So I’ve been making excursions into phylogenetic analysing, and based on advice from Mike Taylor I’ve added a dental character, Euhelopus and Brachiosaurus nougaredi. Based on what I’ve found, I can safely say that NO MATTER WHAT, all characters and taxa add to an analysis, and if there is a dissolved clade that you want resolved, add more taxa or characters.
The strict consensus, which is the only really important analysis, is resolved as (Outgroup (Cetiosaurus, H. priscus, H. delfsi, H. sp., H. utterbacki, Tataouinea, Camarasaurus, Brachiosaurus, B. nougaredi, Futalognkosaurus, Apatosaurus minimus, Atlantosaurus, Euhelopus (A. ajax + Elosaurus) ) ). Now, Atlantosaurus is a pretty bad taxa, second worst known after B. nougaredi in this analysis, so I removed it in one analysis. This generated the tree (Outgroup, all other taxa), which actually dissolves the clade of A. ajax + Elosaurus. Now for the final analysis I removed B. nougaredi, and the tree was resolved as the exact same as with all taxa except without B. nougaredi.
This shows that neither tree was improved by removing a single fragmentary taxon, but to prove my point further I decided to remove both and generate a tree. With both removed, the tree resolved the same as with only Atlantosaurus removed. Now for some reason Atlantosaurus is the taxon that supports the clade of A. ajax + Elosaurus, but I’m not sure how.
I think this is good proof that analyses are better with more information, and further analyses should put this into account before deleting A Priori or A Posteriori.