Scientific name: Caecocypris basimi
Range: A subterranean system in a sinkhole at the Sheik Hadid shrine, near Haditha, Iraq.
When last seen: 1983
Suspected reason for disappearance: Water abstraction from the well itself has lowered the groundwater level, which appears to be a major threat. It is also thought that reduced groundwater levels due to water abstraction and hydrological modifications caused by the construction of a large dam near the Euphrates may have negatively impacted the site.
IUCN conservation status: Critically Endangered
Facts: The subterranean system where the species has previously been recorded is accessed via a well approximately five meters below the shrine. A comprehensive survey of the site in 2012 did not find the species.
Size: The holotype is a mature female at 49mm.