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== Overview ==


  [[File:fakeboys.jpg|400px|right|thumb|[1]]] [[File:ya.png|400px|thumb| Female Gymnobisium species-size reference.[3]]]
{| class="wikitable" style="text-align:center; float:right; margin-left: 10px;
Pseudoscorpions, commonly referred to as false scorpions or book scorpions, are very small arachnids with pincer-like appendages resembling those of scorpions. These pedipalp appendages function similarly to claws and are relatively large in comparison to their overall size. Generally reaching a length of about 2-8 millimeters at maturity, pseudoscorpions often go unnoticed or are commonly mistaken as ticks. Unlike ticks, however, pseudoscorpions are not regarded to be harmful to. In fact, they prey upon many small [[arthropods]], aiding with pest control. [1]
|+ !colspan="2" style="min-width:12em; text-align: center; background-color: rgb(200,150,90)|'''Scientific Classification'''<ref name="ITIS">ITIS USGS Open-File Report 2006-1195: Nomenclature, USGS, n.d. Retrieved from https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=690741#null</ref>
|-
|colspan="2" |[[File:fakeboys.jpg|400px|right|caption]]
|-
!style="min-width:6em; |Kingdom:
|style="min-width:6em; |[[Animals|Animalia]]
|-
!style="min-width:6em; |Phylum:
|style="min-width:6em; |Arthropoda
|-
!style="min-width:6em; |Subphylum:
|style="min-width:6em; |Chelicerata
|-
!style="min-width:6em; |Class:
|style="min-width:6em; |Arachnida
|-
!style="min-width:6em; |Order:
|style="min-width:6em; |Pseudoscorpiones
|}


== Classification ==


*Kingdom- Animalia ([[Animals]])
Pseudoscorpions, also referred to as false scorpions or book scorpions, are small arachnids with pincer-like appendages that resemble those of [[scorpions]]. These appendages, called pedipalps, function similarly to claws and are relatively large in comparison to their overall size. Generally reaching lengths of about 2–8 millimeters at maturity, pseudoscorpions often go undetected or are mistaken for ticks. However, unlike ticks, pseudoscorpions are not regarded as harmful to humans. In fact, they prey upon many small arthropods, aiding with pest control<ref name="Lewis"> Lewis, D. (n.d.). The Benefits of Pseudoscorpions. Retrieved from https://www.extension.iastate.edu/news/2008/mar/071001.htm</ref>.
**Phylum- Arthropoda (Arthropods)
***Subphylum- Chelicerata (Chelicerates)
****Class- Arachnida (Arachnids)
*****Order- Pseudoscorpiones (Pseudoscorpions)


== Characteristics and Morphology ==  
== Characteristics and Morphology ==  


*A common house pseudoscorpion is usually between three and four millimeters.  
[[File:scorp.jpg|350px|left|thumb|Drawings of a pseudoscorpion and a scorpion from JH Comstock’s book. Note that the scale is different for each drawing.<ref name="Comstock">Comstock, J. H., & Gertsch, W. J. (1980). The spider book: A manual for the study of the spiders and their near relatives, the scorpions, pseudoscorpions, whip-scorpions, harvestmen, and other members of the class arachnida, found in America North of Mexico, with analytical keys for their classification and popular accounts of their habits. Ithaca: Comstock.</ref>]] Pseudoscorpions superficially resemble true scorpions; however, they lack an elongated metasoma (tail) and stinger at the end of their abdomens<ref name="Australia">Government of Western Australia. (n.d.). What are pseudoscorpions? Retrieved from http://www.museum.wa.gov.au/catalogues/pseudoscorpions/what-are-pseudoscorpions</ref>.  Another crucial difference between the two types of arachnids is size. The common house pseudoscorpion, ''Chelifer cancroides'', will usually only grow between 2.5–4.5 millimeters (0.10–0.18 in). Generally, pseudoscorpions have an average size of 3 mm (0.1 in), much smaller than the average scorpion<ref name="All">All About Pseudoscorpions - The Predatory False Scorpion. (n.d.) Retrieved from https://www.chaosofdelight.org/pseudoscorpions</ref>.
**Color: yellowish to a brown
**Body: 12- segment abdomen, which only 10 are visible. These segments are protected by plates made of [https://en.wikipedia.org/wiki/Chitin chitin].  
Pseudoscorpions have flat, teardrop shaped bodies with rounded ends. The lower abdomen of a pseudoscorpion, also called the opisthosoma, is composed of 12 segmented sections. These segments are protected by plates made of [https://en.wikipedia.org/wiki/Chitin chitin]. Located on the sides of its cephalothorax (head and thorax), a pseudoscorpion may have 1–2 pairs of eyes, or no eyes at all<ref name="Jacobs">Jacobs Sr., S, (2013). Pseudoscorpions (Department of Entomology). Retrieved from http://ento.psu.edu/extension/factsheets/pseudoscorpions</ref>.
***Shape: flat teardrop or pear like shaped body
 
