Thursday night talk - notes

John Nudds told us how cladistic analysis, where you have to look at the most parsimonious line, doesn't sit well with Linnaen nomenclature. Archaeopteryx was perceived as an "Urvogel" until 1995.
In 1996 feathered dinosaurs were found in China which raised the subject of flight, and did the animals fly "ground up", i.e. could they take off, or were they "tree down" gliders?
There is a temporal paradox - only potential ancestors were younger than Archaeopteryx so, was Archaeopteryx the first bird, or just another feathered dinosaur?
In 2009 Hu et al published on Anchiornis Huxleyi, a feathered troodontid therapod dinosaur from 158-164 Ma. This meant that there was a feathered dinosaur older than Archaeopteryx at 150 Ma and solved the paradox.
Hu, D.; Hou, L.; Zhang, L. & Xu, X. (2009). "A pre-Archaeopteryx troodontid theropod from China with long feathers on the metatarsus". Nature. 461 (7264): 640–643. 
In 2011 Xu et al published on Xiaotingia, another feathered dinosaur and this pulled Archaeopteryx into the clade, and out of its position as a bird ancestor
In 2013 Godefroit described a 3rd avian, Aurornis which also fitted into this cladogram and brings Archaeopteryx back into the avialae but not as the most basal.
See the cladogram in https://en.wikipedia.org/wiki/Xiaotingia

Cladogram following the results of a phylogenetic study by Lefèvreet al., 2017.^[6]

Pennaraptora	†Oviraptorosauria   Paraves     Scansoriopterygidae       †Xiaotingia     †Yixianosaurus               †Pedopenna     †Aurornis         †Serikornis     †Eosinopteryx           †Anchiornis   Eumaniraptora Deinonychosauria   †Troodontidae     †Dromaeosauridae     Avialae   †Archaeopteryx       †Rahonavis       †Balaur       †Jeholornithidae     Euavialae

However, Archaeopteryx was the first avialan with symmetrical feathers and in 2014 Foth and Rauhut used #11 to base a cladogram on feather morphology - it had assymetrical wing feathers. Looks as though there was convergent evolution of flight, both ground up, and tree down.
Foth and Rauhut (2017) described #4 (Haarlem specimen, and the oldest Archaeopteryx, found in the older eastern basins) as a new avian theropod, the first member of the Anchiornothids from Europe.

In 2018 Rauut described #12 (which we will see on Saturday at Dinosauria) - a lovely specimen and older, but it doesn't add much to the story.

Also Kundrat and Nudds did a skull scan of #8 which was 0.5 Ma younger and would have had greater flying ability.

And finally (in 2019, for the time being) Rauhut has described #13 Alcmonavis