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The Moon is generally thought to have formed and evolved through a single or a series of catastrophic heating events, during which most of the highly volatile elements were lost. Hydrogen, being the lightest element, is believed to have been completely lost during this period. Here we make use of considerable advances in secondary ion mass spectrometry to obtain improved limits on the indigenous volatile (CO(2), H(2)O, F, S and Cl) contents of the most primitive basalts in the Moon-the lunar volcanic glasses. Although the pre-eruptive water content of the lunar volcanic glasses cannot be precisely constrained, numerical modelling of diffusive degassing of the very-low-Ti glasses provides a best estimate of 745 p.p.m. water, with a minimum of 260 p.p.m. at the 95 per cent confidence level. Our results indicate that, contrary to prevailing ideas, the bulk Moon might not be entirely depleted in highly volatile elements, including water. Thus, the presence of water must be considered in models constraining the Moon's formation and its thermal and chemical evolution.

Most orders and many families of modern mammals were established during the Palaeogene. Mammalian evolution during this period of time has been correlated with global climatic events1,2,3,4, although the timing, mode and scale of such a climate–evolution link remain debatable1,5,6. The Palaeogene global climate was step-punctuated by a warming across the Palaeocene/Eocene boundary about 55 Myr ago and a cool-off throughout the late Eocene and early Oligocene epochs1,2,7,8,9,10. The most severe cooling was at 33.5 Myr, slightly after the Eocene/Oligocene boundary, and was characterized by a drop in the mean annual temperature and by changes in vegetation from Eocene dense forests to Oligocene more open country5. Here we analyse 33 Palaeogene mammal faunas from the Mongolian Plateau of China and Mongolia. There is a distinct pattern of faunal turnovers: perissodactyl-dominant faunas of the Eocene were abruptly replaced by rodent/lagomorph-dominant faunas of the Oligocene. We interpret the turnovers as having been effected by global climatic shifts and name the prominent biotic reorganization across the Eocene/Oligocene boundary the Mongolian Remodelling, which correlates to the European Grande Coupure.

An important transformation in the evolution of mammals was the loss of the epipubic bones. These are elements projecting anteriorly from the pelvic girdle into the abdominal region in a variety of Mesozoic mammals, related tritylodonts, marsupials and monotremes but not in living eutherian (placental) mammals. Here we describe a new eutherian from the Late Cretaceous period of Mongolia, and report the first record of epipubic bones in two distinct eutherian lineages. The presence of epipubic bones and other primitive features suggests that these groups occupy a basal position in the Eutheria. It has been argued that the epipubic bones support the pouch in living mammals, but epipubic bones have since been related to locomotion and suspension of the litter mass of several attached, lactating offspring. The loss of the epipubic bones in eutherians can be related to the evolution of prolonged gestation, which would not require prolonged external attachment of altricial young. Thus the occurrence of epipubic bones in two Cretaceous eutherians suggests that the dramatic modifications connected with typical placental reproduction may have been later events in the evolution of the Eutheria.

A Cretaceous eucosmodont multituberculate mammal skeleton has been found in Mongolia with all of the bony elements of the shoulder girdle in place. This specimen demonstrates a different forelimb stance from that recently hypothesized for another Cretaceous eucosmodont. Primitively, it retains a separate ossified inter-clavicle, as in monotremes and non-mammalian cynodonts. In other respects it shares with therians and their extinct allies key features associated with mobility of the pectoral girdle and shoulder joint during locomotion, and a more parasagittal forelimb posture. This locomotor transformation appears to have evolved just once among the common ancestors of multituberculates and therians, some time before the Late Jurassic.

WE report here a new locality, Ukhaa Tolgod ('brown hills'), from the Upper Cretaceous of the Gobi Desert of Mongolia, which shows an unmatched abundance of well preserved vertebrate fossils, including the highest concentration of mammalian skulls and skeletons from any Mesozoic site. In the main collecting area (about 4 km2), recovered and uncollected articulated skeletons of thero-pod, ankylosaurian and protoceratopsian dinosaurs represent over 100 individuals. Specimens collected also include skulls (many with associated skeletons) of over 400 mammals and lizards, skeletons (including the first known skull) of the bird Mononykus, and nest sites that preserve the first known theropod dinosaur embryos1. In contrast to other Mesozoic localities, the diversity and abundance of theropods, mammals and lizards are unusually high. The exceptional preservation of vertebrates from the red-bed facies of the Gobi Upper Cretaceous has been attributed to arid conditions2–4, possibly involving catastrophic death and burial during major sandstorms5. Although fossils are found in fluvial facies at Ukhaa Tolgod, high concentrations of excellent specimens in aeolian facies support the argument for rapid entombment in sand. This contrasts with conditions for the terrestrial Upper Cretaceous in North and South America, where accretionary preservation of fossils in fluvial deposits predominates.

