and Tianyulong filaments might have evolved independently of the feathers of theropods.
Here we report a new ornithischian dinosaur,
Kulindadromeus zabaikalicus, with diverse epidermal appendages, including grouped filaments
that we interpret as avianlike feathers. This suggests that all Dinosauria could have had feathers
and that feathers arose for purposes of insulation
and signaling and were only later co-opted for
flight (10, 11).
The new dinosaur comes from the Kulinda
locality (Cherynyshevsky District of Chita Region,
Middle to Late Jurassic (15). The dinosaur bones
are associated with abundant, well-preserved fos-
sils of plants, insect larvae, and freshwater crus-
taceans that suggest deposition in a low-energy,
probably lacustrine, freshwater environment. The
sequence includes tuff deposits and ignimbrites
that indicate local volcanic activity (15).
The description of Kulindadromeus zabai-
kalicus (15) is based on six partial skulls and
several hundred disarticulated skeletons unearthed
from two neighboring monospecific bone beds.
Each individual skeletal element is represented
by a single morphotype, and all of the observed
morphological differences can easily be explained
by ontogenetic and intraspecific variation, as con-
firmed by the detailed study of the partial skel-
etons (15). Therefore, there is no indication that
more than one basal ornithischian is present.
Many of the bones are strongly iron-stained, sug-
gesting partial replacement during diagenesis.
Kulindadromeus zabaikalicus is differentiated from all other dinosaurs by the following
Fig. 1. Skeletal anatomy of Kulindadromeus
zabaikalicus. (A) Composite skeletal reconstruction; photograph (B) and line drawing (C) of the
holotype skull (INREC K3/109) in right lateral view;
(D) proximal portion of right scapula (INREC K3/204)
in lateral view; (E) right scapula (INREC K3/134) in
caudolateral view; (F) left ulna (INREC K3/205) in
medial view; (G) right tibia (INREC K3/207) in caudal
view; (H) right femur (INREC K3/206) in cranial view; (I) right ischium (INREC K3/124) in lateral view; (J) distal caudal vertebra (INREC K3/202) in right lateral view;
(K) mirror image of left ilium (INREC K3/113) in lateral view; (L) dorsal vertebra (INREC 3/112) in right lateral view; (M) mirror image of left pubis (INREC K3/114) in
lateral view. Scale bars, 10 mm. Abbreviations: ac, acetabulum; acp, acromial process; an, angular; aof, antorbital fossa; art, articular; cor, coracoid facet; dpc,
deltopectoral crest; drf, distal radial facet; dt, dentary; fh, femoral head; fr, frontal; gl, glenoid; ilpd, iliac peduncle; imal, inner malleolus; ispd, ischial peduncle;
iss, ischial shaft; j, jugal; l, lacrimal; lcd, lateral condyle; mcd, medial condyle; mf, maxillary fenestra; mx, maxilla; na, nasal; obn, obturator notch; obpr, obturator
process; ns, neural spine; ol, olecranon process; omal, outer malleolus; p, parietal; pap, palpebral; pm, premaxilla; po, postorbital; poac, postacetabular
process; poc, paroccipital process; poz, postzygapophysis; pr, prefrontal; prac, preacetabular process; prf, proximal radial facet; prpu, prepubic process; prz,
prezygapophysis; pupd, pubic peduncle; pus, pubic shaft; q, quadrate; qj, quadratojugal; rap, rostral ascending process; rcd, radial condyle; sa, surangular; sac,
supraacetabular crest; sq, squamosal; ucd, ulnar condyle; 4tr, fourth trochanter.