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The scariest animal that will never hurt you | The Smaller Majority by Piotr Naskrecki

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Of all the animals that you may encounter in a tropical rainforest, none evoke a more visceral, negative reaction in even the most ardent nature lovers than the tailless whipscorpions...

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Comprehensive Description

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The Amblypygi are a group of around 150 species of arachnids commonly known as tailless whip scorpions or whip spiders (Harvey 2002, 2003). In contrast to the Uropygi [=Thelyphonida] (whip scorpions or vinegaroons), amblypygids lack a tail. The long, bulky, and spined pedipalps extending in front of their somewhat flattened bodies are raptorial (i.e., adapted for seizing prey) and the first pair of walking legs are highly modified into very long antenna-like sensory appendages. Amblypygids lack the silk-spinning spinnerets or poison glands of spiders, but their chelicerae are modified as spider-like fangs. (Barnes 1987; Brusca and Brusca 2003) Either the Uropygi or Araneae (spiders) are believed to be the sister clade to the Amblypygi, with Uropygi generally viewed as more likely given current knowledge (Weygoldt 2000; Fahrein et al. 2009).

Amblypygids are widely distributed in warm, humid regions, where they are typically found in protected situations such as under bark or in leaf litter. Some live in caves. Most species are less than 5 cm long (the smallest is less than a centimeter), but the antenniform first pair of legs may be as long as 25 cm. These long "legs" function as both touch receptors and chemoreceptors. Amblypygids hunt at night, walking sideways with their front "legs" extended. When a prey item is encountered, it is grabbed with the pedipalps and torn open with the chelicerae, allowing the body fluids to be imbibed. (Barnes 1987; Brusca and Brusca 2003)

In the few amblypygid species in which reproductive behavior has been observed, the male courts the female with trembling movements of the antenniform legs and rocking body movements directed toward the female. Eventually, a sperm-containing spermatophore is deposited. Using his pedipalps or front legs, the male guides the female over the spermatophore, which she takes up. After fertilization occurs, the female produces a parchment-like membrane that holds her 6 to 60 large eggs underneath her abdomen. She carries the eggs until hatching and subsequently carries the newly hatched offspring. After their first molt, the young amblypygids climb onto the mother's abdomen until the next molt. (Barnes 1987; Brusca and Brusca 2003)

Amblypygids typically feed on arthropods such as crickets, katydids, harvestmen, spiders, millipedes, roaches, and moths (which they are able to snatch out of the air!) (Hebets 2002), but Ladle and Velander (2003) reported a very unusual feeding habit for a Caribbean species inhabiting rocky outcrops adjacent to mountain streams running through primary tropical rainforest on the island of Tobago: here, Heterophrynus cheiracanthus were observed capturing and eating Macrobrachium prawns plucked from the stream.

Rayor and Taylor (2006) reported on their observations of social behavior in amblypygids, which are generally viewed as solitary animals, and review the literature on early parental care and more complex social behaviors in non-spider arachnids in general.

Weygoldt et al. (2010) described the mating and reproductive behavior of Phrynus exsul, the only Old World species of the family Phrynidae (an essentially Neotropical group), and compare it to that of other phrynids. The Neotropical Phrynus were revised by Quintero (1981).

Harvey (2003) provides a dichotomous key to families and a world catalogue of species. Weygoldt (2000) reviewed the biology of the Amblypygi and includes a key to genera as well as basic information about each genus (distinguishing characteristics, geographic distribution, key literature, etc.).

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Amblypygi

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Amblypygi is an ancient order of arachnid chelicerate arthropods also known as whip spiders and tailless whip scorpions (not to be confused with whip scorpions and vinegaroons that belong to the related order Thelyphonida). The name "amblypygid" means "blunt tail", a reference to a lack of the flagellum that is otherwise seen in whip scorpions. They are harmless to humans.[2][3] Amblypygids possess no silk glands or venomous fangs. They rarely bite if threatened, but can grab fingers with their pedipalps, resulting in thorn-like puncture injuries.

As of 2016, 5 families, 17 genera and around 155 species had been discovered and described.[4] They are found in tropical and subtropical regions worldwide; they are mainly found in warm and humid environments and like to stay protected and hidden within leaf litter, caves, or underneath bark. Some species are subterranean; all are nocturnal. Fossilized amblypygids have been found dating back to the Carboniferous period, such as Graeophonus.

