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

RE: Heyuannia and Lu's monograph

jay nair wrote-

Lu mentions two other oviraptorosaurs.

The first (BPV-112) is based on a nearly complete
sacrum, 3 posterior dorsals, 3 articulated anterior
caudals, 2 ilia and portions of the hindlimbs.
Lu refers it to Caenagnathidae gen et sp indet.
BPV-112 is a new taxon, but isn't named because of the
scarce materials. Phylogenetically, it sits closest to
Chirostenotes in Lu's analyses.
Two autopomorphies include the higher ratio of the
height/length of the ilium (not so convincing
considering the variability of ratios in specimens of
Ingenia) and the presense of a large foramen on the
proximal and of the femur.
I think BPV-112 maybe is the first definite
caenagnathid from China. It's from the Maastrichtian
Pingling Formation.

Funny how people don't understand the concept of a specimen being indeterminate. If it's a new taxon with autapomorphies, it can't be gen. et sp. indet.. Lu actually names this in his thesis (which I'm betting is almost identical to this book). When I ran my analysis back in May, it came out as the sister group of Caenagnathoidea.

The second unnamed oviraptorid is unnumbered. It is
specimen E-1 at the Nanxiang Musuem, so Lu temporarily
calls it NXMV.
NXMV is the rear half of a skull & nearly complete
lower jaw, 2 cervicals, 9 dorsals & an incomplete
right pes. Originally thought to be from Paleocene
deposits, a Late Cret age is shown from K-Ar dating
(Pingling Member of the Shanghu Formation).
So NXMV may prove to be the youngest known member of
the Oviraptoridae.  Lu also decides not to name it
because it's still in preparation. Expect a more
detailed publication with a name for NXMV from Lu in
the future.
The lower jaw seems closer to Oviraptor
(philoceratops) in its proportions. The vertebrae have
well developed pleurocoels. NXMV is nested closest to
Heyuannia & Nemegtia in Lu's analysis.

This specimen came out sister to Rinchenia in my analysis.

The most interesting outcome of Lu's strict concensus
tree is that Alvarezsauridae form the sister taxon to
[Therizinosauroidea + Oviraptorosauria] - far away
from a relatively 'basal' Ornithomimosauria.

This happened in the first Theropod Working Group published analysis too. Back in the Ostrom volume.

Graphically, Lu's phylogeny is-

           |  `--Chirostenotes
                 |  `--+--Oviraptor
                 |     `--GIN 100-42

Note he had to exclude Herrerasaurus, Coelophysis and Confuciusornis from Maryanska et al.'s matrix to achieve this result. When the former two are included, Avimimus is the most basal, Microvenator is sister to Chirostenotes+BMV-112, and Oviraptor is the basalmost caenagnathoid.

Compare this to my results as of May-
                             |  `--Heyuannia
                             `--+--Citipati (includes GIN 100-42)
                                `--+--+--ZPAL MgD-I/95
                                   |  `--Ingenia

There are definitely some similarities. They both share the same basic topology-

Since May, I've added many codings for Nemegtia, but I'm in the process of reformatting the drive on the computer with PAUP, so I can't see the codings' effect yet.

Mickey Mortimer