Decomposer
Guides
Polydesmidae
flat-backed millipedes, tractor millipedes
Polydesmidae is a family of millipedes in the order Polydesmida comprising over 240 species across more than 30 genera. These millipedes are characterized by their flattened, plate-like dorsal exoskeletons that give them the common name "flat-backed millipedes." They range from 4 mm to 30 mm in length and display coloration from black through brownish to pallid, rarely vivid. The family has a predominantly Holarctic distribution extending to Mexico, North Africa, and Java, with highest diversity in the Mediterranean region. Several species exhibit notable biological traits, including sexual dimorphism in segment number and chemical defense secretions.
Polypauropus
Polypauropus is a genus of minute soil-dwelling myriapods in the class Pauropoda, established by Remy in 1932. Pauropods are among the smallest myriapods, rarely exceeding 2 mm in length, and are characterized by their branched antennae and reduced body segmentation. The genus belongs to the family Polypauropodidae, which is distinguished by specific morphological features of the antennae and trunk segments. Species within this genus are found in Mediterranean and South Asian regions.
Polyporivora
flat-footed flies
Polyporivora is a genus of flat-footed flies (Platypezidae) comprising approximately eight described species. The genus is distinguished by its obligate association with polypore fungi, where larvae develop within host fruiting bodies. Species occur primarily in the Holarctic region, with documented records from Europe, including recent rediscoveries in Central and Southern Europe. The genus was established by Kessel & Maggioncalda in 1968.
Polyxenus
Polyxenus is a genus of bristly millipedes in the order Polyxenida, the sole extant genus of the family Polyxenidae. These small millipedes are characterized by their distinctive tufts of setae (bristles) and are notable for being among the most morphologically derived millipedes, having lost many ancestral diplopod traits. The genus contains at least 30 valid species and has a broad geographic distribution across multiple continents. Polyxenus species are frequently found in association with ants, serving as either symbionts or specialized prey.
Prionochaeta
small carrion beetles
Prionochaeta is a monotypic genus of small carrion beetles in the family Leiodidae. The sole described species, P. opaca, is found in North America and feeds on decaying animal matter. These beetles are part of the subfamily Cholevinae and contribute to decomposition and nutrient cycling in carrion habitats.
Prochyliza brevicornis
cheese skipper
Prochyliza brevicornis is a species of cheese skipper in the family Piophilidae. Like other members of this family, its larvae are known for their distinctive "skipping" locomotion, achieved by grasping their posterior end with their mouthparts and suddenly releasing to catapult themselves away from threats. The species is part of a group commonly associated with decomposing fatty tissues, particularly in cheese and carrion.
Prochyliza varipes
waltzing fly
Prochyliza varipes is a species of piophilid fly commonly known as the waltzing fly. Males exhibit pronounced sexual dimorphism with elongated, conical heads and long antennae used in territorial combat. The species is associated with carrion, particularly decomposing animal remains. It is most active in early spring, often appearing when melting snow exposes winter-killed animals.
Prostomidae
jugular-horned beetles, Red Log Beetles
Prostomidae is a small family of beetles comprising two extant genera (Prostomis and Dryocora) with approximately 20 species. These elongate, parallel-sided beetles are specialized inhabitants of dead wood, where both larvae and adults develop. The family exhibits a disjunct global distribution: Prostomis occurs in North America, Europe, Africa, the Pacific region and East Asia, while Dryocora is restricted to New Zealand, Australia and Tasmania. An extinct genus, Vetuprostomis, is known from mid-Cretaceous Burmese amber.
Proteinus collaris
Proteinus collaris is a small rove beetle in the family Staphylinidae, described by Hatch in 1957. It belongs to the subfamily Proteininae, a group of beetles often associated with fungal habitats. The species is known from the Pacific Northwest region of North America, with records from coastal British Columbia, Washington, and Alaska. Like other members of the genus Proteinus, it is likely associated with decaying organic matter and fungal fruiting bodies.
