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Uropygi

Uropygi is an order of arachnids, commonly known as whip scorpions or vinegaroons, comprising approximately 120 species in the single Thelyphonidae. These nocturnal are characterized by a robust, heavily sclerotized body typically measuring 2.5 to 8 cm in length (excluding the tail), divided into a prosoma bearing , large pedipalps, and four pairs of legs—the first pair slender and antenniform for sensory perception—along with an opisthosoma of 12 segments ending in a long, flexible, whip-like that lacks a venomous . They possess only two median eyes and rely primarily on tactile and chemosensory cues for navigation and prey detection. Uropygi are distributed worldwide in tropical and subtropical regions, including parts of , southern , Central and , and the , where they inhabit diverse environments such as humid forests, arid grasslands, scrublands, and deserts. Preferring moist or seasonally moist microhabitats, they are often found burrowing in , hiding under rocks, logs, , or leaf litter during the day to avoid and predators. As predators, they emerge at night to hunt , other arachnids, myriapods, and occasionally small vertebrates like , using their powerful pedipalps to seize and crush prey before liquefying and ingesting it with . Despite their formidable appearance, uropygids are harmless to humans, lacking , though they deploy a defensive spray of acetic acid (along with and water) from glands at the base of the , which can reach up to 30 cm and produces a strong to deter threats. Fossils indicate that Uropygi have existed since the period, with around a dozen species described from the , highlighting their ancient lineage among arachnids and evolutionary adaptations for terrestrial life in warm climates. Their reproduction involves indirect sperm transfer via a , with females exhibiting maternal care by guarding eggs and young on their backs until the first disperses. Although not medically significant, uropygids play ecological roles as aerators and predators in their habitats.

Taxonomy and Classification

Etymology and Discovery History

The term "Uropygi" originates from the Ancient Greek words ourá (οὐρά, meaning "tail") and pygḗ (πυγή, meaning "rump" or "buttocks"), alluding to the distinctive flagelliform tail that protrudes from the posterior region of these arachnids. Initial descriptions of uropygids appeared in the mid-18th century, with Carl Linnaeus describing the species as Phalangium caudatum in his Systema Naturae (10th edition, 1758), placing it under the class Insecta in the order Aptera due to superficial resemblances to harvestmen and spiders, though some specimens were also confused with scorpions. The genus Thelyphonus was later established by Pierre André Latreille in 1802, with Thelyphonus caudatus as the type species. Throughout the late 18th and 19th centuries, additional species were described and often misclassified under Scorpiones or Araneae, reflecting limited understanding of their unique morphology, such as the elongated antenniform first legs and non-venomous pedipalps. A significant taxonomic milestone occurred in 1804 when Pierre André Latreille established the ordinal name Thelyphonida (originally as "Thélyphone" in French), recognizing their distinctness from true scorpions and spiders. The family Thelyphonidae was later established by Hippolyte Lucas in 1835. In 1883, Tord Thorell formally erected Uropygi as an independent order in his work on East Indian Arachnida, emphasizing the pygidial gland and as defining features, which solidified their separation from other groups. Subsequent nomenclature shifts treated Thelyphonida as a junior synonym of Uropygi, though it persists in some classifications for the clade excluding . Early taxonomic efforts often conflated Uropygi with the related orders and owing to shared pedipalpal modifications and sensory leg adaptations; for instance, 19th-century schemes lumped them together under broader categories like Pedipalpi, delaying recognition of their separate evolutionary lineages until morphological and later molecular analyses clarified distinctions in the .

Phylogenetic Position and Modern Classification

Uropygi belongs to the class Arachnida within the subphylum and phylum Arthropoda, comprising the order of arachnids known as whip scorpions, with all extant species placed in the single family Thelyphonidae. Historically, the order Uropygi has been defined in a strict sense (Uropygi s.s.) to include only the long-tailed whip scorpions (Thelyphonida), while a broader sense (Uropygi s.l.) encompassed both Thelyphonida and the short-tailed whip scorpions (); however, the current consensus recognizes Uropygi and as distinct orders united within the monophyletic clade Thelyphonida. The Thelyphonidae contains approximately 126 extant (as of 2024) distributed across 16 , with the Mastigoproctus representing the most species-rich , encompassing over 20 described primarily from the . Key diagnostic traits distinguishing Uropygi in modern classification include the modification of the first pair of walking legs into elongate, flagelliform antenniform structures used for sensory exploration, the complete absence of glands, and the presence of two pairs of book lungs for . Recent molecular phylogenetic studies, including phylogenomic analyses published after 2020, have reinforced the of Thelyphonida and positioned it within as part of the Pedipalpi clade (with and ), which is sister to Araneae (spiders), based on multi-locus datasets encompassing mitochondrial and nuclear genes.

