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.
After behavioral recording, we determined body length, body weight, and length of gonopodium on these fish.
Mating is accomplished solely by a gonopodial thrust, in which the male approaches the female, extends his gonopodium, and delivers sperm.
We therefore consulted the illustration of the fully developed gonopodium of P.
exposed to pulp and paper mill effluent, both in the field and in the laboratory, develop an elongated anal fin resembling the male gonopodium (12-15).
geiseri were counted (except at Comal River) and classified as male (presence of gonopodium; Pyke, 2005), female (presence of gravid spot; Peden, 1973), or immature (<10 mm; lack of gonopodium and gravid spot; Haynes and Cashner, 1995) before being released.
Within the Poeciliidae, at least three characters evolved to give rise to the present diversity within the family: (1) internal fertilization using a transformed anal fin, the gonopodium, for sperm transfer, (2) livebearing, and (3) different degrees of maternal provisioning for the developing young (Constantz 1989; Reznick & Miles 1989).
Subsequently, we assessed the effects of these three chemicals on the number of ejaculated sperm cells at the cellular level, body coloration, length of gonopodium (copulatory organ), and relative gonadal weight at the organ level, and finally courtship behavior at the organismal level.
The development of the gonopodium involves the lengthening and thickening of anal fin rays 3-5; the formation of a termination complex at the tip of the fin signals completion of development.
As males mature, the third, fourth, and fifth anal fin rays elongate to form the gonopodium on which distal armaments such as hooks, elbows and serrae develop (Rosen and Gordon, 1953; Chambers, 1987).