''Ancylometes'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of Central and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

semiaquatic In biology, being semi-aquatic refers to various macroorganisms that live regularly in both aquatic and terrestrial environments. When referring to animals, the term describes those that actively spend part of their daily time in water (in ...

spider Spiders (order (biology), order Araneae) are air-breathing arthropods that have eight limbs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude spider silk, silk. They are the largest order of arachnids and ran ...

s first described by

Philipp Bertkau Philipp Bertkau (11 January 1849 – 22 October 1894) was a German zoologist born in Cologne. He studied natural sciences at the University of Bonn, where in 1872 he earned his doctorate. In 1873, he became an assistant at the botanical institute ...

in 1880. Originally placed with the nursery web spiders, it was moved to the

Ctenidae Wandering spiders (''Ctenidae'') are a family of spiders that includes the Brazilian wandering spiders. These spiders have a distinctive longitudinal groove on the top-rear of their oval carapace similar to those of the Amaurobiidae. They are h ...

in 1967 and in 2025 transferred to the new family Ancylometidae, of which it is the only member. The genus name is derived in part from

Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Greek ...

"" ('' ancylo-''), meaning "crooked, bent". These spiders live near ponds, lakes, rivers and other freshwater habitats, and can walk on water like

water striders The Gerridae are a family of insects in the order Hemiptera, commonly known as water striders, water skeeters, water scooters, water bugs, pond skaters, water skippers, water gliders, water skimmers or puddle flies. They are true bugs of the ...

due to fine air-trapping hairs on the tips of their legs. They can also dive under the surface, and can stay underwater for over an hour by using the air trapped in hairs surrounding their

book lung A book lung is a type of respiration organ used for atmospheric gas-exchange that is present in many arachnids, such as scorpions and spiders. Each of these organs is located inside an open, ventral-abdominal, air-filled cavity (atrium) and co ...

s. They will consume anything from insects to small lizards and, occasionally, small fish.

Description

Members of ''Ancylometes'' are among the largest araneomorph spiders, with a typical body length of . They are sometimes referred to as "giant fishing spiders" to distinguish them from ''

Dolomedes ''Dolomedes'' is a genus of large spiders of the family Dolomedidae. They are also known as fishing spiders, raft spiders, dock spiders or wharf spiders. Almost all ''Dolomedes'' species are semiaquatic, with the exception of the tree-dwelling ...

'', a genus of smaller spiders also called "fishing spiders". The largest species is ''A. rufus'', with females that grow to a body length of and a leg span of . Males of the species only grow up to in body length, but usually have longer legs than the females. Both sexes are brown with dark spots on the

abdomen The abdomen (colloquially called the gut, belly, tummy, midriff, tucky, or stomach) is the front part of the torso between the thorax (chest) and pelvis in humans and in other vertebrates. The area occupied by the abdomen is called the abdominal ...

, and males have two thin lines along their

carapace A carapace is a dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tortoises, the unde ...

. They have a 2-4-2 eye pattern and a reduced third claw, characteristics of the Ctenidae and Pisauridae, respectively. Members of this genus can be distinguished from all others by ventral spines found on the tarsi of the third and fourth legs. ''Ancylometes'' and the more fully aquatic '' Argyroneta'' are the only known genera of spiders that can spin webs in water. Though these webs can catch fish, they mostly prey on fish by diving down or lying in wait until prey passes within striking distance. Once caught, these spiders will bring their prey back to the surface before eating it. During mating, the male wraps the female with silk, and the female enters an immobile state. After about a week, she produces a cocoon and carries it with her fangs. After a month, she builds a nursery web above the ground, about in diameter. Over one hundred baby spiders will hatch inside this egg case, each only about long. The baby spiders take about a year to mature. Males only live for sixteen months at most, while females can live for more than two years. The venom of Acyclomete sp, has effects on muscle contraction and preparation of the phrenic nerve diaphragm muscle, 50 μg causes depolarization of the diaphragm muscle fiber membranes. These studies indicate that the Ancylometes venom activates

voltage-gated sodium channels Sodium channels are integral membrane proteins that form ion channels, conducting sodium ions (Na+) through a cell's membrane. They belong to the superfamily of cation channels. Classification They are classified into 2 types: Function In exc ...

. All of these effects of Ancylometes sp. venom on this nerve muscle preparation increase in twitch tension.

Species

, the

World Spider Catalog The World Spider Catalog (WSC) is an online searchable database concerned with spider taxonomy. It aims to list all accepted families, genera and species, as well as provide access to the related taxonomic literature. The WSC began as a series of ...

accepted eleven species: *'' Ancylometes amazonicus'' Simon, 1898 – Peru, Brazil *'' Ancylometes birabeni'' (Carcavallo & Martínez, 1961) – Argentina *'' Ancylometes bogotensis'' ( Keyserling, 1877) – Honduras to Bolivia *'' Ancylometes concolor'' (Perty, 1833) (

type Type may refer to: Science and technology Computing * Typing, producing text via a keyboard, typewriter, etc. * Data type, collection of values used for computations. * File type * TYPE (DOS command), a command to display contents of a file. * ...

) – Brazil, Bolivia, Paraguay, Argentina *'' Ancylometes hewitsoni'' ( F. O. Pickard-Cambridge, 1897) – Bolivia, Brazil *'' Ancylometes japura'' Höfer & Brescovit, 2000 – Brazil *'' Ancylometes jau'' Höfer & Brescovit, 2000 – Brazil *'' Ancylometes pantanal'' Höfer & Brescovit, 2000 – Brazil *'' Ancylometes riparius'' Höfer & Brescovit, 2000 – Brazil *''

Ancylometes rufus ''Ancylometes rufus'' is a species from the genus '' Ancylometes''. The species was originally described by Charles Athanase Walckenaer in 1837. It is typically found near water. It has been seen predating on frogs, '' Dendropsophus melanargy ...

'' (

Walckenaer Baron Charles Athanase Walckenaer (25 December 1771 – 28 April 1852) was a French civil servant, writer, man of letters, and scientist. He was a polymath and wrote extensively on geography, natural history, and literature. Major contributio ...

, 1837) – Northern South America *'' Ancylometes terrenus'' Höfer & Brescovit, 2000 – Brazil

References

External links

Website especially for the Genus ''Ancylometes'': www.ancylometes.com
{{Taxonbar, from=Q2846015 Spiders of South America Araneomorphae genera

Description

Species

References

Further reading

External links