Search

The wings of birds and their closest theropod relatives share a uniform fundamental architecture, with pinnate flight feathers as the key component (1-3). Here we report a new scansoriopterygid theropod, Yiqigen. et sp. nov., based on a new specimen from the Middle-Upper Jurassic period Tiaojishan Formation of Hebei Province, China (4). Yi is nested phylogenetically among winged theropods but has large stifffilamentous feathers of an unusual type on both the forelimb and hindlimb. However, the filamentous feathers of Yi resemble pinnate feathers in bearing morphologically diverse melanosomes (5). Most surprisingly, Yihas a long rod-like bone extending from each wrist, and patches of membranous tissue preserved between the rod-like bones and the manual digits. Analogous features are unknown in any dinosaur but occur in various flying and gliding tetrapods (6-10), suggesting the intriguing possibility that Yi had membranous aerodynamic surfaces totally different from the archetypal feathered wings of birds and their closest relatives. Documentation of the unique forelimbs of Yi greatly increases the morphological disparity known to exist among dinosaurs, and highlights the extraordinary breadth and richness of the evolutionary experimentation that took place close to the origin of birds., Theropoda Marsh, 1881 Maniraptora Gauthier, 1986 Scansoriopterygidae Czerkas et Yuan, 2002 Yi qi gen. et sp. nov. Etymology. The generic and specific names are derived from Mandarin Yi (wing) and [...]

A major unsolved problem in mammalian evolution is the origin of Allotheria, including Multituberculata and Haramiyida (1-5). Multituberculates are the most diverse and best known Mesozoic era mammals and ecologically resemble rodents, but haramiyids are known mainly from isolated teeth, hampering our search for their phylogenetic relationships. Here we report a new haramiyid from the Jurassic period of China, which is, to our knowledge the largest reported so far. It has a novel dentition, a mandible resembling advanced multituberculates and postcranial features adapted for arboreal life. Our phylogenetic analysis places Haramiyida within crown Mammalia, suggesting the origin of crown Mammalia in the Late Triassic period and diversification in the Jurassic, which contrasts other estimated divergence times of crown Mammalia (6-8). The new haramiyid reveals additional mammalian features of the group, helps to identify other haramiyids represented by isolated teeth, and shows again that, regardless of various phylogenetic scenarios, a complex pattern of evolution involving many convergences and/or reversals existed in Mesozoic mammals., Mammalia Linnaeus, 1758 Allotheria Marsh, 1880 Haramiyida Hahn, Sigogneau-Russell and Wouters, 1989 Arboroharamiyidae gen. nov. Arboroharamiya jenkinsi gen. et sp. nov. Etymology. arbor (Latin): tree; Haramiya (Arabic): trickster, petty thief; [...]

The two groups of archosaurs, crocodilians and birds, form an extant phylogenetic bracket for understanding the reproductive behaviour of dinosaurs. This behaviour is inferred from preserved nests and eggs, and [...]

Recent discoveries of feathered dinosaur specimens have greatly improved our understanding of the origin and early evolution of feathers, but little information is available on the ontogenetic development of early feathers (1-7). Here we describe an early-juvenile specimen and a late-juvenile specimen, both referable to the oviraptorosaur Similicaudiptery x (8), recovered from the Lower Cretaceous Yixian Formation of western Liaoning, China (9). The two specimens have strikingly different remiges and rectrices, suggesting that a radical morphological change occurred during feather development, as is the case for modern feathers (10). However, both the remiges and the rectrices are proximally ribbon-like in the younger specimen but fully pennaceous in the older specimen, a pattern not known in any modern bird (10). In combination with the wide distribution of proximally ribbon-like pennaceous feathers and elongate broad filamentous feathers among extinct theropods, this find suggests that early feathers were developmentally more diverse than modern ones and that some developmental features, and the resultant morphotypes, have been lost in feather evolution., Feathers or primitive feathers have been documented in most non-avian coelurosaurian theropod groups on the basis of numerous specimens recovered from the Lower Cretaceous Jehol Group and the Jurassic Daohugou [...]

REPLYING TO G. Mayr & A. Manegold Nature 499, http://dx.doi.org/10.1038/nature12367 (2013) Our explanation that structures preserved in three Early Cretaceous Jehol birds (1) are ovarian follicles is challenged by Mayr [...]

A correction is presented to the article "A new arboreal haramiyid shows the diversity of crown mammals in the Jurassic period," by Xiaoting Zheng, Shundong Bi, Xiaoli Wang, and Jin Meng, which was published in a previous issue.