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. 2014 Jun 5;9(6):e98821.
doi: 10.1371/journal.pone.0098821. eCollection 2014.

A New Basal Hadrosauroid Dinosaur (Dinosauria: Ornithopoda) With Transitional Features From the Late Cretaceous of Henan Province, China

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A New Basal Hadrosauroid Dinosaur (Dinosauria: Ornithopoda) With Transitional Features From the Late Cretaceous of Henan Province, China

Hai Xing et al. PLoS One. .
Free PMC article

Abstract

Background: Southwestern Henan Province in central China contains many down-faulted basins, including the Xixia Basin where the Upper Cretaceous continental sediments are well exposed. The Majiacun Formation is a major dinosaur-bearing stratigraphic unit that occurs in this basin.

Methodology/principal findings: A new basal hadrosauroid dinosaur, Zhanghenglong yangchengensis gen. et sp. nov., is named based on newly collected specimens from the middle Santonian Majiacun Formation of Zhoujiagou Village, Xixia Basin. Two transitional features between basal hadrosauroids and hadrosaurids are attached to the diagnosis of the new taxon, namely five maxillary foramina consisting of four small scattered ones anteroposteriorly arranged in a row and a large one adjacent to the articular facet for the jugal, and dentary tooth crowns bearing both median and distally offset primary ridges. Zhanghenglong also displays a unique combination of plesiomorphic and derived features of hadrosauroids, and is clearly morphologically transitional between basal hadrosauroids and hadrosaurids. Furthermore, some measurement attributes in osteology are applied to the quantitative analysis of Zhanghenglong. For these attributes, the partition of the dataset on most hadrosauroid species resulting from model-based cluster analysis almost matches taxonomic separation between basal hadrosauroids and hadrosaurids. Data of Zhanghenglong on selected measurement attributes straddle the two combinations of intervals of partitioned datasets respectively related to basal hadrosauroids and hadrosaurids. This condition is similar to mosaic evolution of morphological characters present in the specimens of the taxon. The phylogenetic analysis of Hadrosauroidea recovers a clade composed of Zhanghenglong, Nanyangosaurus, and Hadrosauridae with an unresolved polytomy.