**Pedipalps: Claw like. over twice the length of their legs. If they were completely extended, they would measure about seven to nine millimeters across. [1]
As members of the class Arachnida, these small [[invertebrates]] have 8 legs. Pseudoscorpions move by shuffling their legs similar to crabs, allowing them to move as quickly backwards as they do forwards<ref name="Hahn">Hahn, J., & Kells, S. (2018). Pseudoscorpions. Retrieved from https://extension.umn.edu/insect-relatives/pseudoscorpions</ref>.
 
Most pseudoscorpions have yellowish to brown mahogany abdomens, though the pedipalps often contrast in color. These pedipalps grow over twice the length of their legs, measuring 7–9 mm across when fully extended<ref name="Jacobs"></ref>. Pedipalps consist of an immobile hand and a finger. The finger is mobile and controlled by adductor muscles. A venom gland and venom duct are usually located in the finger. Additionally, pseudoscorpions possess a gland located within their chelicerae (jaws) for the purpose of producing silk. Pseudoscorpions use this silk to make cocoons for mating, molting, or enduring cold weather<ref name="All"></ref>.
 
[[File:ya.png|400px|thumb| Female ''Gymnobisium sp.'' — size reference.<ref name="Neethling">Neethling, J.A. (n.d.), Pseudoscorpions: Cryptic Predators of the Soil. Retrieved from http://sergsa.org/pseudoscorpions-cryptic-predators-soil/</ref>|right]]


** When they move, they walk crab like. Interestingly, they can move as fast backwards as they can forwards.
**They have a gland in their jaw that spins silk. This silk makes cocoons for mating, molting, or to keep warm in cold weather.
[[File:cool.jpg|thumb|[7]|left]]


Pseudoscorpions superficially resemble true scorpions, but, they lack the elongated metasoma (tail). [3] Also unlike scorpions, pseudoscorpions have no sting on the end of their flat and oval-shaped abdomens. [6]  A big difference between the two is also size. Pseusoscorpions are so small, that they usually go unnoticed. Scorpions are recognizable when seen. One of the most important features for these creatures are their pedipalps, which both of these creatures have.
== Reproduction and Life Cycle ==
Male pseudoscorpions produce packets of sperm called spermatophores, which they deposit on surfaces for females to take into their bodies. Males often deposit spermatophores even in the absence of a female. Males of certain pseudoscorpion species also perform mating dances to attract females after depositing a spermatophore, during which they grasp the female with their pedipalps and guide her to the spermatophore to fertilize her eggs<ref name="Australia"></ref>. Males of other pseudoscorpion species may directly transfer spermatophores into the female with their pedipalps.  


