Rare Deep-Sea “Ghost Shark” Surfaces Off Costa Rica—See the Eerie Footage Now

A team of Costa Rican and Brazilian marine biologists has confirmed the first-ever sighting of Rhinochimaera costaricana, a deep-sea “ghost shark” pulled from 390–787 m below the Pacific off Puntarenas. The paddle-snouted chimaera—dark brown with near-black fins—was described on 10 June in the journal Zootaxa after DNA sequencing showed up to 4.7 % divergence from its closest relatives, sealing its status as a new species. Lead author Naidely Valeria Vidaurre Quesada, an undergraduate at the University of Costa Rica (UCR), examined three male specimens—one collected near Isla del Caño in 2000 and two netted during Incopesca surveys in 2023. With support from the Deep Ocean Alliance, she compared the finds against historic specimens at London’s Natural History Museum to rule out misidentification. Ghost sharks (order Chimaeriformes) split from true sharks more than 400 million years ago, and their cartilaginous skeletons rarely survive trawling. The discovery of R. costaricana expands the once three-member Rhinochimaera genus—R. africana, R. atlantica and R. pacifica—to four, underscoring how little scientists know about Costa Rica’s abyssal slopes. Researchers say the elongated first-dorsal spine, widely spaced fins and reduced tail tubercles may be adaptations to life in oxygen-poor trenches, where temperatures can plunge below 4 °C. Because deep-sea chimaeras produce few, large eggs and mature slowly, even limited by-catch threatens population viability. The study’s authors urge fisheries managers to tag ghost-shark hot spots along the continental shelf and to add R. costaricana to Costa Rica’s National System of Conservation Areas (SINAC) priority list. Further remotely operated vehicle (ROV) surveys are planned for late 2026 to locate breeding grounds and potential females. For eco-tourism operators marketing “blue-planet” expeditions, the find cements Costa Rica’s reputation as a global biodiversity engine—proving there are still secrets lurking in the deep that can bolster both science and sustainable economic growth.