Conclusions/significance: Zhanghenglong is probably a relatively derived non-hadrosaurid hadrosauroid, based on the inferences made from the morphological comparisons, quantitative evaluation of measurements, and cladistic analysis. In combination with information on the stratigraphy, phylogeny and biogeography, the material of Zhanghenglong provides direct evidence for the hypothesis that hadrosaurids might have originated in Asia.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Simplified geographic map and detailed stratigraphic section showing the locality and horizon of Zhanghenglong yangchengensis.
(A) Geographic map showing the down-faulted basins and depressions (dark grey areas) of southwest Henan Province, China where Upper Cretaceous continental sediments are well developed and the locality of Z. yangchengensis (the black five-pointed star) in the Xixia Basin. (B) Stratigraphic section of the Zhoujiagou outcrop that represents most of the middle portion (Unit 2) of the Majiacun Formation and the upper part of the lower portion (Unit 1) of the same formation, with the horizon of Z. yangchengensis indicated by an arrow. (C) Excavation of the Zhoujiagou locality in 2011.
Figure 2
Figure 2. Reconstruction and restoration of the skeleton of Zhanghenglong yangchengensis.
(A) Skull reconstruction of Z. yangchengensis in left lateral view. (B) Restoration of the head and the anterior part of the neck of Z. yangchengensis in left lateral view. (C) Skeleton reconstruction of Z. yangchengensis in left lateral view. Bones in white are preserved in the specimens of Z. yangchengensis (XMDFEC V0013 and V0014). Bones in grey are unknown. Abbreviations: d, dentary; f, frontal; j, jugal; l, lacrimal; mx, maxilla; na, nasal; pd, predentary; pmx, premaxilla; po, postorbital; prf, prefrontal; q, quadrate; qj, quadratojugal; sa, surangular; sq, squamosal.
Figure 3
Figure 3. Maxilla of Zhanghenglong yangchengensis.
Right maxilla (XMDFEC V0013, holotype) in lateral (A), medial (B), dorsal (C), and anterior (D) views.
Figure 4
Figure 4. Jugal of Zhanghenglong yangchengensis.
Right jugal (XMDFEC V0013, holotype) in lateral (A) and medial (B) views.
Figure 5
Figure 5. Dentary of Zhanghenglong yangchengensis.
Right dentary (XMDFEC V0013, holotype) in lateral (A), medial (B), dorsal (C), and posterior (D) views.
Figure 6
Figure 6. Maxillary and dentary teeth of Zhanghenglong yangchengensis.
(A) Teeth of the right maxilla (XMDFEC V0013, holotype) in labial view. (B) Teeth of the right dentary (XMDFEC V0013, holotype) in lingual view.
Figure 7
Figure 7. First dorsal vertebra of Zhanghenglong yangchengensis.
D1 (XMDFEC V0014, paratype) in anterior (A), posterior (B), and right lateral (C) views.
Figure 8
Figure 8. Anterior-middle dorsal vertebrae of Zhanghenglong yangchengensis.
Four dorsal vertebrae probably representing D4–D7 orderly (XMDFEC V0014, paratype) in anterior (A, D, G, J), posterior (B, E, H, K), and left lateral (C, F, I, L) views.
Figure 9
Figure 9. Scapula and ulna of Zhanghenglong yangchengensis.
Right scapula (XMDFEC V0014, paratype) in lateral (A), medial (B), and proximal (C) views. Right ulna (XMDFEC V0014, paratype) in anterior (D) and posterior (E) views.
Figure 10
Figure 10. Comparison of the foramina on the lateral sides of the maxillae of some hadrosauroid species (all maxillae in lateral view).
(A) Bactrosaurus johnsoni (AMNH 6553). (B) Levnesovia transoxiana (CCMGE 579/12457). (C) Gilmoreosaurus mongoliensis (AMNH FARB 30653, reversed). (D) Amurosaurus riabinini (AEHM 1/12). (E) Edmontosaurus regalis (CMN 2289). (F) Brachylophosaurus canadensis (MOR 1071-8-15-98-573). Positions of maxillary foramina are indicated by arrows.
Figure 11
Figure 11. Comparison of the primary ridges of the tooth crowns in the dentary dental batteries of some hadrosauroid species (all dental batteries in lingual view).
(A) Equijubus normani (IVPP V12534). (B) Probactrosaurus gobiensis (PIN 2232/42-1). (C) Bactrosaurus johnsoni (AMNH 6553). (D) Parasaurolophus tubicen (NMMNH P-25100). (E) Edmontosaurus regalis (CMN 2289). (F) Brachylophosaurus canadensis (CMN 8893).
Figure 12
Figure 12. Bayesian Information Criterion (BIC) plots showing the results of model-based cluster analysis (MCA) implemented in Mclust for the datasets consisting of the values of most hadrosauroids and some basal iguanodontians on six selected measurement attributes (MA) derived from some phylogenetic characters, with the corresponding simplified box plots of the datasets showing the detached intervals respectively related to basal hadrosauroids and hadrosaurids.
BIC plot (A) and box plot (B) for MA1. BIC plot (C) and box plot (D) for MA2. BIC plot (E) and box plot (F) for MA3. BIC plot (G) and box plot (H) for MA4. BIC plot (I) and box plot (J) for MA5. BIC plot (K) and box plot (L) for MA6. Abbreviations: BH, basal hadrosauroids; BI, basal iguanodontians outside of Hadrosauroidea; H, hadrosaurines; L, lambeosaurines.
Figure 13
Figure 13. Strict consensus of 54 most parsimonious trees resulting from the maximum parsimony analysis implemented in the software TNT, showing the suggested systematic position of Zhanghenglong yangchengensis within Hadrosauroidea.
Numbers above nodes represent bootstrap values, whereas those beneath nodes represent Bremer decay values. Bootstrap values lower than 20 and Bremer decay values less than 2 are not shown.
Figure 14
Figure 14. 50% majority rule consensus of 54 most parsimonious trees produced by the maximum parsimony analysis implemented in the software TNT, showing the potential phylogenetic position of Zhanghenglong yangchengensis within Hadrosauroidea.
Numbers above nodes represent bootstrap values, whereas those beneath nodes represent Bremer decay values. Bootstrap values lower than 20 and Bremer decay values less than 2 are not shown.
Figure 15
Figure 15. Strict consensus of 405 most parsimonious trees recovered from the cladistic analysis of Hadrosauroidea, with the participation of Hadrosaurus foulkii (the characters associated with the laterodistal corner of the deltopectoral crest were coded as polymorphic for Brachylophosaurus, Shantungosaurus, and Edmontosaurus).

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References

    1. You H-L, Luo Z-X, Shubin NH, Witmer LM, Tang Z-L, et al. (2003) The earliest-known duck-billed dinosaur from deposits of late Early Cretaceous age in northwest China and hadrosaur evolution. Cretaceous Research 24: 347–355.
    1. Horner JR, Weishampel DB, Forster CA (2004) Hadrosauridae. In: Weishampel DB, Dodson P, Osmólska H, eds. The Dinosauria, second edition. Berkeley: University of California Press. 438–463.
    1. Prieto-Márquez A (2010) Global phylogeny of hadrosauridae (Dinosauria: Ornithopoda) using parsimony and Bayesian methods. Zoological Journal of the Linnean Society 159: 135–502.
    1. Lull RS, Wright NE (1942) Hadrosaurian dinosaurs of North America. Geological Society of America Special Papers 40: 1–242.
    1. Wing SL, Sues H-D (1992) Mesozoic and Cenozoic terrestrial ecosystems. In: Behrensmeyer AK, Damuth JD, Dimichele WA, Potts R, Sues H-D, et al. eds. Terrestrial Ecosystems through Time. London: Chicago University Press. 327–418.

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Grant support

This work was funded by grants from the National Natural Science Foundation of China (41120124002 and 41172037), the Graduate School of China University of Geosciences at Beijing (201225-B3001120058), the China Scholarship Council (20133009-201306400032), and the Department of Land and Resources of Henan Province. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
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