Here's another from the same paper as Tugulusaurus. It's been called a dromaeosaurid, but is it?
Phaedrolosaurus Dong 1973
P. ilikensis Dong 1973
Etymology- "shining lizard", from Greek phethon.
Lianmugin Formation of Tugulu Group, Xinjiang, China
Lectotype- (IVPP V 4024-1) (~7 m) tooth (31 mm)
referred- (IVPP V 4024-2) (2.5-4.2 m) tibiotarsi (320 mm)
(IVPP V 4024-3) proximal femur
Diagnosis- anterior serrations basally absent but tooth mediolaterally thicker than Deinonychus, Saurornitholestes, Velociraptor or Ricardoestesia (provisional diagnosis, may be nomen dubium).
This description is plagued with the same poor translation and figures as Tugulusaurus. The tooth is about twice the size of Deinonychus, which would indicate a theropod about seven meters long. The tibia would indicate an animal 2.5 to 4.2 meters long, depending on what we scale it to.
The holotype is a tooth whose outline is near identical to Deinonychus (fig. 23A in Ostrom 1969). It is compressed, recurved and serrated like most theropods. Serrations extend from the base to the tip of the posterior carina, with eighteen serrations per five mm. The base of the anterior carina is smooth, but serrations are present starting half way up. It is said to be thicker than Deinonychus teeth.
The proximal femur is briefly mentioned, but not described or illustrated. It was found at a separate site, so should not be regarded as Phaedrolosaurus. Barsbold and Osmolska (1999) note that this femur has a wing-like lesser trochantor.
A pair of tibiotarsi were found in the same horizon, but again at a different site, and referred to Phaedrolosaurus. The tibia is fused with the fibula and astragalocalcaneum. It is fairly straight in anterior(?) view and expands proximally. The distal end differs from Deinonychus and Velociraptor in that the calcaneum projects strongly laterally and there is a pronounced step in the lateral projection of the astragalus. The tibia is said to have a conspicuous cnemial crest and be round in cross section. The fibula is very slender and extends to the calcaneum. It is described as having a deep proximomedial fossa and a jacent process (tubercle for m. iliofibularis?) that becomes a ridge at the outer margin. The astragalus has a high ascending process.
Both Molnar (pers. comm. to Glut 1989) and Sues (1977) state that Phaedrolosaurus appears dromaeosaurid. Barsbold and Osmolska (1999) say the wing-like lesser trochantor is distinctly non-dromaeosaurid. Besides these opinions, authors have generally just placed this genus in the Dromaeosauridae without question. Let's compare the remains to dromaeosaurids.
First, note that the tooth, femur and tibiotarsi should not be regarded as pertaining to the same species as there was no association. The tooth shares the lack of basal anterior serrations with dromaeosaurids, but other groups as well. Nothing in it's basic morphology prevents it from being a dromaeosaurid tooth. The wing-like lesser trochantor is unlike the finger-like trochantor in dromaeosaurids. The tibia is fused with the fibula and astragalocacaneum, unlike dromaeosaurids. The deep proximomedial fibular fossa is a plesiomorphic character lost in dromaeosaurids. Phaedrolosaurus does have a high ascending process and fibular-calcaneal contact like dromaeosaurids, but these are coelurosaur symplesiomorphies. So, while the tooth might be dromaeosaurid, the limb elements are most certainly not.
The tooth, which is the only element that should be referred to Phaedrolosaurus, is finely serrated, compressed, recurved and lacks basal serrations anteriorly. The only theropods with these characters are dromaeosaurids, Ricardoestesia and compsognathids. Unfortunately, basal coelurosaur teeth are very rare and undescribed for the most part and Ricardoestesia's affinities are unknown. Pheadrolosaurus is probably either a basal coelurosaur or dromaeosaurid, but exact relations cannot be determined at this time. The tooth is said to be thicker than Deinonychus and Velociraptor. This would also imply it is thicker than Ricardoestesia and Saurornitholestes. Perhaps it is a diagnostic character. If not, one should wait for a detailed comparison of dromaeosaurid teeth (serration frequency, morphology, cross-section) until such a taxon is declared nomen dubium.
The proximal femur referred to Phaedrolosaurus is not oviraptorosaur or eumaniraptoran, as these groups have either finger-like or fused lesser trochantors. The lack of further information makes a more exact placement impossible, although this would allow the possibility of a basal coelurosaur affinity. In this case, it could come from Phaedrolosaurus.
The tibiotarsus has a deep proximomedial fibular fossa, which is unknown in maniraptorans except for oviraptorids. The high ascending process is characteristic of coelurosaurs. The presence of fibular-calcaneal contact eliminates some derived eumaniraptorans (mononykines, troodontids, Rahonavis, pygostylians). The presence of a fused astragalocalcaneum, which is also fused to the tibia, is only known in some maniraptorans. Thus, at first glance, the deep proximomedial fibular fossa and fused tibiotarsus seem to be mutually exclusive in theropods (the first being absent in maniraptorans and the second present). Oviraptorids are the single maniraptoran group with a deep proximomedial fibular fossa and a fused tibiotarsus. Are these tibiotarsi from an oviraptorid? Nothing contradicts this, although better support would be preferred. This is because the fused tibiotarsus may be age-related and have a wider distribution than currently thought. Thus, I recommend the tibiotarsi be classified as a non-eumaniraptoran coelurosaur, possibly oviraptorid. These specimens could therefore belong to Phaedrolosaurus, if it is a basal coelurosaur, but not if it is dromaeosaurid. If the tibiotarsi are oviraptorid, they certainly could not be Phaedrolosaurus. They could also hypothetically be from the same species as the proximal femur, if they aren't oviraptorid. It might be noted that the tibiotarsus is diagnostic, possessing a distinctly medially projecting calcaneum, similar but more extreme than Nedcolbertia, Harpymimus, Aublysodon and Tyrannosaurus.
Those of you who want figures of the tooth and tibiotarsus (one page), contact me offlist. Next I'll do Nanshiungosaurus bohlini. Is it Nanshiungosaurus? We'll find out soon.