The origin and early evolution of birds: discoveries,disputes, and perspectives from fossil evidence

The study of the origin and early evolution of birds has never produced as much excitement and public attention as in the past decade. Well preserved and abundant new fossils of birds and dinosaurs have provided unprecedented new evidence on the dinosaurian origin of birds, the arboreal origin of avian flight, and the origin of feathers prior to flapping flight. The Mesozoic avian assemblage mainly comprises two major lineages: the prevalent extinct group Enantiornithes, and the Ornithurae, which gave rise to all modern birds, as well as several more basal taxa. Cretaceous birds radiated into various paleoecological niches that included fish- and seed-eating. Significant size and morphological differences and variation in flight capabilities, ranging from gliding to powerful flight among early birds, highlight the diversification of birds in the Early Cretaceous. There is little evidence, however, to support a Mesozoic origin of modern avian groups. Controversy and debate, nevertheless, surround many of these findings, and more details are needed to give a better appreciation of the significance of these new discoveries.     

<Emphasis Type="Italic">Jeholornis</Emphasis> compared to<Emphasis Type="Italic"> Archaeopteryx</Emphasis>, with a new understanding of the earliest avian evolution

The recently reported Jeholornis represents the only known bird with a complete long skeletal tail except for Archaeopteryx. Two newly discovered specimens referable to Jeholornis provide some important new information about its anatomy. The tail of Jeholornis is much longer than that of Archaeopteryx and comprises a maximum of 27 caudal vertebrae compared with only 23 in Archaeopteryx. More interestingly, the tail feathers are shaped more like those of dromaeosaurs than those of Archaeopteryx. We conclude that the common ancestor of birds must have a more primitive tail than that in Archaeopteryx, confirming the side branch position of Archaeopteryx in the early avian evolution. The synsacrum is composed of six sacrals, representing a transitional stage between Archaeopteryx and more advanced birds. The scapula of Jeholornis has a dorso-laterally exposed glenoid facet, and the coracoid has a supracoracoid foramen. The presence of a pair of fenestrae in the sternum of Jeholornis has further implications for the air-sac system in early birds. Electronic Supplementary Material  The online version of this article (doi: contains supplementary material, which is available to authorized users.     

<Emphasis Type="Italic">Bonitasaura salgadoi</Emphasis> gen. et sp. nov.: a beaked sauropod from the Late Cretaceous of Patagonia

Ornithischian and theropod dinosaurs were morphologically diverse during the Cretaceous. In contrast, sauropods were relatively more conservative. The anatomy of Bonitasaura salgadoi, a new 9-m titanosaurian sauropod from Upper Cretaceous beds of Patagonia, suggests that sauropod anatomical diversity would have included unexpected items. Its unusual, rectangular lower jaw possesses narrow, anteriorly restricted teeth and shows evidence of a sharp keratinous sheath over the non-dentigerous region that probably worked to guillotine plant material. This discovery definitely demonstrates that titanosaurs acquired a mandibular configuration similar to that of some basal diplodocoids, as had already been suggested by the lower jaw of the controversial genus Antarctosaurus. This oral configuration, plus the beak-like structure and the skull shape, resemble some traits more commonly seen in Laurasian ornithischians, mostly unexpressed in southern continents. A high sauropod morphological diversity seems to be in agreement with the poorly represented ornithischian clades of the southern hemisphere.Communicated by G. Mayr     

Attempts to train goldfish to respond to magnetic field stimuli

Two different conditioning procedures, one appetitive and the other aversive, were used in separate attempts to demonstrate response to magnetic fields in the goldfish, Carassius auratus. Our results lead us to question those of an orientation experiment by Becker, although we recognize the possibility that goldfish may be sensitive primarily to magnetic field direction rather than intensity and that their directional sensitivity may be evidenced most readily by orientation in the field.     

To see or not to see: does previewing a future opponent affect the contest behavior of green swordtail males (<Emphasis Type="Italic">Xiphophorus helleri</Emphasis>)?

Animals assess the fighting ability of conspecifics either by engaging in aggressive interactions or observing contests between others. However, whether individuals assess physical prowess outside the context of aggressive interactions remains unknown. We examined whether male green swordtails (Xiphophorus helleri) extract information about the fighting ability of solitary individuals via observation and whether acquiring such information elicits behavioral modifications. Contests preceded by mutual visual assessment were significantly shorter than fights where only one or neither of the two individuals was informed in advance. Focal animals initiated aggressive behavior more often against larger opponents only after previewing their adversary, indicating that swordtails can extract information about relative body size from watching solitary conspecifics. When a fighting disadvantage is perceived, observers adopt tactics that increase their probability of winning the contest.     

Trihalomethane formation in ozonated and chlorinated surface water

The relatively recent discovery of disinfection by-products has driven the main regulatory organisms to set maximum contaminant levels for certain substances in drinking water. Trihalomethanes can be deemed as the most important group of by-products in chlorinated surface waters. The present work has focused on trihalomethane formation in a full-scale water treatment plant. We studied the effect of several factors, including ozonation, on trihalomethane levels in chlorinated treated water. The treatment scheme also includes an ozonation step. Electronic Publication     

Road trauma among young Australians: Implementing policy to reduce road deaths and serious injury

Objective: The objective of this study was to estimate the likely reduction in road trauma associated with the implementation of effective interventions to reduce road trauma among young Australians.

Methods: A desktop evaluation was conducted to model the likely reduction in road trauma (deaths and serious injuries resulting in hospitalization) among young people aged 17–24 years residing in Queensland, New South Wales, and Victoria. Potential interventions were identified using a rapid literature review and assigned a score based on evidence of effectiveness and implementation feasibility with the 3 highest scoring interventions included in the modeling. Likely reduction in road trauma was estimated by applying the average risk reduction effect sizes for each intervention to baseline risk (passenger or driver death or serious injury per 100,000 population) of road trauma for young Australians. Point estimates were calculated for the potential number of deaths and serious injuries averted in each state and per 100,000 population, with a one-way sensitivity analysis conducted using uncertainty ranges identified.

Results: Peer passenger and night driving restrictions as well as improved vehicle safety measures had the greatest potential to reduce road trauma. Peer passenger restrictions could avert 14 (range: 5–24) and 24 (range: 8–41) hospitalizations per year in Queensland and New South Wales, respectively, and night driving restrictions could avert 17 (range: 7–26), 28 (range: 12–45), and 13 (range: 6–21) hospitalizations annually in Queensland, New South Wales, and Victoria. These interventions reduced fatalities by less than 1 death annually in each state. Improved vehicle safety measures could avert 0–3, 0–4, and 0–3 deaths and 3–91, 4–156, and 2–75 hospitalizations in Queensland, New South Wales, and Victoria.

Conclusions: Key elements of graduated licensing (peer passenger and night driving restrictions) along with vehicle safety interventions offer modest but practically significant reductions in road trauma for young Australians. State governments need to revise current legislation to ensure that these reductions in road trauma can be realized.