A new baby oviraptorid dinosaur (Dinosauria: Theropoda) from the Upper Cretaceous Nemegt Formation of Mongolia

Abstract

Recent discoveries of new oviraptorosaurs revealed their high diversity from the Cretaceous Period in Asia and North America. Particularly, at the family level, oviraptorids are among the most diverse theropod dinosaurs in the Late Cretaceous of Mongolia and China. A new oviraptorid dinosaur Gobiraptor minutus gen. et sp. nov. from the Upper Cretaceous Nemegt Formation is described here based on a single holotype specimen that includes incomplete cranial and postcranial elements. The most prominent characters of Gobiraptor are its thickened rostrodorsal end of the mandibular symphysis and a rudimentary lingual shelf on each side of the dentary. Each lingual shelf is lined with small occlusal foramina and demarcated by a weakly developed lingual ridge. This mandibular morphology of Gobiraptor is unique among oviraptorids and likely to be linked to a specialized diet that probably included hard materials, such as seeds or bivalves. The osteohistology of the femur of the holotype specimen indicates that the individual was fairly young at the time of its death. Phylogenetic analysis recovers Gobiraptor as a derived oviraptorid close to three taxa from the Ganzhou region in southern China, but rather distantly related to other Nemegt oviraptorids which, as the results of recent studies, are also not closely related to each other. Gobiraptor increases diversity of oviraptorids in the Nemegt Formation and its presence confirms the successful adaptation of oviraptorids to a mesic environment.

A new paravian dinosaur from the Late Jurassic of North America supports a late acquisition of avian flight

“…Within Caenagnathoidea, our results should be considered incomplete pending incorporation of characters from Maryanska, Osmolska & Wolsan (2002) and its derivatives. Notable similarities to (Lee et al, 2019) include Nomingia as an oviraptorid and a clade of Nemegtomaia and Heyuannia . Major differences include non-caenagnathoid Ganzhousaurus (one step needed to make oviraptorid; emerges sister to Heyuannia ), caenagnathid Avimimus (three steps to place outside Caenagnathoidea) and Machairasaurus (two steps needed to make oviraptorid; emerges basalmost), and oviraptorid Microvenator (one step needed to make caenagnathid, three steps to move it outside Caenagnathoidea), Gigantoraptor (four steps needed to make caenagnathid; emerges basalmost), and Beibeilong (two steps needed to make caenagnathid; second branching after Microvenator ).…”

The skull evolution of oviraptorosaurian dinosaurs: the role of niche partitioning in diversification

“…The unusual skulls of oviraptorosaurs probably enabled distinctive diets compared to most theropods, although feeding habits are controversial. Direct evidence of herbivory is known in some basal oviraptorosaurs (Ji et al, ; Ji, Lü, Wei, & Wang, ; Xu et al, ), and diets such as herbivory, carnivory, omnivory and durophagy have been proposed for advanced oviraptorosaurs based on their osteological features (Funston & Currie, ; Funston, Currie, & Burns, ; Lee et al, ; Osmolska et al, ; Zanno & Makovicky, ).…”

A new alvarezsaurid dinosaur from the Nemegt Formation of Mongolia

“…The site is located on a gentle slope, and many of the fossils were buried inside the rock. The oviraptorid specimens consist of the holotype of Gobiraptor minutus and at least two other larger undescribed individuals mainly represented by a sacrum and partial hind limb elements 45 . Similarly, alvarezsaurid specimens in this assemblage include postcranial elements of three individuals which share peculiar hind limb morphology of alvarezsaurids, such as the elongated distal hind limbs, greatly reduced fibula, and the unique arctometatarsal condition.…”