Gonopodium

Gonopodium in the Platy (Xiphophorus maculatus)

As a gonopodium (Greek gon "procreation" or gonos "birth", "ancestry" and podion "feet", a plurality of gonopods), one generally refers to a transformed limb which serves for copulation. The term is used both in various groups of arthropods (arthropoda), such as crustacea (Crustacea) and myriapoda, and in bone and cartilaginous fishes. In the arthropods, the gonopods are the converted first pair of legs of the hind (abdomen). Gonopods for bone fishing Edit the source text At the gonopodial point of the end of Guppy there are numerous hook-shaped forts

The gonopodium, or fillet of the fish, is an organ consisting of the transformed rays of the anal fin (anal). With this organ the fertilization of the germ cells in the body of the female and thus the live birthing is possible. This can be found in the case of a living-tooth tooth carp. The gonopodium ends in most species with a more or less distinct hook or claw.

In other species analogous organs with the same function are found, as, for example, the andropodium in the half-billed hay (Hemirhamphodon) or the highland killer (Goodeidae).

In mating, the male introduces the gonopodium shortly into the sexual opening of the female. With the hook or the claw, it can be better held during the transfer of the sperm, in order to increase the fertilization success. Nevertheless, only one out of ten attempts at conquest is successful.

wiki