A gigantic feathered dinosaur from the Lower
Cretaceous of China
, Kebai Wang
, Ke Zhang
, Qingyu Ma
, Lida Xing
, Corwin Sullivan
, Dongyu Hu
, Shuqing Cheng
& Shuo Wang
Numerous feathered dinosaur specimens have recently been recovered
from the Middle–Upper Jurassic and Lower Cretaceous deposits of
northeastern China, but most of them represent small animals
we report the discovery of a gigantic new basal tyrannosauroid,
gen. et sp. nov., based on three nearly complete
skeletons representing two distinct ontogenetic stages from the
Lower Cretaceous Yixian Formation of Liaoning Province, China.
shares some features, particularly of the cranium, with derived
, but is similar to other basal tyrannosauroids
possessing a three-fingered manus and a typical theropod pes.
Morphometric analysis suggests that
differed from tyranno-
saurids in its growth strategy
. Most significantly,
long filamentous feathers, thus providing direct evidence for the pres-
ence of extensively feathered gigantic dinosaurs and offering new
insights into early feather evolution.
The Tyrannosauroidea was one of the longest-lived theropod sub-
groups, with a fossil record extending from the Middle Jurassic to the
. Basal tyrannosauroids are relatively small, and
gigantic ones (adult body mass greater than 1,000 kg) are almost entirely
restricted to the latest Cretaceous
. Four tyrannosauroid taxa have
recently been reported from the Lower Cretaceous of China
although the provenance of one of them, Raptorex kriegsteini,hasbeen
. These taxa range from 1.4 m to about 10 m in
and show considerable morphological disparity: some taxa
closely resemble the highly specialized Tyrannosauridae
others are more similar to generalized coelurosaurs
with discoveries from outside China, these morphologically and
taxonomically diverse basal tyrannosauroid specimens document the
occurrence of a significant radiation in the early history of the group.
Here we report the discovery of a new feathered tyrannosauroid (Figs 1
and 2 and Supplementary Figs 1–3) from the Lower Cretaceous of China
that is close to some Late Cretaceous tyrannosauroids in adult size
(Supplementary Information). Phylogenetic analyses using two differ-
ent theropod matrices place this taxon among basal tyrannosauroids,
but relatively close to the Tyrannosauridae (Fig. 3 and Supplementary
Information). In combination with other recent discoveries, such as
that of the similarly sized Sinotyrannus from the Lower Cretaceous of
, the new find demonstrates that tyrannosauroids were the
dominant large predators in the middleEarly Cretaceous ecosystems of
northeastern China, suggesting that the ecological dominance of the
group was achieved early in their evolution in some geographical
regions at least.
Theropoda Marsh, 1881
Coelurosauria sensu Gauthier, 1986
Tyrannosauroidea Osborn, 1905
Yutyrannus huali gen. et sp. nov.
Etymology. The generic name is derived from ‘yu’ (Mandarin for
‘feathers’) 1‘tyrannus’ (Latin for ‘king’ or ‘tyrant’). The specific name
‘huali’ means ‘beautiful’ in Mandarin, referring to the beauty of the
plumage of this animal.
Holotype. ZCDM (Zhucheng Dinosaur Museum, Shandong)
V5000, a semi-articulated, nearly complete skeleton. A cast of the
specimen is housed at the Institute of Vertebrate Paleontology and
Paleoanthropology as IVPP FV1960.
Paratypes. ZCDM V5001, a nearly complete, articulated skeleton; and
ELDM (Erlianhaote Dinosaur Museum, Inner Mongolia) V1001, an
articulated skeleton missing the tail. Casts of these specimens are housed
at the Institute of Vertebrate Paleontology and Paleoanthropology as
IVPP FV1961 and IVPP FV1962, respectively.
Horizon and locality. Batuyingzi, Beipiao, Liaoning Province, China;
Lower Cretaceous Yixian Formation
Diagnosis. A gigantic tyrannosauroid distinguishable from other tyr-
annosauroids by the unique presence of a rugose, highly fenestrated
midline crest formed bythe premaxillae and nasals, ananteroventrally
projecting orbital process in the area of the junction between the
frontal and jugal processes of the postorbital, a large concavity on
the lateral surface of the main body of the postorbital, and an external
mandibular fenestra located mostly within the surangular. Also differs
from Sinotyrannus in that the morphologically lateral surface of the
maxillary process of the premaxilla faces dorsally, the maxilla lacks an
anterior ramus, the maxillary fenestra is posteriorly positioned, the
antorbital fossa has a posteroventrally sloping ventral margin, and
the ilium has a straight dorsal margin and a postacetabular process
whose ventral margin bears a lobe-like flange.
