Biology, distribution and conservation of a dwarf-group crayfish, Euastacus spinichelatus Morgan, 1997 (Decapoda: Astacidea: Parastacidae), a freshwater crayfish from the Great Dividing Range, New South Wales, Australia.

This article focuses on the biology, distribution, and conservation status of *Euastacus spinichelatus*, a small freshwater crayfish species endemic to high-altitude streams in the Murray-Darling Basin of Australia. Research from two major projects, the Australian Crayfish Project and the federally funded "Saving the Spinys" initiative, revealed significant population declines due to climate change, drought, bushfires, habitat loss, invasive species, and other anthropogenic pressures. Molecular analyses identified divergent lineages and refined the species’ range, which now includes the Namoi River headwaters but excludes some previously assumed tributaries. The species is classified as Endangered under the IUCN Red List and Australia’s Environment Protection and Biodiversity Conservation Act 1999, with urgent recommendations for monitoring, habitat restoration, genetic studies, and public education to support its recovery.