Troodontidae (Dinosauria: Theropoda) from the Upper Cretaceous of Uzbekistan

Abstract

To date three taxa of troodontid theropod dinosaurs have been recognized from Upper Cretaceous strata in two regions of the Kyzylkum Desert in Uzbekistan. The Cenomanian Khodzhakul Formation in the southwestern Kyzylkum Desert has yielded isolated serrated teeth and some postcranial bones of an indeterminate troodontid. In the central Kyzylkum Desert troodontids are known from the Cenomanian Dzharakuduk Formation (Urbacodon itemirensis) and the Turonian Bissekty Formation (Urbacodon sp.). Urbacodon itemirensis is known from a single dentary whereas Urbacodon sp. is represented by isolated teeth, maxilla and dentary

New tyrannosaur from the mid-Cretaceous of Uzbekistan clarifies evolution of giant body sizes and advanced senses in tyrant dinosaurs

“…90-92 million years ago) Bissekty Formation of Uzbekistan. This formation has recently emerged as one of the most important records of midCretaceous dinosaurs globally (9)(10)(11). Possible tyrannosauroid specimens from the Bissekty Formation were reported more than a half century ago (12), and, more recently, several isolated fossils were assigned to the group (9, 13), but none of these has been particularly complete or diagnostic at the species level, and their phylogenetic relationships have been difficult to assess.…”

A Small-Bodied Troodontid (Dinosauria, Theropoda) from the Upper Cretaceous Wulansuhai Formation of Inner Mongolia, China

“…The lateral surfaces apparently lack pneumatic foramina, though the rough surfaces suggest the caudals have been seriously weathered. The ventral surface of the centra are marked by a distinct shallow groove as in other troodontids (Averianov & Sues 2016; Zanno et al . 2011).…”

“…Other detailed morphology of the postzygapophysis remains unclear due to erosion. No trace of a spinopostzygapophyseal fossa is present, a feature that differs from Urbacodon (Averianov & Sues 2016). In anterior or posterior views, the neural canal is oval shaped, which is roughly as big as the spinoprezygapophyseal fossa (Fig.…”

“…The centra are rod-like and amphiplatyan, and all intercentral articular surfaces are only slightly concave. In lateral view, there is no offset between the anterior and posterior articular surfaces, but the dorsal and ventral margins of the vertebra are gently concave at the midpoint as in most other dinosaurs (Averianov & Sues 2016; Norell et al . 2009) (Fig.…”

A new species of troodontid theropod (Dinosauria: Maniraptora) from the Horseshoe Canyon Formation (Maastrichtian) of Alberta, Canada

“…The dorsal surface is dominated by a broad, parasagitally oriented groove that extends from the posterior end of the nasal suture towards the supratemporal ridge. This groove is often cited as a distinctive characteristic of troodontids (Evans et al 2014;Makovicky and Norell 2004), and contrasts with the flat condition seen in adult dromaeosaurids and ornithomimids (Currie 1987b;Longrich 2008a), and the weakly concave frontals of therizinosaurs (Averianov 2016;Averianov and Sues 2016). Laterally, this groove defines a strongly upturned orbital rim.…”