Biological controls upon the physical taphonomy of exceptionally preserved salamanders from the Miocene of Rubielos de Mora,northeast Spain

McNamara, M.E., Orr, P.J., Manzocchi, T., Alcalá, L., Anadón, P. & Peñalver, E. 2011: Biological controls upon the physical taphonomy of exceptionally preserved salamanders from the Miocene of Rubielos de Mora, northeast Spain. Lethaia, Vol. 45, pp. 210–226. The middle Miocene Rubielos de Mora Konservat‐Lagerstätte of northeast Spain is hosted within profundal, finely laminated, lacustrine mudstones. The diverse biota includes abundant salamanders. Most individuals died during separate episodes and sank rapidly postmortem. Specimens are typically preserved in dorso‐ventral aspect, the most hydrodynamically stable orientation. The near‐cylindrical morphology of the body, however, allowed some carcasses to settle in or subsequently re‐orientate into, lateral orientations. Loss of skeletal elements (i.e. reduced completeness) reflects their location within the body and followed a distal to proximal trend. Two stages are identified: initial loss of a small number of phalanges, followed by loss of more proximal limb bones plus additional phalanges. Disarticulation is more complex: it occurred via several mechanisms (notably, abdominal rupture and re‐orientation of part of the body and limbs during decay) and shows no consistent pattern among specimens. The physical taphonomy of the salamanders is controlled predominantly by intrinsic biological factors, i.e. the geometry of the body and of individual skeletal elements, the orientation, inherent strength and location of specific joints and the extent to which soft tissues, particularly the skin, persist during decay. These biological factors probably control patterns of physical taphonomy of other fossil tetrapods with a similar skeletal configuration. □Articulation, completeness, Konservat‐Lagerstätten, orientation, quantitative taphonomy, salamanders.     

Early intervention in psychosis: concepts,evidence and future directions

The rise of the early intervention paradigm in psychotic disorders represents a maturing of the therapeutic approach in psychiatry, as it embraces practical preventive strategies which are firmly established in mainstream health care. Early intervention means better access and systematic early delivery of existing and incremental improvements in knowledge rather than necessarily requiring dramatic and elusive breakthroughs. A clinical staging model has proven useful and may have wider utility in psychiatry. The earliest clinical stages of psychotic disorder are non-specific and multidimensional and overlap phenotypically with the initial stages of other disorders. This implies that treatment should proceed in a stepwise fashion depending upon safety, response and progression. Withholding treatment until severe and less reversible symptomatic and functional impairment have become entrenched represents a failure of care. While early intervention in psychosis has developed strongly in recent years, many countries have made no progress at all, and others have achieved only sparse coverage. The reform process has been substantially evidence-based, arguably more so than other system reforms in mental health. However, while evidence is necessary, it is insufficient. It is also a by-product as well as a catalyst of reform. In early psychosis, we have also seen the evidence-based paradigm misused to frustrate overdue reform. Mental disorders are the chronic diseases of the young, with their onset and maximum impact in late adolescence and early adult life. A broader focus for early intervention would solve many of the second order issues raised by the early psychosis reform process, such as diagnostic uncertainty despite a clear-cut need for care, stigma and engagement, and should be more effective in mobilizing community support. Early intervention represents a vital and challenging project for early adopters in global psychiatry to consider.     

The abundance,distribution and structural characteristics of tree‐holes in Nothofagus forest,New Zealand

Tree‐holes provide an important microhabitat that is used for feeding, roosting and breeding by numerous species around the world. Yet despite their ecological importance for many of New Zealand's endangered species, few studies have investigated the abundance or distribution of tree‐holes in native forests. We used complementary ground and climbed tree surveys to determine the abundance, distribution and characteristics of tree‐holes in undisturbed Nothofagus forest in the Lewis Pass, New Zealand. We found that hole‐bearing trees were surprisingly abundant compared with many other studies, including Australian Eucalyptus species and American beech. In fact, we estimated as many as 3906 tree‐holes per hectare, of which 963 holes per hectare were potentially large enough to provide roost sites for hole‐nesting bats in New Zealand, while only eight holes per hectare were potentially suitable for specialist hole‐nesting birds. This was of great interest as primary cavity‐excavating animals are absent from New Zealand forests, compared with North America and Australia. Moreover, tree‐hole formation in New Zealand is likely to be dominated by abiotic processes, such as branch breakage from windstorms and snow damage. As has been found in many other studies, tree‐holes were not uniformly distributed throughout the forest. Tree‐holes were significantly more abundant on the least abundant tree species, Nothofagus fusca, than on either N. menziesii or N. solandri. In addition to tree species, tree size was also an important factor influencing the structural characteristics of tree‐holes and their abundance in this forest. Moreover, these trends were not fully evident without climbed tree surveys. Our results revealed that ground‐based surveys consistently underestimated the number of tree‐holes present on Nothofagus trees, and illustrate the importance of using climbed inspections where possible in tree‐hole surveys. We compare our results with other studies overseas and discuss how these are linked to the biotic and abiotic processes involved in tree‐hole formation. We consider the potential implications of our findings for New Zealand's hole‐dwelling fauna and how stand dynamics and past and future forest management practices will influence the structural characteristics of tree‐holes and their abundance in remnant forest throughout New Zealand.     

