Short one today,
With yesterday’s addition of two more basal rhinos to the large reptile tree (LRT 1010 taxa) maybe it’s time to change our thinking from ‘either horse or rhino’ to ‘horses are a type of rhino’. We know they are related. Maybe they are more intimately related than we first thought. That would make indricotheres like Paraceratherium giant hornless rhinos again, if you prefer it that way.
Figure 1. Subset of the LRT with the addition of Metamynodon and Amynodon, two former rhinos.
Even though,
in the LRT (subset Fig. 1) fewer taxa intervene at present between indricotheres and horses than indricotheres and extant rhinos, like Ceratotherium. Sort of like, you know, birds are a type of dinosaur. It just takes some getting used to – creating a new mental paradigm following the present data without excluding pertinent taxa.
The Pterosaur Heresies 
Well, perhaps. Have you tried adding more characters pertinent to this question to your matrix, though?
Such as?? I will add characters when necessary or when curiosity attacks again. So far, lumping and splitting are still going strong.