Physical Characteristics

External Morphology

Uropygi, commonly known as whip scorpions or vinegaroons, exhibit a typical of arachnids, divided into a (cephalothorax) and an opisthosoma (abdomen). The is covered by a single , while the opisthosoma consists of 12 distinct tergites and sternites, lacking a post-abdominal or found in scorpions. Adult individuals typically measure 25–85 mm in total length, with the comprising about one-third of the body and the opisthosoma the remainder. The appendages of Uropygi are adapted for , sensory , and prey . They possess small, three-segmented used primarily for feeding, robust pedipalps that serve as pincers for handling prey, and eight walking legs arranged in pairs. Notably, the first pair of legs is highly modified into elongated, whip-like flagella that can extend up to the length of the body, functioning as sensory structures covered in setae. These flagella are multi-segmented and terminate in a whiplike tip. The opisthosoma is dorsoventrally flattened and segmented, housing two pairs of book lungs for , with the anterior pair more prominent. Unlike scorpions, there is no metasoma or ; instead, the posterior end features a long, annulated derived from the last few segments. The entire body is encased in a tough chitinous , often colored reddish-brown to dark brown, providing protection and support. The bears numerous trichobothria, fine sensory hairs distributed across the prosoma and legs for detecting vibrations. Sexual dimorphism in Uropygi is evident primarily in the pedipalps and flagella. Males typically have larger, more robust pedipalps compared to females, aiding in and prey capture. In some , male flagella may exhibit modifications such as increased length or additional segmentation for sensory or functions.

Sensory and Defensive Adaptations

Uropygi exhibit highly specialized sensory systems that emphasize chemosensory and mechanosensory capabilities over vision, reflecting their nocturnal and often subterranean lifestyles. The elongated at the tip of the serves as a primary sensory organ, adorned with numerous sensilla—hair-like structures functioning as both chemoreceptors and mechanoreceptors. These allow detection of chemical cues from prey and environmental vibrations transmitted through substrates, enabling localization from distances of up to approximately 1 meter in some . Visual senses are correspondingly limited; uropygids possess one pair of larger median eyes capable of forming clear images via biconvex lenses and three pairs of smaller lateral eyes with inverted retinas and tapeta, but overall acuity is poor, providing only basic light detection. Defensive adaptations in Uropygi center on chemical deterrence rather than venomous injection, as their lack venom s entirely. Instead, robust pedipalps equipped with pincer-like structures deliver significant crushing force to capture prey or ward off threats, capable of exerting pressure sufficient to subdue small arthropods or inflict painful pinches on larger adversaries. The most distinctive defense is the pygidial located at the base of the tail, which produces and precisely sprays a noxious composed predominantly of , including up to 83% acetic acid alongside octanoic and other acids. This irritant fluid, ejected up to 2 feet with accuracy, causes burning sensations and strong vinegar-like odors that repel predators. Respiratory and cuticular adaptations further support survival in humid, low-oxygen microhabitats. Uropygi utilize two pairs of book lungs for , where atmospheric oxygen diffuses across thin lamellae into the , facilitated by as the primary oxygen-transporting pigment. This system sustains a characteristically low metabolic rate, well-suited to their energy-conserving nocturnal activity patterns. To mitigate risks, the features an epicuticular wax layer that reduces rates at s below approximately 37°C; water loss accelerates dramatically above that temperature due to increased cuticular permeability.

