Microsatellite markers and cytoplasmic sequences reveal contrasting pattern of spatial genetic structure in the red algae species complex Mazzaella laminarioides

Mazzaella laminarioides is a common haploid‐diploid red alga that forms dense beds. This alga has a wide distributional range, covering 3,500 km of the Chilean coast, but is restricted to high rocky intertidal zones. Recently, the existence of three highly divergent genetic lineages was demonstrated for this taxon, and two cytoplasmic markers were used to determine that these lineages are distributed in strict parapatry. Here, using 454 next‐generation sequencing, we developed polymorphic microsatellite loci that cross amplify in all three cytoplasmic lineages. Six sites (i.e., two sites within each lineage) were analyzed using nine microsatellite loci. Our work shows that, although substantial cytoplasmic differentiation occurs within M. laminarioides, the microsatellite loci did not retrieve three nuclear genetic clusters as expected. Indeed, while the northernmost and southernmost cytoplasmic lineages form two strongly divergent nuclear groups characterized by diagnostic alleles, the third cytoplasmic lineage did not form a third nuclear independent group. It is possible that inter‐lineage gene exchange has occurred, particularly at sites along the contact zone between the different cytoplasmic lineages. This nuclear‐cytoplasmic incongruence in M. laminarioides could be explained by incomplete lineage sorting of the nuclear genes or asymmetric introgressive hybridization between the lineages. Finally, highly significant heterozygote deficiencies (suggesting occurrence of intergametophytic selfing) were observed in the three small northernmost sites while the large southernmost sites generally approached panmixia.     

Leaf traits in Chilean matorral: sclerophylly within,among, and beyond matorral,and its environmental determinants

Studies of leaf traits often focus on tradeoffs between growth and resource conservation, but little is known about variation in the mechanical traits that influence resource conservation. This study investigates how leaf mechanical traits vary across matorral vegetation in central Chile, how they correlate with environmental factors, and how these trends compare at a broader geographic scale. Leaf toughness, strength, stiffness, and associated traits were measured in five matorral types in central Chile, and relationships with soil N and P and climate variables were assessed. Trends with soil and climate were then analyzed across shrubland and woodland in Chile, Western Australia, and New Caledonia. Chilean species varied in leaf mechanics and associated traits, both within and among matorral types, with more species in sclerophyll matorral having strong, tough, and stiff leaves than in arid and littoral matorral. Overall, leaves with high leaf dry mass per area were stiffer, tougher, stronger, thicker, denser, with more fiber, lignin, phenolics and fiber per unit protein and less protein: tannin activity and N and P per mass, forming a broad sclerophylly syndrome. Mechanical traits of matorral species were not correlated with soil N or P, or predictably with climate variables, except flexural stiffness (EI_W) which correlated positively with annual reference evapotranspiration (ET₀). However, soil P made strong independent contributions to variation in leaf mechanics across shrublands and woodlands of Chile, Western Australia, and New Caledonia, either separately (strength) or together with ET₀ (toughness) explaining 46–90% of variation. Hence ET₀ was predictive of EI_W in Chilean matorral, whereas soil P was highly predictive of variation in leaf strength, and combined with ET₀ was highly predictive of toughness, at a broader geographic scale. The biological basis of these relationships, however, may be complex.     

Frostbite in a pre-Columbian mummy

Radiographs of a prehistoric inhabitant of the Atacama desert show pathological bone changes which are consistent with frostbite, gangrene and autoamputation. The burial position of the body suggests a reversal of sex roles during life, possibly resulting from the frostbite injuries.     

Environmental determinants in morphospace and diet of the larval blenny Calliclinus geniguttatus from an upwelling ecosystem

The effects of two contrasting environmental conditions in nearshore waters off central Chile on the diet and morphospace of two cohorts of larval labrisomid blenny Calliclinus geniguttatus were studied using geometric morphometrics and gut content analysis. The two environmental conditions corresponded to (a) a cold period with upwelling-favourable southwesterly winds and a mixed water column of cooler water and (b) a warm period with calm winds and stratified warmer water. During the cold period, fish larvae had a more hydrodynamic head shape, longer jaws and a higher feeding incidence, suggesting a greater food supply due to upwelling events and a possible increase in encounter rates in the turbulent environment. In contrast, the larvae from the warm period had a more robust head shape with smaller jaws and a lower feeding incidence, which was related to higher water temperatures and lower wind intensities. The present study suggests that larvae have a rapid response to environmental changes on a short time scale (i.e., from weeks to months), showing a link between environmental conditions and changes in the phenotypic traits and diet of the larval stages of this cryptobenthic species.     

