Feathered Dragons: Studies on the Transition from Dinosaurs to Birds

["Michael Mortimer" <mickey_mortimer111@msn.com>]

I just arrived home a few hours ago, and what awaited me but my copy of 
Feathered Dragons: Studies on the Transition from Dinosaurs to Birds.

Bakker, 2004. Introduction: Dinosaurs acting like birds, and vice versa - an 
homage to the Reverend Edward Hitchcock, first director of the Massachusetts 
Geological Survey. 1-11.

Russell, 2004. The dinosaurian setting of primitive Asian birds. 15-34.
Basically covers the biogeography and ecology of well-known Asian 
formations.  I don't think dinosaurs are plentiful enough to have much 
biogeographical use, and this chapter doesn't change my view.  The presence 
of Tatisaurus and "Dilophosaurus" sinensis in the Lufeng do not show 
congruence with scelidosaur scutes and Dilophosaurus in the Kayenta anymore 
than they would with Zupaysaurus, Cryolophosaurus, Lusitanosaurus, 
Emausaurus, etc..  Mamenchisaurus and Omeisaurus are not well supported as 
members of a distinct lineage (Upchurch and Barrett, 2001), and their 
presence in the Shangshaximiao and Xiashaximiao along with the absence of 
diplodocids there is no more proof of endemism of Late Jurassic Chinese taxa 
than the presence of dicraeosaurids and absence of camarasaurids in the 
Tendaguru is of endemism of Late Jurassic Tanzanian taxa.  There is no 
reason Sinosauropteryx, Beipiaosaurus or Psittacosaurus should be considered 
"relict taxa" in the Yixian.  Hell, segnosaurs and psittacosaurs haven't 
been found in earlier strata, just what are they relicts of?  Similarly (and 
ironically), the so-called "replacing fauna" of ornithomimosaurs, 
dromaeosaurs and iguanodonts are known from pre-Barremian times.  
Interestingly, in table 1.2, only the indeterminate, unnamed and undescribed 
specimens are considered allochthonous to the Djadokhta Formation, not any 
of the named ones.  Suspicious.  A new cf. 'homocephalid' is listed in the 
faunal list for the Hell Creek Formation (Galiano pers. comm. 2001).

Retallack, 2004. End-Cretaceous acid rain as a selective extinction 
mechanism between birds and dinosaurs. 35-64.
You see, vegetation browning would have been detrimental to herbivorous 
dinosaurs and their predators, but not birds.  So why did small theropods 
and non-neornithine birds go extinct?

Burnham, 2004. New information on Bambiraptor feinbergi (Theropoda: 
Dromaeosauridae) from the Late Cretaceous of Montana. 67-111.
Nice expansive osteology, though I question why both quadratojugals had to 
be illustrated in three views, while there are no manual phalanges and 
almost no pedal phalanges illustrated.  Oh well.  I'll be coding this 
tonight.  Let's see... non-pneumatic quadrate with single head, all sacrals 
pleurocoelous, no mesial serrations in premaxillary teeth (though distal 
serrations are present).  It will cause me to separate some characters, as 
it has unfused maxillary interdental plates but fused dentary ones for 
example.

Currie and Varricchio, 2004. A new dromaeosaurid from the Horseshoe Canyon 
Formation (Upper Cretaceous) of Alberta, Canada. 112-132.
Interestingly, high DSDI's are confined to maxillary and dentary teeth, not 
found in premaxillary teeth.  Oh, and guess why they assign Atrociraptor to 
the Velociraptorinae?  That's right, the high DSDI.  As a bonus, we get 
descriptions of a Saurornitholestes maxilla (RTMP 94.12.844) and a cf. 
Bambiraptor maxilla (MOR 553S).  The authors perform a cladistic analysis of 
dromaeosaurids (42 characters), unfortunately using only cranial characters. 
 Their excuse of this being because it was only meant to determine 
Atrociraptor's position in the family is invalid because postcranial 
characters could affect the topology of the other taxa, which Atrociraptor 
would be placed in.  Coelophysis(!), Allosaurus (slightly less !) and 
Troodontidae as outgroups.  No sign of Sinornithosaurus.  The topology is 
(Coelo(Allo(Troo(Drom(Saur(Veloc(Bambi(Atroc,Deinon)))))))).  I'd be 
interested to see the result if the outgroups were Archaeopteryx, 
Sinovenator and Microraptor instead.  Interestingly, we learn Adasaurus has 
4 premaxillary, 11 maxillary and 13 dentary teeth (GIN 100/23) and a DSDI of 
1.00 (20 denticles per 5 mm).  I'll be coding Atrociraptor tonight too.  
Though the cranial reconstruction looks like Dromaeosaurus' posterior skull 
badly fit to Atrociraptor's snout, Skrepnick's life restoration is 
excellent.