Behavior and Life History

Foraging, Diet, and Predation

Uropygi, commonly known as whip scorpions or vinegaroons, are primarily nocturnal predators that under the cover of darkness to avoid diurnal competitors and predators. They rely heavily on their elongated antenniform first pair of legs, which are held aloft and equipped with numerous chemoreceptors and mechanoreceptors to detect prey through tactile vibrations in the and chemical scents in the air. These sensory appendages allow them to locate prey such as crickets, , , millipedes, isopods, and scorpions, as well as softer-bodied like and slugs; occasional small vertebrates, including and frogs, have also been reported in their , though they constitute a minor portion. Juveniles tend to target smaller prey items relative to their body size, reflecting ontogenetic shifts in foraging capabilities. Hunting strategies in Uropygi combine tactics, where individuals remain stationary in burrows or while monitoring for nearby disturbances, with active pursuit when prey is detected at a distance. Once located, the robust, pedipalps rapidly grasp and immobilize the prey, often crushing its , while the pierce the body and inject to initiate extraoral , liquefying internal tissues for easier consumption. This process enables efficient nutrient extraction from otherwise indigestible prey, and Uropygi are also opportunistic , readily consuming carrion such as dead when encountered. composition is dominated by , comprising approximately 80-90% of consumed items, with forming the bulk (e.g., orthopterans at ~23%, hemipterans and at ~14% each in analyzed samples from ); non-insect arthropods like spiders (~17%) and scorpions (~6%) supplement this, underscoring their role as generalist feeders. Prey capture efficiency is notably high, with vinegaroons overpowering most suitable-sized targets, largely attributable to the of their antenniform legs in prey localization and the powerful grip of the pedipalps, which overpower most arthropods within graspable range. This efficacy contributes to their in resource-variable environments, though larger individuals may occasionally fail against oversized or defended prey, leading to selective . Overall, these adaptations position Uropygi as effective nocturnal hunters in terrestrial ecosystems, minimizing energy expenditure while maximizing intake from abundant resources.

Reproduction and Development

Uropygi engage in , with males producing and depositing a that the female uptakes via her genital operculum following elaborate behaviors. Courtship typically initiates when a male encounters a female at night, often during the fall season, and involves tactile interactions using the antenniform flagella for exploration and signaling, as well as displays with the enlarged pedipalps to assess receptivity. The male then grasps the tips of the female's flagella with his , leading her in a characteristic " march" or promenade that can last several hours, during which he positions and deposits the on the for the female to retrieve. Clutch sizes vary by species, typically 20 to 40 eggs (up to 52 in some). After fertilization, females construct a and lay eggs, enclosing them in a moist, silk-like brood sac or pouch attached ventrally to their body. The female carries this sac beneath her abdomen for an of 3 to 5 months (varying by ), during which she remains in the burrow, abstains from feeding, and defends the eggs against threats. Upon hatching, the pale, soft-bodied —resembling miniature adults—climb onto the mother's back, where she provides direct maternal care, transporting and protecting them for 1 to 9 months until their first molt, after which they disperse independently. This extended is characteristic of Uropygi and enhances nymph survival in humid, sheltered microhabitats. Development in Uropygi is hemimetabolous, with nymphs undergoing gradual changes through a series of 4 molts over 3 to 4 years to reach , during which they increase in size and refine features like the flagella and pedipalps. In species such as , maturity is achieved after approximately 3 to 4 years, with molting occurring roughly once per year. Adults in the wild typically live 3 to 7 years, though some may reach 9 years in captivity; is rare or absent across the order, with relying on sexual encounters.

