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. 2025 Jul 11:13:e19664.
doi: 10.7717/peerj.19664. eCollection 2025.

A new neornithischian dinosaur from the Upper Jurassic Tiaojishan Formation of northern China

Yunfeng Yang  1   2 , James L King  2   3   4 , Xing Xu  2   5
Affiliations

A new neornithischian dinosaur from the Upper Jurassic Tiaojishan Formation of northern China

Yunfeng Yang et al. PeerJ. .

Abstract

The Middle and Late Jurassic Yanliao Biota is different from other contemporaneous fossil assemblages in that it lacks neornithischian dinosaurs. Here, we report a new, early-diverging neornithischian, Pulaosaurus qinglong gen. et sp. nov., from the Upper Jurassic Tiaojishan Formation of Qinglong, Hebei Province, of northern China. Diagnostic or noteworthy morphological characteristics of P. qinglong include: five premaxillary teeth; a small boss is present on the caudoventral corner of the dorsal ramus of the jugal; a nuchal crest is located along the parietal; the manus has five digits; a supra-acetabular crest is present on the ilium; the paired arytenoids are gracile and leaf-like in form; the obturator process along the ischium is located near the pubic peduncle; a notch-like shaped obturator opening is present within the pubis; a robust fibular condyle forms a dorsoventrally extending crest on the tibia; a subtriangular flange on the anterior surface of the astragalus extends dorsolaterally along three distal tarsals; three of the distal tarsals are unfused, including a small drop-shaped distal tarsal 3; distal tarsal 3 is pierced by a foramen. A phylogenetic analysis places P. qinglong as one of the earliest-diverging neornithischians yet described. Moreover, P. qinglong represents the second known dinosaur to preserve ossified laryngeal elements, thus suggesting that a bird-like vocalization evolved early in non-avian dinosaur evolution.

Keywords: Laryngeal elements; Neornithischia; Yanliao biota.

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Conflict of interest statement

The authors declare there are no competing interests.

