Elephantine Chewing

Aralosaurus has been reported as elephant-sized based on extrapolations from the skull. The most recently updated (2011) appendix for Dr. Holtz's Dinosaurs encyclopedia lists Aralosaurus as rhino-sized. To differentiate the two, using this appendix's weight ranges, rhino-sized is between 1 and 4 tons while elephant-sized is between 4 and 8 tons. The discrepancy, on Rozhdestvensky's part, is most likely due to simple size extrapolation without regard to the actual weight of an elephant. It is quite possible that an Aralosaurus could have been nearly elephant size but in the same weight range as a rhinoceros. Of course, that could be a difficult thing to have happen: squeezing the weight of a rhino into an elephant sized package and not having extra unused space. 

The nasal protuberance, meanwhile, is not an indication of weight, as far as anyone can tell. The wideness and extension of the protuberance has led to speculation that it may have been useful in intraspecific combat and other mating or display rituals. How the protuberance was formed exactly determines how correct the hypothesis of intraspecific combat could potentially be. If the protuberance is more of a horn than a wide, flat, stable surface for butting, than butting could be lethal. If the protuberance is actually a fractional element of a hollow resonating chamber neither hypothesis above would be correct as the structure would be too fragile for any kind of combat. As a resonating chamber it would definitely be significantly useful in display though. My official opinion is that more evidence would be ideal but the evidence present is very inconclusive.

"Aralosaurus skull" by I. Reid (User:Reid,iain james) - Own work. Licensed under Public domain via Wikimedia Commons