Daily and Social Behaviors

Uropygi exhibit strictly nocturnal activity patterns, emerging from their refuges primarily at night to and explore, while spending the hidden in burrows, under rocks, or within crevices to minimize exposure to and predation risks. This behavior is particularly adaptive in their often arid or tropical habitats, where daytime temperatures and low humidity can lead to significant water loss through their inefficient cuticular barrier, with optimal activity confined to cooler, moister nighttime conditions between approximately 1900 and 0400 hours. By retreating during daylight, individuals avoid extremes that could exceed 45°C, which are lethal, and instead maintain survival rates above 85% in the milder nocturnal environment. Burrowing plays a central role in their daily routine, with individuals excavating shelters using their robust pedipalps to scrape and remove from the surface and walls, forming structures that range from simple vertical shafts to more complex J- or Y-shaped tunnels. These , often constructed in loose, moist substrates, provide secure retreats and can extend several centimeters in depth, allowing uropygids to regulate microclimatic conditions and evade diurnal threats. The process involves gathering loose material into masses with the pedipalps before expelling it from the entrance, enabling efficient construction without relying on other appendages for primary excavation. Social interactions among uropygids are minimal, reflecting a predominantly solitary where adults maintain territories and show little tolerance for conspecifics outside of brief encounters or maternal periods. Cannibalism, particularly toward smaller instars, reinforces this isolation, as spend limited time on the surface and avoid prolonged contact that could lead to aggressive encounters. Consequently, no evidence exists for complex hierarchies, , or group , with most behaviors centered on survival and reproduction rather than communal structures. In response to threats, uropygids adopt a defensive posture involving the elevation of the abdomen, pedipalps, and flagellum (the whip-like tail), which serves to deter predators through display before resorting to chemical defense. From glands at the base of the flagellum, they can project a spray of acetic and caprylic acids up to 1 foot away, producing a strong vinegar-like odor that repels attackers without causing permanent harm to the uropygid itself. This multimodal strategy emphasizes evasion and deterrence over direct confrontation, aligning with their overall cryptic and solitary habits.

Distribution and Ecology

Geographic Range

Uropygi are distributed pantropically and subtropically across the globe, with the majority of the approximately 128 occurring in from to (about 90 species), while around 35-40 species are found in the from the to . hosts a single species, Etienneus africanus, endemic to (, , and ); Uropygi are absent from and , reflecting their strict thermal and humidity requirements. Southeast Asia represents the primary center of diversity for Uropygi, dominated by genera such as Thelyphonus, which accounts for a significant portion of species and exhibits high in regions like . Distributions often appear disjunct, with isolated populations linked to historical biogeographic barriers rather than recent dispersal events. Populations of occur in , facilitated by suitable microhabitats in arid zones. Their limited dispersal capability, characterized by low vagility and dependence on contiguous humid corridors for migration, contributes to localized distributions and high levels of regional .

Habitat Preferences and Adaptations

Uropygi, commonly known as whip scorpions or vinegaroons, primarily occupy humid microhabitats within tropical and subtropical regions, favoring environments that provide shelter and moisture retention. These arachnids are commonly found in leaf litter layers, beneath or rocks, within caves, and in shallow burrows enriched with , where they can maintain proximity to damp conditions essential for their survival. Such preferences reflect their avoidance of exposed, desiccated areas, allowing them to thrive in forested understories and similar concealed niches that buffer against direct and . While most species are restricted to moist habitats, certain uropygids exhibit remarkable adaptations to more arid ecosystems, including deserts and grasslands. For instance, , the largest species, inhabits semi-arid and Mexican regions, utilizing hard soils for burrowing to access subsurface moisture. These adaptations include nocturnal activity patterns and post-rain emergence, enabling activity only when rises, alongside behavioral strategies like selecting sites near sources or in crevices that retain dampness. Overall, uropygids demonstrate tolerance for a range of levels, supporting their physiological needs in both humid and seasonally dry settings. Ecologically, uropygids serve as key predators in their habitats, regulating populations of small such as and other that could otherwise become pests. By ambushing prey in and litter layers, they contribute to arthropod community balance and indirectly facilitate nutrient cycling through the consumption of organisms, promoting in organic-rich environments. Some occasionally inhabit systems as trogloxenes, though true troglomorphic forms with elongated appendages are rare in this order, highlighting their general reliance on surface-level moist refugia. Their low population densities, typically sparse across habitats, underscore their role as specialized, non-dominant contributors to stability.

