Karyotype and C-bands in the annual Inca lily Alstroemeria graminea

Alstroemeria graminea Phil. (Taltalia graminea according to BAYER 1998) is the only annual species described within the genus Alstroemeria L. and its cytogenetic relationship with the perennial species have not been described. In this work, an analysis of the karyotype and the C-banding pattern of Alstroemeria graminea are reported. A. graminea, with an asymmetric karyotype 2n = 2x = 16, shows similar chromosome morphology with respect to the perennial Alstroemeria species previously analysed. However, some differences in relative length and position of the C-bands were observed in A. graminea. These differences were the presence of a centromeric band and an interstitial band in the short arm of pair I and pericentromeric bands in the long arms of pairs 3 and 7, which have not been observed in the other species. The cytogenetic data of the present study on A. graminea are concurrent with other species within the genus Alstroemeria, and do not justify the separation of this species from the genus Alstroemeria and its inclusion in the new monotypic genus Taltalia

C-banding pattern in the geophytic Leontochir ovallei (Alstroemeriaceae)

The monotypic genus Leontochir Phil. (Alstroemeriaceae Dumortier), represented by Leontochir ovallei, is endemic to Chile, and its geographical distribution is restricted to the coastal zone of the Atacama Desert (28 degrees S). In previous cytogenetic studies on L. ovallei a diploid karyotype 2n = 2x = 18 was described. In this work a first analysis of the C-banding pattern of L. ovallei is presented. L. ovallei showed large regions of constitutive heterochromatin within the karyotype, with C-bands on all chromosome pairs except 9. The relative length of the C-bands was 20.0% of the total haploid set length. The presence of large regions of constitutive heterochromatin on the chromosomes was concurrent with the presence of many conspicuous and large chromocenters in the interphase nuclei. According to these results, L. ovallei shows the largest value of relative C-band length so far described within the Alstroemeriaceae. These cytogenetic results on L. ovallei increase the available data on C-banding patterns in Alstroemeriaceae with an additional genus

Comparative karyology of lentic and lotic populations of Diplodon chilensis chilensis (Bivalvia : Hyriidae)

The mean karyotypes of four populations of Diplodon chilensis chilensis (Gray, 1828) (two lentic and two lotic) inhabiting the south of Chile are described and compared. Chromosomes were obtained by squash of cleaving embryos, previously treated with colchicine, fixed in ethanol-acetic acid 3:1 at 4degreesC, and stained using the Feulgen reaction. The karyotype of the four populations is 2n = 34, with metacentric and submetacentric chromosomes. In the population from the Peu-Peu stream, the centromeric position in two chromosome pairs (3 and 10) differs significantly from that in the corresponding pairs from the other populations. Karyotype findings of this study do not support the proposal that the differences described between lentic and lotic populations of D. ch. chilensis may result from genetic differentiation among populations. This study is an initial contribution to the knowledge of cytogenetic characteristics in Chilean populations of Diplodon chilensis chilensis

The combined effects of climate change stressors and predatory cues on a mussel species

In order to make adequate projections on the consequences of climate change stressors on marine organisms, it is important to know how impacts of these stressors are affected by the presence of other species. Here we assessed the direct effects of ocean warming (OW) and acidification (OA) along with non-consumptive effects (NCEs) of a predatory crab and/or a predatory snail on the habitat-forming mussel Perumytilus purpuratus. Mussels were exposed for 10–14 weeks to contrasting pCO2 (500 and 1400 μatm) and temperature (15 and 20 °C) levels, in the presence/absence of cues from one or two predator species. We compared mussel traits at sub-organismal (nutritional status, metabolic capacity-ATP production-, cell stress condition via HSP70 expression) and organismal (survival, oxygen consumption, growth, byssus biogenesis, clearance rates, aggregation) levels. OA increased the mussels' oxygen consumption; and OA combined with OW increased ATP demand and the use of carbohydrate reserves. Mussels at present-day pCO2 levels had the highest protein content. Under OW the predatory snail cues induced the highest cell stress condition on the mussels. Temperature, predator cues and the interaction between them affected mussel growth. Mussels grew larger at the control temperature (15 °C) when crab and snail cues were present. Mussel wet mass and calcification were affected by predator cues; with highest values recorded in crab cue presence (isolated or combined with snail cues). In the absence of predator cues in the trails, byssus biogenesis was affected by OA, OW and the OA × OW and OA × predator cues interactions. At present-day pCO2 levels, more byssus was recorded with snail than with crab cues. Clearance rates were affected by temperature, pCO2 and the interaction between them. The investigated stressors had no effects on mussel aggregation. We conclude that OA, OW and the NCEs may lead to neutral, positive or negative consequences for mussels