Description and comparisons. ZCDM V5000 probably represents an
adult individual, given that the neurocentral sutures on all of the visible
vertebrae are closed and the sacrals are fused together. With a femoral
length of 85 cm, ZCDM V5000 even exceeds the adult sizes of some
Late Cretaceous tyrannosauroids, such as Dryptosaurus (77 cm) and
Appalachiosaurus (79cm). ZCDM V5000 is estimated to have had a
mass of about 1,414 kg as a living animal, on the basis of an empirical
, and ZCDM V5001 and ELDM V1001 are estimated to have
had respective masses of 596kg and 493kg. Both ZCDM V5001 and
ELDM V1001 display fusion features, such as visible neurocentral
sutures on all of the presacral vertebrae, suggesting an ontogenetic
stage considerably earlier than that inferred for ZCDM V5000. On
the basis of data on the growth of other large tyrannosauroids
ELDM V1001 is estimated to be at least 8years younger than
The most striking cranial feature of Y. huali is a highly pneumatic
midline crest resembling those of Guanlong
and the carcharodonto-
, although in Y. huali the crest is formed by
premaxillary and nasal portions that are only loosely articulated
with each other. The dorsal margin of the crest bears a series of low
prominences that are likely to be homologous to the rugosities seen in
all Late Cretaceous tyrannosauroids
. The cranium of Y. huali also
exhibits some features thatoccur consistently in basal, butnotderived,
Institute of Vertebrate Paleontology and Paleoanthropology, Key Laboratory of Evolutionary Systematics of Vertebrates, Chinese Academy of Sciences, 142 Xiwai Street, Beijing 100044, China.
Paleontological Museum, Shenyang Normal University, 253 North Huanghe Street, Shenyang 110034, China.
Zhucheng Dinosaur Museum, Zhucheng, Shandong, 262200, China.
School of the Earth
Sciences and Resources, China University of Geosciences, 28 Xueyuan Road, Beijing 100083, China.
Department of Biological Sciences, University of Alberta, 11145 Saskatchewan Drive, Edmonton,
Alberta T6G 2E9, Canada.
Graduate University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China.
92 | NATURE | VOL 484 | 5 APRIL 2012
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. The elliptical externalnaris is large and posteriorly
positioned; a sharp groove runs along the anterior margin of the
premaxilla; the maxilla bears a sharp groove paralleling the ventral rim
of the antorbital fossa; the jugal has a raised, anteroposteriorly orientated
rim; and the surangular has a long anterior flange. Previous studies have
suggested that some of these features are synapomorphies of the basal
, but our phylogenetic analysis optimizes
several of these features as synapomorphies of the Tyrannosauroidea.
However, many other cranial features of Y. huali are more similar to
those of derived tyrannosauroids
. For example, the skull is large
and deep; the premaxilla has a proportionally deep main body and a
maxillary process whose morphologically lateral surface faces dorsally
in adults; the maxilla has a markedly convex ventral margin and a
posteriorly tapering main body; the lacrimal is in the shape of a ‘7’;
the cornual process of the lacrimal is a large conical structure; the
postorbital has a wide jugal process and a suborbital process extending
into the orbit; the squamosal has an anteroposteriorly orientated
quadratojugal process that intrudes into the infratemporal fenestra;
the quadratojugal has a large posterior process that overlaps the posterior
surface of the quadrate; the external mandibular fenestra is small; the
dentary has a strongly concave dorsal margin and a posteriorly located
inflection point between the anterior and ventral margins in lateral view;
and the surangular has a prominent horizontal ridge.
The vertebrae are not pneumatized to the degree seen in the
Tyrannosauridae, but they show initial development of some features
that are characteristic of derived tyrannosauroids
. These features
include prominent flanges for ligament attachment on the anterior and
posterior margins of the neural spines of the cervical and dorsal vertebrae,
tall neural spines on the posterior cervical vertebrae, laterally placed
prezygapophyses on the middle cervical vertebrae, and anteroposteriorly
shortened dorsal vertebrae with posteriorly placed neural spines.
