 |
|
| |
|
| [花之故都] |
[恐龙之乡] |
| |
|
| [鸟类的祖籍] |
[昆虫王国]] |
| |
|
| [鱼类乐园 |
[哺乳动物摇篮] |
|
|
|
| condition and in having slender, strongly
curved claws8,20.Microraptor gui can be unequivocally referred to
Dromaeosauridae based on the following derived characters20: extremely
elongate prezygapophyses and chevrons; manual phalanges III-1 signifi-cantly
longer than III-2; specialized pedal digit II; and longmetatarsal
V. Furthermore it can be referred to Microraptor on the basis of the
following features20: metacarpal III subequal to metacarpal II in
length; extremely short manual phalanx III-2 that is less than one-quarter
of manual III-1 length; manual III-3 extremely slender and shorter
than III-1 in length, and small distal articulation |
of manual III-3 skewed ventrally. However,
a few features it from M. zhaoianus. A prominent biceps tuberocity
is present close to the proximal end of the radius and this feature
has not been reported in most other non-avian theropods except a
recently described therizinosauroid22. As in most birds, M. gui has
a
proportionately very short manual digit I (metacarpal I á phalanx
I-1/metacarpal II length ratio is 0.80–0.84). For comparison, this
ratio is 0.97 in M. zhaoianus and more than 1.0 in most other nonavian
theropods and the basal birds Archaeopteryx and Confuciusornis.
The pubis of M. gui is strongly curved (1208), whereas the |
 |
Figure 1 Microraptor gui. a, Skeleton of Microraptor
gui (IVPP V13352). Scale bar, 5 cm.
b, A computerized tomography (CT) image of the major part of the IVPP
V13352.
Scale bar, 13 cm. Scanning was performed using a CT machine (LightSpeed
Qx/i) at an
energy level of 140 kV and 250 mA. The images were collected at a
size of 800 ￡ 600
pixels. On the basis of comparison of adjacent fracture-face geometries,
density of
adjacent pieces, and continuity across fractures of bones (see ref.
45), we find a few
pieces are unverified or assembled in the wrong position (marked by
asterisks). For |
example, one small piece containing the anterior
end of the skull and a medium-sized
piece near the right forelimb preserving some arm feathers are dubious.
The latter is
actually from the counter slab. However, the CT information suggests
that most pieces lie
together in their natural relationships, including pieces containing
the forelimb, hindlimb
and associated feather impressions. This is concordant with microscopic
observations.
c, A reconstruction of M. gui showing the morphology and distribution
of the pennaceous
feathers. Scale bar, 6 cm. |
Figure 2 Feathers of IVPP V13352
and TNP00996. Feathers attached to the skull (a), the
tail (d), the forelimb (f), the manual digit I (i), and the hindlimb
(g) of IVPP V13352, and to
the skull (b) and the tail (e) of TNP00996; close-up of the skull
feathers of TNP 00996 (c),
and of secondaries (h) and large pennaceous feathers on distal metatarsus
(j) of IVPP |
V13352. Note the pennaceous
feathers attached to the digit (i) that might be a precursor
to the alula. This is concordant with the fact that M. gui has a short
manual digit I, because
the alula is often associated with a reduced alular digit except in
Protopteryx 24. Scale bar,
5 cm. |
|
|
|
