A forgotten rodent from the Garden of Eden: what really happened to the long-tailed nesokia rat in the Mesopotamian marshes?

The greater part of expected mammalian extinctions will be of smaller-bodied mammals, including rats which are more generally known only as pests and carriers of pathogens. We address the long-tailed nesokia rat, which is among the least studied Palaearctic mammals. The species is known from merely five specimens, collected between March 1974 and January 1977 within a radius of 30 km around Qurna inside the seasonally flooded Mesopotamian marshes in southern Iraq. In the 1990s, this extensive aquatic habitat has been deliberately reduced to <15% of its original area and the IUCN expressed fear that such a disaster “almost certainly” caused the extinction of the long-tailed nesokia. Although the interventions after 2003 reversed the shrinking trend and marshes started to expand, the continuous presence of the long-tailed nesokia could not be unambiguously confirmed. We provide meagre evidence suggesting that the rat might be still present in the marshes. Next, our habitat modelling shows that the area of the long-tailed nesokia might be more extensive than expected with a highly suitable habitat covering 15,650 km2 of Mesopotamian marshland in Iraq (between Basra and Salah Ad Din provinces) and the Hawizeh Marshes in the adjacent Iranian Khuzestan.