Microsegnosauridae, a group of small, insectivorous maniraptors was one of the stranger radiations of Therizinosauria.  Evolving in the Oligocene, migrosegnosaurids became quite common during the Miocene and Pliocene, when they spread across Eurasia.  Several well-preserved skeletons show small, lightly-built creatures with long, tubular snouts and powerful forelimbs.  The retroverted pubis of the therizinosaurs was, with the microsegnosaurs, greatly reduced and pulled forward, like that of a basal coelurosaur, while the legs were reletively long and slender.  The obvious explanation for these adapatations is that these dinosaurs were ant-eaters, although exactly why ants were so tempting as a food source that the therizinosaurs could completely abandon their former lifestyle and favor of their consumption is unknown.
 

(Text by Daniel Bensen)

(Picture by Matti Aumala)

    The early Oligocene microsegnosaurid Formicornithoides europeanus is the first known species of myrmicophagous therizinosaurs. When the fragmentary skull and limb material the species is known from was first discovered, it couldn't be indisputably identified as a therizinosaurid. It wasn't before the discovery of Microsegnosaurus that the animal could be properly classified.

(Text by Matti Aumala)