Protopiophila latipes
cheese skipper
Protopiophila latipes is a species of cheese skipper in the family Piophilidae. It has been observed reproducing on carrion in advanced stages of decomposition. Males of this species do not exhibit mate-guarding behavior, distinguishing it from the related P. litigata where males actively guard females.
Psectrosciarinae
Psectrosciarinae is a subfamily of minute black scavenger flies within the family Scatopsidae (order Diptera). These small, dark-colored flies are poorly studied compared to other scatopsid groups, with limited biological and ecological documentation available. The subfamily is distinguished from the nominate subfamily Scatopsinae primarily by subtle morphological differences in wing venation and genitalic structures. Most species are associated with decaying organic matter and moist microhabitats.
Pseudosinella sexoculata
Pseudosinella sexoculata is a species of elongate springtail in the family Entomobryidae, described by Schött in 1902. Members of this genus are characterized by their slender, scaled bodies and are typically found in soil and leaf litter habitats. The specific epithet "sexoculata" refers to the presence of six eyes (ocelli), a diagnostic feature distinguishing it from related species. Like other entomobryomorph springtails, it possesses a furcula for jumping and lacks a collophore on the first abdominal segment.
Psiloscelis abnormalis
clown beetle
Psiloscelis abnormalis is a species of clown beetle in the family Histeridae, described by Mann in 1924. It is known from limited distribution records in the northern Great Plains region of North America, specifically from the Canadian provinces of Manitoba and Saskatchewan and the U.S. state of North Dakota. Like other members of Histeridae, it is presumed to be associated with decomposing organic matter, though specific ecological details remain undocumented.
Psychoda alternata
trickling filter fly, drain fly, moth fly
Psychoda alternata is a small moth fly (family Psychodidae) native to North America that has become cosmopolitan through human transport. Adults are about 4 mm long with broad, hairy wings held rooflike over the body. The species is strongly associated with wastewater treatment systems, where larvae feed on microbial biofilms in trickling filters and percolating beds. It has also been documented as an emerging nuisance pest in potted plants at commercial nurseries. Adults are short-lived, non-feeding, and primarily active in subdued light.
Psychoda sigma
moth fly
Psychoda sigma is a small moth fly in the family Psychodidae, commonly known simply as 'moth fly.' First described by Kincaid in 1899, this species belongs to the subgenus Tinearia within the genus Psychoda. Moth flies are characterized by their dense body pilosity and small size, typically measuring only a few millimeters in length. The species has been documented in North America and parts of Europe, including Belgium and Denmark.
Psyllipsocus
Psyllipsocus is a genus of cave-dwelling barklice comprising more than 50 described species. Members of this genus inhabit dark, humid microhabitats including caves, rock crevices, and similar subterranean environments. The genus was established by Selys-Longchamps in 1872 and represents one of the most species-rich genera within the family Psyllipsocidae.
Ptecticus
soldier flies
Ptecticus is a large genus of soldier flies (Stratiomyidae: Sarginae) comprising at least 150 described species worldwide, with roughly 40 species documented from the Old World alone as of 2000. Adults display variable body coloration—yellow, brown, or black—with abdominal transverse stripes, dusky wings, and often translucent second abdominal segments. A well-developed inner projection on the second antennal segment characterizes most species. The genus exhibits wasp-mimicry in appearance and behavior. Larvae are broad, flat, segmented maggots found in fermenting fruit and rotting vegetal material.
Ptenothrix maculosa
Ptenothrix maculosa is a globular springtail in the family Dicyrtomidae, native to the temperate west coast of North America from Alaska to California. First described by Swedish entomologist Henrik Schött in 1891, this species exhibits extreme color polymorphism, leading to decades of misidentification and the synonymization of several conjectured undescribed species. Definitive identification requires microscopic examination of setal arrangements on the abdomen and furca. It serves as a decomposer in woodland ecosystems and has become a focal species for citizen science monitoring through photo-based identification.