Physical description

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Detail of pedipalps
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Parts of an amblypygid, from Pocock (1900)[5]

Amblypygids range from 5 to 70 centimetres (2.0 to 27.6 in) in legspan.[4][6] Their bodies are broad and highly flattened, with a solid carapace and a segmented abdomen. Most species have eight eyes; a pair of median eyes at the front of the carapace above the chelicerae and 2 smaller clusters of three eyes each further back on each side.

Amblypygids have raptorial pedipalps modified for grabbing and retaining prey, much like those of a mantis.[7] The first pair of legs act as sensory organs and are not used for walking. The sensory legs are very thin and elongate, have numerous sensory receptors, and can extend several times the length of body.[4]

Behavior

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Damon diadema mother carrying young

Amblypygids have eight legs, but use only six for walking, often in a crab-like, sideways fashion. The front pair of legs are modified for use as antennae-like feelers, with many fine segments giving the appearance of a "whip". When a suitable prey is located with the antenniform legs, the amblypygid seizes its victim with large spines on the grasping pedipalps, impaling and immobilizing the prey. This is typically done while climbing the side of a vertical surface and looking downward at their prey.[8] Pincer-like chelicerae then work to grind and chew the prey prior to ingestion. The Tailless Whip Scorpion may go for over a month in which no food is eaten; often times this is due to premolt. Due to the lack of venom the tailless whip scorpion is very nervous in temperament, retreating away if any dangerous threat is sensed by the animal.

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Comparing the front and back legs of an Amblypygid

Courtship involves the male depositing stalked spermatophores, which have one or more sperm masses at the tip, onto the ground, and using his pedipalps to guide the female over them.[9] She gathers the sperm and lays fertilized eggs into a sac carried under the abdomen. When the young hatch, they climb up onto the mother's back; any which fall off before their first molt will not survive.

Some species of amblypygids, particularly Phrynus marginemaculatus and Damon diadema, may be among the few examples of arachnids that exhibit social behavior. Research conducted at Cornell University suggests that mother amblypygids communicate with their young with her antenniform front legs, and the offspring reciprocate both with their mother and siblings. The ultimate function of this social behavior remains unknown.[10] Amblypygids hold territories that they defend from other individuals.[11]

The amblypygid diet mostly consists of arthropod prey, but this opportunistic predator has also been observed feeding on vertebrates.[4] Amblypygids generally do not feed before, during, and after molting. Like other arachnids, an amblypygid will molt several times during its life.[4] Molting is done from hanging from the underside of a horizontal surface in order to use gravity to assist in separating the old exoskeleton from the animal.

As pets

Several species are sold and kept as pets including Damon diadema, Damon medius, Damon variegatus, Euphrynichus amanica, Heterophrynus batesii, Acanthophrynus coronatus, Phrynus marginemaculatus and Paraphrynus mexicanus.[12] Tailless Whip Scorpions are kept in tall (>18 inches), glass enclosures which allows for two things: Enough vertical space for climbing and moulting and allows for enough heat to dissipate in order to keep enclosure between 70°F and 75°F. Two inches of substrate is used at the bottom of the cage to allow for the opportunity to burrow and also serves as a method to retain water in order to keep the humidity above 75%. Tailless Whip Scorpions live anywhere between 5-10 years. Feeding can include small insects such as crickets, mealworms, and roaches.[13][14]

Genera

The following genera are recognised:[15][16]

Palaeoamblypygi Weygoldt, 1996
Paracharontidae Weygoldt, 1996
Euamblypygi Weygoldt, 1996
Charinidae Weygoldt, 1996
Neoamblypygi Weygoldt, 1996
Charontidae Simon, 1892
Unidistitarsata Engel & Grimaldi, 2014

family unspecified

  • Kronocharon Engel & Grimaldi, 2014 (1 species, Cretaceous)
Phrynoidea Blanchard, 1852
Phrynichidae Simon, 1900
Phrynidae Blanchard, 1852
incertae sedis
  • Sorellophrynus Harvey, 2002 (1 species, Upper Carboniferous)
  • Thelyphrynus Petrunkevich, 1913 (1 species, Upper Carboniferous)

