Far below the surface of Costa Rica’s Pacific coast, where sunlight disappears and fishing grounds give way to deep water, three unusual fish specimens had been sitting in scientific collections for years. They would eventually become the basis for describing a species unknown to science. At the centre of that work was Naidely Valeria Vidaurre-Quesada, a biology student at the University of Costa Rica who became the lead author of the study. The fish belonged to the chimaera family, a little-known group of cartilaginous animals related to sharks and rays and often called ghost sharks. The species, named Rhinochimaera costaricana, was formally described in Zootaxa on June 10, 2026.
Costa Rica’s deep waters held clues to a new ghost shark species
According to the study published in Zootaxa, titled, ‘A new species of Rhinochimaera Garman 1901 (Holocephali: Chimaeriformes: Rhinochimaeridae) from the Eastern Pacific Ocean’ reveals the first of the three specimens was collected in 2000 near Isla del Caño. Two more were recovered much later, in 2023, during fisheries research off Cabo Blanco in Puntarenas. All three were male, measuring between 775 and 830 millimetres long. Their habitat was far removed from the familiar coastal waters of Costa Rica. The specimens came from depths between 390 and 787 metres, placing them in a part of the Pacific that remains difficult to study directly. For years, individual specimens can exist in collections without their significance being fully understood. In this case, bringing the material together allowed Vidaurre-Quesada and her colleagues to examine whether the fish represented a known species or something that had escaped scientific recognition.
Naidely Vidaurre-Quesada: The scientist behind a new ghost shark discovery
Naidely Valeria Vidaurre-Quesada is a biology student and researcher at the University of Costa Rica. She was the lead author of the scientific study that formally described Rhinochimaera costaricana, a previously unrecognised deep-sea ghost shark from Costa Rica’s Pacific waters. As reported by The Costa Rican News ,as part of the research, she travelled to the Natural History Museum in London, where she examined older specimens and records of the Rhinochimaera genus. This helped the team determine that the Costa Rican specimens were distinct from the three species already known. Her work shows how museum collections, fisheries research and modern genetic analysis can come together to reveal species that have remained scientifically overlooked for years.
DNA evidence revealed the fish was unlike the three known species
The Rhinochimaera genus already contained three recognised species: R. africana, R. atlantica and R. pacifica. Establishing a fourth required the Costa Rican specimens to be compared with those existing species. DNA sequences provided another line of evidence. The specimens showed genetic differences of 3.9% from R. africana, 4.5% from R. atlantica and 4.7% from R. pacifica. Taken alongside the anatomical characteristics, those differences supported the conclusion that the Costa Rican fish was not simply a regional form of one of the existing species. The scientific name reflects its origin. Rhinochimaera costaricana places the animal within its genus while identifying Costa Rica in its species name.
Old museum specimens helped Vidaurre-Quesada confirm a new species
Museum collections can provide a useful second look at discoveries like this. A specimen that appears unusual in one collection may turn out to resemble an animal preserved decades earlier somewhere else. Comparing historical material helps researchers avoid giving a new name to something that has already been documented. In Vidaurre-Quesada's case, the work helped establish that the Costa Rican specimens represented a species distinct from the three Rhinochimaera species already recognised.
How fisheries research helped uncover the shark
The discovery also says something about where scientific knowledge can come from. Two of the specimens were obtained during fisheries research rather than a dedicated search for a previously unknown chimaera. That connection between fisheries work and zoological collections gave researchers access to animals from depths that are difficult to reach and observe routinely. Once transferred to the UCR Museum of Zoology, the specimens could be examined, compared and preserved for future work. The collaboration stretched beyond Costa Rica as well. The UCR and Incopesca worked with researchers at the Federal University of Pará in Brazil, while the examination of historical material took Vidaurre-Quesada to the Natural History Museum in London.