Figures

Figure 1
Figure 1. The photograph of the whole skeleton of Pulaosaurus qinglongin left lateral view (IVPP V30936).
Photo credit: Hailong Zhang.
Figure 2
Figure 2. The skull of Pulaosaurus qinglongin left lateral view (IVPP V30936).
(A) Photograph. (B) Outline drawing Abbreviations: Adf, Anterior dentary foramen; Ang, Angular; Art, articular; Ary, arytenoid; A Int, Axial intercentrum; At Int, Atlantal intercentrum; Bo, Basioccipital; Bsp, Basisphenoid; Cera, Ceratobranchial; Cr, Cervical rib; Ecp, Ectopterygoid; Exo, Exoccipital; Fr, Frontal; J, Jugal; Jb, Jugal boss; Lcr, Lacrimal; Ld, Left dentary; Lsp?, Laterosphenoid?; L spl, Left splenial; M, maxilla; Ms, the Meckelian sulcus; Na, Nasal; Nc, Nuchal crest; Nf, Nutrient foramina; Odp, Odontoid process; P, Pterygoid; Pa, parietal; Pal, Palatine; Pa p, Paraoccipital process; Pb, Palpebral; Po, Postorbital; PP, Pterygoid process of basisphenoid; Prd, Predentary; Prf, Prefrontal; Prm, Premaxilla; Sq, Squamosal; Q, Quadrate; Qj, Quadratojugal; Rd, Right dentary; R spl, right splenial; Spo, Supraoccipital; Sur, surangular; 3rd C, the 3rd cervical vertebrate.
Figure 3
Figure 3. The photo of several skull elements in lateral view.
(A) The photograph of the visible part of the maxilla. (B) The photograph of the jugal. (C) The line drawing of the jugal. (D) The photograph of the quadratojugal. (E) The photograph of the pterygoid. (F) The line drawing of the pterygoid. (G) The photograph of partial braincase. (H) The line drawing of partial braincase. Photo credit: Hailong Zhang.
Figure 4
Figure 4. The teeth of IVPP V30936 under the microscope.
(A) The premaxillary teeth and the most anterior cheek teeth. (B) The anterior cheek teeth. (C) The middle cheek teeth. (D) The posterior cheek teeth. Photo credit: Yunfeng Yang.
Figure 5
Figure 5. Arytenoids and ceratobranchials of Pulaosaurus qinglong in laterodorsal view (IVPP V30936).
(A) The photograph of ceratobranchials and arytenoids. (B) The line drawing of ceratobranchials and arytenoids. Abbreviations: ap, arytenoid process; c, ceratobranchial; lw, laterodorsal wings of the arytenoids; mw, mediodorsal wings of the arytenoids. Photo credit: Hailong Zhang.
Figure 6
Figure 6. Cervical series of Pulaosaurus qinglong: (IVPP V30936). Atlas, axis and 3rd cervical visible in left lateral view; from 4th cervical to 9th cervical visible in dorsal view.
(A) The photograph of the cervical series. (B) The line drawing of the cervical series. Abbreviation: a int, axial intercentrum; cr, cervical rib; dia, diapophysis; ns, neural spine; od p, odontoid process; pa, parapophysis; pop, postzygapophysis; tp, transverse process. Photo credit: Hailong Zhang.
Figure 7
Figure 7. The visible dorsal vertebrae and the ossified tendons in lateral view.
(A) Dorsal ribs and ossified tendons in lateral view. (B) The photograph of four visible dorsal vertebrae. (C) The line drawing of four visible dorsal vertebrae. Abbreviations: C, Centrum; Dia, Diapophysis; NA, the Neural Arch; NS, the Neural Spine; Post, Postzygapophysis. Photo credit: Hailong Zhang.
Figure 8
Figure 8. Caudal vertebrae series of Pulaosaurus qinglong in left lateral view (IVPP V30936).
(A) The proximal caudal vertebrae. (B) The middle caudal vertebrae. (C) The distal caudal vertebrae. Photo credit: Hailong Zhang.
Figure 9
Figure 9. The pectoral girdle of Pulaosaurus qinglong (IVPP V30936) in lateral view and the sternum of Pulaosaurus qinglong (IVPP V30936) in ventral.
Photo credit: Hailong Zhang.
Figure 10
Figure 10. The left humerus in view.
Photo credit: Hailong Zhang.
Figure 11
Figure 11. The left ulna, the left radius in anterior view and the left manus in view.
Abbreviations: DC, Distal Carpal; Int, Intermedium; R, Radiale; U, Ulnare; Mc I, Metacarpal I; Mc II, Metacarpal II; Mc III, Metacarpal III; Mc IV, Metacarpal IV; Mc V, Metacarpal V; I-1, Phalanx I-1; I-2, Phalanx I-2; II-1, Phalanx II-1; II-2, Phalanx II-1; II-3, Phalanx II-3; III-1, Phalanx III-1; III-2, Phalanx III-2; III-3, Phalanx III-3; III-4, Phalanx III-4; IV-1, Phalanx IV-1; IV-2, Phalanx IV-2; IV-3, Phalanx IV-3; V-1, Phalanx V-1; V-2, Phalanx V-2. Photo credit: Hailong Zhang.
Figure 12
Figure 12. The pelvic girdle in lateral view.
