Rare shrimp resurfaces in Benghazi’s caves
LIBYA – A scientific report published by the British website Bioengineer has revealed the rediscovery of a blind cave shrimp, known scientifically as Typhlocaris lethaea, in the groundwater beneath the city of Benghazi after nearly a century in which its presence went undocumented — a find that sheds light on the hidden biodiversity beneath the city.
The report — followed and summarised by Al-Marsad — said scientists had confirmed that the pale, eyeless shrimp, which was seen in Lethe Cave in 1920, still survives despite earlier fears that it had died out altogether, after it reappeared in unexpected locations.
It said field surveys carried out in 2023 and 2024 recorded the species in two caves in the Al-Kuwayfiyah area, extending its known range by 9 kilometres and showing that the groundwater network beneath the Benghazi plain is more interconnected and biologically richer than previously thought.
From a 1920 discovery to fears of extinction
According to the report, the story of Typhlocaris lethaea began with a chance observation by a man named Vito Zanon, who noticed decapod crustaceans in the cave, also known as “Al-Jakh Al-Kabir”, and sent specimens to the Italian zoologist Bruno Parisi, who attributed them to a species called Typhlocaris galilea.
The report added that this species is found near the Tabgha spring by Lake Tiberias in the eastern Mediterranean. A specimen was then sent to the Scottish zoologist William Thomas Calman at the British Museum, where a careful comparison with the original specimen showed that the Libyan species was different.
Parisi formally described the Libyan species in 1920 as Typhlocaris lethaea, the report said, after which it suddenly disappeared from view: the species was never mentioned again in the scientific literature, and a recent molecular review of the entire genus failed to turn up a single specimen.
The report noted that the International Union for Conservation of Nature (IUCN) lists the Libyan species as data deficient, leaving open the worrying possibility that it had already become extinct, and pointed out that the Typhlocaris genus itself is one of the most mysterious lineages of subterranean crustaceans in the Mediterranean region.
Traits of a rare Mediterranean species
The report said all known species of these organisms, adapted exclusively to life in the total darkness of classic groundwater habitats, are completely eyeless and carry no body pigment, and are distinguished by a longitudinal suture behind the antennae that runs along the sides of the carapace.
It added that this structural feature helps taxonomists tell them apart from other decapod crustaceans, stressing that only four valid species are known, all of them found exclusively around the Mediterranean, with none in the open sea.
Typhlocaris lethaea is the only species known from the southern shore of the Mediterranean, the report said, making it unique as an endemic of Benghazi’s caves, and its rediscovery owes much to cave explorations carried out in 2007 and 2009 by an Italian research team.
Cave exploration and the University of Benghazi’s role
The report added that the University of Benghazi’s Department of Earth Sciences worked with the Italian team. The cave forms part of a chain of collapse sinkholes aligned from north-east to south-west and divides into two main branches, and during the first exploration in January 2007 several crustaceans believed likely to be Typhlocaris lethaea were found.
According to the report, the crustaceans were seen resting on the sandy, muddy bed of the first branch of an underground lake fed by a saline aquifer. They had settled in dark areas a few metres from the landing platform, and the exceptional clarity of the water allowed the team to photograph one of them.
This, the report said, provided the first visual evidence in decades that the species still survived. The decisive breakthrough came in 2023, when researchers turned their attention to the Al-Kuwayfiyah area north-east of Benghazi, a semi-urban area of nearly 835 square kilometres that is full of karst features.
Al-Kuwayfiyah finds and specimen records
The report said these features include caves and collapse sinkholes of various sizes linked to complex underground drainage networks carved into the carbonate rocks of the Benghazi Formation. In July 2023, it said, the team explored Al-Khadim Cave, about 15 kilometres north-east of Benghazi at an altitude of 21 metres.
There, the report added, the research team found Typhlocaris lethaea resting on a muddy rock surface just a few centimetres from the water — the first such find in more than 100 years, and from an entirely different cave system — while the explorers noticed something else during the same visit.
A completely white louse-like creature no more than a few millimetres long was observed, the report said, pointing to a hidden community of unpigmented subterranean organisms still awaiting documentation. In October 2023, it said, another Typhlocaris lethaea specimen was sighted on the muddy floor of a cave in the Al-Kuwayfiyah area.
According to the report, researchers from the University of Benghazi’s zoology and earth sciences departments returned on 7 December 2024 to confirm these sightings and provide physical evidence, collecting two specimens with a dip net from the surface of the first underground lake, preserving them in a 96% ethanol solution and taking them to the Department of Zoology for further study.
Both specimens turned out to be female, each 5 centimetres long, the report said. The team also measured the physical conditions of the habitat, recording an average water temperature of 22C, an average air temperature of 21C, an average pH of 7.67 and an average salinity of 4.72 parts per thousand.
The report added that this slightly saline chemical make-up is consistent with an aquifer feeding these underground lakes, and that all the shrimp sightings were in parts of the caves in total darkness, mirroring the conditions described in Parisi’s original discovery.
The groundwater network and its hidden links
The report said this consistency across sites separated by nearly a century and 9 kilometres carried real biological significance, as the new records extend the species’ range by the same distance north of the original site at Bu Atni to the Al-Kuwayfiyah area, just 4 kilometres south-west of the Mediterranean coast.
Besides confirming that the shrimp still survives in Lethe Cave, the report said, the findings showed that it is widespread throughout the groundwater of the Benghazi plain rather than clinging on in a single fragile pool, with the researchers pointing to a likely abundance of these organisms, at least in the Al-Kuwayfiyah cave systems.
The report added that the expansion of its known range changes its apparent risk of extinction by adding new sites, noting that the most intriguing findings concern hydrology: the presence of the same groundwater-dwelling shrimp in the Lethe caves in the Bu Atni area and in Al-Khadim Cave and others in Al-Kuwayfiyah points to something important.
That, the report said, is that the underground water systems are somehow connected, since species living in these waters simply cannot cross the land between them. The researchers stressed the need to use cave-biology methods to analyse the DNA of these groundwater-dwelling animals and identify the biogeographical links between underground watercourses.
According to the report, the researchers also stressed the importance of using conventional hydrogeological techniques to map these hidden channels, and suggested that this approach could be applied in future research not only to Typhlocaris lethaea but also to other animals that may be spread through the area’s underground waterways.
Pollution risks and the need for protection
The report added that this shows the shrimp itself is a living indicator of the structure of the aquifer, while environmental concerns cast a shadow over the discovery: shrimp species of the Typhlocaris genus are classified as endangered and appear on the IUCN Red List.
This, the report said, has not prevented caves where these species live from being left without legal protection. Some have already been affected by human activity and face high levels of groundwater pumping and pollution — pressures that could lead to a rapid deterioration of the aquifers on which the species depends.
The report said the researchers stressed the need to involve local stakeholders in efforts to conserve these unique cave ecosystems and their biological communities, as the greatest threat to a species that survived a century of disappearance in the dark waters beneath Benghazi may not be disappearance, but the growing human footprint above it.
The report concluded that Typhlocaris lethaea offers both a warning and a rare second chance to protect Libya’s hidden subterranean heritage.