References

  1. ^ Garwood, Russell J.; Dunlop, Jason A.; Knecht, Brian J.; Hegna, Thomas A. (2017). "The phylogeny of fossil whip spiders". BMC Evolutionary Biology. 17 (1): 105. doi:10.1186/s12862-017-0931-1. PMC 5399839. PMID 28431496.
  2. ^ "Pedipalpi". The international wildlife encyclopedia. 1 (3 ed.). Tarrytown, NY: Marshall Cavendish. 2002. p. 1906. ISBN 0-7614-7267-3. Retrieved 2011-10-29.
  3. ^ Takashima, Haruo (1950). "Notes on Amblypygi Found in Territories Adjacent to Japan". Pacific Science. 4 (4): 336–338. hdl:10125/9019. ISSN 0030-8870.
  4. ^ a b c d e Chapin, KJ; Hebets, EA (2016). "Behavioral ecology of amblypygids". Journal of Arachnology. 44 (1): 1–14. doi:10.1636/V15-62.1.
  5. ^ R. I. Pocok (1900). Fauna of British India. Arachnida.
  6. ^ Weygoldt, Peter (2000). Whip Spiders (Chelicerata: Amblypygi): Their Biology, Morphology and Systematics. ISBN 8788757463.
  7. ^ Robert D. Barnes (1982). Invertebrate Zoology. Philadelphia, PA: Holt-Saunders International. pp. 617–619. ISBN 0-03-056747-5.
  8. ^ Ladle, Richard J.; Velander, Kathryn (2003). "Fishing behavior in a giant whip spider". The Journal of Arachnology. 31: 154–156. doi:10.1636/0161-8202(2003)031[0154:FBIAGW]2.0.CO;2 – via ResearchGate.
  9. ^ Peter Weygoldt (1999). "Spermatophores and the evolution of female genitalia in whip spiders (Chelicerata, Amblypygi)" (PDF). Journal of Arachnology. 27 (1): 103–116. Archived from the original (PDF) on 2008-05-17.
  10. ^ Rayor, Linda (December 2017). "Social Behavior in Amblypygids, and a Reassessment of Arachnid Social Patterns". Journal of Arachnology. 31 (12): 399–421. doi:10.1636/S04-23.1.
  11. ^ Chapin KJ; Hill-Lindsay S (2015). "Territoriality evidenced by asymmetric intruder-holder motivation in an amblypygid". Behavioural Processes. 122: 110–115. doi:10.1016/j.beproc.2015.11.014.
  12. ^ "Tail-less Whip Scorpion - Damon medius". exotic-pets.co.uk. Retrieved 2019-07-13.
  13. ^ "Tailless Whip Scorpion Care Sheet". Reptile Centre. Retrieved December 27, 2019.
  14. ^ "Tailless Whip Scorpion: Facts, Lifespan, Care, Feeding, & Breeding". AllPetsDirectory. Retrieved 27 December 2019.
  15. ^ Mark S. Harvey (2003). "Order Amblypygi". Catalogue of the smaller arachnid orders of the world: Amblypygi, Uropygi, Schizomida, Palpigradi, Ricinulei and Solifugae. CSIRO Publishing. pp. 3–58. ISBN 978-0-643-06805-6.
  16. ^ Engel, M.S.; Grimaldi, D.A. (2014). "Whipspiders (Arachnida: Amblypygi) in amber from the Early Eocene and mid-Cretaceous, including maternal care". Novitates Paleoentomologicae. 9: 1–17.
  17. ^ Dunlop, J.A.; Zhou, G.R.S.; Braddy, S.J. (2007). "The affinities of the Carboniferous whip spider Graeophonus anglicus Pocock, 1911 (Arachnida:Amblypygi)". Earth and Environmental Science Transactions of the Royal Society of Edinburgh. 98 (2): 165–178. doi:10.1017/S1755691007006159.

"
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Amblypygi: Brief Summary

provided by wikipedia EN

Amblypygi is an ancient order of arachnid chelicerate arthropods also known as whip spiders and tailless whip scorpions (not to be confused with whip scorpions and vinegaroons that belong to the related order Thelyphonida). The name "amblypygid" means "blunt tail", a reference to a lack of the flagellum that is otherwise seen in whip scorpions. They are harmless to humans. Amblypygids possess no silk glands or venomous fangs. They rarely bite if threatened, but can grab fingers with their pedipalps, resulting in thorn-like puncture injuries.

As of 2016, 5 families, 17 genera and around 155 species had been discovered and described. They are found in tropical and subtropical regions worldwide; they are mainly found in warm and humid environments and like to stay protected and hidden within leaf litter, caves, or underneath bark. Some species are subterranean; all are nocturnal. Fossilized amblypygids have been found dating back to the Carboniferous period, such as Graeophonus.

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