Zanno et al. present a poster on what was previously reported by Zanno (2008) as another Falcarius bonebed in the Cedar Mountain Formation of Utah, but which seems to be a more derived therizinosaur now. Originally differences were thought to be ontogenetic, but size comparisons and histology disproved this. In the new taxon, "the more prominent development of the altiliac condition of the ilium, large distal boot of the pubis measuring more than half the pubic length, relatively straight and acuminate symphyseal aspect of the dentary, reduced recurvature of the dentary teeth, and marked ventral displacement of the mandibular condyle of the quadrate appear distinct."
Larson et al. performed a morphometric analysis of Dinosaur Park coelurosaur frontals, and found that supposed therizinosaur frontal CMN 12355 grouped with Troodon, so is troodontid instead. Since Erlikosaurus wasn't included, I'm not sure how powerful this analysis is however. They say CMN 12355 "shares the following features with Troodon: a shallow lateral wall defining the fossae for the olfactory system, the exclusion of the supratemporal fossa from the dorsal surface of the frontal, and a raised orbital rim." Yet Erlikosaurus also has a shallow lateral olfactory wall (Lautenschlager et al., 2014), both therizinosaurs and troodontids are polymorphic for raised orbital rims (e.g. present in Falcarius and the Nanchao therizinosaur embryo, absent in Sinornithoides), and Troodon, Erlikosaurus and CMN 12355 all have dorsal exposure of the supratemporal fossa. They further state CMN 12355 "differs from the holotype of Erlikosaurus (IGM 100/111) in the construction of the lacrimal-frontal joint", and indeed the prefrontal-frontal articular surface in Erlikosaurus (which doesn't even have lacrimal-frontal contact) isn't exposed dorsally, unlike the contact in Troodon and CMN 12355. In comparing them myself, CMN 12355's orbital outline resembles Erlikosaurus more, but the supratemporal fossae are intermediate in their separation. Ventrally, the less anteriorly expanded olfactory bulbs and more posteriorly expanded cerebral fossae are similar to Troodon, but the prefrontal/lacrimal facet is placed far more anteromedially then in either Troodon or Erlikosaurus. So in the end I'm not convinced either way, and think CMN 12355 might belong to something else entirely. Larson et al. state "this removes the only record of a therizinosaur from the well-sampled Campanian-Maastrichtian fossil record of North America, suggesting the extinction of this group in North America prior to the Campanian,", but besides two more Dinosaur Park frontals referred to therizinosaurs by Currie (1992, 2005), there's also the pedal ungual RTMP 79.15.1 he mentions. Ryan and Russell (2001) list a cervical from the Scollard Formation of Alberta (RTMP 86.207.17), and Russell (1984) reported a therizinosaurid astragalus from the Hell Creek Formation of Montana. So maybe these other records are misidentified too, but there's more work to be done before we can reach Larson et al.'s conclusion.
|Supposed therizinosaur or troodontid frontal CMN 12355 (after Sues, 1978). Ventral (left) and dorsal (right) views.|
Allain reports a new Ichthyovenator specimen which preserves "the complete cervical skeleton and the first dorsal vertebra, as well as the left pubis, seven additional caudal vertebrae and three teeth." Interestingly, "the first dorsal vertebra of Ichthyovenator is nearly identical to the holotypic vertebra of the enigmatic theropod Sigilmassasaurus brevicollis", so there's more evidence Sigilmassasaurus is Spinosaurus. "In addition to the peculiar morphology of posterior cervical and anterior dorsal vertebrae, the straight unserrated crowns of the teeth of Ichthyovenator suggest it is more closely related to Spinosaurinae than previously thought." Since my analysis including Ichthyovenator in partially corrected versions of Allain et al.'s and Carrano et al.'s matrices found it to take 0-2 more steps to be a spinosaurid than a carnosaur, and this new data provides those extra steps, I now agree the genus is spinosaurid and possibly spinosaurine.
