Giant hutia
The giant hutias are an extinct group of large rodents known from fossil and subfossil material in the West Indies. One species, "Amblyrhiza inundata", is estimated to have weighed between , big specimens being as large as an American black bear. This is twice as large as the capybara, the largest rodent living today, but still much smaller than "Josephoartigasia monesi", the largest rodent known. These animals were probably used as a food source by aboriginal humans. All giant hutias are in a single family, Heptaxodontidae, which contains no living species; this grouping seems to be paraphyletic and artificial, however.
Largest organisms
The lion's mane jellyfish ("Cyanea capillata") is the largest cnidaria species, of the class Scyphozoa. The largest known specimen of this giant, found washed up on the shore of Massachusetts Bay in 1870, had a bell diameter of , a weight of . The tentacles of this specimens were as long as and were projected to have a tentacular spread of about making it one of the longest extant animals.
The largest roundworm, "Placentonema gigantissima", is a parasite found in the placentas of sperm whales which can reach up to in length.