Lysosome motility and distribution: Relevance in health and disease

Lysosomes are dynamic organelles, which can fuse with a variety of targets and undergo constant regeneration. They can move along microtubules in a retrograde and anterograde fashion by using motor proteins, kinesin and dynein, being main players in extracellular secretion, intracellular components degradation and recycling. Moreover, lysosomes interact with other intracellular organelles to regulate their turnover, such as ER, mitochondria and peroxisomes.The correct localization of lysosomes is relevant in several physiological processes, including appropriate antigen presentation, neurotransmission and receptors modulation in neuronal synapsis, whereas hepatic lysosomes and autophagy are master regulators of nutrient homeostasis.Alterations in lysosome function due to mutation of genes encoding lysosomal proteins, soluble hydrolases as well as membrane proteins, lead to lysosomal storage diseases (LSDs). Lysosomes containing undegraded substrates are finally stacked and therefore miss positioned inside the cell, leading to lysosomal dysfunction, which impacts a wide range of cellular functions.     

Differential effects of emergent Nothofagus dombeyi on growth and basal area of canopy species in an old‐growth temperate rainforest

Question: Does overyielding of tree species mixtures in vertically stratified forests depend on complementary light use? Location: Andes of south‐central Chile. Methods: Basal area data were obtained from 80 circular plots distributed regularly throughout old‐growth stands with an emergent Nothofagus dombeyi tier over a canopy composed mainly of Laureliopsis philippiana and Saxegothaea conspicua. Radial growth was measured from cores obtained from trees at the centre of each plot. The effects of competition on growth were evaluated through a competition index (CI) based on distances to and diameters of the two nearest neighbours. Results: Overall, basal area of the canopy species was only weakly affected by the number of N. dombeyi per plot, and with basal area of N. dombeyi. However, the two main canopy species responded differently: whereas basal area of S. conspicua was negatively correlated with that of N. dombeyi, that of L. philippiana showed no response. Radial growth of S. conspicua was negatively correlated with CI calculated from canopy trees and more weakly so from emergent N. dombeyi. In contrast, radial growth of L. philippiana was not affected by competition with either canopy or emergent neighbours. Conclusions: Results indicate that emergent N. dombeyi tend to depress growth and basal area of S. conspicua, but not of the more shade‐tolerant L. philippiana. This supports the proposal that enhancement of wood production in stratified mixtures will be greatest when component species have strongly contrasting light use traits.     

Glacidorbidae (Gastropoda: Heterobranchia) in South America: revision and description of a new genus and three new species from Patagonia

The Glacidorbidae, a family restricted to the Gondwanan realm (Tasmania, southeastern and southwestern Australia, and southern Argentina and Chile), previously included five genera with 20 identified species; 19 of them are Australian, with one genus and species, Gondwanorbis magallanicus (Meier-Brook & Smith, 1976 Meier-Brook, K. & Smith, B.J. (1976) Glacidorbis Iredale, 1943, a genus of freshwater prosobranchs with a Tasmanian-Southeast Australian-South Andean distribution. Archive für Molluskenkunde 106, 191–198. [Google Scholar]), from South America. Here we describe two new species of Gondwanorbis: Gondwanorbis fueguensis n. sp. from the freshwater gastropods province of Southern Patagonia (Argentina) and Gondwanorbis tricarinatus n. sp. from Chile, and a new genus and species from the freshwater gastropods province of northern Patagonia (Argentina), Patagonorbis nahuelhuapensis n. sp and n. gen.

http://www./zoobank.org/urn:lsid:zoobank.org:pub:62EA0972-3AEF-4188-8E6D-F10895CE2BEF