Preservation of three-dimensional anatomy in phosphatized fossil arthropods enriches evolutionary inference

External and internal morphological characters of extant and fossil organisms are crucial to establishing their systematic position, ecological role and evolutionary trends. The lack of internal characters and soft-tissue preservation in many arthropod fossils, however, impedes comprehensive phylogenetic analyses and species descriptions according to taxonomic standards for Recent organisms. We found well-preserved three-dimensional anatomy in mineralized arthropods from Paleogene fissure fillings and demonstrate the value of these fossils by utilizing digitally reconstructed anatomical structure of a hister beetle. The new anatomical data facilitate a refinement of the species diagnosis and allowed us to reject a previous hypothesis of close phylogenetic relationship to an extant congeneric species. Our findings suggest that mineralized fossils, even those of macroscopically poor preservation, constitute a rich but yet largely unexploited source of anatomical data for fossil arthropods

Vomeropterygopalatina in larval Ichthyosaura alpestris apuanus (Amphibia: Urodela) and comments on the formation of the definite vomer in the Salamandridae

We studied the mouth roof of some larval stages of the Alpine newt Ichthyosaura alpestris apuanus, collected in summer 1977 in the field, using total preparations stained with Alizarinred, X-ray computed microtomography, and scanning electron microscopy. In all specimens we found traits indicating a delayed metamorphosis, i.e. a temporarily slowed down or even halted development of traits dependent on thyroid hormones (TH), and a slight further growth of probably TH-independent traits. Especially noteworthy is the temporary partial fusion of vomer and palatine forming a vomeropterygopalatinum. Presence of vomeropterygopalatina was recently shown in overwintering larvae of the related species Lissotriton vulgaris. On the basis of these findings we suggest that vomeropterygopalatina appear to be a quite frequent side effect of delayed metamorphosis. Further, we hypothesize that large parts of the larval vomer become incorporated into the definite (transformed) vomer. Three larvae in the series showed developmental stages of the vomerine bar, a posterior outgrowth of the vomer, typical for salamandrids, which is formed around metamorphosis. Development of the vomerine bar begins on the front end of the larval vomer and not (as generally assumed) on its posterior inner edge. These findings support our previous view that the formation of the vomerine bar in L. vulgaris and I. a. apuanus is more complex than literature assumes. However, due to some shortcomings regarding number and preservation of the available larvae a deeper study is needed using standardized conditions and a more complete developmental series of these (protected) or related species to substantiate the observations reported here

The "tooth systems" of Lissotriton vulgaris (Amphibia: Urodela) with special regard to delayed metamorphosis

A study on the cranial morphology, especially on the tooth bearing (dental) systems of several preserved developmental stages (from early premetamorphic larvae, in which most skull elements were already present and ossified or ossified in part, to transformed adult) of the smooth newt Lissotriton vulgaris (Salamandridae) was undertaken. We used μCT (to visualize the ossified elements in general and their relationships to each other) and an overall Alizarinred staining (to at best visualize teeth, replacement teeth, tooth buds and, after removing the oral mucosa, the course of dental laminae). Specimens cleared and stained with Alzarinred and Alcianblue were shown to be less suitable for our questions. In one case we used histological sections to follow the course of dental laminae, and in a second case scanning electron microscopy to show the structure of teeth in detail. The general sequence, growth, and changes of the bony elements including the "dental systems", especially around metamorphosis, known from several other salamandrids are largely confirmed. Concerning the "tooth systems", metamorphic events include the late appearance of the maxillae, resorption of the coronoids and palatines including their tooth-patches, remodelling of the vomer, i.e. resorption of the vomerine larval tooth-patch, formation of the edentate vomerine plate, and outgrowth of the monstichously dentate vomerine bar (typical for salamandrids). We show evidence that the larval vomer is not completey resorbed and that, unlike what has been described for Salamandra salamandra, the development of the vomerine bar is probably preceded by a shift of the dental lamina towards the middle of the palate, leaving a broad area between larval vomer and dental lamina. We hypothesize that the connective tissue in this area ossifies later and extends posteriorly forming the vomerine bar. It is noteworthy that in nearly all larvae vomer and intact pterygopalatinum were very close together either on one side or on both sides leading in overwintered larvae to the fusion of the vomer and the palatinal portion of the pterygopalatinum, primarily on one side. The zone of fusion is always characterized by a buccal notch. We think that in L. vulgaris the formation of "vomeropterygopalatina" is supported by the close proximity of the two bones and that these bones may fuse due to an imbalance between differentiation- and growth rate (indirectly caused by low temperatures). Approximation and especially fusion of the two bones correspond with the extension of the vomerine dental lamina into the area of the palatine, which temporally provides the latter with teeth. Overwintered larvae show further deviations concerning growth and differentiation of the mouth roof, which can be also interpreted as signs of delayed metamorphosis. They retain, for example, a largely intact dentate palatine, but with some regression of its tooth-patch, while the larval vomer is enlarged anteriorly and posteriorly and its number of teeth has increased; and the largely intact pterygopalatinal bony bridge. Further, maxillae begin to ossify. All larvae obviously have reached a late premetamorphic larval stage before the delay has started

Distribution and temporal behavior of particulate matter over the urban area of Buenos Aires

This paper contributes for the first time in Buenos Aires city to the temporal and horizontal distribution of the PM2.5 and PM10 concentrations. Their variations and relationships with relevant variables that characterize the air pollution potential of the urban air shed are also given. The measurements were carried out for one year from May 2006 to May 2007. During this period, particulate matter (PM) was continuously measured at one reference station and alternatively for shorter time periods at six different sites. The values and temporal variations on a daily and seasonal basis were consistent with the ventilation potential of the atmosphere. The cold season, which had the lowest values of the ventilation coefficient, indicated higher probabilities of poor air quality and this was confirmed by the higher concentrations of PM10 and PM2.5 measured. At the reference station, the daily EU limit value for PM10 was exceeded 36 times during one year while the Buenos Aires limit value was exceeded only once. The PM10 annual mean value was almost 70% of the Buenos Aires annual limit. The PM2.5 annual mean value (15 μg m-3) was same as the regulated one (15 μg m-3). The correlation between PM10 and PM2.5 concentrations and frequencies of wind directions showed that the highest concentrations were observed when the wind was from the city (land wind) and lowest concentrations when the wind was from Rio de La Plata (fluvial wind). The concentrations during land wind events exceeded the Buenos Aires PM2.5 annual limit value. The ratio of PM2.5 to PM10 was 0.44, which indicates the coarse particles (>2.5 μm) originated from road dust, soil re-suspension and abrasion processes are the dominated fractions of PM. Results of random PM measurements at 60 sites showed that PM2.5 was more homogeneously distributed over the city than PM10.Fil: Arkouli, Marcelina. Universität Stuttgart; AlemaniaFil: Ulke, Ana Graciela. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias de la Atmósfera y los Océanos; ArgentinaFil: Endlicher, Wilfried. Universität zu Berlin; AlemaniaFil: Baumbach, Günter. Universität Stuttgart; AlemaniaFil: Schultz, Eckart. Deutscher Wetterdienst; AlemaniaFil: Vogt, Ulrich. Universität Stuttgart; AlemaniaFil: Müller, Marlen. Universität zu Berlin; AlemaniaFil: Dawidowski, Laura Elena. Comisión Nacional de Energía Atómica; ArgentinaFil: Faggi, Ana Maria. Universidad de Flores; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Wolf Benning, Uta. Universität zu Berlin; AlemaniaFil: Scheffknecht, Günter. Universität Stuttgart; Alemani