A New Oviraptorosaur (Dinosauria: Oviraptorosauria) from the Late Cretaceous of Southern China and Its Paleoecological Implications

<div><p>A new oviraptorosaur <i>Nankangia jiangxiensis</i> gen. et sp. nov. is described on the basis of a partial postcranial skeleton with a partial lower jaw collected from the Upper Cretaceous Nanxiong Formation of Ganzhou, in Jiangxi Province of southern China. The new taxon is diagnosed by: (1) a mandibular symphysis that is not turned down; (2) neural spines of the cranial caudal vertebrae that are wider transversely than anteroposteriorly, forming a large posterior fossa with rugose central areas; (3) a femoral neck extending at an angle of about 90 to the shaft; and (4) a ratio of femur to tibia length of 0.95. Phylogenetic analysis recovers <i>Nankangia</i> as basal to the oviraptorid <i>Yulong</i>, but more derived than <i>Caenagnathus</i>, which also has a mandibular symphysis that is not turned down. The coexistence of <i>Nankangia jiangxiensis</i>, <i>Ganzhousaurus nankangensis, Jiangxisaurus ganzhouensis</i>, an unnamed oviraptorid from Nanxiong Basin and <i>Banji long</i> suggests that they occupied distinct ecological niches. <i>Nankangia</i> may have been more herbivorous than carnivorous.</p></div

Femur, tibia, and proximal tarsals of <i>Nankangia</i> (GMNH F10003).

<p><b>A</b>, Left femur in posterior view; <b>B</b>, Right femur in posterior view; <b>C</b>, Close up of the distal portion of the right femur in posterior view, showing the pathological area; <b>D</b>, Right femur and tibia in anterior view; <b>E</b>, Close-up of the distal portion of the tibia, the astragalus, and the calcaneum in anterior view; <b>F</b>, Left femur in lateral view. Abbreviations: ap., ascending process of astragalus; cal., calcaneum; f1–f3, fossae 1–3; path., pathological areas. Scale bar  = 1 cm in <b>C</b>; 5 cm in other images.</p

Right humerus of <i>Nankangia</i> (GMNH F10003), in posterior (A), anterior (B), medial (C), and lateral (D) views.

<p>Scale bar  = 5 cm.</p

Scapulocoracoids of <i>Nankangia</i> (GMNH F10003) in lateral (right scapulocoracoid) and medial (left scapulocoracoid) views.

<p>Abbreviations: acr., acromion of the scapula; cf., coracoid foramen; cr., coracoid; hlpp., horn-like posteroventral process; lsc., left scapula; rsc., right scapula. Scale bar  = 5 cm.</p

Comparisons of lower jaws (anterior ends) of some oviraptorosaurs.

<p><b>A</b>, <i>Caudipteryx</i> sp. (IVPP 12430, modified from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0080557#pone.0080557-Zhou1" target="_blank">[14]</a>) (reversed); <b>B</b>, <i>Yulong mini</i> (HGM 41HIII-0109); <b>C</b>, <i>Khaan mckennai</i> (IGM 100/973, modified from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0080557#pone.0080557-Balanoff1" target="_blank">[12]</a>); <b>D</b>, <i>Nemegtomaia barsboldi</i> (GIN100/2112); <b>E</b>, <i>Incisivosaurus gauthieri</i> (IVPP V13326); <b>F</b>, <i>Chirostenotes pergracilis</i> (CMN 8776: <i>Caenagnathus collinsi</i>, from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0080557#pone.0080557-Currie2" target="_blank">[27]</a>; reversed); <b>G</b>, “<i>Caenagnathus</i> cf. <i>sternbergi</i>” (RTMP 92.36.390, from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0080557#pone.0080557-Currie2" target="_blank">[27]</a>). <b>H</b>, <i>Nankangia jiangxiensis</i> gen. nov. (GMNH F10003). Scale bars  = 1 cm.</p

Comparison of ilia among selected oviraptorosaurs in right lateral view.

<p><b>A</b>, Left ilium of <i>Caudipteryx dongi</i> (reversed); <b>B</b>, Left ilium of <i>Chirostenotes pergracilis</i> (reversed); <b>C</b>, Right ilium of <i>Ingenia yanshini</i>; <b>D</b>, Right ilium of <i>Rinchenia mongoliensis</i>; <b>E</b>, Right ilium of <i>Heyuannia huangi</i>; <b>F</b>, Right ilium of <i>Nemegtomaia barsboldi</i>; <b>G</b>, Left ilium of <i>Nomingia gobiensis</i> (reversed); <b>H</b>, Left ilium of <i>Shixinggia oblita</i> (reversed); <b>I</b>, Left ilium of <i>Luoyanggia liudianensis</i> (reversed); <b>J</b>, Right ilium of <i>Nankangia jiangxiensis</i> gen. et sp. nov. <b>A</b>–<b>H</b> are modified from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0080557#pone.0080557-L5" target="_blank">[17]</a>, <b>I</b> is from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0080557#pone.0080557-L6" target="_blank">[21]</a>. No scale.</p

Pelvic girdle of <i>Nankangia</i> (GMNH F10003).

<p><b>A</b>, Partial left pelvis (missing dorsal edge of ilium and most of pubis) in lateral view. <b>B</b>, Partial right pelvis (missing pubis) in lateral view. <b>C</b>, Pubes in left lateral view. Abbreviations: dv., dorsal vertebrae; ili., ilium; isc., ischium; pub., pubis. Scale bar  = 5 cm.</p

Vertebral column of <i>Nankangia</i> (GMNH F10003).

<p><b>A</b>, Dorsal vertebrae in left lateral view (partially obscured by adhered pubis); <b>B</b>, Sacral vertebrae in ventral view; <b>C</b>, Cranial caudal vertebrae in right lateral view; <b>D</b>, Detail of cranial-most caudal vertebra in right lateral view; <b>E</b>, Cranial caudal neural spine in posterior view; <b>F</b>, Middle and posterior caudal vertebrae in right lateral view. Abbreviations: inf f., infradiapophyseal fossa; infr f1., infradiapophyseal fossa 1; infr f2., infradiapophyseal fossa 2;, infr. prf., infraprezygapophyseal fossa; ns., neural spine; p., parapophysis; pf., posterior fossa on the neural spine; pnf., pneumatic fossa; pre., prezygapophysis; pub., pubis; trp., transverse process. Scale bars  = 1 cm in <b>D</b>, <b>E</b>; others are 5 cm.</p

Strict consensus of two most parsimonious trees obtained by PAUP, based on analysis of 20 taxa and 182 characters [31].

<p>Each tree has a length of 370 and was recovered via a branch and bound search (CI = 0.58, HI = 0.42, RI = 0.69).</p

Supplementary Tables S1 - S5 and Figure S1 from Incubation behaviours of oviraptorosaur dinosaurs in relation to body size

Table S1: Mid- to Upper Cretaceous oviraptorosaur egg and clutch specimens examined in this study; Table S2: Results of regression analyses for clutch volume (mm3, in logarithmic scale) against adult body mass (kg, in logarithmic scale) in living crocodylian and precocial bird species (n = 180) in order to predict adult body mass for the elongatoolithid specimens; Table S3: Outer and inner clutch diameters of various oviraptorosaur egg taxa; Table S4: Eggshell thickness of various oviraptorosaur egg taxa; Table S5: Eggshell porosity and predicted nest type in various oviraptorosaur egg taxa; Figure S1. Comparisons of egg shape in oviraptorosaurs