Evolutionary and Fossil Record

Phylogenetic Relationships

Uropygi, commonly known as whip scorpions, occupy a well-defined position within the class as part of the clade, which also encompasses the orders Araneae (spiders), (whip spiders), and (short-tailed whip scorpions). This grouping is supported by both morphological and molecular evidence, highlighting shared respiratory and appendage structures that distinguish from other s. Within , Uropygi forms a monophyletic to , collectively comprising the Thelyphonida. Morphological synapomorphies uniting include the presence of two pairs of book lungs in the ground pattern, derived from a common ancestral , and specialized pedipalps adapted for sensory or functions. These traits contrast with the single pair of book lungs in scorpions and the tracheal systems in other arachnids, underscoring a shared evolutionary history of terrestrial . Molecular phylogenies, drawing from nuclear ribosomal genes such as 18S and 28S rRNA and mitochondrial markers like and 12S rRNA, consistently affirm the of and the Uropygi-Schizomida sister relationship across studies from the 2010s onward. For instance, phylogenomic analyses using transcriptomic data have resolved as a robust with high support, integrating Uropygi based on concatenated gene alignments. Divergence time estimates place the origin of Thelyphonida (Uropygi + ) in the Upper period, approximately 300 million years ago, aligning with the earliest fossil records and broader terrestrialization events during the . The split from the common ancestor of is inferred to have occurred slightly earlier, around 350-400 million years ago, though precise timings vary with calibration methods. Uropygi lacks certain basal traits, such as pectines found in scorpions, reflecting derived modifications within . Despite these advances, gaps persist in Uropygi , particularly in comprehensive phylogenomic sampling across all genera, with many species represented only by limited molecular data. Debates continue regarding intra-order branching patterns, such as relationships among Uropygi subfamilies, due to incomplete sampling and potential long-branch attraction artifacts in early molecular studies. Ongoing efforts with expanded genomic datasets are addressing these uncertainties to refine evolutionary relationships.

Known Fossils and Evolutionary Insights

The fossil record of Uropygi is notably sparse, comprising a limited number of described specimens that provide glimpses into their ancient and . The earliest unequivocal s date to the late period, approximately 318–300 million years ago, from coal measure deposits in and . Fossils assigned to Thelyphonida, such as Geralinura carbonaria from the Mazon Creek Lagerstätte in , exhibit subchelate pedipalps and a segmented on the tail, highlighting early diversification within the order. Mesozoic records are primarily known from inclusions, underscoring the persistence of Uropygi in tropical environments. from (, ca. 99 Ma) has yielded several well-preserved specimens, including the recently described Crethypoctonus kachinus (Thelyphonida: Thelyphonidae) from 2023, which features a robust body and specialized appendages adapted for subterranean or litter-dwelling habits. Other finds, such as Mesothelyphonus xiaoae described in 2025 with an associated phoretic , further illustrate symbiotic relationships in ancient ecosystems. In total, approximately 13 described demonstrate continuity in whip-like antenniform legs and defensive structures from to times, with no confirmed records beyond the Eocene for Thelyphonida. These fossils offer key evolutionary insights, revealing Uropygi adaptations to humid, forested paleo-environments such as coal swamps and tropical lowlands, where moisture-retentive habitats likely favored their chemosensory and predatory strategies. The presence of whip-like appendages in early fossils suggests these traits were established by the late , potentially contributing to niche partitioning among early arthropods during periods of high atmospheric humidity and plant diversification. Post-2020 discoveries from , including Crethypoctonus and Mesothelyphonus xiaoae, indicate Gondwanan dispersal patterns, as Myanmar's block retained faunal links to southern continents during the , supporting a tropical origin and persistence for the order. However, the incomplete record—dominated by exceptional preservations in and —emphasizes the need for expanded studies of and deposits to better resolve Uropygi's role in evolution.