Norell, Makovicky and Clark, 2004. The braincase of Velociraptor. 133-143.

Godfrey and Currie, 2004. A theropod (Dromaeosauridae, Dinosauria) sternal 
plate from the Dinosaur Park Formation (Campanian, Upper Cretaceous) of 
Alberta, Canada. 144-149.

Novas, 2004. Avian traits in the ilium of Unenlagia comahuensis 
(Maniraptora: Avialae). 150-166.
Argues, contra the TWG, that Unenlagia shows several avialan traits 
(lobe-shaped preacetabular process [I don't see this myself]; medially 
constricted acetabulum; enlarged supratrochanteric process; reduced brevis 
fossa; concave dorsal margin of postacetabular process; reduced femoral 
head; fourth trochanter absent; proximodorsal ischial process).  Anyway, 
it's good to get more info on Unenlagia's ilium.  Now for the other bones.

Wright, 2004. Bird-like features of dinosaur footprints. 167-181.

Grellet-Tinner and Chiappe, 2004. Dinosaur eggs and nesting: Implications 
for understanding the origin of birds. 185-214.
Takes 22 more steps to have crurotarsan birds (yeah, technically that's 
impossible, but you know what I mean), in a cladistic analysis using only 
egg characters.  And Troodon shares blade-shaped shell unit crystallization 
with birds, which Citipati lacks.

Varricchio and Jackson, 2004. Two eggs sunny-side up: Reproductive 
physiology in the dinosaur Troodon formosus. 215-233.
Contains a painfully outdated Troodon illustration.

Hopp and Orsen, 2004. Dinosaur brooding behavior and the origin of flight 
feathers. 234-250.
Finally out, and with a great update of the classic naked nesting 
oviraptorid pic by Orsen.

Chatterjee and Templin, 2004. Feathered coelurosaurs from China: New light 
on the arboreal origin of avian flight.
Someone needs to tell the authors Sinosauropteryx has a posteriorly facing 
glenoid, and could not extend its arms high over its back.  I also have a 
hard time seeing it and Caudipteryx as arboreal, given their short arms, 
unreversed halluces, straight unguals, etc..

Wellnhofer, 2004. The plumage of Archaeopteryx: Feathers of a dinosaur? 
282-300.
Dismisses Praeornis as a leaf despite recent SEM studies suggesting it's a 
feather.  Overall, a confusing Discussion section.  He brings up the 
feathers on Sinosauropteryx and Sinornithosaurus (though apparently not 
noticing NGMC 91 has stage 3 feathers), and says "unless we take these 
dinosaurs as living fossils of their time [because they preserve feathers 
but lived later than Archaeopteryx], it is equally possible to assume that 
integumentary filaments may have evolved independently and convergently in a 
variety of reptilian groups not closely related to each other."  Why would 
taxa NOT be expected to retain plesiomorphic integument?  Are all more basal 
taxa supposed to die out, or convergently evolve their own stage 3 feathers 
once they see birds do it?  Wellnhofer also seems to have grave problems 
with the concept of a feathered non-bird, like Caudipteryx.  Especially one 
that is contemporaneous with more derived birds.  He seems amiable to the 
hypothesis oviraptorosaurs are birds, basing this on Elzanowski's (1999) 
four cranial characters (see 
http://www.cmnh.org/dinoarch/2000Dec/msg00487.html), Nomingia's pygostyle 
(now we have Beipiaosaurus with one too), uncinate processes (as in other 
maniraptorans), Citipati's brooding behavior (in Troodon too), and of 
course, Caudipteryx's feathers.  He also claims the angle between the manus 
and ulna could potentially distinguish birds from other theropods, with a 
specimen of Velociraptor (it had better not be IGM 100/25- the fighting 
one), Protarchaeopteryx and basal coelurosaurs showing high angles, and 
Caudipteryx, Archaeopteryx and other birds showing low angles.  Wellnhofer 
ends with the supposed impossibility of drawing a boundary between reptile 
and bird, that cladistics doesn't solve the problem, etc..  The problem is a 
taxonomic one, not a phylogenetic one.  Just decide on a point, and all is 
solved.  We've been saying Archaeopteryx is the most primitive known bird 
for years, just draw the line at Aves (sensu Chiappe) and be done with it.  
There are scientific problems to solve.

Bakker and Bir, 2004. Dinosaur crime scene investigations: Theropod behavior 
at Como Bluff, Wyoming, and the evolution of birdness. 301-342.

Mickey Mortimer

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