Socio-genetic structure of mound-building mice, Mus spicilegus, in autumn and early spring

Mus spicilegus has become a popular biological model species in the last decade because of the evolutionary interest of its behavioural particularities (the building of mounds, bi-parental care and monogamous mating system). The genetic structure of M. spicilegus populations should reflect those life-history traits. Although many studies have reported on mound-building mouse populations in the field or in a semi-natural enclosure, only one used hyper variable genetic markers to assess parentage and social structure. In the present study conducted in Hungary, we analysed individuals from seven highly populous mounds in autumn with the set of loci used in a previous study. Our results confirmed that mounds are inhabited by juveniles from several parental units, but revealed population differences. In a capture–recapture field session in spring, we assessed genetic relationships between individuals after dispersal from the mounds, the other key moment of the life cycle of this species. The results indicate that the social structure at this moment reflects a transition phase between the large over-wintering groups and the monogamous pairs described later in the year. Social bounds forged during the long winter cohabitation may have lasting effects on social and genetic structure of this species. This scenario is discussed in respect of the available literature on this species as well as other species.  © 2008 The Linnean Society of London, Biological Journal of the Linnean Society , 2008, 93 , 689–699.     

Morphological and mitochondrial DNA analyses indicate the presence of a hybrid zone between two species of leaf beetle (Coleoptera; Chrysomelidae) in Southern Spain

The present study reports a case where the survey of morphological and mitochondrial DNA variation among populations of a species complex of leaf beetle, the Gonioctena variabilis complex, has lead to the identification of a hybrid zone between two species of the complex in Southern Spain. The complex is divided into four species distributed around the western Mediterranean region. The four species, G. variabilis, Gonioctena aegrota, Gonioctena gobanzi, and Gonioctena pseudogobanzi, are traditionally determined by differences in the morphology of the male genitalia (aedeagus). To gain insight into the history of the speciation process within this species complex, we sampled populations in Portugal, Spain, Southern France, and Northern Italy. We sequenced a portion of the mitochondrial control region of each individual collected. A haplotype network of these sequences was found to comprise four distinct groups of sequence types, separated by a relatively large number of mutations. Moreover, in most of the samples for which morphological and molecular variation is available, there is a one‐to‐one correspondence between haplotype group, defined by mitochondrial sequence variation, and morphological groups defined on the basis of the aedeagus, showing evidence of four historically independent evolutionary units. This supports the use of the aedeagus morphology as a taxonomically informative trait in this species complex and a recent taxonomic revision upgrading four formerly subspecies, corresponding to the evolutionary units identified in the present study, to species status. However, some of the individuals from our samples in Southern Spain, morphologically identified as G. aegrota, were found to possess mitochondrial sequences typical of G. pseudogobanzi. The opposite case was also found. This suggests the presence of a zone of contact and hybridization between G. aegrota and G. pseudogobanzi. The location of this hybrid zone appears to be unusual. We identify historical scenarios that may explain our observations. © 2008 The Linnean Society of London, Biological Journal of the Linnean Society, 2008, 94 , 105–114.     

Nuclear Genome Sequence Survey of the Dinoflagellate Heterocapsa triquetra

ABSTRACT. Dinoflagellates have among the largest nuclear genomes known, but we know little about their contents or organisation. Given the interest in dinoflagellate ecology, cell biology, and evolutionary biology, there are many reasons to thoroughly investigate the contents of dinoflagellate genomes, but because of their large size the only thorough samples to date have relied on expressed sequence tag surveys to analyse cDNAs. To complement this, there are some studies of the physical properties of dinoflagellate chromosomes, but no direct survey of the nature of the sequences contained within them. To start to build a picture of the contents of these genomes, we have sequenced over 230,000 bp from the nuclear genome of Heterocapsa triquetra, which has been estimated to be 18–23 billion base pairs in total. The survey includes one putative gene with two relict spliced leaders, one putative pseudogene, and a small number of low‐complexity repeats, transposons, and other putative selfish elements, all of which account for about 5% of the survey. Another 5% of the survey was long, complex repeats, some highly represented. By far the greatest fraction of the survey (89.5%) is made up of non‐repeated sequence with no similarity to any other known sequence.     

