Given the small number of bones that are referrable to
Tingmiatornis, it is difficult to infer much about the animal. However, the thickness of the
cortical bone (on average, ) and the relative length of the
humerus suggest that it was apparently capable of flight and likely also diving, similar to the possible
hesperornithine Pasquiaornis.
Tingmiatornis can be differentiated from the latter by numerous traits including larger size, a more globe-shaped
dorsal condyle on the humerus, an
olecranon process of the
ulna that does not project outward as strongly, as well as a smaller bicipital tubercle of the ulna.
Tingmiatornis also differs from
Ichthyornis in the following ways: the
head of the humerus is more rounded and projects further downwards; the deltopectoral crest of the humerus is narrower and curves slightly forwards; the secondary pneumotricipital
fossa of the humerus is deeper; and the expansion of the humerus known as the bicipital crest is longer, with a slightly convex bottom edge that transitions smoothly into the rest of the humerus rather than being hatchet-shaped. ==Discovery and naming==