Dianthropy is the property of a star system in Xenothropology where two sentient species emerge in the same star system. It is also often used as a general term to describe instances where more than two occur. Correct terms may be used instead, such as Trianthropic, Quadanthropic, and so on.
There are two main forms of Dianthropy; Xenodianthropic and Monodianthropic.
Xenodianthropic Systems Edit
Xenodianthropy occurs when a system has two planets which have each evolved separate sentient life. Because of the often narrow band of the Habitable Zone of a star, this form is relatively rare. However, while it is less common than Monodianthropy, this form is more likely to be peaceful and thus more examples of it continue to exist to the present.
Monodianthropic Systems Edit
Monodianthropy is where a single planet in the system has produced two sentient species. In the vast majority of cases, monodianthropic species are hostile toward each other due to competing at a pre-civilised level of development. As such, extinction often occurs to one of the two species, making this form of dianthropy rarely observed.