Lately there seems to be quite a bit a dinosaur stuff in the news. The biggest story is the shake up of dinosaur evolutionary history, a possible new phylogeny.
An uppity (if you don’t have some fun with sarcasm and tongue-in-cheek statements stop reading now) graduate student (Mathew G.Baron) from some lowly intellectual backwater school called Cambridge collected mass amounts of data (74 species and 457 characteristics) threw them into a computer program and it spit out a phylogenetic tree different to the established tree.
Some of the characteristics Baron used…
- The level of ridge present along the upper jaw:
present; 2, rounded/bulbous longitudinal ridge present “
- “Skull proportions: 0, preorbital skull length more than 45% of basal skull length; 1, preorbital length less than 45% of basal skull length“
- “Skull length (rostral–quadrate): 0, 15% or less of body length; 1, 20–30% of body length”
- Holes, called foramen, in the skull: “Premaxillary foramen (anterior premaxillary foramen): 0, absent; 1, present”
- Other holes, called fenestra: “Small fenestra positioned dorsally on thesurangular-dentary joint: 0, absent; 1, present “
- Position of extensions and bulges on the femur - “Pendent fourth trochanter… Transverse expansion of distal femur :
AND 450 more… Sounds exhausting and it is if believe Baron’s Twitter:
“Its been a heck of 7 days since #ORNITHOSCELIDA became a thing... back to regular #phdlife now... coffee, writing and little-to-no sleep!”
If you’ve published a major paper like this his grad school committee should just say ‘you’re done’ and sign all the paperwork needed to get him his PhD.
Traditionally, dinosaurs have been separated into two major groups the bird-hipped and the lizard-hipped, these are known as Ornithischia and Saurischia respectively. The major feature that differentiates them, you might figure this from the name, is the hip structure. In ornithischians the pubis bone points backward while is saurischians it points forward. From my brief description you might think this is a quick and easy separating characteristic among the dinosaurs - but there are/were a huge number of exceptions to these groupings so this seemingly easy separator never really was that good at separating (hip Images below; stolen from Wikipedia).
Here’s the paper: Good luck getting through the paywall :-(
http://www.nature.com/nature/journal/v543/n7646/extref/nature21700.pdf