Cytogenetic analyses in Trinomys (Echimyidae, Rodentia), with description of new karyotypes

Trinomys Thomas (1921) is a terrestrial genus of spiny rats endemic to the Brazilian areas of Atlantic Forest and the transitional areas of Cerrado and Caatinga. Although most species have been already karyotyped, the available cytogenetic information is mostly restricted to diploid and fundamental numbers. We analyzed the chromosomes of two Trinomys species: Trinomys moojeni (2n = 56, FN = 106) and Trinomys setosus setosus (2n = 56, FN = 106 and 2n = 56, FN = 108). Our analyses included GTG- and CBG-banding, silver-staining of the nucleolar organizer regions, and chromosome mapping of telomeres and 45S rDNA by fluorescent in situ hybridization (FISH). Comparative GTG- and CBG-banding suggested that the interspecific variation may be due to rearrangements such as pericentric inversions, centromere repositioning, and heterochromatin variation. We report two new karyotypes for T. s. setosus and describe for the first time the banding patterns of the two Trinomys species

Mammals, Volta Grande Environmental Unity, Triângulo Mineiro, states of Minas Gerais and São Paulo, Southeastern Brazil

The Volta Grande Environmental Unity represents one of the few remnants of Cerrado protected by a reserve in the Triângulo Mineiro region, municipalities of Conceição das Alagoas (19°55' S, 48°23' W) and Miguelópolis (20°12' S, 48°03' W), in the states of Minas Gerais and São Paulo, respectively. The mammalian fauna of this reserve was inventoried between 2003 and 2004 to generate estimates about taxonomic composition, richness, and abundance of species. A sampling effort of 832 trapping-nights resulted in 24 species recorded. Cumulative curves suggest that the overall inventory is not complete and that more species are likely to be registered. The majority of species recorded is widespread along the Cerrado, but include some noteworthy records of endangered species, such as the Giant anteater (Myrmecophaga tridactyla) and the Manned wolf (Chrysocyon brachyurus). The record of the arboreal cricetid rodent Oecomys bicolor represents a slight extension of the southeastern limit of its distribution

Food availability outweighs ocean acidification effects in juvenileMytilus edulis: laboratory and field experiments

Ocean acidification is expected to decrease calcification rates of bivalves. Nevertheless in many coastal areas high pCO2 variability is encountered already today. Kiel Fjord (Western Baltic Sea) is a brackish (12-20 g kg-1) and CO2 enriched habitat, but the blue mussel Mytilus edulis dominates the benthic community. In a coupled field and laboratory study we examined the annual pCO2 variability in this habitat and the combined effects of elevated pCO2 and food availability on juvenile M. edulis growth and calcification. In the laboratory experiment, mussel growth and calcification were found to chiefly depend on food supply, with only minor impacts of pCO2 up to 3350 μatm. Kiel Fjord was characterized by strong seasonal pCO2 variability. During summer, maximal pCO2 values of 2500 μatm were observed at the surface and >3000 μatm at the bottom. However, the field growth experiment revealed seven times higher growth and calcification rates of M. edulis at a high pCO2 inner fjord field station (mean pCO2 ca. 1000 μatm) in comparison to a low pCO2 outer fjord station (ca. 600 μatm). In addition, mussels were able to outcompete the barnacle Amphibalanus improvisus at the high pCO2 site. High mussel productivity at the inner fjord site was enabled by higher particulate organic carbon concentrations. Kiel Fjord is highly impacted by eutrophication, which causes bottom water hypoxia and consequently high seawater pCO2. At the same time, elevated nutrient concentrations increase the energy availability for filter feeding organisms such as mussels. Thus M. edulis can dominate over a seemingly more acidification resistant species such as A. improvisus. We conclude that benthic stages of M. edulis tolerate high ambient pCO2 when food supply is abundant and that important habitat characteristics such as species interactions and energy availability need to be considered to predict species vulnerability to ocean acidification

Dissolution: The achilles' heel of the triton shell in an acidifying ocean

© 2018 Harvey, Agostini, Wada, Inaba and Hall-Spencer. Ocean acidification is expected to negatively impact many calcifying marine organisms by impairing their ability to build their protective shells and skeletons, and by causing dissolution and erosion. Here we investigated the large predatory "triton shell" gastropod Charonia lampas in acidified conditions near CO2 seeps off Shikine-jima (Japan) and compared them with individuals from an adjacent bay with seawater pH at present-day levels (outside the influence of the CO2 seep). By using computed tomography we show that acidification negatively impacts their thickness, density, and shell structure, causing visible deterioration to the shell surface. Periods of aragonite undersaturation caused the loss of the apex region and exposing body tissues. While gross calcification rates were likely reduced near CO2 seeps, the corrosive effects of acidification were far more pronounced around the oldest parts of the shell. As a result, the capacity of C. lampas to maintain their shells under ocean acidification may be strongly driven by abiotic dissolution and erosion, and not under biological control of the calcification process. Understanding the response of marine calcifying organisms and their ability to build and maintain their protective shells and skeletons will be important for our understanding of future marine ecosystems

Ocean acidification and temperature rise: effects on calcification during early development of the cuttlefish Sepia officinalis

