FIRST OCCURRENCE OF FOOTPRINTS OF LARGE THERAPSIDS FROM THE UPPER PERMIAN OF EUROPEAN RUSSIA

Abstract:  Large footprints of terrestrial tetrapods have been found in the Cis-Urals region of European Russia. The footprint horizon is in Late Permian (Changhsingian) deposits of the Vyatkian Gorizont (uppermost Tatarian) approximately 50 m below the local Permian/Triassic boundary. Seventeen randomly orientated footprints were excavated and are referred to the ichnospecies Brontopus giganteus . The footprints were emplaced in a reddish-brown mudstone that was deposited from suspension beneath shallow ponded water in a floodplain environment. They were subsequently cast by the base of the overlying fine-grained sandstone, which was deposited from a sheet-flood event. The footprints were produced by a large therapsid, possibly a dinocephalian, but more probably a dicynodont, and represent the first ichnological record of the Therapsida from the Upper Permian of Russia.     

Remodelling of Neuromuscular Systems During Insect Metamorphosis

During metamorphosis in the hawkmoth, Manduca sexta, the larvalthoracic legs are replaced by a new set of adult legs that includenew sensory neurons and muscles, and participate in new patternsof locomotor activity. Larval leg motoneurons persist to innervatethe new adult leg muscles, but undergo striking changes in dendriticmorphology that are regulated by the insect steroid, 20-hydroxyecdysone.In the periphery, the motor terminals regress as larval musclesdegenerate, and expand as new adult muscles form from myoblasts.Evidence obtained both in vivo and in vitro suggests that theproliferation of myoblasts during metamorphosis is dependentupon innervation.     

Evolution and function of horns and hornlike organs in female ungulates

The evolutionary bases for horns, antlers, and tusks in male ungulate mammals have been extensively investigated, but the reasons for the presence or absence of hornlike organs in female ungulates have not been thoroughly reviewed. Here I examine (1) the taxonomic distribution of horns and hornlike organs in females and evidence on the evolutionary history of the trait; (2) behavioural evidence on the uses of horns and hornlike organs by females and socio-ecological correlations with female hornedness or hornlessness; and (3) evidence on the role of genes and hormones in controlling the expression of female horns. In cervids, antlered females may be rare because of a constraint to regrow antlers yearly, if at all, small social group sizes, and a direct linkage between androgen production and the initiation of antler growth. For non-cervid ungulate females, there appear to be no overriding or unifying aptive factors governing the evolutionary development of horns or hornlike organs, although the trait may be aptive in some cases.     

Temporal and spatial variation in ecosystem metabolism and food web carbon transfer in a wet‐dry tropical river

1. High light availability and stable base flow during the dry season promote primary production in perennial rivers of the wet–dry tropics, in contrast to production during the wet season which is often limited by turbidity and scouring. The Mitchell River of northern Queensland (Australia) was studied to understand controls on aquatic production and respiration in the dry season in relation to spatial and temporal gradients of light and temperature. 2. At three sites along the river, whole‐ecosystem gross primary production (GPP) and respiration (ER) were measured from diel changes of dissolved oxygen using the open‐channel single station method. Using stable carbon and nitrogen isotope analysis, aquatic consumers and their potential basal food resources were also assessed to determine food web relationships at the beginning and end of the dry season. 3. Nutrient limitation of aquatic net primary production was implied from the oligotrophic conditions and high algal C:N ratios. Rates of GPP were comparable with other tropical and temperate rivers and were regulated by light availability. 4. Respiration rates were high and similar to other tropical and subtropical rivers. Up to 52% of temporal variation of ER was explained by temperature, while P/R was lowest at the downstream site. 5. Benthic algae were the major carbon source for primary and secondary benthic consumers (insects) in the dry season but not for higher consumers (fish and crustaceans). Despite high rates of ER, which were probably supported by decaying terrestrial C3 plant material, this carbon source was not identified as contributing to animal consumer biomass. 6. While benthic algal production in the dry season sustained benthic invertebrates, the importance of external subsidies of carbon along the river, probably from the floodplain, was emphasised for fish and large invertebrates, which evidently were feeding on carbon sources not present in channel waterholes during the dry season.     

