[D] Qinlingosaurus luonanensis [sG] [T]
Describer
Xue, Zhang & Bi, 1996
Time
Cretaceous Late Maastrichtian
Classification
Saurischia Sauropodomorpha Sauropoda
Diet
Herbivore
Fossilsite
Hongtuling Formation, Shaanxi, China
Length
15-20 meter
Info
Genus - Typespecies
Comments by Mickey Mortimer
Etymology
\\\\\\\"Qinling lizard from Luonan\\\\\\\", Luonan being the region of Shaanxi it was found in and Qinling being a mountain range. Hongtuling Formation, Shaanxi, China Maastrichtian, Late Cretaceous
Holotype
(NWUV 1112) caudal(?) vertebra, two other vertebrae, ilium, distal ischium
Diagnosis
Very large pointed preacetabular process extending anteriorly past pubic peduncle for about 25% of the ilium\\\\\\\'s length (measured in a horizontal axis with \\\\\\\"horizontal\\\\\\\" being parallel to a line drawn connecting the ventral tips of both peduncles) main measurements - sacral vertebra 168 mm - ilium 770 mm -
Description
This is fairly close in size to Phuwiangosaurus, for instance with an ilium of 860 mm and therefore of normal sauropod size of 15-20 meters long, depending on what family of sauropods it belongs to. Like Shanyangosaurus, this species has just a small diagnosis/description, but is represented partially in a plate.
Three vertebrae are reported, but only one is shown. I\\\\\\\'m no sauropod expert, but it appears to be a proximal caudal vertebra, although there is a large circular process on the right that I\\\\\\\'m itching to call a sacral rib. It\\\\\\\'s shown in lateral and ventral(?) view. The neural spine expands distally to form a wedge in lateral view and the centrum\\\\\\\'s not extremely procoelous, so if it is a caudal vertebra, this isn\\\\\\\'t a titanosaur, but I\\\\\\\'m not trusting my identification at this point. The ilium is typically sauropod, but is shown with different outlines in medial and lateral views. One photo lacks the dorsal region of the ilial blade, so I\\\\\\\'ll depend on the other photo for my description of the outline.
The ilium appears typically sauropod, with a reduced ischial peduncle, anteriorly projecting preacetabular process and semicircular dorsal outline. The preacetabular process projects anteriorly more than most other sauropods, about 23-27% of the ilium\\\\\\\'s total length past the pubic peduncle (measured along an x-axis, which is a line touching the ventral border of the ilial peduncles). The preacetabular process is deep and pointed and the posterodorsal margin of the ilial blade is slightly concave, though this may be due to erosion or perspective.
The ischial peduncle is very small, so that the postacetabular process projects beneath the x-axis described above. The text indicates the preacetabular and postacetabular processes \\\\\\\"curve largely outward\\\\\\\". A ischial fragment is mentioned in the materals list and a \\\\\\\"distal part of pelvic\\\\\\\" in the stratigraphical section, so I\\\\\\\'m concluding the ischial fragment is from the distal portion. It is unfortunate this is not described or figured, as it could aid greatly in identifying this species.
Relationships
This is very difficult, as the ilium is the only bone that\\\\\\\'s figured well enough for me to trust it. It\\\\\\\'s obviously more advanced than Kotasaurus, based on the semicircular dorsal outline, which is to be expected. If you trust the author\\\\\\\'s statement of the preacetabular process \\\\\\\"curving largely outward\\\\\\\", that could mean that it is a neosauropod. The reduced ischial peduncle is also supposed to be a neosauropod synapomorphy (Upchurch, 1998).
The preacetabular process is pointed, so it\\\\\\\'s not a titanosauriform (although Haplocanthosaurus also seems to have a rounded preacetabular process). On the other hand, the preacetabular process\\\\\\\'s elongation is matched only in Haplocanthosaurus and titanosaurs. So an elongate pointed preacetabular process is an apomorphy for this species (which is good, because it seems to lack others and none are listed in the diagnosis). I recommend this species be kept as Neosauropoda incertae sedis until an actual sauropod expert can examine the figures.