larval host plants, false indigo species (Amorpha californica and A. fruticosa), and is most abundant at the Shutamul Bear River Preserve near Auburn. Despite its cultural prominence, the species remains rarely encountered in the wild due to its fast, high-flying behavior and specific habitat requirements.
Zoniagrion exclamationis
Exclamation Damsel
Zoniagrion exclamationis, commonly known as the Exclamation Damsel, is a species of damselfly in the family Coenagrionidae. It is the sole species in its genus and is endemic to western North America. The species was first described by Selys in 1876 and is recognized by its distinctive coloration and patterning. It is a relatively well-documented damselfly with over 300 observations recorded on citizen science platforms.
Zuphiini
Zuphiini is a tribe of ground beetles in the family Carabidae, established by Bonelli in 1810. The tribe contains at least 23 genera and more than 120 described species with a worldwide distribution. Members of the genus Coarazuphium within this tribe include obligate cave-dwelling (troglobitic) species found in iron ore caves in Brazil's Carajás region, which harbors the highest diversity of obligatory cave-dwelling beetles in the country.