Spore morphology and ornamentation in the genus Blechnum

A study of the spores of 64 neotropical and palaeotropical taxa of the genus Blechnum was performed using scanning electron microscopy (SEM). Two basic types of perispores were recognised: perispore smooth or only slightly ornamented (laevigate, with micro-granules or micro-lamellae, venulose and rugulate), and perispore ornamented (rugate, low reticulate, cristatereticulate, orbiculate, and colliculate). SEM observations allow for distinguishing differences in the structure of perispores, but the character does not correlate with the ornamentation. The smooth exospore predominates among the studied species. Results suggest that perispore characters have important diagnostic value, since different combinations of ornamentation/ structure were found among the studied species. Moreover, when spore characters are considered together with other morphological traits of the sporophytes and the habit of plants, ornamentation of spores becomes a useful complementary feature at the specific level. The results are discussed in light of the recent systematic studies and emphasise that any eventual subdivision of the genus Blechnum must include characters of the sporophyte as well as spore features to ensure a more robust classification than the previously proposed. The spores also show a significant affinity between Blechnum and other genera of Blechnaceae, which was also suggested by recent phylogenetic studies.Facultad de Ciencias Naturales y Muse

Bivalve distribution in hydrographic regions in South America: historical overview and conservation

Based on literature review and malacological collections, 168 native freshwater bivalve and five invasive species have been recorded for 52 hydrographic regions in South America. The higher species richness has been detected in the South Atlantic, Uruguay, Paraguay, and Amazon Brazilian hydrographic regions. Presence or absence data were analysed by Principal Coordinate for PhylogenyWeighted. The lineage Veneroida was more representative in hydrographic regions that are poorer in species and located West of South America. The Mycetopodidae and Hyriidae lineages were predominant in regions that are richest in species toward the East of the continent. The distribution of invasive speciesLimnoperna fortuneiis not related to species richness in different hydrographic regions there. The species richness and its distribution patterns are closely associated with the geological history of the continent. The hydrographic regions present distinct phylogenetic and species composition regardless of the level of richness. Therefore, not only should the richness be considered to be a criterion for prioritizing areas for conservation, but also the phylogenetic diversity of communities engaged in services and functional aspects relevant to ecosystem maintenance. A plan to the management of this fauna according to particular ecological characteristics and human uses of hydrographic regions is neededFil: Pereira, Daniel . Universidade Federal Do Rio Grande Do Sul; BrasilFil: Dreher Mansur, Maria Cristina . Universidade Federal Do Rio Grande Do Sul; BrasilFil: Duarte, Leandro D. S. . Universidade Federal Do Rio Grande Do Sul; BrasilFil: Schramm de Oliveira, Arthur . Universidade Federal Do Rio Grande Do Sul; BrasilFil: Mansur Pimpao, Daniel . Universidade Federal Do Rio Grande Do Sul; BrasilFil: Tasso Callil, Claudia . Universidade Federal Do Mato Grosso Do Sul; BrasilFil: Ituarte, Cristian Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; ArgentinaFil: Parada, Esperanza . Plataforma de Investigación en Ecohidrología y Ecohidráulica (ECOHYD); ChileFil: Peredo, Santiago . Plataforma de Investigación en Ecohidrología y Ecohidráulica (ECOHYD); ChileFil: Darrigran, Gustavo Alberto. Universidad Nacional de la Plata. Facultad de Cs.naturales y Museo. Div.zoologia Invertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Scarabino, Fabrizio . Museo Nacional de Historia Natural; UruguayFil: Clavijo, Cristhian. Museo Nacional de Historia Natural; UruguayFil: Lara, Gladys . Universidad Católica de Temuco; ChileFil: Miyahira, Igor Christo . Universidade do Estado do Rio de Janeiro; BrasilFil: Raya Rodriguez, Maria Teresa . Universidade Federal Do Rio Grande Do Sul; BrasilFil: Lasso, Carlos . Instituto de Investigacion de Recursos Biologicos Alexander von Humboldt; Colombi