clasper on:
[Wikipedia]
[Google]
[Amazon]
In 
Male cartilaginous fish have claspers formed from the posterior portion of their
In biology
Biology is the scientific study of life. It is a natural science with a broad scope but has several unifying themes that tie it together as a single, coherent field. For instance, all organisms are made up of cells that process hereditary ...
, a clasper is a male
Male (symbol: ♂) is the sex of an organism that produces the gamete (sex cell) known as sperm, which fuses with the larger female gamete, or ovum, in the process of fertilization.
A male organism cannot reproduce sexually without access t ...
anatomical structure found in some groups of animals, used in mating.
Male cartilaginous fish have claspers formed from the posterior portion of their pelvic fin
Pelvic fins or ventral fins are paired fins located on the ventral surface of fish. The paired pelvic fins are homologous to the hindlimbs of tetrapods.
Structure and function Structure
In actinopterygians, the pelvic fin consists of two en ...
which serve to channel semen
Semen, also known as seminal fluid, is an organic bodily fluid created to contain spermatozoa. It is secreted by the gonads (sexual glands) and other sexual organs of male or hermaphroditic animals and can fertilize the female ovum. Semen i ...
into the female's cloaca
In animal anatomy, a cloaca ( ), plural cloacae ( or ), is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles and birds, a ...
during mating. The act of mating in some fish including shark
Sharks are a group of elasmobranch fish characterized by a cartilaginous skeleton, five to seven gill slits on the sides of the head, and pectoral fins that are not fused to the head. Modern sharks are classified within the clade Selachimo ...
s usually includes one of the claspers raised to allow water into the siphon through a specific orifice
An orifice is any opening, mouth, hole or vent, as in a pipe, a plate, or a body
* Body orifice, any opening in the body of a human or animal
*Orifice plate, a restriction used to measure flow or to control pressure or flow, sometimes given speci ...
. The clasper is then inserted into the cloaca, where it opens like an umbrella to anchor its position. The siphon then begins to contract, expelling water and sperm. The claspers of many shark species have spines or hooks, which may hold them in place during copulation. Male chimaeras have cephalic claspers (tenacula) on their heads, which are thought to aid in holding the female during mating.
In entomology, it is a structure in male insects that is used to hold the female during copulation
Sexual intercourse (or coitus or copulation) is a sexual activity typically involving the insertion and thrusting of the penis into the vagina for sexual pleasure or reproduction.Sexual intercourse most commonly means penile–vaginal penetra ...
(see Lepidoptera genitalia
The study of the genitalia of Lepidoptera is important for Lepidoptera taxonomy in addition to development, anatomy and natural history. The genitalia are complex and provide the basis for species discrimination in most families and also in fa ...
for more).
See also
*Sexual coercion among animals
Sexual coercion among animals is the use of violence, threats, harassment, and other tactics to help them forcefully copulate.Smuts, Barbara BMale Aggression and Sexual Coercion of Females in Nonhuman Primates and Other Mammals: Evidence and The ...
References
{{reflist Fish anatomy Insect anatomy Animal reproductive system