This study investigated the effects of seawater pH (i.e., 8.10, 7.85 and 7.60) and temperature (16 and 19 °C) on (a) the abiotic conditions in the fluid surrounding the embryo (viz. the perivitelline fluid), (b) growth, development and (c) cuttlebone calcification of embryonic and juvenile stages of the cephalopod Sepia officinalis. Egg swelling increased in response to acidification or warming, leading to an increase in egg surface while the interactive effects suggested a limited plasticity of the swelling modulation. Embryos experienced elevated pCO2 conditions in the perivitelline fluid (>3-fold higher pCO2 than that of ambient seawater), rendering the medium under-saturated even under ambient conditions. The growth of both embryos and juveniles was unaffected by pH, whereas 45Ca incorporation in cuttlebone increased significantly with decreasing pH at both temperatures. This phenomenon of hypercalcification is limited to only a number of animals but does not guarantee functional performance and calls for better mechanistic understanding of calcification processes

Regional adaptation defines sensitivity to future ocean acidification

Physiological responses to temperature are known to be a major determinant of species distributions and can dictate the sensitivity of populations to global warming. In contrast, little is known about how other major global change drivers, such as ocean acidification (OA), will shape species distributions in the future. Here, by integrating population genetics with experimental data for growth and mineralization, physiology and metabolomics, we demonstrate that the sensitivity of populations of the gastropod Littorina littorea to future OA is shaped by regional adaptation. Individuals from populations towards the edges of the natural latitudinal range in the Northeast Atlantic exhibit greater shell dissolution and the inability to upregulate their metabolism when exposed to low pH, thus appearing most sensitive to low seawater pH. Our results suggest that future levels of OA could mediate temperature-driven shifts in species distributions, thereby influencing future biogeography and the functioning of marine ecosystems

Taxonomic identity and geographic variation of Oligoryzomys BANGS, 1900 (Rodentia, Cricetidae) in southern Minas Gerais

Os roedores do gênero Oligoryzomys são animais com ampla distribuição no Brasil, ocorrendo em praticamente todos os estados. Nove espécies são reconhecidas para o país, no entanto, a separação entre elas é bastante difícil, devido a grande similaridade morfológica entre elas. Além disso, muitas espécies são simpátricas em algumas áreas, dificultando ainda mais a sua separação. Uma dessas áreas é a Zona da Mata de Minas Gerais, inserida no domínio da Mata Atlântica, onde duas espécies do gênero são encontradas, O. flavescens e O. nigripes. Desta forma, o objetivo deste trabalho foi caracterizar morfologicamente populações simpátricas dessas espécies, comparando-as espacialmente e temporalmente. Foram tomadas 30 medidas cranianas para a elaboração das análises morfométricas. As estatísticas descritiva e multivariada foram realizadas para a visualização dos padrões morfométricos. As duas espécies, em especial O. nigripes, apresentaram grandes variações intra e interpopulacionais, tanto quantitativas, como qualitativas, não apenas para o crânio, mas também para a cor dos pêlos. Muitas dessas variações tiveram influência etária. Diferenças cranianas entre O. flavescens e O. nigripes foram mínimas, com o crânio da segunda espécie pouco maior em algumas medidas. Variações espaciais existiram, mas aparentemente não foram influenciadas pela altitude ou distância entre as populações. Variações temporais também existiram, sendo os espécimes coletados há 40 anos maiores que os coletados há menos de 10 anos. Esses resultados mostraram a dificuldade que existe na caracterização dessas espécies indicando que deve haver mais estudos utilizando várias ferramentas taxonômicas, a fim de delimitar e conhecer melhor as espécies do gênero.Rodents of the genus Oligoryzomys are widely distributed in Brazil, occurring in virtually all states. Nine species are recognized for the country; however, the distance between them is quite difficult due to great morphological similarity between them. In addition, many species are sympatric in some areas, further hindering their separation. One of this area is Zona da Mata of Minas Gerais, inserted in the Atlantic Forest domain. Two species of the genus are found in this area, O. flavescens and O. nigripes. Thus, the objective was to characterize morphologically sympatric populations of these species, comparing them spatially and temporally. Thirty measurements of the cranium were taken for the morphometric analysis. Descriptive and multivariate statistics analysis were performed to visualize the morphometric patterns. These two species, primarily O. nigripes, show great intrainterpopulation variation, both quantitative and qualitative, not just in the cranium, but also in the hair color. Many of these variations were age effects. Cranial differences among O. flavescens and O. nigripes were minimal, but in some aspects the second specie was bigger. Spatial variations existed, but apparently were not affected by altitude or distance between populations. Time variations also existed, and the specimens collected 40 years ago are bigger than those collected less than 10 years ago. These results demonstrate the difficulty that exists in the characterization of these species indicating that there should be more studies taxonomic using various tools in order to define and better understand the species of this genus.Coordenação de Aperfeiçoamento de Pessoal de Nível Superio

Bats (Mammalia: Chiroptera) of Mata do Paraíso research station, Viçosa, Minas Gerais, Brazil

The aim of this study was to document the records of bat species collected at the Estação de Pesquisa Treinamento e Educação Ambiental (EPTEA) da Mata do Paraíso, a small fragment of Atlantic Rainforest of 200 ha in Viçosa, Minas Gerais, Brazil. Original data was obtained by capture sessions with mist nets from November 2007 to October 2008, and complemented with material from the collection database of Museu de Zoologia João Moojen, Universidade Federal de Viçosa. We found a total of 17 bat species distributed in five families at the EPTEA Mata do Paraíso