The shoulder girdle is in general plesiomorphic, as indicated by the
relative robustness of the scapular blade, the weakly expanded distal
end of the scapula, and the large coracoid foramen. The forelimbs are
also similar to those of basal tyrannosauroids in retaining a typical
basal coelurosaurian design, including a three-fingered manus
The pelvis displays several derived features
: the dorsal margin of
the ilium is mostly straight, the ventral margin of the postacetabular
process of the ilium bears a prominent lobe-like flange, the pubic boot
is large and forms a distinct anterior expansion, and the ischium is
much more slender than the pubis. The hindlimbsare generally similar
to those of basal tyrannosauroids, and the distal segments are propor-
tionally short, more similar to allosauroids and basal tyrannosauroids
than to tyrannosaurids
Filamentous integumentary structures are preserved in all three
specimens. Those preserved in ZCDM V5000 are evidently associated
with the posterior caudal vertebrae. As preserved, they are parallel to
each other and form an angle of about 30uwith the long axis of the tail.
The filaments are at least 15 cm long. They are too densely packed for it
to be possible to determinewhether they are elongate broad filamentous
feathers (EBFFs) like those seen in the therizinosauroid Beipiaosaurus,
slender monofilaments, or compound filamentous structures. Those of
ZCDM V5001 are near the pelvis and pes. They are filamentous struc-
tures, but morphological details are not preserved. In ELDM V1001,
integumentary filamentsare visible extending fromthe dorsal side of the
neck, and near a limb bone that is tentatively identified as a humerus.
Those extending from the neck measure more than 20cm, and those
along the humerus at least 16cm. Although feather preservation is
patchy in these specimens, as occurs even in some fossil birds from
the Jehol Group that undoubtedly had plumage covering most of the
body, the distribution of the preserved filamentous feathers in the three
specimens of Y. huali implies that this taxon had an extensively
cav l lp
lu ga lt l
(ZCDM V5000 and ZCDM V5001).
a, Photograph of the slab preserving ZCDM V5000 and ZCDM V5001. b,Line
drawing of the slab. Abbreviations: cav, caudal vertebra; cev, cervical vertebra;
dr, dorsal rib; dv, dorsal vertebra; ga, gastralia; lfe, left femur; lfi, left fibula; lh,
left humerus; lil, left ilium; lis, left ischium; lm, left manus; lp left pes; lr, left
radius; ls, left scapula;lt, left tibiotarsus; lu, left ulna; ma, mandible; pu, pubis; rc,
right coracoid; rfe, right femur; rh, right humerus; ril, right ilium; rm, right
manus; rp, right pes; rr, right radius; rs, right scapula; rt, right tibiotarsus; ru,
right ulna; sk, skull; sy, synsacrum.
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feathered integument in life. This has also been inferred for Dilong,
and some other non-avian feathered dinosaurs
Morphological variations. Some morphological differences between
ZCDM V5000, ZCDM V5001 and ELDM V1001 may represent
ontogenetic variations. With increasing maturity, for example, the
skull becomes deeper and more robust, the premaxilla becomes
narrower and taller, the anterior portion of the premaxilla becomes
more medially orientated, the lateral surface of the maxillary process of
the premaxilla rotates to face dorsally, and the maxillary fenestra
becomes more anteriorly located. Several other morphological varia-
tions, such as the presence of a relatively straight dorsal margin of the
ilium in ZCDM V5000 and ELDM V1001 and a convex one in ZCDM
V5001, are more difficult to interpret in ontogenetic terms. They may
reflect individual genetic variation or sexual dimorphism.
A morphometric analysis suggests that Y. huali differed in its growth
pattern from the highly specialized tyrannosaurids (Supplemen-
tary Information). Using femur length as a standard proxy for overall
size, the scapula and ilium display negative allometry in Y. huali
(in contrast to positive allometry and near isometry, respectively, in
). The radius, metacarpus and distal hindlimb segments
are negatively allometric in both Y. huali and the Tyrannosauridae, but
the negative allometry of the metacarpus, tibia and metatarsus is much
stronger in Y. huali than in tyrannosaurids
This discovery has implications for early feather evolution.
Although some gigantic dinosaurs are likely to have been feathered
, the largest previously known non-avian dinosaur in which
direct evidence for a feathery covering is available is Beipiaosaurus
(adult body mass about 1/40 that of ZCDM V5000). The discovery of
Y. huali provides solid evidence for the existence of gigantic feathered
dinosaurs and, more significantly, of a gigantic species with an extens-
ive feathery covering.
Gigantism affects many aspects of animal structure and function.