Ptenothrix marmorata
Ptenothrix marmorata is a globular springtail species in the family Dicyrtomidae, characterized by its rounded body form typical of the order Symphypleona. The species was originally described by Packard in 1873 under the genus Dicyrtoma. As with other members of its family, it possesses a furcula (springing organ) for locomotion and is part of the diverse soil microarthropod community. The specific epithet 'marmorata' refers to a marbled coloration pattern.
Ptenothrix palmata
Ptenothrix palmata is a species of globular springtail in the family Dicyrtomidae, first described by Folsom in 1902. As a member of the order Symphypleona, it possesses the rounded, globular body form characteristic of this group. The species has been documented from Arctic, subarctic, and northern North American regions, including Pacific North America. Like other dicyrtomids, it inhabits moist microhabitats in forest floor environments.
Ptenothrix undescribed
Ptenothrix is a genus of globular springtails (Collembola: Sminthuridae). The genus contains multiple species, with at least one undescribed species known to occur in North America. Springtails in this genus are small, soil-dwelling hexapods that contribute to decomposition and nutrient cycling in terrestrial ecosystems. The undescribed status indicates formal taxonomic description is pending.
Pteroxanium
scaly-winged barklice
Pteroxanium is a genus of scaly-winged barklice in the family Lepidopsocidae, first described by Enderlein in 1922. The genus comprises approximately eight described species distributed across multiple continents. Members are characterized by their distinctive scaled wings, a trait that distinguishes them from many other barklice groups. The genus includes species found in both tropical and temperate regions, with records from the Americas, Europe, and insular localities.
Pteryx
Pteryx is a genus of minute feather-winged beetles in the family Ptiliidae. Adults are less than 1 mm in length and inhabit rotting wood, particularly under bark of decaying logs and stumps. The genus exhibits wing polymorphism, with individuals occurring in either a normal winged form or a vestigial-winged neonate form characterized by pale pigmentation and reduced eyes. Pteryx is distributed across the Northern Hemisphere in Eurasia and North America, with highest abundance in northern bogs and swampy habitats.
Ptomaphagus californicus
Ptomaphagus californicus is a species of small carrion beetle in the family Leiodidae, described by J.L. LeConte in 1853. The species is known from California and broader North America. As a member of the carrion beetle family, it is associated with decomposing organic matter, though specific ecological details for this species remain limited in published sources.
Ptomaphagus nevadicus
Ptomaphagus nevadicus is a small carrion beetle in the family Leiodidae, first described by Horn in 1880. It is a member of the subfamily Cholevinae, a group commonly associated with decomposing organic matter. The species has a broad distribution across western and central North America, extending into Mexico.
Ptomaphagus ulkei
Ptomaphagus ulkei is a small carrion beetle in the family Leiodidae, described by Horn in 1885. It is distributed across eastern North America, with records from Alabama, Georgia, Indiana, Kentucky, Maryland, North Carolina, New York, Virginia, and Washington D.C. As a member of the subfamily Cholevinae, it is associated with carrion and decomposing organic matter.
Ptycta lineata
Ptycta lineata is a barklouse species in the family Psocidae, described by Mockford in 1974. It occurs across the Caribbean, Middle America, and southern North America. Like other members of its genus, it inhabits dead leaf litter and surface vegetation in humid environments. The species is one of approximately 70 described in the genus Ptycta.
Pyralis manihotalis
Tropical Meal Moth
Pyralis manihotalis is a small pyralid moth with a pan-tropical distribution, described by Achille Guenée in 1854. It is frequently associated with stored products and decaying organic matter, earning it the common name Tropical Meal Moth. The species has been documented in an unusually wide range of habitats, including caves where self-sustaining populations feed on bat guano. Adults are nocturnal and attracted to ultraviolet light.
