Feeding traces left by colonies of dermestid beetles in specimen MPC-D 107/15.

<p>Articular surfaces have been completely obliterated in the left forearm (A), left leg and pes (B), as well as in the right forearm (C). Circular borings are particularly evident in the left side of the skull (D–F). G, Bone-chip burrow found under the skull of the specimen. H, large traces of reworked sediment under the skeleton.</p

Hands of <i>Nemegtomaia barsboldi</i>.

<p>A, preserved elements and reconstructed manus of MPC-D 107/15 in dorsal (a1) and lateral (a2) views: B, right manus of MPC-D 107/16 in dorsal (b1) and medial (b2) views; C, left manus of MPC-D 107/16 in medial (c1) and dorsal (c2) views, with the preserved distal portions of radius and ulna. <b>lr</b>, left radius; <b>lu</b>, left ulna. Scale bar 5 cm. Illustration by Marco Auditore.</p

Phylogeny of Oviraptoridae.

<p>Phylogenetic analysis of Oviraptoridae was performed by adapting the matrix of Longrich et al. (3) and using the exhaustive search algorithm of PAUP* 4.0b10. Numbers next to clades indicate bootstrap support value/decay value.</p

Eggs of <i>Nemegtomaia barsboldi</i>.

<p>Details of eggs preserved in the upper layer of eggs in specimen MPC-D 107/15. Scale bar A–E 5 cm.</p

Nest and preserved elements of <i>Nemegtomaia barsboldi</i> (MPC-D 107/15).

<p>A, dorsal view; B, left lateral view; C, right lateral view; D, posterior view. <b>lf</b>, left femur; <b>lfi</b>, left fibula; <b>lh</b>, left humerus; <b>lm</b>, left manus; <b>lp</b>, left pes; <b>lpu</b>, left pubis; <b>lr</b>, left radius; <b>ls</b>, left scapula; <b>lt</b>, left tibia; <b>lu</b>, left ulna; <b>rf</b>, right femur; <b>rfi</b>, right fibula; <b>rh</b>, right humerus; <b>rp</b>, right pes; <b>rpu</b>, right pubis; <b>rs</b>, right scapula; <b>rt</b>, right tibia; <b>sk</b>, skull. Scale bar 10 cm. Reconstruction by Marco Auditore.</p

Skeletons of <i>Nemegtomaia barsboldi</i> specimens (known elements in grey).

<p>A, the holotype (MPC-D 100/2112); B, MPC-D 107/15 (the left side of the skull, left forelimb, pubis and toes are reversed and superimposed to the right side). C, MPC-D 107/16 (the left forelimb is reversed and superimposed to the right side). In D, the preserved elements of MPC-D 107/15 and 16 are scaled to and superimposed on the holotype (the skull depicted is that of the better preserved MPC-D 100/2112). Scale bar 20 cm. Illustration by Marco Auditore.</p

The nest of <i>Nemegtomaia barsboldi</i>, MPC-D 107/15.

<p>A, disposition of preserved eggs within the nest. Eggshells have been recovered under the skull (B), left pes (C) and leg (D), suggesting the direct apposition of the oviraptorid on top of the eggs. During the early excavation of the nest, it was possible to document a lower layer of eggs lying approximately 10 cm below the body (E–G).</p

Skull of <i>Nemegtomaia barsboldi</i> (MPC-D 107/15).

<p>A, preserved elements of the right side; B, preserved elements of the left side; C, reversed elements of the left side superimposed to those of the right side (where elements of both sided overlap, the grey is darker); D, reconstruction of the skull. <b>an</b>, angular; <b>d</b>, dentary; <b>ec</b>, ectopterygoid; <b>eo</b>, exoccipital; <b>f</b>, frontal; <b>j</b>, jugal; <b>l</b>, lacrimal; <b>m</b>, maxilla; <b>n</b>, nasal; <b>p</b>, parietal; <b>pm</b>, premaxilla; <b>po</b>, postorbital; <b>q</b>, quadrate; <b>qj</b>, quadratojugal; <b>sa</b>, surangular; <b>sq</b>, squamosal; <b>sr</b>, sclerotic ring. Scale bar 10 cm. Illustration by Marco Auditore.</p

Location map showing the position of the measured section discussed in the text.

<p>A, Northern <i>Sayr</i>, where specimen MPC-D 107/15 was collected. B, lithostratigraphic logs showing the relative stratigraphic occurrence of the interfingering Baruungoyot and Nemegt formations. C, In-situ and partially reworked caliche glaebules and concretions, Baruungoyot Formation. D, tubular burrow fills interpreted as nonmarine invertebrate feeding traces, Baruungoyot Formation. E, cross-bedded deposits in the basal deposits of the Nemegt Formation. F, photograph showing the interfingering contact between the Baruungoyot and Nemegt formations in the Northern Sayr (litho-log c). MPC-D 107/15 was collected just below the Nemegt tongue deposits.</p

The Nemegt locality the Gobi Desert, southern Mongolia.

<p>A, map showing the location of the study area within southern Mongolia; B, the Nemegt area is located a few kilometers south of the massif of the same name; C, a detail of the Nemegt locality (<i>sensu</i> 5), showing the exact locations of specimens described in this study.</p