German paleontologist Dolf Seilacher had not yet won his Crafoord—the prestigious honor awarded by the same Swedish academy that gives out the Nobel Prize—when he was collecting specimens in Puerto Rico back in the 1980s. The research station had pulled a gigantic Bathynomus isopod, a huge bug-like crustacean roughly 12.7 inches (32.2 centimeters) long, up from a trap that had lain in wait 1,640 feet (500 meters) deep along the ocean floor.
Seilacher, sadly, passed away in 2014, long before he or anyone else realized that this specimen was actually representative of a previously unknown species. Now, over three decades after it was dredged up from the Caribbean, Tübingen paleontology student Benedikt Kästle and the curator of the university’s Paleontological Collection, Ingmar Werneburg, have finally given this creature a proper name. This roly-poly or pillbug-like giant isopod, long mislabelled as a Bathynomus giganteus has now been formally ID’ed under the brand new species name, Bathynomus tuebingoborikensis.
“The new species is very closely related to another giant species found off the Yucatán Peninsula in Mexico,” Kästle said in a statement, noting that this hefty isopod technically “falls into the category of ‘colossogiants.’”
Living large
To get even more technical, giant undersea isopods really do stem from the same order of crustaceans as woodlice, like the tiny brickwork woodlouse (Porcellio spinicornis) seen skulking around masonry and stonework across Europe and North America. But unlike those insect-like land crustaceans, which only grow between 0.4 and 0.6 inches (10 and 15 millimeters) long, species from the gigantic Bathynomus genus can reach up to 20 inches (50 centimeters)—making them some of the largest invertebrates on Earth.
These Starship Troopers-esque buggers can get heavy too: as much as 5.7 pounds (2.6 kilograms) in some cases, enclosed within sturdy exoskeletons suitable for depths as far as 8,200 feet (2,500 meters) below sea level.
According to Werneburg, the entire Bathynomus genus, which today can be found in oceans across the world, likely first took shape in the Gulf of Mexico during the Miocene epoch over 15 million years ago, not far from where B. tuebingoborikensis was found.
“At that time, the Isthmus of Panama was open, leaving a strait between North and South America, and the marine animals were able to spread westward, initially as far as Japan,” Werneburg explained in a statement.
Prehistoric isopods took about another 10 million years, onward into the Miocene–Pliocene boundary, to evolve into species near the sizes of today’s largest representatives of the crustacean. As Earth cooled, so-called “giant” isopod species from the Miocene, which only ever reached 5.9 inches (15 cm) in length, eventually gave rise to much larger cousins in the Indian and Pacific oceans.
“These veritable colossi grew to more than 25.2 centimeters (9.9 inches) in length and were physiologically perfectly adapted to the new climatic conditions,” according to Werneburg.
Big bug hunters
Kästle and Werneburg turned to 3D imaging via micro-computed tomography to take the granular slices of the Tübingen specimen needed to properly distinguish it from the other “colossogiants” it had been mistaken for. The late Seilacher, in his day, was somewhat renowned for making his landmark achievements without even the use of a computer, so it’s perhaps no wonder that the subtle, but numerous, features that distinguish B. tuebingoborikensis failed to capture his attention.
The micro-computed tomography “permitted the detailed observation of the mouthparts, which are often neglected in species descriptions of Bathynomus although this anatomical area is useful for the taxonomy of [aquatic isopods or] Cirolanidae,” the pair wrote in their new study, published Thursday in Scientific Reports.
In a nod to the species’ long journey, the researchers chose its name as a portmanteau of the indigenous Taíno name for Puerto Rico, Boríken, and the city of Tübingen, Germany, where Seilacher helped preserve the find for their unexpected rediscovery.