Pyrochroidae
Fire-colored Beetles, Fire-coloured Beetles, Red Cardinal Beetles
Pyrochroidae is a family of beetles commonly known as fire-colored beetles or red cardinal beetles, comprising approximately 150 species distributed worldwide except Antarctica. Members of this family are saproxylic, with larvae developing beneath bark and in decaying woody debris of dead logs. The family was expanded to include most former members of the defunct family Pedilidae. Many species in the subfamily Pyrochroinae exhibit distinctive comb- or antler-like antennae.
Quateiella
Quateiella is a genus of minute black scavenger flies (Diptera: Scatopsidae) established by Cook in 1975. It belongs to the tribe Swammerdamellini within the subfamily Scatopsinae. The genus is poorly known, with no observations recorded on major biodiversity platforms and limited published information available.
Quedius fulvicollis
Quedius fulvicollis is a rove beetle (family Staphylinidae) described by Stephens in 1833. Originally placed in the genus Raphirus, it is now classified within the large genus Quedius. The species has a Holarctic distribution, occurring across Europe, Russia, Central Asia, Iceland, and North America. As a member of Staphylininae, it likely occupies ground-dwelling habitats and contributes to decomposition processes, though specific ecological studies are limited.
Rainieria antennaepes
Rainieria antennaepes is a stilt-legged fly (family Micropezidae) native to eastern North America. The species is notable for its distinctive behavior of holding its white-tipped front legs aloft and waving them to mimic the antennae of ichneumonid wasps—a form of protective mimicry. It is the only member of its genus occurring in North America, making identification straightforward within its range. The specific epithet "antennaepes" translates to "antenna foot," directly referencing this remarkable leg display.
Reticulitermes tibialis
Arid-land Subterranean Termite, Arid Land Subterranean Termite
Reticulitermes tibialis, commonly known as the arid-land subterranean termite, is a native North American termite species adapted to dry environments. It is distinguished from congeneric species primarily by its habitat preferences and genetic characteristics, as morphological differences are minimal. The species occurs across the western and north-central United States, where it serves as an important decomposer of cellulose in arid ecosystems. Unlike some other Reticulitermes species, it causes relatively limited structural damage due to its preference for areas with low human population density.
Revelieria
Revelieria is a genus of small beetles in the family Latridiidae, established by Perris in 1869. The genus contains two described species: Revelieria genei (originally described by Aubé in 1850) and Revelieria california (described by Fall in 1899). Latridiidae beetles are commonly known as plaster beetles or minute brown scavenger beetles.
Rhegmoclema edwardsi
Rhegmoclema edwardsi is a species of minute black scavenger fly in the family Scatopsidae, a group of small, dark-colored flies commonly associated with decaying organic matter. The species was described by Collin in 1954. Members of this family are typically found in moist, shaded environments where decomposing vegetation or fungi occur.
Rhegmoclema halteratum
Rhegmoclema halteratum is a minute black fly in the family Scatopsidae, commonly known as minute black scavenger flies or dung midges. The species was described by Meigen in 1838. Members of this genus are characterized by reduced wing venation and are generally associated with decaying organic matter. Like other scatopsids, they are likely decomposers in nutrient cycling, though specific ecological details for this species remain poorly documented.
Rhiscosomididae
Rhiscosomididae is a small family of millipedes in the order Chordeumatida, containing the single genus Rhiscosomides with seven described species. The family was established by Silvestri in 1909. These millipedes are known from western North America, with records from British Columbia, Washington, Oregon, and California.
Rhyopsocus
bird nest barklice
Rhyopsocus is a genus of barklice in the family Psoquillidae, commonly referred to as bird nest barklice. The genus contains more than 20 described species. These insects are associated with bird nests, where they feed on organic debris. They are small, soft-bodied insects typical of the order Psocodea.
Rhyopsocus celtis
Rhyopsocus celtis is a species of psocid (barklouse) in the family Psoquillidae, described by Mockford in 2016. The specific epithet "celtis" indicates its association with hackberry trees (Celtis spp.), which serve as its host. The species belongs to a small genus of psocids that inhabit dead or dying woody vegetation.
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.
