No abstract

Dinosaur Plumage Coloration and appearance provide important behavioral and evolutionary information in animals. However, for the most part, we do not know the coloration of fossil terrestrial animals. Li et al. (p. 1369 , published online 4 February) have reconstructed the appearance of a theropod dinosaur by mapping features of its well-preserved feathers and comparing them with modern samples from birds. Feather color is partly determined by melanosome density and shape, and this information is preserved in a recently discovered fossil from China. The dinosaur was gray with white limbs and had a reddish crest and a speckled face.

Iridescent feather colors involved in displays of many extant birds are produced by nanoscale arrays of melanin-containing organelles (melanosomes). Data relevant to the evolution of these colors and the properties of melanosomes involved in their generation have been limited. A data set sampling variables of extant avian melanosomes reveals that those forming most iridescent arrays are distinctly narrow. Quantitative comparison of these data with melanosome imprints densely sampled from a previously unknown specimen of the Early Cretaceous feathered Microraptor predicts that its plumage was predominantly iridescent. The capacity for simple iridescent arrays is thus minimally inferred in paravian dinosaurs. This finding and estimation of Microraptor feathering consistent with an ornamental function for the tail suggest a centrality for signaling in early evolution of plumage and feather color.

Inference of colour patterning in extinct dinosaurs has been based on the relationship between the morphology of melanin-containing organelles (melanosomes) and colour in extant bird feathers. When this relationship evolved relative to the origin of feathers and other novel integumentary structures, such as hair and filamentous body covering in extinct archosaurs, has not been evaluated. Here we sample melanosomes from the integument of 181 extant amniote taxa and 13 lizard, turtle, dinosaur and pterosaur fossils from the Upper-Jurassic and Lower-Cretaceous of China. We find that in the lineage leading to birds, the observed increase in the diversity of melanosome morphologies appears abruptly, near the origin of pinnate feathers in maniraptoran dinosaurs. Similarly, mammals show an increased diversity of melanosome form compared to all ectothermic amniotes. In these two clades, mammals and maniraptoran dinosaurs including birds, melanosome form and colour are linked and colour reconstruction may be possible. By contrast, melanosomes in lizard, turtle and crocodilian skin, as well as the archosaurian filamentous body coverings (dinosaur 'protofeathers' and pterosaur 'pycnofibres'), show a limited diversity of form that is uncorrelated with colour in extant taxa. These patterns may be explained by convergent changes in the key melanocortin system of mammals and birds, which is known to affect pleiotropically both melanin-based colouration and energetic processes such as metabolic rate in vertebrates, and may therefore support a significant physiological shift in maniraptoran dinosaurs.

Microraptor zhaoianus is known from several specimens collected in western Liaoning Province, China. However, several aspects of the morphology of Microraptor remain unknown or ambiguous due to poor preservation of the described specimens. A well-preserved new specimen of Microraptor zhaoianus is described in this study. This specimen preserves signifi¬ cant morphological details that are not present or are poorly preserved in the other Microraptor specimens including aspects of the skull, the rib cage, and the humerus. These new characters corroborate Microraptor as a member of the Dromaeosauridae as previously suggested and support the close relationship of troodontids and dromaeosaurids (Deinonychosauria). The morphology of the rib cage also suggests Microraptor and the early volant avialans very likely may have shared a similar mechanism to assist respiration.

No abstract

The Jurassic Yanliao theropods have offered rare glimpses of the early paravian evolution and particularly of bird origins, but, with the exception of the bizarre scansoriopterygids, they have shown similar skeletal and integumentary morphologies. Here we report a distinctive new Yanliao theropod species bearing prominent lacrimal crests, bony ornaments previously known from more basal theropods. It shows longer arm and leg feathers than Anchiornis and tail feathers with asymmetrical vanes forming a tail surface area even larger than that in Archaeopteryx. Nanostructures, interpreted as melanosomes, are morphologically similar to organized, platelet-shaped organelles that produce bright iridescent colours in extant birds. The new species indicates the presence of bony ornaments, feather colour and flight-related features consistent with proposed rapid character evolution and significant diversity in signalling and locomotor strategies near bird origins.

a Ni-Co sulfides are considered as promising electrode materials for electrochemical pseudocapacitors because of their rich redox chemistry and great structural flexibility with low cost. However, traditional Ni-Co sulfides still suffer from poor electrochemical performance due to relatively low electronic conductivity and structural instability. Herein, we present facile syntheses of hollow Ni-Co sulfide nanoboxes with tunable compositions, i.e., NiCo2S4 and Ni2CoS4, by using a lowtemperature wet-chemistry method. The resultant Ni-Co sulfides demonstrate high specific capacitances with enhanced cycling stability and rate capability. The NiCo2S4 electrode exhibits a capacitance of 1588 F g -1 at 2 A g -1 and a capacitance retention of 88.2% at 5 A g -1 after 4000 cycles, while the Ni2CoS4 electrode exhibits a capacitance of 1200 F g -1 at 2 A g -1 and a capacitance retention of 90.5% at 5 A g -1 after 4000 cycles. All the experiment results illustrate nanostructured Ni-Co sulfides to be promising electrode materials for high-performance supercapacitors.We present the facile syntheses of hollow Ni-Co sulfide nanoboxes with tunable compositions, i.e., NiCo 2 S 4 and Ni 2 CoS 4 , as electrode materials for high-performance electrochemical pseudocapacitors.The resultant Ni-Co sulfides demonstrate high specific capacitances with enhanced cycling stability and energy density, which are superior to most of Ni-Co sulfide electrodes reported in previous literature papers.