gonopodium


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gonopodium

(gŏn′ə-pō′dē-əm)
n. pl. gono·podia (-pō′dē-ə)
The modified anal fin of the male of certain fishes, such as guppies, used to transfer sperm into the female.
References in periodicals archive ?
To estimate male size at maturity, we examined the development of the gonopodium.
The gonopodium was swung forward and the fish was stripped by gently stroking the abdomen with a tiny metal rod toward the gonopodium, hereby evacuating an ejaculate on a glass plate.
Mating is accomplished solely by a gonopodial thrust, in which the male approaches the female, extends his gonopodium, and delivers sperm.
Males from these populations differ in both size-specific behavioral rates (Ptacek and Travis 1996) and size-specific morphometry, particularly in the dimensions of the dorsal fin and gonopodium (Travis, Ptacek, and Martin, unpubl.
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 in males, the gonopodium, for sperm transfer, (2) livebearing, and (3) different degrees of maternal provisioning for the developing young (Constantz 1989; Reznick & Miles 1989).
Spermatozeugmata (mature sperm bundles) came out at the base of the gonopodium and were collected by using an aspirator.
Separation between juveniles and adults for both species were according to Aranha and Caramaschi (1999) who stated that specimens lower than 20 mm TL that did not show indication of gonopodium development or reproductive activity were assigned as juveniles.
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).
Sexual maturity in males was based on the elongation of the anal fin into the gonopodium, and was determined in accordance with the descriptions of Turner (1941).
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).