Salina
Salina is a genus of elongate-bodied springtails in the family Paronellidae, first described by MacGillivray in 1894. The genus contains approximately five described species. These springtails are distributed across tropical and subtropical regions including the Amazon, Andean regions, the Caribbean, and continental Southeast Asia. They are characterized by their slender, elongated body form typical of the Paronellidae family.
Salina banksi
Salina banksi is a species of elongate-bodied springtail in the family Paronellidae, first described by A.D. MacGillivray in 1894. Springtails (Collembola) are small, wingless hexapods that are among the most abundant terrestrial arthropods, though individual species are often poorly documented. The specific epithet "banksi" honors the naturalist Joseph Banks. This species belongs to a genus and family characterized by elongated body forms adapted for life in soil and leaf litter communities.
Sancassania anomala
Sancassania anomala is a species of mite belonging to the family Acaridae, within the order Sarcoptiformes. These mites are part of the diverse oribatid mite fauna, a group primarily known for their role in decomposition and nutrient cycling in soil ecosystems. The genus Sancassania includes species commonly associated with stored products, decaying organic matter, and various substrates where they feed on fungi and detrital material. Specific information about S. anomala remains limited in publicly available sources.
Saprinus oregonensis
clown beetle
Saprinus oregonensis is a species of clown beetle in the family Histeridae, first described by LeConte in 1844. The species is distributed across western North America, with records from Canada (Alberta, British Columbia, Manitoba, Saskatchewan), the United States (California, Colorado, New Mexico, Oregon, Washington), and Mexico. As a member of the Saprininae subfamily, it belongs to a group of predatory beetles commonly associated with carrion, dung, and other decomposing organic matter.
Saprinus pensylvanicus
Pennsylvania Clown Beetle
Saprinus pensylvanicus is a species of clown beetle in the family Histeridae, distributed across eastern North America from New England to Florida. Like other histerid beetles, it is predatory and associated with decomposing organic matter. The species is part of a diverse genus of small, compact beetles known for their shiny appearance and habit of playing dead when disturbed.
Sarcophaga
Common Flesh Flies
Sarcophaga is a large genus of true flies (Diptera) comprising over 1000 species worldwide. These flies are commonly known as flesh flies due to the necrophagous habits of many species. Adults are medium to large-sized with characteristic gray coloration, three longitudinal dark stripes on the thorax, and checkered abdominal patterning. Species identification requires microscopic examination of male genitalia due to uniform external morphology. The genus exhibits diverse life histories including necrophagy, coprophagy, parasitism, and parasitoidism.
Sargus bipunctatus
twin-spot centurion, Twin-Spot Centurion Fly
Sargus bipunctatus, commonly known as the twin-spot centurion, is a European soldier fly in the family Stratiomyidae. Adults range from 10–14 mm in body length and display sexual dimorphism in coloration. The species is associated with decaying organic matter, where females oviposit and larvae develop. It has been observed in both open and wooded habitats from July through November.
Scaphidium
shining fungus beetles
Scaphidium is a genus of shining fungus beetles in the family Staphylinidae. Members are small beetles with compact, rounded bodies and short elytra that leave much of the abdomen exposed. The genus contains approximately 62 described species distributed across multiple continents.
Scaphisoma
shining fungus beetles
Scaphisoma is the most diverse genus of Scaphidiinae, with 766 described species and subspecies distributed almost worldwide. Members are commonly known as shining fungus beetles due to their association with fungi. The genus occurs across multiple continents including Asia, Africa, Europe, and the Americas, with 38 species recorded from the Neotropical region and seven now known from Brazil. Species have been documented from polyporoid fungi and other fungal substrates.
Scathophaga crinita
Scathophaga crinita is a species of dung fly in the family Scathophagidae. It is one of approximately 30 species in the genus Scathophaga, a group commonly known as dung flies. Members of this genus are typically associated with animal feces, where adults feed and females lay eggs. The larvae develop in dung, playing a role in decomposition.