[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Re: Feduccia Reviews Paul's DOTA, Comments

Nicholas Gardner wrote-

> The only published response (that I am aware of) to the ABSRDists claims
> that Caudipteryx is a flightless bird, is-
> L.M. Chiappe & Gareth J. Dyke (2002).  The Mesozoic Radiation of Birds.
> Annu. Rev. Ecol. Sys. 33:91-124
> Now, for discussions on this list, refer to-
> http://www.cmnh.org/dinoarch/2000Aug/msg00303.html
> http://www.cmnh.org/dinoarch/2000Oct/msg00042.html
> http://www.cmnh.org/dinoarch/2001Feb/msg00333.html

Actually, a paper was written for the exact purpose of refutting Jones et
al.'s arguments-
Christiansen and Bonde, 2002. Limb proportions and avian terrestrial
locomotion. J. Ornithol., 143, pg. 356-371.
Not without its problems, but a good study nonetheless.  I have a pdf if
anyone wants it.
Here's a critique of Jones et al. I wrote on 6-21-02, before I knew of
Christiansen and Bonde's paper.

There are several problems with this paper.  Yangchuanosaurus,
Staurikosaurus and Carnotaurus were analyzed, but do not have
preserved metatarsi.  Indeed, Carnotaurus' distal tibia is unknown,
but a tibial length is given.  Afrovenator is as well, but doesn't
preserve metatarsal III, so they use metatarsal IV's length instead.
Metatarsal IV is invariably shorter than III in theropods, so this
would make its legs shorter than in reality.  A higher value of 344 mm
is estimated from the metatarsal proportions of its relative
Eustreptospondylus (=Magnosaurus?).  Dilophosaurus' tibia is listed as
30 mm shorter than it is, making it's legs seem shorter as well.
Their Daspletosaurus tibial and metatarsal lengths are way off (by 68%
and 64% respectively).  Their Velociraptor lengths are inaccurately
estimated, as new material (Norell and Makovicky 1999) shows it to
have a longer tibia.  I can only guess they judged it by Paul's 1988
illustration, as they use his femoral length estimate.  Jones et al.
opt not to include Sinornithoides and Bambiraptor because they are
subadult specimens, although they both have birdlike proportions.  But
subadult specimens of the less birdlike Liliensternus, Ceratosaurus,
Eustreptospondylus and Yangchuanosaurus are used.  Their Albertosaurus
specimen (AMNH 5458) is really Gorgosaurus libratus, but they use
another specimen of that species (NMC 2120) as Gorgosaurus.  So they
apply two names to one species.  I can only hope such numerous errors
are not present in the bird measurements or torso measurements.  Jones
et al. also ignore the fact that in most theropods, the proximal and
distal tarsals are not fused to the tibia and metatarsus respectively,
which artificially lowers most of their hindlimb lengths.  Also note
the over-representation of non-coelurosaurs and conspicuous absence of
several birdlike taxa (troodontids, alvarezsaurids, Avimimus) and
basal birds (Archaeopteryx, Rahonavis).  In any case, I entered Jones
et al.'s data (with the corrections noted above) into Excel and added
some other taxa to see what it really says.
There is indeed a general pattern of neornithines having longer
hindlimbs than most coelurosaurs.  However, there are some
coelurosaurs that plot in the neornithine area (Sinosauropteryx,
Nomingia, Avimimus, Sinornithosaurus, Microraptor).  Nomingia and
perhaps Avimimus are closely related to Caudipteryx, while
Sinornithosaurus and Microraptor are close to (if not members of)
Avialae.  So this might be expected.  Sinosauropteryx is very basal
though, leading me to measure the trunk length directly from Currie
and Chen (2001), which indicated that Jones et al.'s measurement was
some 30% too short.  Substituting the correct value puts it back in
the coelurosaur area.  Saurornithoides and Shuvuuia are just outside
the neornithine range, congruent with their placement as
maniraptorans.  Caudipteryx is in the neornithine area, as noted by
Jones et al..  Also in the neornithine section are the secondarily
flightless avians Yandangornis and Patagopteryx.  Some very important
taxa are well within the main coelurosaurian area though.  These are
Protarchaeopteryx, Archaeopteryx and Rahonavis.  Note the former was
conspicuously absent from Jones et al.'s dataset.  They state "We find
it a striking coincidence that the only unambiguously feathered
theropod was also the only known theropod likely to have utilized
locomotory mechanisms identical to those of cursorial birds".  If
Protarchaeopteryx is also a "secondarily flightless,
post-Archaeopteryx cursorial bird", as Jones et al. claim Caudipteryx
is, why doesn't it have birdlike proportions?  And why do the avian
Archaeopteryx and Rahonavis have unbirdlike proportions?

