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RE: Ligabuesaurus leanzai



Brad McFeeters wrote:

Bonaparte, J.F., González Riga, B.J. & S. Apesteguía, 2006. Ligabuesaurus leanzai gen. et sp. nov. (Dinosauria, Sauropoda), a new titanosaur from the Lohan Cura Formation (Aptian, Lower Cretaceous) of Neuquén, Patagonia, Argentina. Cretaceous Research, in press.

AFAIK, this is the THIRD dinosaur to be named after Dr Giancarlo Ligabue, together with two other South American taxa, _Ligabueino andesi_ (theropod) and _Agustina ligabuei_ (sauropod). Trivia question: Is there anybody who's had more dinosaurs named after him/her? (I know Ned Colbert has three.)


The humerus/femur ratio of _Ligabuesaurus_ is 0.9 (1.49m/1.66m), which is a little bigger than _Chubutisaurus_ (0.86). It's not clear if such long forelimbs evolved independently of true brachiosaurids, or is plesiomorphic for titanosauriforms. If the latter is true, this could undermine the monophyly of Brachiosauridae (my opinion, not the authors') - especially since there are similarities in the cervicals between _Ligabuesaurus_, _Brachiosaurus_ ("Giraffatitan"), and _Sauroposeidon_.

_Ligabuesaurus_'s closest relative appears to be _Phuwiangosaurus_. Given that _Ligabuesaurus_ is recovered as above _Brachiosaurus_ but below _Andesaurus_, it would be a titanosaur under Wilson and Sereno's (1998) stem-based definition ("titanosauriforms closer to _Saltasaurus_ than to _Brachiosaurus_ and _Euhelopus_"), which was essentially followed by Sereno (2005). However, under Salgado et al's (1997) node-based definition ("all descendents of the most recent common ancestor of _Andesaurus_ and Titanosauridae"), _Ligabuesaurus_ would not be a titanosaur. Though given that Titanosauridae is not accepted as a valid taxon, that definition is probably passe.

No body armor is preserved.

Cheers

Tim