References

  1. [1]
    Uropygi - Whip scorpions: facts, distribution & population - BioDB
    Order Uropygi – Whip scorpions (120 sp); Family; Genus; Species. Uropygi – Whip scorpions. They emit a vinegar-smelling substance that can deter predators and ...
  2. [2]
    Description of a new fossil Thelyphonida (Arachnida, Uropygi) and ...
    Jan 3, 2024 · Introduction. Whipscorpions (Thelyphonida/Uropygi) form a distinct group among arachnids, characterized by a large, robust, heavily sclerotized ...
  3. [3]
    Uropygi - Soil Ecology Wiki
    May 2, 2025 · The arachnid order Uropygi contains organisms more commonly known as whip scorpions or vinegaroons. Although they may be referred to as ...
  4. [4]
    Thelyphonus - Lander University
    Two median eyes are present. Arachnida C. Arachnids are the terrestrial descendents of the early aquatic chelicerates. The taxon includes the mites, scorpions ...
  5. [5]
    WAC - Uropygi - World Arachnid Catalog
    Uropygi Distribution Browser. ; Costa Rica, 1, Species List ; Cuba, 3, Species List ; Czechia, 2, Species List ; Dominican Republic, 3, Species List.
  6. [6]
    EENY493/IN890: Giant Whip Scorpion Mastigoproctus giganteus ...
    Mastigoproctus giganteus giganteus is the only whip scorpion found in the United States. This subspecies occurs in Arizona, Florida, New Mexico, Oklahoma, ...Introduction · Description · Life History And Habitat
  7. [7]
    [PDF] 1)Class: Arachnida Order: Uropygi Common Name: Whipscorpion ...
    Whipscorpions usually are nocturnal predators of insects, spiders and occasionally small vertebrates such as lizards. By day, whipscorpions often hide under ...
  8. [8]
    Arachids - Susan Masta - Portland State University
    They feed on arthropods, and have a digestive tract similar to other arachnids. The first ricinuleid was described from a paleontological specimen by W.
  9. [9]
    Order Uropygi - English Definition & Meaning - WordZo
    Etymology. The name "Uropygi" is derived from Greek, with "uro" meaning tail and "pyge" meaning rump, referring to the tail-like appendage. The name reflects ...
  10. [10]
    The smaller arachnid orders: diversity, descriptions and distributions ...
    Dec 21, 2007 · The smaller arachnid orders: diversity, descriptions and distributions from Linnaeus to the present (1758 to 2007)*
  11. [11]
    Uropygi Thorell 1883 | Field Guide and Catalogues
    Uropygi Thorell 1883 · Order · Thelyphonida Latreille, 1804: 130 (as Thélyphone); Petrunkevitch, 1949: 262-263; Petrunkevitch, 1953: 95; Waterlot, 1953: 576-577 ( ...Missing: history classification Linnaeus
  12. [12]
    Harvey, M. S. Uropygi. In. Catalogue of the Smaller Arachnid Orders ...
    Oct 23, 2025 · This authoritative catalogue will greatly assist readers in finding the correct taxonomic name for any given family, genus or species within each of the six ...
  13. [13]
    Phylogeny of the Neotropical Hypoctonine Whip-Scorpions ...
    Sep 30, 2024 · ... Uropygi Thorell, 1883 [3,4,5,6,7]. A single family of whip-scorpions, Thelyphonidae Lucas, 1835, with 25 genera (16 extant and 9 fossil) and ...
  14. [14]
    Uropygi - an overview | ScienceDirect Topics
    Vinegaroons comprise a small arachnid (spiders, scorpions and their kin) order, the Uropygi, containing around 115 species in 16 genera.Missing: etymology | Show results with:etymology
  15. [15]
    Three new species of the giant vinegaroon genus Mastigoproctus ...
    Oct 6, 2023 · The genus ranges from southern USA to South America, and includes seven species from Mexico: M.
  16. [16]
    The phylogeny of fossil whip spiders - PMC
    Apr 21, 2017 · Our data suggest that Graeophonus is a crown group amblypygid, and falls within a monophyletic Paleoamblypgi clade, but outside the family ...
  17. [17]
    Recent progress and prospects for advancing arachnid genomics
    ... book lung. While lacking silk or venom glands, the order Uropygi is of biological interest due to the group's pygidial glands, which produce a noxious spray ...
  18. [18]
    New mitochondrial genomes of three whip spider species from the ...
    Nov 1, 2024 · In early cladistics studies and recent molecular phylogenetic ... On the other arachnids, all the Araneae and Thelyphonida species ...
  19. [19]
