Flattened-body
Guides
Baconia venusta
clown beetle
Baconia venusta is a species of clown beetle in the family Histeridae, described by John Lawrence LeConte in 1845. The genus Baconia is renowned for brilliant coloration and bizarrely flattened body forms, with species exhibiting jewel-like metallic hues that are rare in the Histeridae family. Species in this genus are believed to be predators of wood-boring beetles and their larvae, with some attracted to bark beetle pheromones. B. venusta is one of approximately 116 species in the genus, most of which were described in a 2013 systematic revision.
Charaphloeus flavosignatus
lined flat bark beetle
Charaphloeus flavosignatus is a species of lined flat bark beetle in the family Laemophloeidae, a group characterized by their dorsoventrally flattened bodies adapted for living under bark. The species was described by Schäffer in 1910. It is known from North America. Like other members of its family, it likely inhabits dead or dying wood where it feeds on fungal hyphae.
Cherokia georgiana georgiana
Cherokia georgiana georgiana is a millipede subspecies in the family Xystodesmidae, characterized by its black body with yellow wedge-shaped posterolateral markings and a wrinkled dorsal surface. It belongs to the order Polydesmida, a group distinguished by lateral expansions of dorsal segments into "paranota" that give a flattened appearance. Like other members of its genus and related genera, it produces hydrogen cyanide (HCN) as a chemical defense against predators, with its bright coloration serving as aposematic warning signals.
Cynaeus depressus
Cynaeus depressus is a species of darkling beetle in the family Tenebrionidae, first described by Horn in 1870. The species is characterized by its dorsoventrally flattened body form, an adaptation that distinguishes it within the genus. Distribution records indicate presence in Mexico, Norway, and Sweden, though the species appears to be rare or poorly collected based on limited observation data. The specific epithet "depressus" refers to this flattened body morphology.
Hololepta populnea
clown beetle
Hololepta populnea is a species of clown beetle in the family Histeridae, first described by John Lawrence LeConte in 1851. The species is distributed across southwestern United States and Mexico, extending into Central America. As a member of the genus Hololepta, it exhibits the characteristic flattened body form adapted for life under bark and in tight spaces. The specific epithet 'populnea' suggests an association with Populus (poplar/cottonwood) trees, though this host relationship requires confirmation.
Ledrinae
Flat-headed Leafhoppers
Ledrinae is a subfamily of leafhoppers within Cicadellidae, comprising approximately 300 species across 38 genera in five tribes (Ledrini, Rubrini, Xerophloeini, Afrorubrini, and Hespenedrini). The group represents an early-branching, morphologically distinctive lineage considered one of the oldest within Cicadellidae. A major 2009 revision redefined the subfamily's boundaries, removing Stenocotini and Thymbrini to Tartessinae and synonymizing Petalocephalini with Ledrini. Diversity is concentrated in Australia, Africa, and the Oriental region, with China alone hosting over 180 species.
Loricerinae
Loricerinae is a subfamily of ground beetles in Carabidae, established by Bonelli in 1810. It is monogeneric, containing only the genus Loricera. These beetles are recognized for their distinctive flattened, shield-like body form and association with moist habitats. The subfamily is relatively small in species diversity but has a broad geographic distribution.
Platycryptus californicus
California Flattened Jumping Spider
Platycryptus californicus is a jumping spider in the family Salticidae native to North and Central America. The species is characterized by its dorsoventrally flattened body, an adaptation that allows it to hide in narrow crevices. It is closely related to and frequently confused with Platycryptus undatus (the Tan Jumping Spider), though the two species have different geographic ranges. Platycryptus californicus is primarily found in western North America, extending from Canada through the western United States and into Mexico.
Platydesmida
Feather Millipedes
Platydesmida is an order of millipedes containing two families (Andrognathidae and Platydesmidae) and over 60 described species. Members are characterized by a strongly flattened body with lateral extensions (paranota) on each segment. The order is notable for containing some of the few documented examples of paternal care in arthropods, with males of certain species coiling around and guarding eggs and young. The only known fossil record consists of a specimen from mid-Cretaceous Burmese amber (~100 Ma) belonging to the extant genus Andrognathus.
Platypezinae
flat-footed flies
Platypezinae is a subfamily of small, fungus-associated flies in the family Platypezidae, commonly known as flat-footed flies. The subfamily contains approximately 250 described species across at least 14 valid genera. Members are distinguished by flattened bodies, distinctive wing venation, and modified hind legs with broadened tibiae and tarsi. The genus Microsania is cosmopolitan in distribution, while Agathomyia is primarily Holarctic with some Oriental representatives.
Platypsyllus
beaver beetle
Platypsyllus is a monotypic genus of beetles in the family Leiodidae, subfamily Platypsyllinae. The sole species, P. castoris, is a highly specialized commensal associated exclusively with beavers. It exhibits extreme morphological adaptations including dorsoventral flattening, eyelessness, flightlessness, and modified mouthparts forming a sucking pump—features that distinguish it from all other beetles and reflect its unique lifestyle in the dense fur of its host.
Porcellanidae
Porcelain Crabs
Porcellanidae, commonly known as porcelain crabs, is a family of decapod crustaceans in the infraorder Anomura. Despite their common name and superficial resemblance to true crabs (Brachyura), they are more closely related to squat lobsters and hermit crabs. The family contains approximately 30+ genera and is distributed worldwide in marine environments, with highest diversity in tropical and subtropical regions. Many species exhibit commensal relationships with other marine organisms.
Selenops
Flatties, Crescent-eyed Spiders, Wall Crab Spiders
Selenops is a genus of spiders in the family Selenopidae, commonly known as "flatties" due to their extremely flattened bodies. The genus comprises approximately 132 species distributed across arid and semi-arid regions worldwide, including the southwestern United States, Florida, the Caribbean, and tropical regions of Asia, Africa, and the Americas. These spiders are notable for being the first documented arachnids capable of controlled gliding when falling, using their flattened bodies and laterigrade legs to steer toward tree trunks rather than falling to the ground. They exhibit some of the fastest turning movements recorded in terrestrial legged animals when attacking prey from behind.
Tenuipalpidae
Flat mites, False spider mites
Tenuipalpidae, commonly known as flat mites or false spider mites, are a family of phytophagous mites in the order Trombidiformes. They are closely related to spider mites (Tetranychidae) but are distinguished by their dorsoventrally flattened bodies and reduced mobility. Members are typically reddish in color and slow-moving. Several species are significant agricultural pests, including Raoiella indica, Brevipalpus phoenicis, B. californicus, B. obovatus, and B. lewisi.
Trogulus
harvestmen
Trogulus is a genus of harvestmen (Opiliones) in the family Trogulidae, characterized by large, elongated and flattened bodies with relatively short legs. The genus contains the largest known harvestman by body length, Trogulus torosus. Species-level identification is difficult due to highly uniform external morphology across the genus, necessitating molecular and morphometric approaches for taxonomy. The genus exhibits unexpectedly high cryptic diversity, with molecular estimates suggesting three times more species than currently described.
Valgus
Valgus is a genus of small scarab beetles in the family Scarabaeidae, subfamily Cetoniinae. Most described species occur in Asia, with some extending into northern Africa and Europe. Three species are native to the New World, and one species is found in South Africa. Adults are characterized by their strongly flattened bodies and distinctive scale-like setae covering both dorsal and ventral surfaces.