Vandellia
Encyclopedia
Vandellia is a genus
of catfish
es (order
Siluriformes) of the family
Trichomycteridae
. It includes three species, V. beccarii, V. cirrhosa, and V. sanguinea. Vandellia is the most well-known genus of parasitic catfishes also known as candiru
, known for their alleged habit of entering the human urethra
.
River basin and rivers of Guyana
. V. cirrhosa is distributed in the Amazon River
basin. V. sanguinea inhabits the Amazon, Orinoco, and Essequibo
River basins.
and the anal fin and converging onto the caudal fin. V. sanguinea may grow to 5.3 centimetre
s (2.1 in
) SL
. V. cirrhosa grows up to 17.0 cm (6.7 in) SL.
(consume blood) parasites, like all other members of the subfamily Vandelliinae
. V. cirrhosa uses visual and chemo-sensory orientation to find potential hosts
. 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
arteries, and the blood is pumped into its gut by the host's blood pressure
; 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
s. Some host fish species (Colossoma macropomum) are able to hamper the attacks of V. cirrhosa by pressing the fish under the membranous gill-cover flap, or by using its pectoral fin to press it against the flank or to sweep it from the gill-cover edge. V. cirrhosa has been known to enter the urethra
of humans urinating under water; presumably it mistakes the urea for water exhausted from gills.
When inactive, V. cirrhosa burrows in sandy or soft, muddy bottoms. V. beccarii has been captured free-swimming.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of catfish
Catfish
Catfishes 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 heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...
es (order
Order (biology)
In scientific classification used in biology, the order is# a taxonomic rank used in the classification of organisms. Other well-known ranks are life, domain, kingdom, phylum, class, family, genus, and species, with order fitting in between class and family...
Siluriformes) of the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Trichomycteridae
Trichomycteridae
Trichomycteridae is a family of catfishes commonly known as the pencil or parasitic catfishes. This family includes the infamous candiru fish, feared by some people for its alleged habit of entering into the urethra of humans....
. It includes three species, V. beccarii, V. cirrhosa, and V. sanguinea. Vandellia is the most well-known genus of parasitic catfishes also known as candiru
Candirú
Candiru or candirú , also known as cañero, toothpick fish, or vampire fish, are a number of genera of parasitic freshwater catfish in the family Trichomycteridae; all are native to the Amazon River...
, known for their alleged habit of entering the human urethra
Urethra
In anatomy, the urethra is a tube that connects the urinary bladder to the genitals for the removal of fluids out of the body. In males, the urethra travels through the penis, and carries semen as well as urine...
.
Distribution
V. beccarii originates from the OrinocoOrinoco
The Orinoco is one of the longest rivers in South America at . Its drainage basin, sometimes called the Orinoquia, covers , with 76.3% of it in Venezuela and the remainder in Colombia...
River basin and rivers of Guyana
Guyana
Guyana , officially the Co-operative Republic of Guyana, previously the colony of British Guiana, is a sovereign state on the northern coast of South America that is culturally part of the Anglophone Caribbean. Guyana was a former colony of the Dutch and of the British...
. V. cirrhosa is distributed in the Amazon River
Amazon River
The Amazon of South America is the second longest river in the world and by far the largest by waterflow with an average discharge greater than the next seven largest rivers combined...
basin. V. sanguinea inhabits the Amazon, Orinoco, and Essequibo
Essequibo
Essequibo may refer to:* The Essequibo River is one of the larger South American rivers located in the country of Guyana.* The former Dutch colony of Essequibo, in the region of the river...
River basins.
Description
V. beccarii can be distinguished from other vandelliines by its square or slightly emarginate caudal fin and the colour pattern of two dark bands extending from the dorsal finDorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...
and the anal fin and converging onto the caudal fin. V. sanguinea may grow to 5.3 centimetre
Centimetre
A centimetre is a unit of length in the metric system, equal to one hundredth of a metre, which is the SI base unit of length. Centi is the SI prefix for a factor of . Hence a centimetre can be written as or — meaning or respectively...
s (2.1 in
Inch
An inch is the name of a unit of length in a number of different systems, including Imperial units, and United States customary units. There are 36 inches in a yard and 12 inches in a foot...
) SL
Fish measurement
Fish measurement refers to the measuring of the length of individual fish and of various parts of their anatomy. These data are used in many areas of ichthyology, including taxonomy and fisheries biology.-Overall length:...
. V. cirrhosa grows up to 17.0 cm (6.7 in) SL.
Ecology
These species are hematophagousHematophagy
Hematophagy is the practice of certain animals of feeding on blood...
(consume blood) parasites, like all other members of the subfamily Vandelliinae
Vandelliinae
The Vandelliinae are a subfamily of catfishes of the family Trichomycteridae. Vandelliines are hematophagous, feeding on the blood of larger fish...
. V. cirrhosa uses visual and chemo-sensory orientation to find potential hosts
Host (biology)
In biology, a host is an organism that harbors a parasite, or a mutual or commensal symbiont, typically providing nourishment and shelter. In botany, a host plant is one that supplies food resources and substrate for certain insects or other fauna...
. 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
Aorta
The aorta is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it branches off into two smaller arteries...
arteries, and the blood is pumped into its gut by the host's blood pressure
Blood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
; 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
Second
The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....
s. Some host fish species (Colossoma macropomum) are able to hamper the attacks of V. cirrhosa by pressing the fish under the membranous gill-cover flap, or by using its pectoral fin to press it against the flank or to sweep it from the gill-cover edge. V. cirrhosa has been known to enter the urethra
Urethra
In anatomy, the urethra is a tube that connects the urinary bladder to the genitals for the removal of fluids out of the body. In males, the urethra travels through the penis, and carries semen as well as urine...
of humans urinating under water; presumably it mistakes the urea for water exhausted from gills.
When inactive, V. cirrhosa burrows in sandy or soft, muddy bottoms. V. beccarii has been captured free-swimming.