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

Details on Huaibasaurus



Hello fellow list-members!  Recently, George announced the new Chinese
sauropod Huaibasaurus and thanks to him and Tracy Ford, I now have the
description.  In the interest of illuminating everyone as to the morphology
and relationships of this species (especially since it was assigned to a
monotypic family), I offer a brief description.

Huaibasaurus Pang and Cheng 2000
H. allocotus Pang and Cheng 2000
"unusual North China reptile" (Huabei= phoenetic annotation of Chinese
characters for "North China", allocot= Greek for unusual)
Late Cretaceous
Huiquanpu Formation, Shanxi and Hebei, China
holotype- (HBV-20001) two teeth, incomplete postcranial skeleton
paratype- (HBV-20002) incomplete left humerus
material- two teeth, four cervical vertebrae, four dorsal vertebrae, five
sacral vertebrae, one complete rib, twenty-one caudal vertebrae, eleven
chevrons, scapulae, coracoids, humerus, radius, ilium, pubes, ischia,
femora, tibiae, fibulae, broken vertebrae, cervical and dorsal ribs
size- 20 meters long, 5 meters high
teeth- parallel-sided, no serrations, ridges on anterior and posterior
margins, spatulate crown, width/hieght ratio between Dicraeosaurus and
Brachiosaurus
cervical vertebrae- opisthocoelous, pleurocoelous, ventral surface with
lateral ridges, bifurcated neural spines with no central process, centra
subcircular in anterior view, cervical ribs longer than centra
dorsal vertebrae- oval pleurocoels, undivided neural spines, opisthocoelous,
neural spine flatted transversely
sacral vertebrae- five
caudal vertebrae- amphicoelous, no pleurocoels, neural arch displaced
anteriorly, chevrons open and not forked
scapulocoracoid- proximal scapula not expanded much, coracoid rounded
forelimb- 79% of hindlimb length, no humeral proximolateral process of
Upchurch (1998, C160), humerus/femur = .78, radius/humerus = .77
pelvis- preacetabular processes rounded and not flared laterally, dorsal
edge of ilium convex, ischial peduncle reduced, ischium 76% of pubic length,
not directed ventrally, distal end slightly expanded
hindlimb- femur transversely oval in section, lateral bulge present, fourth
trochantor on caudolateral edge of shaft, tibia 75% of femur
Systematic position- The authors state H. allocotus is closer to diplodocids
and titanosaurids than to vulcanodontids, cetiosaurids, brachiosaurids and
camarasaurids using the old system of peg vs. spatulate teeth.  They
conclude it is most closely related to the titanosaurids (although not
Phuwiangosaurus or Opisthocoelicaudia) and say that "Titanosaurus" falloti
should be reassigned to Huaibasaurus.  I added H. allocotus to the data
matrix of Upchurch (1998) and found it to be the sister group to
Phuwiangosaurus based on bifurcated cervical neural spines without a small
central process and coracoid rounded (reversal).  Characters acquired
convergently by H. allocotus are:
- ventral surface of cervical centra transversely concave and laterally
bound by ridges
- elongation index values for caudal dorsal centra less than 1.0 (reversal)
- neural spines of proximal caudals craniocaudally compressed
- proximal end of scapula with small acromial process (reversal)
- width across ischial shaft divided by ischial length .2-.3
- tibia/femur ratio more than .7
As for the claim that "Titanosaurus" falloti is close to H. allocotus,
Allian et al. (1999) found that this species is indeterminate and assigned
it's materal to a new species, Tangvayosaurus hoffeti, which they placed
closest to Phuwiangosaurus.  So, Pang and Cheng weren't completely wrong in
their conclusion.

reference- Pang and Cheng, 2000. A new family of sauropod dinosaur from the
Upper Cretaceous of Tianzhen, Shanxi Province, China. Acta Geologica Sinica,
vol. 74, no. 2, 117-125.

As for the other new genus mentioned by George, Chuanjiesaurus anaensis, the
entire paper is in Chinese, so I cannot decipher it, although it may be from
the "Dawan" Formation, and three limb ratios, listed in order are .83, .65
and .67.  It has nine cervical vertebrae.  The skeleton includes at least
twelve articulated vertebrae, a scapula, humerus and other limb bones and
ribs.

Finally, the description of Mamenchisaurus youngi was also sent (and is also
in Chinese).  The skeleton is complete except for some dorsal ribs, all
caudals past the eighth (except for six mid caudals), all chevrons except
for three proximal ones, the sternal plates, clavicles, an ilium, a pubis, a
femur, a tibia, a fibula and one pes.There are eighteen cervicals, twelve
dorsals and five sacrals.  The skull is very well preserved and similar to
Euhelopus.  Other details include 8 maxillary teeth, 22-24 dentary teeth and
manual phalangeal formula 2-2-3-2-2.

I hope this helped those of you without the references at hand.  If anyone
has any questions, feel free to ask.

Mickey Mortimer