Short one today.
Imagining the weight of a pterosaur known from bits and pieces requires extrapolation from data provided by smaller, but similar hollow-boned vertebrates. A graph of height vs. weight in large pterosaurs and large birds (Fig. 1) might help, but estimates at the far end still vary greatly. As you can see, hollow bones make a big difference. It may be surprising, that a stork at 1.3 m (5 ft) tall weighs about 5 kilograms (15 lbs). Pterosaurs were similar.
does it make sense that the smaller Q. sp. weighed no more than 15kg (33 lbs)? Does it make sense that the larger one, Q. northropi, known from fewer bones, might weigh between an unlikely 20kg (44 lbs) to a more reasonable 125 kg (275 lbs)? Here are some other largest pterosaurs for more comparisons (Fig. 2).