Heavy Metal Accumulation in the Tissues and Organs of Pelophylax ridibundus (Pallas, 1771) and Pelophylax lessonae (Camerano, 1882) (Amphibia: Ranidae) Living in the Waterbodies of Nizhniy Novgorod

A comprehensive atomic-emission study and comparative assessment were done of the content and distribution of heavy metals (Mn, Cu, Cr, Al, Fe, Zn, and Sr) in the organs and tissues (muscles, skin, bones, gonads, liver, heart, spleen, and blood) of marsh and pool frogs collected in the lakes of a big industrial city (Nizhni Novgorod). High concentrations of heavy metals were found in the spleen (Cr), bones (Zn and Sr), liver (Cu) of lake frogs. High coefficients of the biological absorption of Mn, Sr, Zn (bone tissue), Fe (liver, spleen), and Cu (heart) were found in pool frogs. The cumulative properties of heavy metals were estimated from the accumulation coefficient established. Species regularities of heavy metal accumulation from water are presented in descending order as the following series: Zn > Cr > Al > Cu > Fe > Sr > Mn for pool frogs; and Fe > Zn > Mn > Cu > Cr > Al > Sr for marsh frogs. The priority intake of chromium, manganese, aluminum and strontium from the aqueous medium into the body occurred through the skin. Active zinc accumulation occurred mainly through food, which was confirmed by high values of the biological absorption coefficient of zinc for the liver of Pelophylax ridibundus and Pelophylax lessonae. The dependence of the heavy metal accumulation in the muscles from the organs in contact with the external environment (skin) and the digestive system (liver) was established by regression analysis. The most important adaptation of tailless amphibians is their ability to prevent excessive accumulation of heavy metals in their body, while living in the conditions of increased environmental pollution. Our results obtained speak for the high accumulation of heavy metals in the body of tailless amphibians, determined by the conditions of the aquatic environment and the bioavailability of these metals.

Species-Specific Features of Neuron-Glial Populations in the Brain of Tailless Amphibians

The midbrain roof and cerebellum cortex are the main integrative centers in amphibians. They serve to analyze and process nerve impulses, form the organism’s response, regulate and coordinate movements, connect amphibians with their environments. The present study addresses the relationship between the species of the tailless amphibians inhabiting the southern part of the Krasnoyarsk region (Bufo bufo Linnaeus, Rana arvalis Nilsson, Pelophylax ridibundus Pallas, and Rana amurensis Boulenger) and the morphological parameters of the populations of neurons and glia in layer VI of the midbrain roof and layers of the cerebellum cortex. The species-specific structure of amphibians’ brain regions has been found to be evident not only at the organ level (size and shape), but also at the level of the organization of neuron and glial cell populations. Distinctive species-specific differences can be found in the parameters of cell area (the area of the body, the area of the nucleus and the area of the cytoplasm) and the distribution density of neurons and gliocytes. The development of specific morphological features at the cellular level of the arrangement of the midbrain and cerebellum layers in different species of tailless amphibians is associated with long-term phylogenetic transformations of their nervous system and adaptation of amphibians to the terrestrial-aquatic habitat

Species diversity and distribution of the amphibians and reptiles of Balgarka Natural Park, Central Stara Planina, Bulgaria

The amphibians and reptiles occurring in Balgarka Natural Park (NP), are a representative sample of the lowland and middle mountain range herpetofauna of the Stara Planina Mountains. Here we present the first detailed and targeted mapping for the NP. The data were collected mostly in 2012–2013, mainly based on visual searches using the transect method; additionally we sampled using funnel-trapping and dip-netting for the aquatic species. We collected data for all 96 of the 2×2 km UTM squares of the NP. Based on 1155 observations we identified ca. 7673 individuals (including amphibian larvae), from 10 species of amphibians (~46% of the species diversity at the national level), from which 4 were salamanders (Caudata, ~50%) and 6 tailless amphibians (Anura, ~43%), and 13 species of reptiles (Reptilia, ~35%), including 3 turtles (Testudines, 75%), 5 lizards (Sauria, ~33%), and 5 snakes (Serpentes, 28%).

THE EFFECTS OF ILLUMINATION ON THE EARLY DEVELOPMENT OF AMPHIBIANS (AMPHIBIA: ANURA AND CAUDATA)

The effects of illumination on the early development of four amphibian species — Lissotriton vulgaris (Linnaeus, 1758), Triturus cristatus (Laurenti, 1768), Rana arvalis (Nilsson, 1842), and R. temporaria (Linnaeus, 1758) — have been studied. In general, the rate of their early development is rather independent of illumination. The eggs of tailless amphibians develop almost similarly under any illumination conditions, whereas the eggs of tailed amphibians better develop at an illumination of 700 lx. Illumination mainly influences the survival rate of embryos and prolarvae, which increases at low light intensities and decreases in the dark. Possible mechanisms and causes underlying the observed facts are discussed.

New Data on the Anomalies of Tailless Amphibians of the Volga Basin

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