The roles of pre‐ and post‐hatching growth rates in generating a latitudinal cline of body size in the eastern fence lizard (Sceloporus undulatus)

Countergradient variation in norms of reaction can dampen the direct effects of environmental influences on phenotypic traits, allowing phenotypic similarity among populations despite exposure to different environmental conditions. Such norms of reaction may occur at any phase of the life‐history (e.g. growth rates during both embryonic and postembryonic stages may influence geographical variation in adult body size). We collected gravid female lizards (Sceloporus undulatus) from northern (Indiana), central (Mississippi), and southern (Florida) populations, spanning almost the full latitudinal range of the species. Adult females from the southern population were smaller. Intrinsic growth rates of hatchlings were higher for the central population than for the other two populations. This pattern does not parallel the countergradient variation previously found in embryonic developmental rates among these populations. Earlier hatching enhanced survival rates of juveniles to a similar degree among populations, although juvenile survival rates in the field generally increase with latitude in this species. Our data reveal geographical variation in the ways in which intrinsic developmental/growth rates and survival shift during ontogeny, and suggest that latitudinal patterns in adult body size (such as Bergmann's rule) can result from both faster growth, and longer periods of growth. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 202–209.     

Improving biodiversity monitoring

Effective biodiversity monitoring is critical to evaluate, learn from, and ultimately improve conservation practice. Well conceived, designed and implemented monitoring of biodiversity should: (i) deliver information on trends in key aspects of biodiversity (e.g. population changes); (ii) provide early warning of problems that might otherwise be difficult or expensive to reverse; (iii) generate quantifiable evidence of conservation successes (e.g. species recovery following management) and conservation failures; (iv) highlight ways to make management more effective; and (v) provide information on return on conservation investment. The importance of effective biodiversity monitoring is widely recognized (e.g. Australian Biodiversity Strategy). Yet, while everyone thinks biodiversity monitoring is a good idea, this has not translated into a culture of sound biodiversity monitoring, or widespread use of monitoring data. We identify four barriers to more effective biodiversity monitoring in Australia. These are: (i) many conservation programmes have poorly articulated or vague objectives against which it is difficult to measure progress contributing to design and implementation problems; (ii) the case for long‐term and sustained biodiversity monitoring is often poorly developed and/or articulated; (iii) there is often a lack of appropriate institutional support, co‐ordination, and targeted funding for biodiversity monitoring; and (iv) there is often a lack of appropriate standards to guide monitoring activities and make data available from these programmes. To deal with these issues, we suggest that policy makers, resource managers and scientists better and more explicitly articulate the objectives of biodiversity monitoring and better demonstrate the case for greater investments in biodiversitymonitoring. There is an urgent need for improved institutional support for biodiversity monitoring in Australia, for improved monitoring standards, and for improved archiving of, and access to, monitoring data. We suggest that more strategic financial, institutional and intellectual investments in monitoring will lead to more efficient use of the resources available for biodiversity conservation and ultimately better conservation outcomes.     

Oviposition Sites of the Saltmarsh Mosquito, Aedes vigilax (Skuse) (Diptera: Culicidae), at Homebush Bay, Sydney, NSW—A Preliminary Investigation

Eggs of the saltmarsh mosquito, Aedes vigilax (Skuse), were collected in two saline wetlands at Homebush Bay in Sydney in February and March 1994 as part of an extensive study on the mosquito fauna of the area. Within the mangrove forest, very few eggs were found on mangrove trunks or pneumatophores. Within the saltmarshes, the distribution of eggs was very clumped. Few eggs were found on bare mud, and eggs were found mainly on the soil beneath the samphire plant, Sarcocornia quinqueflora , in the Bicentennial Park wetlands, and beneath S. quinqueflora and the marine couch, Sporobolus virginicus , in the Newington wetlands. Sporobolus appeared to be the preferred habitat plant although its distribution was limited.     

The skeletal taphonomy of Archaeopteryx: a quantitative approach

A new technique is described for taphonomic investigation of fossil vertebrates with a high degree of skeletal articulation and completeness, and applied to analysis of the taphonomy of Archaeopteryx. The known skeletal remains of Archaeopteryx can be assigned to two preservational types: (A) well-articulated and almost complete skeletons, and (B) less complete and more disarticulated skeletons, but with some well-articulated sub-units. Differences between these categories are most likely a function of time elapsed between death and burial, and these groups are interpreted as samples of a larger possible range of taphonomic variation. The specimens represent parts of a decay spectrum rather than a decay sequence, and there is no evidence for a regional drift pattern. Digital crossover in the hands of Archaeopteryx , previously considered an anatomical condition, is interpreted as a post-mortem artefact.