with a center devoid of eggs. The nest of Beibeilong was composed of two layers of eggs, despite other Macroelongatoolithus nests preserving only a single layer of eggs. When brooding the nest, the adult would have sat in the centre of the clutch, as also proposed for the smaller oviraptorids. Most notably, the team suggested that the entire Beibeilong nest was likely in an advanced stage of incubation when it was buried given that perinate skeletal remains were found in association with 2–3 eggs in the block specimen, including Baby Louie itself. They also noted that Macroelontaoolithus (including eggs associated with Beibeilong) and other elongatoolithid eggs/nests are very similar in clutch configuration, overall morphology, as well as eggshell texture and histology. These traits indicate that both caenagnathids and oviraptorids probably had fairly comparable nesting behaviours, but also that these features are ancestral for at least the whole Caenagnathoidea (superfamily containing both Caenagnathidae and Oviraptoridae). In 2018, Kohei Tanaka and team examined several egg clutches of numerous oviraptorosaur specimens, including egg clutches assigned to Macroelongatoolithus, in order to evaluate how the nest configuration correlates to the body size in oviraptorosaur incubation behaviour. Eggshell porosity reflects that eggs of almost certainly all oviraptorosaurs were exposed in the nest without an external covering. Though most oviraptorosaur nests have eggs arranged in a circular fashion, the morphology of the nest is different in smaller and larger species. Small-bodied oviraptorosaurs (such as oviraptorids with small Elongatoolithus eggs) arranged their nests packed with eggs and a rather small nest center. In contrast, large-bodied oviraptorosaurs (like Beibeilong or Gigantoraptor with large Macroelongatoolithus eggs) built their nests in a ring-like fashion with a considerably large center devoid of eggss. These nest strategies indicate that whereas small-sized oviraptorosaurs sat directly on the eggs, gigantic oviraptorosaurs, such as Beibeilong or Gigantoraptor, likely sat on the central area devoid of eggs. Tanaka and colleagues pointed out that this adaptation was beneficial to avoid egg-crushing because of the body dimensions of nesting adults, and also could have allowed some body-contact during incubation in these giant oviraptorosaurs. Paleoenvironment Beibeilong remains have been recovered from the Gaogou Formation located in the Xixia Basin, a unit that dates back to the Late Cretaceous epoch about 96 million and 88 million years ago (Cenomanian-Coniacian stages). This unit is separated into three members: an upper member characterized by alluvial fan and traction current deposits; and the middle