W porzÄ
dku systematycznym - od ptakĂłw do bardziej bazalnych archozaurĂłw, wiele dostÄpnych za darmo (tytuĹ na zielono - link):
1)
Zhou, Z.-H., Zhang, F.-C., and Li, Z.-H. 2009.
A new basal ornithurine bird (Jianchangornis microdonta gen. et sp. nov.) from the Lower Cretaceous of China. Vertebrata PalAsiatica 47(4):299-310.
A new genus and species of a basal ornithurine bird is reported from the Lower Cretaceous skeleton of a sub-adult individual. It is distinguishable from other known ornithurines by possessing a combination of features including at least 16 small and conical teeth on the dentary, scapula strongly curved, metacarpal I robust and wider than other metacarpals, first manual digit long and extending beyond distal metacarpal II, and length ratio of humerus+ulna+metacarpal II to femur+tibiotarsus+tarsometatarsus is approximately 1.1. Phylogenetic analysis indicates that the the new taxon is a basal ornithurine. Jianchangornis represents the second Early Cretaceous bird with the preservation of a predentary bone, which may further confirm that a predentary could be a feature common to Mesozoic ornithurines. The advanced features of the pectoral girdle, sternum and wings of the new bird indicate its powerful flight capability, and the hindlimb bone and toe proportions as well as the ungual morphology suggest a terrestrial locomotion similar to those of Yanornis and Yixianornis. The associated fish fragments may indicate a piscivorous diet consistent with the dentation of the new bird. The discovery of a new basal ornithurine further shows that the diversification of the Ornithurae is probably no less than the enantiornithes and the near lakeshore adaptation had definitely played a key role in the early ornithurine radiation.
2)
Joseph E. Peterson, Michael D. Henderson, Reed P. Scherer & Christopher P. Vittore. Face Biting On A Juvenile Tyrannosaurid And Behavioral Implications. Palaios, 2009; 24 (11): 780 DOI: 10.2110/palo.2009.p09-056r
The juvenile tyrannosaurid specimen BMR P2002.4.1 possesses a series of four partially healed, oblong lesions along the left maxilla and nasal bones. The morphology of the lesions and their positioning and orientation are compatible with the jaws of the specimen, suggesting that the lesions may have been the result of a bite from an attacker of similar size and species as the bite victim. Bone remodeling of the lesions indicates partial healing and demonstrates that the injury was not fatal. The injury appears to have affected the growth of the skull, causing a slight warping of the left maxilla and a slight leftward curvature of the nasal. Previous examples of intraspecific behavior in theropods have noted various injuries on skulls; the majority of documented injuries are in adults. The presence and nature of these wounds suggests that juvenile tyrannosaurid behavior included intraspecific aggression among similar-sized individuals, as has been observed in modern crocodilians. Although it is not possible to unequivocally infer behavior from a fossil specimen, as a juvenile animal it is unlikely that the behavior directly reflects sexual competition or conflict, although it may represent learning behavior for later conflict as competing adults or territoriality over food or spatial resources.
3)
Sereno, P.C., and Brusatte, S.L. 2009. Comparative assessment of tyrannosaurid interrelationships. Journal of Systematic Palaeontology. doi: 10.1017/S1477201909990034.
We employ a new comparative method to four cladistic analyses of tyrannosaurid dinosaurs to identify root causes for differences between phylogenetic results. The comparative method is a three-step procedure that (1) adjusts competing hypotheses so they share equivalent taxonomic scope, (2) isolates the character data relevant to the common problem, and (3) divides relevant character data into shared and novel partitions. It is then possible to quantify the degree of similarity between character data using three indices (ancestor similarity index, character similarity index and character state similarity index).
The most parsimonious cladograms generated by the four analyses of tyrannosaurids appear fairly congruent, with two subclades present in all four analyses (Albertosaurus and Gorgosaurus versus Daspletosaurus, Tarbosaurus and Tyrannosaurus). A comparative examination of the underlying character data, however, highlights striking differences in character selection and significant differences in character state scores. Character selection and differences in scoring are root causes for phylogenetic incongruence. Comparative analysis reveals the existence of many data-level differences that remain largely obscured when comparison is limited to the most parsimonious cladograms.
4)
Xu, X., and Guo, Y. 2009.
The origin and early evolution of feathers: insights from recent paleontological and neontological data. Vertebrata PalAsiatica 47(4):311-329.
Recent paleontological and neontological studies on feathers and feather-like integumentary structures have improved greatly our understanding of the origin and early evolution of feathers. New observations on some non-avian dinosaur specimens preserving integumentary structures, in combination with recent paleontological and neontological data, provide additional insights into this important evolutionary issue. Five major morphogenesis events are inferred to have occurred sequentially early in feather evolution before the origin of the Aves, and they are: 1) appearance of filamentous and tubular morphology, 2) formation of follicle and barb ridges, 3) appearance of rachis, 4) appearance of planar form, and 5) formation of pennaceous barbules. These events produce several morphotypes of feathers that are common among non-avian archosaurs but are probably lost later in avian evolution, and they also produced several morphotypes of feathers that are nearly identical or identical to those of modern birds. While feathers of non-avian dinosaurs exhibit many unique features of modern feathers, some of them also possess striking features unknown in modern feathers. Several models of evolutionary origin of feathers based on developmental data suggest that the origin of feathers is a completely innovative event and the first feathers have nothing to do with reptilian scales. We believe, however, that the defining features of modern feathers might have evolved in an incremental manner rather than in a sudden way. Consequently, an evolutionary model characteristic of both transformation and innovation is more acceptable for feather evolution. The function of the first feather is inferred to be neither related to flight nor to insulation. Display or heat dissipation, among others, remains viable hypotheses for initial function of feathers. An integrative study is promising to provide much new insights into the origin of feathers.
