The anatomy of alvarezsaurid tails

[Halichoeres]

A new study examines alvarezsaurid tails, using the articulations between vertebrae and the inferred muscle attachments to guess at their function. The authors say the anatomical traits are "indicators of an exceptional capacity to change rotational inertia" (translation: they could turn on a dime).

The alvarezsaur Haplocheirus (A) compared with some other maniraptorans:


Paper (paywall, but you might could get the pdf): https://www.sciencedirect.com/science/article/pii/S0195667120301762

[ceratopsian]

That's a very neat translation!