== Reproduction ==
The eggs mature within a female's brood pouch, which is connected to the abdomen. In a single brood, 20–50 young can hatch. Young remain with the mother for a brief period after hatching, eventually dispersing<ref name="Jacobs"></ref>. Most pseudoscorpion species have a lifespan of several years, during which they go through three molting stages before reaching maturity. Pseudoscorpions spend an average of 2 to 3 years as mature adults<ref name="Missouri">Missouri Department of Conservation: Pseudoscorpions. (n.d) Retrieved from https://mdc.mo.gov/discover-nature/field-guide/pseudoscorpions</ref>.
The males produce sperm, which is then packaged and planted for the female. Males of most families that have been studied just deposit a [[spermatophore]] without engaging or even in the presence of a female. The females find this and draw it in. Males of ''Serianus'' do deposit in front of the female, but there is no physical connection between the two. The members of the Cheliferoidea perform an elaborate mating dance, where males actively call to females, taking the female using his pedipalps. He then deposits a spermatophore and assists the female to move over the spermatophore, where she will draw it in. Later on, the eggs then mature internally. [5]


== Diet and Feeding Behaviors ==
== Diet and Feeding Behaviors ==


This venom is used during hunting. The pseudoscorpion uses this venom to immobilize and and capture their prey. While digesting, they pour their semi-corrosive saliva over their prey to aid in a smooth digestion, then they eat the liquid remains. This mechanism helps them feed, but it is not harmful to humans or other pets. [4]
Pseudoscorpions are carnivorous, preying on a variety of small [[insects]], [[mites]], and larvae. Often targeting common house pests such as booklice, clothes moths, dust mites, and ants, pseudoscorpions are able to survive indoors for extended periods<ref name="Missouri"></ref>. Pseudoscorpions use the venom glands in their pedipalps to immobilize prey. They deposit semi-corrosive saliva on their prey to facilitate smooth external digestion before ingesting the liquid remains. This venom is a key mechanism in the feeding process of pseudoscorpions, yet it is harmless to humans and pets<ref name="Lewis"></ref>.


== Distribution ==
== Distribution ==


There are over 3,300 identified species of pseudoscorpions, only 200 of which inhabit North America.[4] These small arachnids are found worldwide, ranging from the tropical regions of the globe- which is where the most dense and diverse populations are found- to the temperate cold regions. Pseudoscorpions have spread to island territories as well, with endemic species being recorded within the Canary Islands and the Maltese Islands.
There are over 3,300 identified species of pseudoscorpions. They are found worldwide, ranging from tropical regions, where the densest and most diverse populations are found, to temperate cold regions. Pseudoscorpions have also spread to island territories, with endemic species being recorded in the Canary Islands and the Maltese Islands.
Across these regions, these [[organisms]] can be located dwelling in many different types of habitats and environments. Species are found under tree bark and within tree hollows, beneath the soil surface, under leaf litter, under stones and within rock fractures, inside caves, on ocean shores, and within buildings and homes. Indoors, pseudoscorpions are commonly observed in rooms containing many books. Thus, explaining their alternate name of book scorpions, they feed upon the booklice and dust [[mites]] that often reside within bookshelves.
Across these regions, these [[organisms]] can be found in many different types of habitats and environments<ref name="Comstock"></ref>. They are typically located under tree bark, within tree hollows, beneath the [[soil]] surface, under leaf litter, under stones, in rock fractures, inside caves, on ocean shores, and within buildings and homes. Pseudoscorpions are commonly found indoors in rooms with many books, feeding on booklice and dust mites that often inhabit bookshelves, which led to the coining of the name 'book scorpions'<ref name="Missouri"></ref>.
 
 




  [[File:scorp.jpg|350px|right|thumb|[7] Drawings of a pseudoscorpion and a scorpion from JH Comstock’s book. Note that the scale is different for each drawing.]]