5)
Liang, X., Wen, S., Yang, D., Zhou, S., and Wu, S. 2009. Dinosaur eggs and dinosaur egg-bearing deposits (Upper Cretaceous) of Henan Province, China: occurrences, palaeoenvironments, taphonomy and preservation. Progress in Natural Science 19(11):1587-1601. doi: 10.1016/j.pnsc.2009.06.012.
The Upper Cretaceous dinosaur egg-bearing deposits in Henan Province, central China are divided into three ormations in ascending order: Gaogou, Majiacun and Sigou. The Gaogou Formation belongs to alluvial fan deposits containing the fossil dinosaur egg assemblage of Faveoloolithus, Dendroolithus, Dictyoolithus, Paraspheroolithus and Longiteresoolithus. The Majiacun Formation is interpreted as braided stream to meandering stream deposits with assemblage of Ovaloolithus, Paraspheroolithus, Placoolithus, Dendroolithus, Prismatoolithus, rare Youngoolithus and Nanhiungoolithus. The Sigou Formation is shallow lacustrine/palustrine to low-sinuosity river sedimentary rocks with assemblage of Macroolithus, Elongatoolithus, Ovaloolithus and Paraspheroolithus.
To date, 37 oospecies, 13 oogenera and 8 oofamilies of dinosaur eggs have been distinguished. Autochthonous dinosaur eggs are preserved in the floodplain deposits, whereas allochthonous and parautochthonous dinosaur eggs are preserved in the alluvial fans. This suggests that river floodplains are the best environments for the preservation of numerous autochthonous dinosaur eggs. The preservation of most dinosaur eggs in brown to red calcic palaeosoils, muddy siltstones or mudstones suggests that the paleoclimate of the nesting area was semiarid. The presence of gray and green mudstone and coal layers, however, indicates that there existed an ephemeral subhumid climate during the middle and Late Cretaceous. It is suggested that such a climate was favorable for the development of meandering streams in a vegetated environment.
6)
Wang, X., Kellner, A.W.A., Jiang, S., and Meng, X. 2009.
An unusual long-tailed pterosaur with elongated neck from western Liaoning of China. Anais da Academia Brasileira de Ciências 81(4):793-812. doi: 10.1590/S0001-37652009000400016.
A new long-tailed pterosaur, Wukongopterus lii gen. et sp. nov, is described based on an almost complete skeleton (IVPP V15113) representing an individual with an estimated wing span of 730 mm. The specimen was discovered in strata that possibly represent the Daohugou Bed (or Daohugou Formation) at Linglongta, Jianchang, Liaoning Province, China. Wukongopterus lii is a non-pterodactyloid pterosaur diagnosed by the first two pairs of premaxillary teeth protruding beyond the dentary, elongated cervical vertebrae (convergent with Pterodactyloidea), and a strongly curved second pedal phalanx of the fifth toe. The specimen further has a broken tibia that indicates an injury occurred while the individual was still alive. Taphonomic aspects provide indirect evidence of an uropatagium, supporting the general hypothesis that at least all non-pterodactyloid pterosaurs show a membrane between the hind limbs. A phylogenetic analysis including most non-pterodactyloid pterosaurs shows that Wukongopterus lii gen. et sp. nov. lies outside the Novialoidea, being cladistically more primitive than the Rhamphorhynchidae and Campylognathoides. This analysis differs from previous studies and indicates that more work is needed before a stable picture of non-pterodactyloid pterosaur relationships is achieved.
7)
Costa, F.R., and Kellner, A.W.A. 2009.
On two pterosaur humeri from the Tendaguru beds (Upper Jurassic, Tanzania). Anais da Academia Brasileira de Ciências 81(4):813-818. doi: 10.1590/S0001-37652009000400017.
Jurassic African pterosaur remains are exceptionally rare and only known from the Tendaguru deposits, Upper Jurassic, Tanzania. Here we describe two right humeri of Tendaguru pterosaurs from the Humboldt University of Berlin: specimens MB.R. 2828 (cast MN 6661-V) and MB.R. 2833 (cast MN 6666-V). MB.R. 2828 consists of a three-dimensionally preserved proximal portion. The combination of the morphological features of the deltopectoral crest not observed in other pterosaurs suggests that this specimen belongs to a new dsungaripteroid taxon. MB.R. 2833 is nearly complete, and because of a long and round proximally placed deltopectoral crest it could be referred to the Archaeopterodactyloidea. It is the smallest pterosaur from Africa and one of the smallest flying reptiles ever recorded. These specimens confirm the importance of the Tendaguru deposits for the Jurassic pterosaur record. This potential, however, has to be fully explored with more field work.