Whale fossil identified as new species on permanent display at Gunma Prefectural Museum of Natural History in Tomioka Officially confirmed using 3D scanning: Tokyo Shimbun TOKYO Web

The Gunma Prefectural Museum of Natural History (Tomioka City) announced that a whale fossil excavated from South America, which is on permanent display at the museum, has been identified as a new species. It has been known for 20 years that it was likely a new species, but it has now been officially confirmed through the use of 3D scanning. (Kazutaka Hamono)

The fossil was discovered in 1987 in the Pisco Formation in the Aguada de Lomas region of southern Peru. It was purchased by the prefecture in 1991 as a specimen intact from the ground, and has been on permanent display at the Natural History Museum since it opened in 1996.

The new species is related to the fin whale and is included in the genus Inca whale. Compared to other species of this genus, the nasal bone remains further forward and has a wider distance from the head. It was found to be a new species, with more primitive whale characteristics. It lived about 7 to 8 million years ago, and is said to be a young, immature individual with a body length of about 10 meters.

In 2004, the Natural History Museum conducted joint research with a doctor from a New Zealand university and confirmed that the fossil had different characteristics from existing fossils. However, because the specimen was lying on the ground, detailed examination was difficult. In 2016, two specimens found in the same stratum and located in Japan were confirmed to belong to a new genus of Inca whales, and research accelerated. Around the same time, research using 3D scanning began at the same museum, which led to the current results.

The specimen at the museum is in a very good state of preservation, with the entire body visible except for part of the tail. It is said that traces of whiskers, which normally do not remain in fossils, can also be seen. The shape of its bones and whiskers indicates that it was a nimble swimmer with quick turns, and that it ate a variety of foods, including small fish.

Previous exhibits labeled it as a member of the fin whale family, but the plan is to change the display to indicate that it is a new species. Curator Toshiyuki Kimura, who conducted the research, said, “I’m glad to know what kind of creatures the fossils on display were.I want visitors to learn about this and think about the biodiversity of the past.”