== References ==
== References ==
[1] Jacobs, S., Sr. (2013). Pseudoscorpions (Department of Entomology). Retrieved from http://ento.psu.edu/extension/factsheets/pseudoscorpions
<references />
 
[2] Mosco, R., & Wicks, M. (n.d.). Book Scorpion [Cartoon]. In Your Wild City.
 
[3] Neethling, J. A. (n.d.). Pseudoscorpions: Cryptic Predators of the [[Soil]]. Retrieved from http://sergsa.org/pseudoscorpions-cryptic-predators-soil/
 
[4] Hahn, J., & Kells, S. (2018). Pseudoscorpions in homes. Retrieved from https://www.extension.umn.edu/garden/insects/find/pseudoscorpions/
 
[5] Government of Western Australia. (n.d.). What are pseudoscorpions? Retrieved from http://www.museum.wa.gov.au/catalogues/pseudoscorpions/what-are-pseudoscorpions
[6] Lewis, D. (n.d.). The Benefits of Pseudoscorpions. Retrieved from https://www.extension.iastate.edu/news/2008/mar/071001.htm
 
[7] Comstock, J. H., & Gertsch, W. J. (1980). The spider book: A manual for the study of the spiders and their near relatives, the scorpions, pseudoscorpions, whip-scorpions, harvestmen, and other members of the class arachnida, found in America North of Mexico, with analytical keys for their classification and popular accounts of their habits. Ithaca: Comstock.

Latest revision as of 23:40, 7 March 2025

Scientific Classification[1]
caption
caption
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Pseudoscorpiones


Pseudoscorpions, also referred to as false scorpions or book scorpions, are small arachnids with pincer-like appendages that resemble those of scorpions. These appendages, called pedipalps, function similarly to claws and are relatively large in comparison to their overall size. Generally reaching lengths of about 2–8 millimeters at maturity, pseudoscorpions often go undetected or are mistaken for ticks. However, unlike ticks, pseudoscorpions are not regarded as harmful to humans. In fact, they prey upon many small arthropods, aiding with pest control[2].

Characteristics and Morphology

Drawings of a pseudoscorpion and a scorpion from JH Comstock’s book. Note that the scale is different for each drawing.[3]

Pseudoscorpions superficially resemble true scorpions; however, they lack an elongated metasoma (tail) and stinger at the end of their abdomens[4]. Another crucial difference between the two types of arachnids is size. The common house pseudoscorpion, Chelifer cancroides, will usually only grow between 2.5–4.5 millimeters (0.10–0.18 in). Generally, pseudoscorpions have an average size of 3 mm (0.1 in), much smaller than the average scorpion[5].

Pseudoscorpions have flat, teardrop shaped bodies with rounded ends. The lower abdomen of a pseudoscorpion, also called the opisthosoma, is composed of 12 segmented sections. These segments are protected by plates made of chitin. Located on the sides of its cephalothorax (head and thorax), a pseudoscorpion may have 1–2 pairs of eyes, or no eyes at all[6].

As members of the class Arachnida, these small invertebrates have 8 legs. Pseudoscorpions move by shuffling their legs similar to crabs, allowing them to move as quickly backwards as they do forwards[7].

Most pseudoscorpions have yellowish to brown mahogany abdomens, though the pedipalps often contrast in color. These pedipalps grow over twice the length of their legs, measuring 7–9 mm across when fully extended[6]. Pedipalps consist of an immobile hand and a finger. The finger is mobile and controlled by adductor muscles. A venom gland and venom duct are usually located in the finger. Additionally, pseudoscorpions possess a gland located within their chelicerae (jaws) for the purpose of producing silk. Pseudoscorpions use this silk to make cocoons for mating, molting, or enduring cold weather[5].

Female Gymnobisium sp. — size reference.[8]


Reproduction and Life Cycle

Male pseudoscorpions produce packets of sperm called spermatophores, which they deposit on surfaces for females to take into their bodies. Males often deposit spermatophores even in the absence of a female. Males of certain pseudoscorpion species also perform mating dances to attract females after depositing a spermatophore, during which they grasp the female with their pedipalps and guide her to the spermatophore to fertilize her eggs[4]. Males of other pseudoscorpion species may directly transfer spermatophores into the female with their pedipalps.