Extensive filamentous integumentary coverings such as feathers and
hair are partly or even primarily insulative in function, but some large
mammals have become almost entirely hairless because their low
surface-to-volume ratios permit them to retain metabolic heat even
without a pelage (although large mammals living in cold environ-
ments, such as the bovid Bison bison, retain substantial fur). Gigantic
tyrannosauroids have been suggested to lack an extensive feathery
covering for analogous reasons
. This interpretation derives some
support from reported impressions of small patches of scaly skin
and there is certainly no direct fossil evidence for the presence of
feathers in gigantic Late Cretaceous tyrannosauroids. The discovery
of Y. huali, however, indicatesthat at least one gigantic dinosaur had an
extensive insulative coatof feathers, showing in turn that drastic reduc-
tion of the plumage was not an inevitable consequence of very large
body size. If Late Cretaceous tyrannosaurids such as Tyrannosaurus
rex were similar to Y. huali in this respect, both basal and derived
tyrannosauroid dinosaurs would differ from mammals in lacking a
tendency to lose their integumentary covering as result of gigantism.
Alternatively, if scales were indeed the dominant integumentary
structures in most Late Cretaceous tyrannosauroids, the presence of
long feathersin the gigantic Y. huali could representan adaptation to an
unusually cold environment. Y. huali lived during a period (the
Barremian–early Albian) that has been interpreted as considerably
colder than the rest of the Cretaceous (a mean annual air temperature
of about 10 uC in western Liaoning, in contrast with about 18uCata
similar latitude in the Late Cretaceous)
. Most gigan tic Late Cretaceous
tyrannosauroids, by contrast, lived in a warm climate that was con-
ducive to the loss of an extensive insulative feathery covering, although
populations inhabiting cold environments such as the landthat is now
Alaska would have been a notable exception
extent and nature of the integumentary covering changed over time in
response to shifts in body size and the temperature of the environment
throughout tyrannosauroid evolutionary history, as has clearly
occurred in some mammalian taxa
. However, it must be noted that
Selected elements of
(ZCDM V5000, ZCDM V5001 and
ELDM V1001). a, Photograph of the skull and mandible of ELDM V1001.
b, Line drawing of the skull and mandible of ELDM V1001. c–h, filamentous
integumentary structures preserved in the three specimens: c, along the
posterior caudal vertebrae of ZCDM V5000; d, along the cervical vertebrae of
ELDM V1001; e,f, along a limb bone of ELDM V1001; g,h, near the pes of
ZCDM V5001 (fand hare close-up views). Abbreviations: aop, accessory
orbital process; clp, cultriform process; co, concavity; cp, cornual process; g,
groove; lec, left ectopterygoid; lpa, left palatine; ls, left squamosal; mf, maxillary
fenestra; np, nasal prominences; pnr, pneumatic recesses; r, ridge; sp.,
suborbital process; sr, surangular ridge.
94 | NATURE | VOL 484 | 5 APRIL 2012
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the plumage is only partly preserved in all three known specimens of
Y. huali, and the possibility that the feathers had only a restricted
distribution on the body cannot be completely excluded. If this was
so, the feathers might have functioned primarily as display structures
as in some other non-avian theropod groups
Received: 26 November 2011; accepted 27 January 2012.
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Supplementary Information is linked to the online version of the paper at
Acknowledgements We thank L. Zhang for discussions, R. Li, H. Zang and X. Ding for
illustrations, and H. Wang, L. Xiang and R. Cao for preparing the specimens. We thank
the Zhucheng Municipal Government and Erlianhaote Municipal Government for
support. This study was supported by grants from the National Natural Science
Foundation of China and Special Funds For Major State Basic Research Projects of
Author Contributions X.X.designed the project. X.X., K.W., K.Z., Q.M., L.X., C.S.,D.H., S.C.
and S.W. performed the research. X.X., C.S. and Q.M. wrote the manuscript.
Author Information Reprints and permissions information is available at
www.nature.com/reprints. The authors declare no competing financial interests.
Readers are welcome to comment on the online version of this article at
www.nature.com/nature. Correspondence and requests for materials should be
addressed to X.X. (email@example.com).
A simplified cladogram showing the systematic position of
among the Tyrannosauroidea. Silhouettes indicate body size and
possible extent of plumage. Different tyrannosauroids seem to have attained
gigantic body size independently in the Early and Late Cretaceous, but only in
the Early Cretaceous is there direct evidence of a gigantic form with an
extensively feathered integument. This may reflect the relatively cold climate of
the middle Early Cretaceous. See also Supplementary Information.
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