    [PDF] The rediscovery of a relict unlocks the first global phylogeny of whip ...
    Apr 27, 2022 · Outgroup sampling leveraged previous phylogenomic works that have established Amblypygi as the sister group of vinegaroons. (Thelyphonida), and ...
  20. [20]
    Geralinura Carbonaria (Arachnida; Uropygi) from Mazon Creek ...
    Aug 6, 2025 · Overall, whip scorpions can be recognized by their robust pedipalps, first pair of tactile appendages and a long, slender, whip-like flagellum ( ...Missing: flagelliform | Show results with:flagelliform
  21. [21]
    Comparative microscopic anatomy of Schizomida - ScienceDirect.com
    It is formed by an anterior sclerotized extension of the frons of the propeltidium (epistomo-labral plate). It has the shape of an apically pointed rod that ...
  22. [22]
    Neural Organization of the Sensory Appendages of the Whip ...
    These two appendages bear numerous sensory hairs. Each segment of the flagellum also bears at its base an oval membranous region called 'Fenestra Ovalis'. The ...
  23. [23]
    The visual system of Thelyphonida (whip scorpions): Support for ...
    Together with Schizomida, Amblypygi, and Araneae, they form the clade Tetrapulmonata (the orders typically with four lungs), well supported by molecular and ...
  24. [24]
    Chemistry, ontogeny, and role of pygidial gland secretions ... - PubMed
    The organic composition of the secretion consists of 83% acetic acid, 15% octanoic acid, 1% (Z)-5-octenoic acid, 0.0002% of the corresponding (E)-isomer, 0.11% ...Missing: defensive adaptations tail
  25. [25]
    Whip Scorpions: Are They Poisonous? - WebMD
    Mar 5, 2025 · Whip scorpions are not known to cause problems to humans and pets if left alone. They're not known to bite humans, and their bites are not venomous.What Are Whip Scorpions? · Featured · Health Risks Of Whip...
  26. [26]
    Arachnid - Respiratory System, Gases, Tracheae - Britannica
    Book lungs are found in hardened pockets generally located on the underside of the abdomen. Diffusion of gases occurs between the hemolymph circulating within ...
  27. [27]
    Water balance in the whipscorpion, Mastigoproctus giganteus ...
    Transpiration demonstrated a marked increase in rate at 37.5°C which was independent of saturation deficit suggesting the presence of a wax-like material in ...
  28. [28]
    Metabolic Rate in the Whip-Spider, Damon Annulatipes (Arachnida
    mass: 640+/-66 mg) shows continuous gas exchange, as might be expected from its possession of book lungs, and at 21 degrees C has a metabolic rate of 30.22 ...Missing: Uropygi respiration hemocyanin<|separator|>
  29. [29]
    Mastigoproctus giganteus | INFORMATION - Animal Diversity Web
    Mastigoproctus giganteus is one of the largest species of vinegaroons, growing to lengths of 40 to 60 mm, not including the tail.
  30. [30]
    Giant Vinegaroon - Oakland Zoo
    Species Specifics. Within the genus Mastigoproctus, there are 15 species. The Giant vinegaroon, M. giganteus, has a total of 3 subspecies, all found in North ...
  31. [31]
    [PDF] Diel activity patterns and diet of the giant whipscorpion ...
    Flower (1901) reported that the whipscorpion Thelyphonus schimkewitschi readily consumed dead insects and pieces of over-ripe banana in captivity, as well as ...
  32. [32]
    Vinegaroons (Uropygi: Mastigoproctus tohono) in a multi-predator ...
    Oct 20, 2022 · Vinegaroons are considered dangerous prey for several reasons, including their defensive spraying of toxic fatty acids on predators and their ...
  33. [33]
    The Inside(s) Story of Extra-Oral Digestion in Predaceous Arthropoda
    Aug 7, 2025 · The study of extra-oral digestion is of general interest because it helps explain the success of over 80% of the predaceous families of the ...Missing: uropyg | Show results with:uropyg
  34. [34]
    The history of short-tailed whip scorpions: changes in body size and ...
    Jun 12, 2024 · In addition, fossil and extant representatives of Thelyphonida, the sistergroup to Schizomida + Proschizomus, are larger, well in the centimetre ...
  35. [35]
    Whip Scorpion Care sheet | Reptile Forums
    Jan 28, 2008 · Up to 35 eggs are laid in a burrow, within a mucous membrane that preserves moisture. Mothers stay with the eggs and do not eat. The white ...Missing: silk | Show results with:silk
