The good news is that both publishable projects are near completion and could very well be submitted in January. For the Lori project, I just have to check several characters for the maniraptoran OTUs and run the final analysis, then send it to Hartman. These were characters that I refined or quantified, and a few that replaced bad characters. Every taxon that can be usefully resolved is in there, even Halszkaraptor and Almas (which was already included as IGM 100/1323, that I studied at the AMNH). The former doesn't resolve as a basal deinonychosaur and the latter doesn't group with IGM 100/1128, contrary to the only published results for either. Btw, if anyone can write macros for TNT or get me in contact with J. Salvador Arias of the Universidad Nacional de Tucumán, it'd be greatly appreciated.
For the Ornithoscelida project, my team (Cau, Gardner, Deccechi and Marjanovic) and I basically have to provide references for some scores (which I'm responsible for as I did the scoring, and so am the one causing the holdup), complete the bibliography and finish the conclusions. And create figures. I was briefly disheartened by the publication of Langer et al. (2017), but our paper is so much more extensive and explicit that I feel it will significantly add to the conversation, and Langer et al. messed up quite a bit too. For instance, remember how Baron et al. (2017) scored 30 taxa that lack preserved integument as lacking filaments? Langer et al. only changed nine of those scores to unknown despite perhaps being the most obvious error in the matrix. We detail some of their errors in the paper as well.
See you all in 2018!
References- Wild, 1973. Die Triasfauna der Tessiner Kalkalpen. XXIII. Tanystropheus longobardicus (Bassani) (Neue Ergebnisse). Schweizerische Palaontologische Abhandlungen. 95, 1-162.
Baron, Norman and Barrett, 2017. A new hypothesis of dinosaur relationships and early dinosaur evolution. Nature. 543, 501-506.
Langer, Ezcurra, Rauhut, Benton, Knoll, McPhee, Novas, Pol and Brusatte, 2017. Untangling the dinosaur family tree. Nature. 551, E1-E3.
Good news is awesome news :3
ReplyDelete"The former doesn't resolve as a basal deinonychosaur".
ReplyDeleteNow I am terribly curious.
:-)
Me too - but for different reasons, no doubt. I'm especially curious, because of the potential link between the 'swim stroke' of Halszkaraptor and the flight stroke of birds/microraptorines. Did the halskaraptorine swim stroke evolve from the flight stroke (as in the swim stroke of modern diving birds), or independently (which the original description implies)? Fascinating, either way.
DeleteI'm not convinced Halszkaraptor was semiaquatic. The nares aren't more retracted than e.g. Gallus or Struthio, the latter of which has even more of a platyrostral condition. The premaxillary neurovascular network is not compared to terrestrial maniraptorans. The arm seems too short to be used actively in swimming. Aquatic reptiles have larger III to II manual digit ratios because just about every reptile except for theropods retains that primitive condition. And sure figure 4b has it in the area of wing-propelled swimmers, but only close to one and doesn't show where terrestrial maniraptorans would fall out.
DeleteI've wondered about the short forelimbs of Halszkaraptor. This, plus the fact that the hindlimbs are totally unsuited to aquatic locomotion. I'm not convinced it was a swimmer or diver.
DeleteBut I'm still holding out hope that the forelimbs (and neck) were adapted for some kind of motion underwater. But the 'swim stroke' might not have been used for aquatic locomotion (i.e. propulsion). Perhaps the forelimbs of Halszkaraptor were used for a predatory purpose underwater - sweeping prey (like fish) toward the jaws while it stood still in the water. This is what I thought when I first read the paper.
Halszkaraptor forelimbs are weird. So something is going on. But like alvarezsaurs (very weird + very short forelimbs), I'm not convinced by the 'conventional' explanation (swimming for halszkaraptorines, digging for alvarezsaurs).
Halszkaraptor's arms seem most notable to me for being reduced compared to the ancestral maniraptoran/paravian. Reduced structures often have more variable anatomy since they're under less adaptive selection, so you'll get things like a long digit III, shorter penultimate phalanges, etc.. The cervicals suggest emphasis on a strike with the head, as in swans, turtles, drepanosaurs, etc. so maybe this replaced the arms in predation. A possibility is that the large sternum, robust outer digit, posteriorly keeled ulna and bone splints by digit III indicate a well developed wing used in intraspecific combat like some modern birds. Seems more plausible to me than anything involving water.
DeleteI'm increasingly attracted to the view that many theropods used their forelimbs not for predation (grasping and holding prey) but for intraspecific combat and/or as a last-resort defense against bigger predators. They (theropod forelimbs) really don't seem to have been much use for catching prey, even in long-armed taxa. Limited anterior reach, and almost no manual prehension.
DeleteWhy does my reply keep getting deleted?!?
DeleteI agree that the arms seem too short for locomotion.
sweeping prey (like fish) toward the jaws while it stood still in the water
They seem way too short for that, too, given the length of the neck. The hypothesis that therizinosaurs used their hands to increase their reach for food has the same problem.
almost no manual prehension.
...with one hand.
The snout of Halszkaraptor is way too different from that of Struthio for being comparable. What matters is that it differs from almost all non-neornithine theropods. Only ornithomimosaurs and spinosaurids approach in some elements Halszkaraptor: interesting that both have been suggested to have an aquatic diet.
DeleteTwo independent morphometric analyses (one on whole set of measurements in 3 dimensions, not just length) both place Halszkaraptor forelimb among aquatic sauropsids.
Pending a test of your scenarios, I would appreciate explanation of the results of the morphometric analyses.
Note that we did not suggest a propulsive role for the forearm, but more conservatively stated that forelimb assisted during locomotion in water.
Last, Halszkaraptor finger proportions differ from most reptiles with the third finger longer than the second, and cluster uniquely with long-necked aquatic forms.
Again, an alternative explanation of all these results is welcome.
Same here. Could it be that the Lori data puts it as a more derived animal? Does it recover as a troodont of some kind? All sorts of things...all just waiting to be answered soon.
ReplyDeleteCurse you, Lori! You and your shaking of maniraptor phylogeny are most tantalizing, yet frustratingly out-of-reach for now! :p
Great to hear you're on the brink of submitting two manuscripts. Piece of piss. Next comes the hard part: the review process. ;-)
ReplyDeleteon a totally unrelated note...does anybody know if the dml archives (dml.cmnh.org) are dead? There has been no update there since the 4 January. Also, I've tried to subscribe to the list, but the subscription email bounces always back
ReplyDeleteTry sending a query to Mary Kirkaldy MKIRKALDY@aol.com
DeleteOver on SV-POW! Mary said the CMNH is working on the software glitch that prevented archiving.
DeleteYay! I should have time for the Ornithoscelida manuscript very soon. :-)
ReplyDeleteI've begun. It turns out a lot of writing still remains to do, and there are plenty of unresolved minor issues in the comments.
DeleteI've done some more, and will do more tomorrow, but there are pretty tight limits on what I can do...
Delete