(A) The photograph of the left ilium in lateral view. (B) The line drawing of the left ilium in lateral view. (C) The photograph of the left pubis and the left ischium in lateral view, the missing part supplemented by the line drawing. (D) The CT scaning image of the left pubis and the left ischium. Abbreviations: bf-brevis fossa, bsopp-the bony sheet on the proximal pubis, ip-the ischial peduncle, isc, ischium; opi, the obturator process of the ischium; pop, the postacetabular process; prep, the preacetabular process; pup, the pubic peduncle; sc, the supra-acetabular crest. Photo credit: Hailong Zhang.
Figure 13
Figure 13. The femora of Pulaosaurus qinglong (IVPP V30936).
(A) The left femur in medial view. (B) The right femur in medial view. Photo credit: Hailong Zhang.
Figure 14
Figure 14. The tibiae and the fibulae.
(A) The left tibia and the left fibula in view. (B) The right tibia and the right fibula in medial view. Photo credit: Hailong Zhang.
Figure 15
Figure 15. The right and left astragali, the right and left pedes and the right calcaneum.
(A) The right astragalus and calcaneum in anterior view, right metatarsals in dorsal view and the phalanges in lateroventral view. (B) The left astragalus in dorsal view, the right distal tarsals and metatarsals in ventral view and the right phalanges in lateral view. (C) The left calcaneum in anterior view. Abbreviations: ast-astragalus, cal-calcaneum, dt-distal tarsal, mt-metatarsal, I-1-phalanx I-1, I-2-phalanx I-2, II-1-phalanx II-1, II-2-phalanx II-2, II-3-phalanx II-3, III-1-phalanx III-1, III-2-phalanx III-2, III-3-phalanx III-3, III-4-phalanx III-4, IV-1-phalanx IV-1, IV-2-phalanx IV-2, IV-3-phalanx IV-3, IV-4-phalanx IV-4, IV-5-phalanx IV-5. Photo credit: Hailong Zhang.
Figure 16
Figure 16. The gut contents preserved in IVPP V30936.
P-Pebbles; I-Impressions of possible plant seeds. Photo credit: Hailong Zhang.
Figure 17
Figure 17. The strict consensus tree from 26,901 most parsimonious trees including 74 taxa and 380 characters generated by the analysis.
Nodes: 1-Ornithischia, 2-Heterodontosauria, 3-Thyreophora, 4-Pachycephalosauria, 5-Iguanodontia, 6-Neoceratopsia.
Figure 18
Figure 18. The reduced consensus tree from 572 most parsimonious trees including 70 taxa and 380 characters generated by the analysis.
Nodes: 1-Ornithischia, 2-Heterodontosauridae, 3-Genasauria, 4-Thyreophora, 5-Neornithischia, 6-Cerapoda, 7- Pachycephalosauria, 8-Ornithopoda, 9-Iguanodontia, 10-Ceratopsia, 11-Chaoyangsauridae, 12-Neoceratopsia.
Figure 19
Figure 19. The strict consensus tree generated by analysis 2 based on the character matrix dataset provided by Fonseca et al. (2024).
Figure 20
Figure 20. The strict consensus tree generated by the analysis based on the dataset of Fonseca et al. (2024) with implied weight K=12.
Figure 21
Figure 21. The hyoaryngeal apparatuses in different taxa of Archosauria.
(A) The line drawing of Pinacosaurus grangeri (IGM100/3186) hyolaryngeal apparatus based on the 3D reconstruction. (B) The line drawing of Pulaosaurus qinglong (IVPP V30936) hyolaryngeal apparatus. (C) The line drawing of Nothoprocta sp. (AMNH6502) hyolaryngeal apparatus. (D) The line drawing of Tomistoma schlegelii (AMNH R113078) hyolaryngeal apparatus. All the specimens involved except for IVPP V30936 are from the supplementary materials provided by Yoshida, Kobayashi & Norell (2023). Abbreviations: AP-Arytenoid Process, Ary-Arytenoid, Bh-Basihyal, Cera-Ceratobranchial, Cr-Cricoid, Dlw-Dorsolateral wing, Dmw-Dorsomedial wing, Epi-Epibranchial, lw-the laterodorsal wing, mw-the mediodorsal wing. Illustration credit: Junki Yoshida, Ph.D.
Figure 22
Figure 22. Evolution of hyolaryngeal elements in Archosauria.
The figure is adapted from illustration by Tatsuya Shinmura (Yoshida, Kobayashi & Norell, 2023). Yellow-arytenoid, green-first pair of ceratobranchials, black-second pair of ceratobranchials, red-cricoid, white-basihyal, blue-procricoid, orange-paraglossal, grey-epibranchials. Numbers represent the ancestral state of characteristics: 1-Laryngeal vocal source, 2-Loss of second ceratobranchials, 3-Procrocoid, 4-Arytenoid process, 5- Arytenoid process, 6-Ossified larynx, 7-Immobile lungs, 8-Procrocoid, 9-Paraglossal. Illustration credit: Junki Yoshida.
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