THE mid-Cenozoic immigration of rodents and primates to South America (when it was widely isolated by oceans) represents a pre-eminent problem in the biogeographical history of placental mammals. The unexpected discovery of South America's earliest rodent in the central Chilean Andes provides information critical to resolving the source area and primitive morphology of South American caviomorphs, suggesting an African origin for the group. This rodent is part of a new fossil mammal fauna1, the first diverse assemblage known for a critical 15–25 million year gap in the fossil record. We report here that cooccurrence of numerous higher-level taxa otherwise restricted to older or younger intervals identifies this fauna as representing a new biochronological interval preceding the Deseadan (South American Land Mammal Age), previously the earliest occurrence of rodents and primates on the continent. Radioisotopic dating corroborates biostratigraphy in identifying the new Andean rodent as the earliest known from the continent.

The OPCS report on cancer incidence and mortality in the vicinity of nuclear installations in England and Wales provides a mass of information that is so large that it should be possible to detect quite small changes in disease levels with considerable confidence. The data on cancer mortality are less subject to selective bias than the registration data on which incidence rates are based, and they provide the firmest grounds on which evidence of any effect can be obtained. These data show conclusively that there has been no general increase in cancer mortality in the vicinity of nuclear installations in a 22-year period beginning several years after the opening of the installations that have released the largest amounts of radionuclides to the environment. On the contrary, the mortality from cancer has tended to be lower in the LAAs in the vicinity of nuclear installations than in control LAAs selected for their presumed comparability with the former. This is unlikely to be due to a protective effect of ionizing radiation and suggests that, despite the efforts that were made to choose comparable control areas, there were non-installation differences between the populations relevant to the risk of dying from one or other type of cancer. Detailed examination of the few types of cancer that were relatively more common in the installation areas suggest that several of the differences were most likely to be due to chance, diagnostic artefacts or social factors rather than to any hazard specifically related to the installations. One disease provides a possible exception: namely, leukaemia in the age group 0-24 years. Two other diseases need further investigation, multiple myeloma and Hodgkin's disease in the older age group 25-74 years. The excess mortality rates recorded from these cancers were not large, and it has yet to be established that they are not due to general confounding by other environmental or socio-economic factors.

Ataxia-telangiectasia (AT) is a human autosomal recessive disorder of childhood1,2 characterized by: (1) progressive cerebellar ataxia with degeneration of Purkinje cells; (2) hypersensitivity of fibroblasts and lymphocytes to ionizing radiation3; (3) a 61-fold and 184-fold increased cancer incidence in white and black patients, respectively4; (4) non-random chromosomal rearrangements in lymphocytes; (5) thymic hypoplasia with cellular and humoral (IgA and IgG2) immunodeficiencies; (6) elevated serum level of alphafetoprotein; (7) premature ageing; and (8) endocrine disorders, such as insulin-resistant diabetes mellitus. A DNA processing or repair protein is the suspected common denominator in this pathology5. Heterozygotes are generally healthy; however, the sensitivity of their cultured cells to ionizing radiation is intermediate between normal individuals and that of affected homozygotes6. Furthermore, heterozygous females are at an increased risk of breast cancer7,8. These findings, when coupled with an estimated carrier frequency of 0.5–5.0%, suggest that (1) as many as one in five women with breast cancer may carry the AT gene7 and that (2) the increased radiation sensitivity of AT heterozygotes may be causing radiation therapists to reduce the doses of radiation used for treating cancer in all patients10. To identify the genetic defect responsible for this multifaceted disorder, and to provide effective carrier detection, we performed a genetic linkage analysis of 31 families with AT-affected members. This has allowed us to localize a gene for AT to chromosomal region 11q22-23.

The Mammals of North America, 2nd Edn. By E. Raymond Hall. Two volumes, pp.1,181. ISBN Vol. 1 0-471-05443-7; ISBN Vol. 20-471-05444-5. (Wiley: 1981.) $59.85, £33.25 per volume; two-volume set $106.40, £59.15.