Tentyria mucronata is a glossy black, ground-dwelling darkling beetle (family: Tenebrionidae) measuring 10 to 15 mm long. A specialist of Mediterranean coastal sand dunes, this robust insect thrives in bright sunshine from spring through autumn, frequently seen darting rapidly across open sand. As vital detritivores in a harsh ecosystem, adults feed on decaying plant and animal matter, while their cylindrical, yellowish larvae live underground, consuming organic debris and root material near dune grasses. I crossed paths with several of these fascinating, swift beetles navigating the sun-drenched sands of a beach on Ilha Deserta in Faro, Portugal.