OLOROTITAN PHYLOGENY (long)

["Nick Gardner" <ratites637@hotmail.com>]

In light of the description of the new hadrosaurid from the Amur region of 
eastern Russia, _Olorotitan arharensis_, I think some necessary discussion 
is due in regards to those often neglected on this list dinosaurs known as 
ornithischians.

GODEFROIT ET AL. 2003's ANALYSIS

Their original analysis found the following phylogeny-

--+-- _Bactrosaurus_
 `--+-- HADROSAURINAE
    `-- LAMBEOSAURINAE
       |-- _Tsintaosaurus
       `--+-- _Jaxartosaurus_
          `--+-- _Amurosaurus_
             `--+-- PARASAUROLOPHINI
                |  |-- _Charonosaurus_
                |  `-- _Parasaurolophus_
                `-- HYPACROSAURINI
                   |-- _Lambeosaurus_
                   `--+-- _Corythosaurus_
                      |-- _Hypacrosaurus_
                      `-- _Olorotitan_

Their outgroup, _Bactrosaurus_ was coded as "0" for all of the characters in 
the analysis.  However, this was incorrect for at least one character, the 
ilial antitrochanter, which according to J. Head (2001), was present in 
_Bactrosaurus_.

An issue of concern regarding Godefroit et al.'s analysis, is character 6 
(Frontal longer than wide [0], wider than long [1]).  They use a second 
state for the reversal in _Parasaurolophus_, quote: secondary elongation 
resulting of the backwards extension of the frontal platform [2].  It's not 
necessarily the same state, but I suggest that the character be revised 
perhaps to reflect only a certain part of the frontal.  I've not had the 
chance to see many hadrosauroid skulls (much less an ornithischian) in 
dorsal view, so I when I did my analysis, I used only the first two states 
and coded _P._ as having the plesiomorphy.  Thoughts from others on the 
list?

MY ANALYSIS OF IGUANODONTS... ERR... HADROSAUROIDS :-D

I was already working on a larger analysis of derived iguanodontians when I 
decided to take a look at _Olorotitan_.  I don't doubt that _Olorotitan_ 
wasn't a hypacrosaurinid, but I felt the need to re-run the analysis with 
characters I was more sure of.  My current analysis only includes characters 
from Casanovas et al. 1999, Godefroit et al. 2003, and Head 2001.  This 
meant that if I included the more basal taxa for at least this run (such as 
_Jinzhousaurus_, _Fukuisaurus_, _Probactrosaurus_, _Ouranosaurus_, and the 
Horse Mane Mountain hadrosauroid) it might have made the analysis mucked up 
with taxa that could not be coded as anything other than "?" or "0".  I 
decided to follow the phylogeny of Head 2001 and use _Eolambia_ as an 
outgroup for the rest of the taxa included.  I also included the Fontllonga 
mandible described by Casanovas et al. 1999 and (surprise, surprise) it 
occupies the same position as it did in that paper.  I choose not to include 
_Gilmoreosaurus_ because I lack sufficient references in order to code it 
for most of Godefroit et al.'s characters.  Actually, I would appreciate it 
if someone could post onlist the references for the following taxa:  
Tsintaosaurus, Bactrosaurus, Amurosaurus, Jaxartosaurus, Gilmoreosaurus, 
Pararhabdodon, Nanyangosaurus, & Telmatosaurus.

Tree length = 56
Consistency Index = 0.8929
15 taxa, 53 characters

--+-- _Eolambia_
 `--+-- _Protohadros_
    |-- _Bactrosaurus_
    `--+-- _Telmatosaurus_
       `--+-- Fontllonga Mandible
          `-- EUHADROSAURIA
             |-- HADROSAURINAE
             |  |-- _Prosaurolophus_
             |  |-- _Saurolophus_
             |  |-- _Brachylophosaurus_
             |  `-- _Edmontosaurus_
             `-- LAMBEOSAURINAE
                |-- PARASAUROLOPHINI
                |  |-- _Parasaurolophus_
                |  `-- _Charonosaurus_
                `-- HYPACROSAURINI
                   |-- _Olorotitan_
                   |-- _Corythosaurus_
                   |-- _Hypacrosaurus_
                   `-- _Lambeosaurus_

Apomorphy List (ACCTRAN)*

Fontllonga + Euhadrosauria
7(1):  Dentary tooth crowns narrow
9(1):  Form of dentary teeth not recurved

Euhadrosauria
6(1):  Coronoid process rostrally oriented
10(1):  Median carina symmetrical relative to the midline of the dentary 
crown
12(1):  Secondary ridges on dentary teeth absent

Hadrosaurinae
17(1):  Angle between the crown and root of dentary teeth less than 130 
degrees
35(1):  Maxilla nearly symmetrical in lateral view
46(1):  Distal end of ilium tapering distally

Lambeosaurinae
8(2):  Height/mesiodistal length ratio of dentary crowns more than 3
11(1):  Median carina on dentary teeth sinuous
19(1):  Ratio 'length/minimal width' of the parietal less than 2
21(1):  Hollow supracranial crest
23(1):  Frontal wider than long
24(1):  Premaxillary foramen absent
26(1):  Lateral and dorsal processes of the premaxilla contact each other 
behind the external naris
30(1):  Caudal portion of the prefrontal participating in the lateroventral 
border of the hollow supracranial crest
31(1):  Lateral side of the squamosal elevated
33(1):  Rostral process of the jugal truncated in lateral view
37(1):  Ectopterygoid ridge strongly developed on the lateral side of the 
maxilla
42(1):  Deltopectoral crest of humerus strongly developed, extending down 
below the mid-point of the humeral shaft
53(1):  Supratemporal fenestrae rounded in dorsal view

Parasaurolophini
18(1):  Parietal does not participate in the occipital region of the skull
22(1):  Deeply excavated frontal platform occupying the rostral part of the 
frontal in adults
47(1):  Distal head of fibula greatly expanded and club-shaped
48(1):  Cranial ascending process of astragalus equilateral in shape

Hypacrosaurini
25(1):  Lateral premaxillary process extending further backwards past the 
lacrimal
27(1):  Cavum nasi proprium elongate
28(1):  Nasal 50% or more of the hollow supracranial crest

*-- How do you set the character search to DELTRAN in PAUP * 4.0b10?  I want 
to rerun the analysis, but I don't know how to change the settings.

REFERENCES:

Casanovas, M., Pereda Suberbiola, X., Santafe, J., & Weishampel, D., 1999.  
A primitive euhadrosaurian dinosaur from the uppermost Cretaceous of the 
Ager syncline (southern Pyrenees, Catalonia).  Geologie en Mijnbouw 78: 
345-356

Godefroit, P., Bolotsky, Y., & Alifanov, V., 2003.  A remarkable 
hollow-crested hadrosaur from Russia: an Asian origin for lambeosaurines.  
C. R. Paleovol 2: 143-151

Head, J., 2001.  A reanalysis of the phylogenetic position of Eolambia 
caroljonesa (Dinosauria, Iguanodontia).  Journal of Vertebrate Paleontology 
21(2): 392-396




nick gardner
 = paleoartist
 = paleogeek




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