Fish
Poecilia formosa
The Amazon molly (Poecilia formosa) is a natural hybrid of the Atlantic molly (P. mexicana) and the sailfin molly (P. latipinna) and was the first unisexual vertebrate detected. The hybrid origin was later confirmed using molecular methods, and currently P. mexicana is considered to be the maternal ancestor and P. latipinna the paternal ancestor. Amazon mollies depend on sperm from males of their ancestors (P. mexicana and P. latipinna), but P. formosa females typically produce unreduced eggs, are fully clonal, and use sperm only to trigger embryogenesis (gynogenesis). Amazon mollies occur in sympatry with one of their ancestors and the current limit of their distribution is in the lower Rio Grande valley and the Nueces River in Texas, USA and south along the Gulf coast of Mexico to the Rio Tuxpan.
