gonopodium


Also found in: Dictionary, Medical, Wikipedia.

gonopodium

[‚gän·ə′pōd·ē·əm]
(vertebrate zoology)
Anal fin modified as a copulatory organ in certain fishes.
Mentioned in ?
References in periodicals archive ?
vittata exhibit the most distinct and differentiated genitalia of all Gambusia species (similar to the male gonopodium of G.
The researchers tested two ideas for the function of the claws - one for their role in securing sperm in place at the tip of the gonopodium just before it is inserted into the female, the other for grasping unreceptive or resistant females during mating to aid in sperm transfer.
circled around a female and performed a swinging movement of their gonopodium directly in front of a female.
gracilis is a dimorphic species with marked secondary sexual differences in size and the presence of a gonopodium in males, a characteristic shared by all poeciliids (Rodriguez 1977).
After behavioral recording, we determined body length, body weight, and length of gonopodium on these fish.
Mating occurs when the male swims up to the female from behind, swings his gonopodium down and onto the female's egg spot, and delivers sperm.
In mosquitofish, once the testes mature, a male's testosterone production soars, a gonopodium develops, and then growth ceases.
Males mature at larger body size (10-14 mm), take longer to mature (40-50 d), and maturity is indicated by development of the gonopodium, a modified anal fin used for sperm transfer (Constanz 1989).
Gonopodial thrusting is an attempt at forced insemination without female cooperation; a male orients himself behind a female, brings his gonopodium to a forward position, and attempts to insert it forcefully into the female's gonopore.
The structure of the gonopodium of 10 mature males examined matches the description by Rosen (1960), and most specimens display diagnostic characters mentioned by Miller et al.
Having four hooks on the gonopodium may provide a means of overcoming female resistance, latching on to the gonopore and transferring sperm in a manner that facilitates effective sperm transfer.
frenatus, the only ways to determine the sex of an individual were to observe the gonopodium on the anterior portion of the anal fin, which was often difficult to see due to light conditions or viewing angle, or to observe the fish in a mating or agonistic interaction.