Jaime Headden wrote-

>   Alvarezsaurids are treated as ornithomimids; wholly on apparent
> data apart from Sereno's analysis which identified the relationship on
> evidence, analyzed elsewhen on the list, and deriving from Larry Martin's
> where (as published in DinoFest perhaps?), several of the features that
> found and some rather horrible and plastic features (much wider
> than given) gave us a really bad stab at cladistic analysis (which
Feduccia is
> adopting a result of despite indicating his distate for this subject, no
> there). Despite this, Feduccia provides this data as incontrivertible and
> no further discussion.

Papers which I'm sure contributed more to Feduccia's opinion than Sereno's
(1999; 2001) are-
Martin and Rinaldi, 1994. How to tell a bird from a dinosaur. Maps Digest
17(4) 190-196.
Martin, 1995. The relationship of Mononykus to ornithomimid dinosaurs. JVP
15(3) 43A.
Martin, 1997. The difference between dinosaurs and birds as applied to
Mononykus. Dinofest International. 337-343.

The latter has perhaps the worst cladistic analysis I've seen.
The two included birds (Archaeopteryx, Ichthyornis) somehow manage to appear
BASAL TO the outgroup (supposedly based on Petrolacosaurus) in his consensus
tree.  This is impossible in PAUP.  And surely Martin didn't believe this
himself, as he thinks dinosaurs and birds are both archosaurs at least.
Furthermore, both birds and both ornithomimids (Ornithomimus and
Struthiomimus) are coded identically in his matrix, so are redundant and
only one of each should have been included.

His consensus tree-
|  `--Ichthyornis
`--+--all zero outgroup
      |  `--Deinonychus

Just look at the matrix-
outgroup   00000 00000 00000 00000 00000 00000 00000 00000 00
Archaeopte 01111 11011 01001 11000 00100 01000 01110 00010 10
Ichthyorni 01111 11011 01001 11000 00100 01000 01110 00010 10
Troodontid 10001 11000 00000 00110 01101 10011 00001 11100 00
Ornithomim 10000 001?? ??110 00110 11011 10111 00001 10101 01
Struthiomi 10000 001?? ??110 00110 11011 10111 00001 10101 01
Oviraptori 1000? ??1?? ??100 00111 01111 10011 00001 10001 00
Mononykus  100?1 10000 11?10 00111 11011 10111 00101 11101 01
Deinonychu 00000 00000 00110 00100 01001 00011 10001 00001 01
Tyrannosau 00010 00000 00110 00100 01001 00011 10001 00100 01

And character list-
1. head shorter than femur.
2. postorbital absent.
3. orbital process of quadrate present.
4. pneumatic articular.
5. dorsal tympanic recess.
6. caudal tympanic recess.
7. ventral pneumatic recess(?).
8. edentulous.
9. bases of teeth constricted.
10. tooth root wider than crown.
11. tooth crown wider than root.
12. teeth serrationless.
13. external mandibular fenestra.
14. clavicles absent.
15. clavicles attach to coracoids.
16. laterally directed glenoid.
17. scapula paralell to dorsal series and placed dorsally.
18. posteriorly directed glenoid.
19. coracoid elongated anteroposteriorly.
20. elongate sternum with lateral coracoidal attachments.
21. elongate olecranon process.
22. less than four carpals.
23. semilunate carpal largely restricted to metacarpal II.
24. metacarpal I greatly enlarged.
25. forelimb shorter than hindlimb.
26. short dorsal ribs.
27. short, flattened proximal chevrons.
28. elongate postacetabular process.
29. supracetabular crest.
30. ischium not horizontal.
31. opisthopubic.
32. fourth trochanter reduced.
33. fibula-calcaneum contact absent.
34. pretibial bone.
35. ascending process on astragalus.
36. astragalus forming both medial and lateral condyles of tibiotarsus.
37. calcaneum absent.
38. arctometatarsus.
39. reversed hallux.
40. digit I most robust in manus.
41. chevrons start at last sacral.
42. body transversely compressed.

Critiquing it would be too easy, so I'll leave it to all of you to laugh at.

Mickey Mortimer