''Vandellia'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

catfish Catfish (or catfishes; order Siluriformes or Nematognathi) are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the three largest species alive, ...

es native to

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. The species in this genus are the most well-known of the

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has c ...

catfishes also known as candiru, known for their alleged habit of entering the human

urethra The urethra (from Greek οὐρήθρα – ''ourḗthrā'') is a tube that connects the urinary bladder to the urinary meatus for the removal of urine from the body of both females and males. In human females and other primates, the urethra con ...

Species

There are currently three recognized species in this genus: * '' Vandellia beccarii'' di Caporiacco, 1935 * '' Vandellia cirrhosa''

Valenciennes Valenciennes (, also , , ; nl, label=also Dutch, Valencijn; pcd, Valincyinnes or ; la, Valentianae) is a commune in the Nord department, Hauts-de-France, France. It lies on the Scheldt () river. Although the city and region experienced a s ...

, 1846 (Candiru) * '' Vandellia sanguinea''

Eigenmann Eigenmann is a surname. Notable persons with that surname include: * Andi Eigenmann (born 1990), Filipino actress * Carl H. Eigenmann (1863–1927), German–American ichthyologist, husband of Rosa Eigenmann * Eduardo de Mesa Eigenmann, birth name ...

, 1917

Distribution

''V. beccarii'' originates from the

Orinoco The Orinoco () is one of the longest rivers in South America at . Its drainage basin, sometimes known as the Orinoquia, covers , with 76.3 percent of it in Venezuela and the remainder in Colombia. It is the fourth largest river in the wor ...

River basin and rivers of

The Guianas The Guianas, sometimes called by the Spanish loan-word ''Guayanas'' (''Las Guayanas''), is a region in north-eastern South America which includes the following three territories: * French Guiana, an overseas department and region of France * ...

. ''V. cirrhosa'' is distributed in the

Amazon Basin The Amazon basin is the part of South America drained by the Amazon River and its tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries of Bolivi ...

. ''V. sanguinea'' inhabits the Amazon, Orinoco, and

Essequibo River The Essequibo River (Spanish: ''Río Esequibo'' originally called by Alonso de Ojeda ''Río Dulce'') is the largest river in Guyana, and the largest river between the Orinoco and Amazon. Rising in the Acarai Mountains near the Brazil–Guyana bor ...

basins.

Description

''V. beccarii'' can be distinguished from other vandelliines by its square or slightly

emarginate The following is a list of terms which are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (a single leaf blade or lamina) or compound (with several leaflets). The edge of the leaf may be regular o ...

caudal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

and the colour pattern of two dark bands extending from the

dorsal fin A dorsal fin is a fin located on the back of most marine and freshwater vertebrates within various taxa of the animal kingdom. Many species of animals possessing dorsal fins are not particularly closely related to each other, though through conv ...

and the

anal fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as se ...

and converging onto the caudal fin. ''V. sanguinea'' may grow to 5.3

centimetre 330px, Different lengths as in respect to the Electromagnetic spectrum, measured by the Metre and its deriveds scales. The Microwave are in-between 1 meter to 1 millimeter. A centimetre (international spelling) or centimeter (American spellin ...

s (2.1 in) SL. ''V. cirrhosa'' grows up to SL.

Ecology

These species are

hematophagous Hematophagy (sometimes spelled haematophagy or hematophagia) is the practice by certain animals of feeding on blood (from the Greek words αἷμα ' "blood" and φαγεῖν ' "to eat"). Since blood is a fluid tissue rich in nutritious pro ...

(blood-consuming)

parasite Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has ...

s, like all other members of the subfamily

Vandelliinae The Vandelliinae are a subfamily of catfishes (order Siluriformes) of the family Trichomycteridae. Vandelliines are hematophagous, feeding on the blood of larger fish. Members of this subfamily may be known as candirú, notorious for occasionall ...

. ''V. cirrhosa'' uses visual and chemo-sensory orientation to find potential

hosts A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places *Host, Pennsylvania, a village in Berks County People *Jim Host (born 1937), American businessman *Michel Host ( ...

. It is active both during the daytime and nighttime while foraging. ''V. cirrhosa'' enters the gill chambers of larger fish to suck blood. It bites mostly at the ventral or dorsal

aorta The aorta ( ) is the main and largest artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries (the common iliac arteries). The aorta distributes ...

arteries, and the blood is pumped into its gut by the host's

blood pressure Blood pressure (BP) is the pressure of circulating blood against the walls of blood vessels. Most of this pressure results from the heart pumping blood through the circulatory system. When used without qualification, the term "blood pressure" r ...

; it does not need any special sucking or pumping mechanism to quickly engorge itself with blood, but simply uses its needle-like teeth to make an incision in an artery. ''V. cirrhosa'' is able to engorge itself enormously; the ingested blood is visible through the swollen belly. Some kind of valve or sphincter is likely present to prevent reflux of ingested blood. The time required to engorge itself with blood and leave the host's gill chamber ranges from 30–145

second The second (symbol: s) is the unit of time in the International System of Units (SI), historically defined as of a day – this factor derived from the division of the day first into 24 hours, then to 60 minutes and finally to 60 seconds ...

s. Some host fish species (''

Colossoma macropomum The tambaqui (''Colossoma macropomum'') is a large species of freshwater fish in the family Serrasalmidae. It is native to tropical South America, but kept in aquaculture and introduced elsewhere. It is also known by the names black pacu, black- ...

'') are able to hamper the attacks of ''V. cirrhosa'' by pressing the fish under the bony gill-cover flap, or by using its

pectoral fin Fins are distinctive anatomical features composed of bony spines or rays protruding from the body of a fish. They are covered with skin and joined together either in a webbed fashion, as seen in most bony fish, or similar to a flipper, as ...

to press it against the flank or to sweep it from the gill-cover edge. ''V. cirrhosa'' is reputed to be able to enter the

of humans urinating under water; presumably it mistakes the urea for water exhausted from gills, however this has never been clinically proven. When inactive, ''V. cirrhosa'' burrows in sandy or soft, muddy bottoms. ''V. beccarii'' has been captured free-swimming.

References

{{Taxonbar, from=Q267766 Trichomycteridae Catfish genera Freshwater fish genera Catfish of South America Fish of the Amazon basin Taxa named by Achille Valenciennes