Discordant mitochondrial and nuclear gene phylogenies in emydid turtles: implications for speciation and conservation

Do phylogenies and branch lengths based on mitochondrial DNA (mtDNA) provide a reasonable approximation to those based on multiple nuclear loci? In the present study, we show widespread discordance between phylogenies based on mtDNA (two genes) and nuclear DNA (nucDNA; six loci) in a phylogenetic analysis of the turtle family Emydidae. We also find an unusual type of discordance involving the unexpected homogeneity of mtDNA sequences across species within genera. Of the 36 clades in the combined nucDNA phylogeny, 24 are contradicted by the mtDNA phylogeny, and six are strongly contested by each data set. Two genera (Graptemys, Pseudemys) show remarkably low mtDNA divergence among species, whereas the combined nuclear data show deep divergences and (for Pseudemys) strongly supported clades. These latter results suggest that the mitochondrial data alone are highly misleading about the rate of speciation in these genera and also about the species status of endangered Graptemys and Pseudemys species. In addition, despite a strongly supported phylogeny from the combined nuclear genes, we find extensive discordance between this tree and individual nuclear gene trees. Overall, the results obtained illustrate the potential dangers of making inferences about phylogeny, speciation, divergence times, and conservation from mtDNA data alone (or even from single nuclear genes), and suggest the benefits of using large numbers of unlinked nuclear loci. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 445–461.     

Detarieae sensu lato (Fabaceae) from the Late Oligocene (27.23 Ma) Guang River flora of north‐western Ethiopia

New species of caesalpinioid legumes, Cynometra sensu lato and Afzelia, are described from the Late Oligocene (27.23 Ma) Guang River flora in north‐western Ethiopia. Both taxa show leaf characteristics that are shared with extant species in the Guineo‐Congolian, Sudanian and/or Zambezian regions of Africa today. The presence of these two species in Ethiopia during the Palaeogene provides further evidence of the importance of the legume tribe Detarieae in northern and north‐eastern Africa throughout much of the Cenozoic, even although the clade is poorly represented in these regions today. The fossil record documents a significant palaeogeographical and evolutionary history of Detarieae in Africa, especially compared with that of Europe and Anatolia. Based on this evidence, it is unlikely that significant diversification of extant African Detarieae took place on the Eurasian landmass. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 163 , 44–54.     

Inter‐regional comparison of land‐use effects on stream metabolism

1. Rates of whole‐system metabolism (production and respiration) are fundamental indicators of ecosystem structure and function. Although first‐order, proximal controls are well understood, assessments of the interactions between proximal controls and distal controls, such as land use and geographic region, are lacking. Thus, the influence of land use on stream metabolism across geographic regions is unknown. Further, there is limited understanding of how land use may alter variability in ecosystem metabolism across regions. 2. Stream metabolism was measured in nine streams in each of eight regions (n = 72) across the United States and Puerto Rico. In each region, three streams were selected from a range of three land uses: agriculturally influenced, urban‐influenced, and reference streams. Stream metabolism was estimated from diel changes in dissolved oxygen concentrations in each stream reach with correction for reaeration and groundwater input. 3. Gross primary production (GPP) was highest in regions with little riparian vegetation (sagebrush steppe in Wyoming, desert shrub in Arizona/New Mexico) and lowest in forested regions (North Carolina, Oregon). In contrast, ecosystem respiration (ER) varied both within and among regions. Reference streams had significantly lower rates of GPP than urban or agriculturally influenced streams. 4. GPP was positively correlated with photosynthetically active radiation and autotrophic biomass. Multiple regression models compared using Akaike’s information criterion (AIC) indicated GPP increased with water column ammonium and the fraction of the catchment in urban and reference land‐use categories. Multiple regression models also identified velocity, temperature, nitrate, ammonium, dissolved organic carbon, GPP, coarse benthic organic matter, fine benthic organic matter and the fraction of all land‐use categories in the catchment as regulators of ER. 5. Structural equation modelling indicated significant distal as well as proximal control pathways including a direct effect of land‐use on GPP as well as SRP, DIN, and PAR effects on GPP; GPP effects on autotrophic biomass, organic matter, and ER; and organic matter effects on ER. 6. Overall, consideration of the data separated by land‐use categories showed reduced inter‐regional variability in rates of metabolism, indicating that the influence of agricultural and urban land use can obscure regional differences in stream metabolism.     

Co‐limitation of photosynthetic capacity by nitrogen and phosphorus in West Africa woodlands

Photosynthetic leaf traits were determined for savanna and forest ecosystems in West Africa, spanning a large range in precipitation. Standardized major axis fits revealed important differences between our data and reported global relationships. Especially for sites in the drier areas, plants showed higher photosynthetic rates for a given N or P when compared with relationships from the global data set. The best multiple regression for the pooled data set estimated V_cmax and J_max from N_DW and S. However, the best regression for different vegetation types varied, suggesting that the scaling of photosynthesis with leaf traits changed with vegetation types. A new model is presented representing independent constraints by N and P on photosynthesis, which can be evaluated with or without interactions with S. It assumes that limitation of photosynthesis will result from the least abundant nutrient, thereby being less sensitive to the allocation of the non‐limiting nutrient to non‐photosynthetic pools. The model predicts an optimum proportionality for N and P, which is distinct for V_cmax and J_max and inversely proportional to S. Initial tests showed the model to predict V_cmax and J_max successfully for other tropical forests characterized by a range of different foliar N and P concentrations.