McFeeters et al. do a rather cool thing and examine reports of ornithomimids from Foremost, Oldman and Milk River Formations of Western North America. They find pedal material from the
Lu et al. (misspelled as La in the abstract book) report yet another new oviraptorid from the Nanxiong Formation in addition to the prefix-triangle of Ganzhousaurus nankangensis, Nankangia jiangxiensis and Jiangxisaurus ganzhouensis, as well as the juvenile Banji long. These all actually fall out in different parts of the tree in the Lori analysis, and at least three do in the Anzu analysis, so maybe they're all valid. This new taxon is known from a partial skeletopn with incomplete skull and mandible and is "characterized by an anterodorsally sloping occiput and quadrate (shared with Citipati), a small circular supertemporal fenestra (much smaller than the lower temporal fenenstra), and the dorsal margin of the dentary above the external mandibular fenestra is strongly concave ventrally." In what I assume is a version of the Maryanska et al. analysis used in all current oviraptorosaur papers, it falls out sister to Citipati. This matches one of the named Nanxiong species in the Lori analysis, so maybe we finally have a synonymy. Might I suggest we start a new prefix-triangle and name this one 'Longia nanxiongia', then the next named species can be 'Nanxiongsaurus banjiensis'.
Button et al. have a poster on a new coelurosaur found in 2012
Poust et al. present the tenth supposed new Jehol microraptorian species, D2933 from the Jiufotang Formation. This "possesses several autapomorphies, including more than 29 tail vertebrae, inclined pneumatic foramina on the dorsal vertebrae, and an unusually large coracoid fenestra", and is supposedly sister to Sinornithosaurus The Cryptovolans holotype has 28-30 caudals, other Microraptor specimens often have about 26, and no complete tail is known in described Sinornithosaurus. While the Microraptor hanqingi specimen lacks inclined dorsal pleurocoels (I assume that means anterodorsally oriented), we don't know the condition in any other described microraptorian specimen. Finally, I don't know how big the supracoracoid fenestra is in D2933, but Sinornithosaurus specimens have fenestrae varying in size between 27 and 35 percent of coracoid height. Poust et al. state "all visible neurocentral sutures, and proximal tarsals remain unfused. The porous surface texture of the cortical bone and poor ossification of long bone articular surfaces further supports an immature status. Histologic samples of the tibia, fibula, and humerus confirm that it was about one year old and still growing at death." As D2933 is smaller than Sinornithosaurus, differences could be ontogenetic, and indeed increased ossification with age could shrink the supracoracoid fenestra's size. It has "filamentous feathers, pennaceous feathers extending from the fore- and hindlimbs, and two long plumes extending more than 12 cm beyond the caudal series", which the authors contrast with Sinornithosaurus that shows "only branching filamentous feathers." They propose "that this simplified condition is a secondary loss of feathers, either as a feature of the genus [Sinornithosaurus], or as part of an ontogenetic loss of 'advanced' feather types in adults." Or maybe it's taphonomic, as described Sinornithosaurus specimens are disarticulated. Much as with Lefevre et al.'s talk, I think we need a Lagerstatten rule for dinosaurs- 'Do not ascribe to phylogeny that which can be explained by taphonomy'.
Kobayashi et al. present a poster on what I assume is a specimen of "Gallimimus" mongoliensis that's basically identical to their 2007 SVP abstract, so I hope we see this taxon published soon.
Gerke and Wings have an interesting study of Late Jurassic German theropod teeth. "Four Langenberg Quarry teeth, previously assigned to velociraptorine dinosaurs, are removed from Dromaeosauridae and regarded as belonging to Tyrannosauroidea, Neotheropoda and Megalosauridae based on their dental characters." Maybe their DFA analysis could be used to classify other supposed dromaeosaur teeth that plague studies depending on Dinosaur Park morphologies.
Malafaia et al. present information on a new Lourinha megalosauroid specimen represented by "several cranial fragments including an incomplete left maxilla." Several characters differ from Torvosaurus, known there from T. gurneyi. So this may be Lourinhanosaurus, which is coelurosaurian in Carrano et al.'s tetanurine matrix partly due to miscoding it as lacking a pubic obturator fenestra.
|Velocipes guerichi holotype proximal fibula in a (lateral), b (posterior), c (medial) and d (anterior) views, with proximal view on top and cross sections at right (after Huene, 1932).|
That's it for SVP 2014. Hope you enjoyed my theropod rundown.
Edit: Thanks to Brad McFeeters for correcting some of the information here, with the corrected info bolded above and the original wrong text crossed out. It's like peer review for blogs. :)