Museum Specimen Identified as New Giant Isopod Species

A gigantic Bathynomus isopod measuring 12.7 inches (32.2 centimeters) long, dredged up from 1,640 feet (500 meters) deep in Puerto Rico during the 1980s, has finally been identified as a new species. Tübingen paleontology student Benedikt Kästle and Paleontological Collection curator Ingmar Werneburg formally named the crustacean Bathynomus tuebingoborikensis, correcting decades of mislabeling that previously categorized the specimen as Bathynomus giganteus.

Specimen Mislabeled for Decades Before 3D Imaging Identification

The deep-sea crustacean was originally collected by German paleontologist Dolf Seilacher in the 1980s before he won his Crafoord Prize, a prestigious honor awarded by the same Swedish academy that distributes Nobel Prizes. Seilacher passed away in 2014 without realizing the specimen represented an undescribed species. Kästle and Werneburg used micro-computed tomography 3D imaging to examine granular slices of the fossilized or preserved creature, focusing on anatomical features that previous researchers overlooked. Benedikt Kästle said in a statement that the new species is very closely related to another giant species found off the Yucatán Peninsula in Mexico, noting that this hefty isopod technically falls into the category of colossogiants.

Evolutionary History Traced Back to the Gulf of Mexico

Giant undersea isopods belong to the same crustacean order as terrestrial woodlice, such as the tiny brickwork woodlouse (Porcellio spinicornis) found across European and North American stonework. While land woodlice only grow between 0.4 and 0.6 inches (10 and 15 millimeters) long, Bathynomus specimens can reach up to 20 inches (50 centimeters) and weigh up to 5.7 pounds (2.6 kilograms) inside sturdy exoskeletons built for depths reaching 8,200 feet (2,500 meters) below sea level. Werneburg explained that the Bathynomus genus likely originated in the Gulf of Mexico during the Miocene epoch more than 15 million years ago, when the open Isthmus of Panama allowed marine animals to migrate westward toward Japan. Prehistoric isopods required roughly another 10 million years, stretching into the Miocene–Pliocene boundary, to reach modern sizes as Earth’s oceans cooled.

Micro-CT Scans Reveal Distinct Mouthparts of the Puerto Rican Colossogiant

Seilacher achieved his landmark paleontological career without utilizing computers, which contributed to the subtle diagnostic features of the specimen going unnoticed for decades. Kästle and Werneburg wrote in their published study that 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 Cirolanidae. Their findings were published in Scientific Reports. To honor the creature’s long path to classification, the researchers formed the species name by combining the indigenous Taíno name for Puerto Rico, Boríken, with Tübingen, Germany, where Seilacher preserved the sample for eventual rediscovery.