A new crocodilian from the Lower Cretaceous Crato Formation of north-eastern Brazil

A new mesosuchian crocoddian from the Nova Olinda Member of the Crato Formation (Lower Cretaceous, Aptian) of north-eastern Brazil is described. Susisuchus anatoceps gen. et sp. nov. is the first crocodillan to be reported from this formation. It is represented by an incomplete, partially articulated skeleton: the skull and mandible, partial postcranial axial skeleton, forelimbs and portions of the osteodermal skeleton. Preservation of soft tissues includes the skin surrounding both forelimbs and the digits of the right hand. The state of preservation of the specimen suggests that it was incorporated into the basin as a desiccated carcass. Susisuchus anatoceps is one of the oldest crocodilians with a eusuchian-type dorsal shield, comprising a tetraserial paravertebral shield and, either side of this, two sagittal rows of accessory osteoderms. It also possesses amphicoelous thoracic, lumbar and caudal vertebrae. This combination of postcranial features have never before been seen in a crocodilian and warrant the erection of a new family within Mesosuchia: Susisuchidae. Taxonomically, S. anatoceps is similar to a number of Lower Cretaceous mesosuchians previously considered to have given rise to eusuchians, most notably the Glen Rose crocodilian and a new, but as yet undescribed crocodillan from the Lower Cretaceous Winton Formation of western Queensland, Australia. Preliminary preparation of the Winton crocodilian indicates that it may belong to Susisuchidae, supporting the hypotheses of interchange between the vertebrate faunas of South America and Australia during the Lower Cretaceous.

Distribution of the monarch butterfly, Danaus plexippus (L.) (Lepidoptera : Nymphalidae), in western North America

The standard model for the migration of the monarch butterfly in western North America has hitherto been movement in the autumn to overwintering sites in coastal California, followed by a return inland by most individuals in the spring. This model is based largely on observational and limited tagging and recovery data. In this paper we test the model by plotting many years of museum and collection records on a monthly basis on a map of the region. Our plots suggest a movement of Oregon, Washington and other north-western populations of summer butterflies to California in the autumn, but movement of more north-easterly populations (e.g. from Idaho and Montana) along two pathways through Nevada, Utah and Arizona to Mexico. The more westerly of these two pathways may follow the Colorado River south as indicated by museum records and seasonal temperature data. The eastern pathway may enter northern Utah along the western scarp of the Wasatch Mountains and run south through Utah and Arizona. Further analysis of distributions suggests that monarch butterflies in the American West occur primarily along rivers, and there are observations indicating that autumn migrants often follow riparian corridors. More data are needed to test our new model; we suggest the nature of the data required. (c) 2005 The Linnean Society of London.

Social inequalities in male mortality, and in male mortality from smoking: indirect estimation from national death rates in England and Wales, Poland, and North America

Background There are substantial social inequalities in adult male mortality in many countries. Smoking is often more prevalent among men of lower social class, education, or income. The contribution of smoking to these social inequalities in mortality remains uncertain. Methods The contribution of smoking to adult mortality in a population can be estimated indirectly from disease-specific death rates in that population (using absolute lung cancer rates to indicate proportions due to smoking of mortality from certain other diseases). We applied these methods to 1996 death rates at ages 35-69 years in men in three different social strata in four countries, based on a total of 0.6 million deaths. The highest and lowest social strata were based on social class (professional vs unskilled manual) in England and Wales, neighbourhood income (top vs bottom quintile) in urban Canada, and completed years of education (more than vs less than 12 years) in the USA and Poland. Results In each country, there was about a two-fold difference between the highest and the lowest social strata in overall risks of dying among men aged 35-69 years (England and Wales 21% vs 43%, USA 20% vs 37%, Canada 21% vs 34%, Poland 26% vs 50%: four-country mean 22% vs 41%, four-country mean absolute difference 19%). More than half of this difference in mortality between the top and bottom social strata involved differences in risks of being killed at age 35-69 years by smoking (England and Wales 4% vs 19%, USA 4% vs 15%, Canada 6% vs 13%, Poland 5% vs 22%: four-country mean 5% vs 17%, four-country mean absolute difference 12%). Smoking-attributed mortality accounted for nearly half of total male mortality in the lowest social stratum of each country. Conclusion In these populations, most, but not all, of the substantial social inequalities in adult male mortality during the 1990s were due to the effects of smoking. Widespread cessation of smoking could eventually halve the absolute differences between these social strata in the risk of premature death.