Natures wonders: ancient isopods (Introduction)

by David Turell , Wednesday, August 10, 2022, 15:07 (625 days ago) @ David Turell

Have been around for 200-300 million years:

https://www.sciencealert.com/a-new-deep-sea-giant-isopod-has-been-discovered-in-the-gul...

'A group of football-sized isopods have been roaming the seafloor like giant, blown-up roly-poly bugs for 200 or 300 million years, even through the dinosaur extinction event.

"One of the largest living species today, Bathynomus giganteus, can be found at depths of more than 2,500 meters (8,200 feet). It was first caught off the Gulf of Mexico in 1879, and as it turns out, it might be two species rolled up in one.

"A modern analysis of known giant isopods living in the deep sea has found subtle yet significant differences in their DNA and morphology (their shape and structure).

***

"The curious specimen was found off the Yucatán Peninsula between 600 and 800 meters deep, where B. giganteus has been found before. But there was something off about this one. It was slightly shorter in total length, measuring in at 26 centimeters (10 inches), and its antennae were relatively long.

"While further data is needed to confirm the specimen's exact taxonomic ranking, researchers suspect it represents a new separate species of Bathynomus, and they have named it B. yucatanensis.

***

"Today, scientists have cataloged about 20 species of living creatures that belong to the Bathynomus genus.

"While these aquatic animals might look similar to giant terrestrial woodlouse, they are also distantly related to crabs, shrimp and lobsters.

"In comparison to their relatives, however, we know next to nothing about giant isopods. What we do know suggests they are well-equipped to deal with major extinction events. Sometimes, they can go without food for years.

"That's probably necessary in the deep, where nutrients are rare and fiercely competed over. When a meal becomes available, it pays to get to the table first.

"In 2019, when researchers dropped an alligator carcass into the Gulf of Mexico, it took a mere day for a troop of giant Bathynomus bugs to descend on the meal. Some of them ate so much they began toppling over as though stupefied."

Comment: A non-evolving form is a living fossil. It's role seems to be a bottom scavenger but it must also be food for someone else in that ecosystem.