New copepod species highlights fragile biodiversity in Bermuda’s caves

It is the only member of the Tetragoniceps genus living in caves and could represent an ancient, early-diverging member of its evolutionary lineage.

Bermuda’s Walsingham cave system harbors a wide diversity of cave-dwelling animals not found anywhere else in the world; now, one more joins their ranks as researchers of the University of Cambridge, the Bermuda Institute of Ocean Sciences and Senckenberg am Meer German Centre for Marine Biodiversity Research have discovered a new copepod species.

Three close-up views of a translucent shrimp-like creature, showcasing its segmented body and delicate antennae against a dark background.
Confocal laser scanning microscopy images of Tetragoniceps bermudensis.

Copepods are some of the most diverse of all crustaceans, found everywhere from freshwater ponds to the open ocean. These tiny organisms are some of the most abundant animals in the marine plankton, and an essential component of food webs worldwide. However, their huge diversity remains rather poorly known, particularly in challenging environments like subterranean caves.

The new Bermudian copepod, Tetragoniceps bermudensis, was first collected in 2016 by Sahar Khodami, Pedro Martinez Arbizu, and Leocadio Blanco-Bercial from the Bermuda Institute of Ocean Sciences and the Senckenberg am Meer German Centre for Marine Biodiversity Research, who ventured into Roadside Cave through a narrow passageway in Bermuda’s ancient limestone bedrock. However, it was only when researchers analysed it in detail, in 2024, that T. bermudensis was confirmed to be an entirely new species. Like other members of Bermuda’s cave fauna, Tetragoniceps bermudensis – named after the country where it was discovered – might represent an ancient, early-diverging member of its evolutionary lineage, the research team say. Together with other ancient crustaceans inhabiting the island’s caverns, it persisted in a secluded, delicate underground ecosystem relatively free from competitors and predators.

“The new species of copepod crustacean, Tetragoniceps bermudensis, is the first of its genus from Bermuda, as well as the first known cave-dwelling species of the genus anywhere in the world and only the second within its family, Tetragonicipitidae,” says lead author Giovanni Mussini of the University of Cambridge’s Department of Earth Sciences. “This finding from Roadside Cave adds to the great diversity of endemic crustaceans (and other cave fauna) found in the island’s network of limestone caves.”

The team during the sampling expedition to Roadside Cave in 2016.

The team only found one female egg-bearing individual at Roadside Cave, a small cavern in Bermuda. It is hard to estimate just how rare the new species is based on a single specimen, but the finding “suggests a correspondingly limited area and a probable endemic status, consistent with the high degree of endemism typical of Bermuda’s cave-dwelling fauna,” the researchers write in their paper in the journal ZooKeys.

Roadside Cave, where the new species was found, may face threats from “urban development, vandalism, dumping, littering and pollution, and sediment disturbance due to unlawful access by humans and domesticated animals,” which makes protecting this small creature all the more urgent. The researchers call for formal protection of the cave and for robust enforcement of existing measures to protect its precious fauna.

“The discovery of this species highlights that there remains a cryptic diversity of cave-dwelling species still to be discovered even in a densely populated island like Bermuda, whose hidden, underground biodiversity is all too often overlooked,” Mussini says in conclusion.

Research article:

Mussini G, Niimi YJ, Khodami S, Kihara TC, Martinez Arbizu P, Blanco-Bercial L (2025) A new species of Tetragoniceps Brady, 1880 (Copepoda, Harpacticoida, Tetragonicipitidae) from an anchialine cave in Bermuda, with an updated key to the species of the genus. ZooKeys 1239: 1-19. https://doi.org/10.3897/zookeys.1239.144436

New species of Brazilian copepod suggests ancient species diversification and distribution

A new species of groundwater copepod has been discovered in the rocky savannas of Brazil – an ecosystem suffering from heavy anthropogenic impact. Upon description, the tiny crustacean turned out to also represent a previously unknown genus. It is described by Dr. Paulo H. C. Corgosinho, Montes Claros State University, Brazil, and his team in the open access journal Zoosystematics and Evolution.

Prior to the discovery of the new species, named Eirinicaris antonioi, only one genus of its subfamily (Parastenocaridinae) had been recorded in the Neotropical region, which comes to show that related species had already spread across a huge range when the ancient supercontinent Gondwana split apart.

The new copepod measures about 0,300 mm and can be told apart by its morphological characteristics, including unusual sensorial structures at the rear part of the body, as well as unique sexual dimorphism.

The copepods of the family Parastenocarididae are adapted to life in groundwater, where they thrive between sand grains. These tiny creatures measure less than 1 mm, ranging between 0,200 and 0,400 mm in length. They can be found in various microbiotopes along rivers, lakes and human-made structures, such as dug or artesian wells. Alternatively, these copepods might be associated with mosses and other semi-terrestrial environments.

“This is the first species described from Goiás state, Central Brazil,” explain the authors. “With the discovery of this new species our knowledge about the geographical distribution of the copepod family Parastenocarididae is increased. Our project highlights the vast amounts of undiscovered biodiversity of the Brazilian rocky savannas, which are under high anthropogenic threat.”

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Original source:

Corgosinho PHC, Schizas NV, Previattelli D, Falavigna da Rocha CE, Santos-Silva EN (2017) A new genus of Parastenocarididae (Copepoda, Harpacticoida) from the Tocantins River basin (Goiás, Brazil), and a phylogenetic analysis of the Parastenocaridinae. Zoosystematics and Evolution 93(1): 167-187. https://doi.org/10.3897/zse.93.11602