The eggs mature within a female's brood pouch, which is connected to the abdomen. In a single brood, 20–50 young can hatch. Young remain with the mother for a brief period after hatching, eventually dispersing[6]. Most pseudoscorpion species have a lifespan of several years, during which they go through three molting stages before reaching maturity. Pseudoscorpions spend an average of 2 to 3 years as mature adults[9].

Diet and Feeding Behaviors

Pseudoscorpions are carnivorous, preying on a variety of small insects, mites, and larvae. Often targeting common house pests such as booklice, clothes moths, dust mites, and ants, pseudoscorpions are able to survive indoors for extended periods[9]. Pseudoscorpions use the venom glands in their pedipalps to immobilize prey. They deposit semi-corrosive saliva on their prey to facilitate smooth external digestion before ingesting the liquid remains. This venom is a key mechanism in the feeding process of pseudoscorpions, yet it is harmless to humans and pets[2].

Distribution

There are over 3,300 identified species of pseudoscorpions. They are found worldwide, ranging from tropical regions, where the densest and most diverse populations are found, to temperate cold regions. Pseudoscorpions have also spread to island territories, with endemic species being recorded in the Canary Islands and the Maltese Islands. Across these regions, these organisms can be found in many different types of habitats and environments[3]. They are typically located under tree bark, within tree hollows, beneath the soil surface, under leaf litter, under stones, in rock fractures, inside caves, on ocean shores, and within buildings and homes. Pseudoscorpions are commonly found indoors in rooms with many books, feeding on booklice and dust mites that often inhabit bookshelves, which led to the coining of the name 'book scorpions'[9].


References

  1. ↑ ITIS USGS Open-File Report 2006-1195: Nomenclature, USGS, n.d. Retrieved from https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=690741#null
  2. ↑ 2.0 2.1 Lewis, D. (n.d.). The Benefits of Pseudoscorpions. Retrieved from https://www.extension.iastate.edu/news/2008/mar/071001.htm
  3. ↑ 3.0 3.1 Comstock, J. H., & Gertsch, W. J. (1980). The spider book: A manual for the study of the spiders and their near relatives, the scorpions, pseudoscorpions, whip-scorpions, harvestmen, and other members of the class arachnida, found in America North of Mexico, with analytical keys for their classification and popular accounts of their habits. Ithaca: Comstock.
  4. ↑ 4.0 4.1 Government of Western Australia. (n.d.). What are pseudoscorpions? Retrieved from http://www.museum.wa.gov.au/catalogues/pseudoscorpions/what-are-pseudoscorpions
  5. ↑ 5.0 5.1 All About Pseudoscorpions - The Predatory False Scorpion. (n.d.) Retrieved from https://www.chaosofdelight.org/pseudoscorpions
  6. ↑ 6.0 6.1 6.2 Jacobs Sr., S, (2013). Pseudoscorpions (Department of Entomology). Retrieved from http://ento.psu.edu/extension/factsheets/pseudoscorpions
  7. ↑ Hahn, J., & Kells, S. (2018). Pseudoscorpions. Retrieved from https://extension.umn.edu/insect-relatives/pseudoscorpions
  8. ↑ Neethling, J.A. (n.d.), Pseudoscorpions: Cryptic Predators of the Soil. Retrieved from http://sergsa.org/pseudoscorpions-cryptic-predators-soil/
  9. ↑ 9.0 9.1 9.2 Missouri Department of Conservation: Pseudoscorpions. (n.d) Retrieved from https://mdc.mo.gov/discover-nature/field-guide/pseudoscorpions
Retrieved from "http://soil.evs.buffalo.edu/index.php?title=Pseudoscorpions&oldid=11634"