Guppy
Poecilia reticulata
3.8 mm
Gonopodium length (modified anal fin), base of gonopodium to distal tip, excluding the hood; measured from photographs of the left side of live-collected adult males (least-squares mean adjusted for body length; SE 0.009 mm)
The male guppy's 'penis' is a remodelled anal fin, the gonopodium. To mate, he moves it out of its resting position and inserts the tip into the female's genital pore.
Margin note: Filed under fins, for administrative purposes.
Sources
- de Lira J.J.P.R., Yue Y., Levasseur S., Kelly C.D., Hendry A.P. (2021) The complex ecology of genitalia: Gonopodium length and allometry in the Trinidadian guppy. Ecology and Evolution 11(9):4564–4576 doi:10.1002/ece3.7351
Drawn from
- de Lira et al. 2021, Fig. 1 (adult): Lateral line drawing of an adult male guppy with the gonopodium hanging below the belly and the hood beside it; used for gonopodium length:width and placement on the body