  36. [36]
    Notes on the life history and reproductive biology of the Giant whip ...
    Size ranges of the different stages are given. Moulting seems to occur once a year. Postembryonic development up to maturity therefore takes about four years.
  37. [37]
    Vinegaroon (Uropygi) - Species, Lifespan, Size, Diet, & Pictures
    Mar 30, 2024 · Vinegaroons are terrestrial arthropods of the Arachnid order Uropygi, also called Thelyphonida. Commonly known as 'whip scorpions' or 'uropygids.Description · Body Plan · Taxonomy
  38. [38]
    [PDF] Temperature and water relations of the giant whip scorpion ...
    In contrast, little information is available on temperature and moisture relations of desert whip scorpions (Arachnida, Uropygi). The giant whip scorpion, ...
  39. [39]
    neoichnology of the whip scorpion mastigoproctus giganteus ...
    Mar 1, 2013 · The pedipalps were used to dig sediment from the surface and from burrow walls (Fig. 3A). The sediment was gathered into a loose mass and held ...Whip Scorpion Ecology And... · Burrow Morphology · Discussion
  40. [40]
    World Arachnid Catalog
    No readable text found in the HTML.<|control11|><|separator|>
  41. [41]
    Systematic Revision of the Giant Vinegaroons of the Mastigoproctus ...
    Feb 1, 2018 · Thelyphonida is among the smallest arachnid orders, comprising 15 extant genera and 121 species, as well as five extinct genera, for a total of ...
  42. [42]
    Whip scorpion | Nocturnal, Venomous, Burrowing - Britannica
    Oct 31, 2025 · The scorpions have a short stinger with a swollen base enclosing a poison gland, and the whip scorpions (order Uropygi) and micro whip scorpions ...Missing: characteristics biology
  43. [43]
    Types of shelter sites used by the giant whipscorpion ...
    Aug 7, 2025 · ... This species is unique among whipscorpions in that it lives in both humid and arid environments and is native to North America. Specimens of ...
  44. [44]
    Spiders and related groups - ScienceDirect.com
    The wind scorpions (order Solifugae) do not occur in caves except as accidentals. The whip scorpions (order Uropygi) rarely occur as trogloxenes in tropical ...
  45. [45]
    ADAPTATIONS OF ARTHROPODA TO ARID ENVIRONMENTS 1
    whip-scorpions, Mastigoproctus giganteus. By using the sensitive front legs, the animals first detect nonhorizontal surfaces and, provided the substrate is ...
  46. [46]
  47. [47]
    The affinities of the Carboniferous whip spider Graeophonus ...
    Aug 6, 2025 · A new fossil whip scorpion (Arachnida: Uropygi: Thelyphonida) is described from the Upper Carboniferous (Westphalian A) of the Bickershaw ...<|control11|><|separator|>
  48. [48]
    Geralinura Carbonaria (Arachnida; Uropygi) from Mazon Creek ...
    Mar 3, 2017 · Order UropygiThorell, 1883. Discussion. Both Thorell's Uropygi and the older name Thelyphonida Latreille, 1804 have been used as the ordinal ...
  49. [49]
    A new genus of whip scorpion (Arachnida: Thelyphonida
    Thelyphonida, commonly known as whip scorpions or vinegaroons, are characterized by their claw-like pedipalps, which are used for crushing prey, and long and ...Missing: nomenclature | Show results with:nomenclature
  50. [50]
    A new whip scorpion (Arachnida: Thelyphonida) with a phoretic mite ...
    May 26, 2025 · A new genus of whip scorpion (Arachnida: Thelyphonida: Thelyphonidae) from Mid-Cretaceous Kachin amber of Northern Myanmar. Cretac Res. 2023;153 ...
  51. [51]
    (PDF) The fossil record of whip spiders: the past of Amblypygi
    These remarkable animals have changed little over evolutionary time, with complete fossils dating back to the Carboniferous (300 mya) and fossil fragments ...
  52. [52]
    The fossil record of whip spiders: the past of Amblypygi | PalZ
    Mar 31, 2021 · We review here all fossil whip spider specimens, figure most of them as interpretative drawings or with high-quality photographs including 3D imaging.
  53. [53]
    X-ray microtomography of the late Carboniferous whip scorpions ...
    First global molecular phylogeny and biogeographical analysis of two arachnid orders (Schizomida and Uropygi) supports a tropical Pangean origin and mid ...