Limusaurus inextricabilis

Perhaps the most remarkable thing about this small Jurassic theropod was that Limusaurus underwent considerable morphological change as it grew into adulthood. This dinosaur is known from nineteen specimens found in three batches in China during the early 2000’s. They apparently died having become trapped in mud pits (the scientific name Limusaurus inextricablis, meaning ‘stuck-in-the-mud lizard’, rather cruelly makes reference to this dismal fate).

Very unusually for a dinosaur, a range of juvenile, sub-adult and adult specimens are known, and the differences between them are many. Most surprising of all — researchers have recently shown that Limusaurus lost its teeth altogether as it progressed into adulthood.

You’d think that this might bring one or two evolutionary disadvantages (although frankly, if you’re gonna get stuck in a patch of mud, then what use would teeth be anyway?) — but researchers actually believe that the change in diet brought on by ontogenetic edentalism (a.k.a. ‘tooth loss’) helped reduce feeding competition between adults and offspring. Today, some modern animals also show a similar pattern of development. The lesson here is that your kids will tend to survive better if you stop eating all their food.

Oh, and also keep them away from mud.

IMPORTANT NOTICE: Limusaurus had rather large eye sockets, suggesting it may have been a nocturnal species.

FURTHER READING: Here’s a link to the paper, which is published tomorrow, describing the drastic changes that Limusaurus underwent as it grew into adulthood. Whoever said we’re not up-to-speed here at Obscure Dinosaur of the Day?!