Fig. 1: Morphological and ecological diversity of Niphargus species.

Adaptive radiation of Niphargus produced several morphotypes that inhabit distinct subterranean habitats and niches. Different-sized morphotypes can occur together in cave lakes, and differently shaped morphotypes can occur together in interstitial habitats¹⁷. These morphotypes evolved in at least five adaptive radiation events from hypothetical small-bodied ancestors from the shallow interstitial habitat^20,23. Appendages are abbreviated as app. Photographs used with author’s permission: Denis Copilaş-Ciocianu (shallow subterranean), Teo Delić (all others).