Assessing the geographic range of Black‐fronted Ground‐Tyrants (Muscisaxicola frontalis) using extralimital and winter range occurrence records and ecological niche modeling

ABSTRACT Estimating the geographic range of a species can be complicated by insufficient occurrence data and a lack of information about range limit determinants. Accurate estimates of species distributions are needed to assess the impacts of anthropogenic actions and for exploring evolutionary and ecological processes that maintain biological diversity. After documenting several extralimital locations for Black‐fronted Ground‐Tyrants (Muscisaxicola frontalis; Tyrannidae), we questioned the accuracy of the current winter range estimate. We provide specimen and observation records from central and southern Peru that represent new information about the winter distribution of Black‐fronted Ground‐Tyrants. We used ecological niche models generated from new extralimital records and records from the winter range to assess the current range estimate. We also tested winter and extralimital niche models for model equivalency using a resampling technique available through Maxent and ENM Tools. Niche models developed with locations from the winter range predicted with high probability (>90%) the area of the extralimital records. Reciprocally, niche models developed with the extralimital locations predicted the majority of the winter range locations, although the probability was lower for some locations and the most southerly points were not included in the prediction. The test for model equivalency did not distinguish the two models, suggesting the possibility that the extralimital records were from poorly sampled areas of the true winter range. Smaller scale habitat associations of Black‐fronted Ground‐Tyrants, such as a preference for sparsely vegetated slopes, were documented that were more specific than published accounts. Finally, we present the first case of frugivory in Muscisaxicola with the identification of Cumulopuntia boliviana ignescens (Cactaceae) seeds and pericarp in all five stomach samples of Black‐fronted Ground‐Tyrants collected in southern Peru.     

A phylogenetic appraisal of Sigmodontinae (Rodentia,Cricetidae) with emphasis on phyllotine genera: systematics and biogeography

Here, we present a comprehensive phylogenetic analysis based on nuclear and mitochondrial DNA sequences of rodents of the subfamily Sigmodontinae. The emphasis is placed on the large tribe Phyllotini; sampling includes for the first time in any molecular‐based phylogenetic analysis representatives of several genera traditionally considered to be phyllotines. Given the broad taxonomic sampling, results provide substantial improvements in our knowledge on both the structure of the sigmodontine radiation and of phyllotine phylogenetic relationships. For instance, the tribe Ichthyomyini was not recovered monophyletic. Similarly, in a novel hypothesis on the contents of the tribe Phyllotini, it is shown that unlike Galenomys, the genera Chinchillula, Neotomys and Punomys are not phyllotines. The later genera together with Andinomys, Euneomys, Irenomys and Juliomys form part of novel generic clades of mostly Andean sigmodontine rodents. More in general, results strongly suggest the occurrence of several instances of putative morphological convergence among distinct sigmodontine lineages (e.g. among now considered to be ichthyomyines; between Phyllotini and some Andean taxa; among Euneomys‐Neotomys and Reithrodon). Finally, we suggest that the historical biogeography of the sigmodontine rodents is far more complex than earlier envisioned.     

Elevation provenance affects photosynthesis and its acclimation to temperature in the high-Andes alpine herb Phacelia secunda

• We analysed whether Phacelia secunda populations from different elevations exhibit intrinsic traits associated with diffusive and biochemical components of photosynthesis, and if they differ in acclimation of photosynthesis to warmer temperatures. We hypothesized that P. secunda will have similar photosynthetic performance regardless of altitudinal provenance and that plants from high elevations will have a lower photosynthetic acclimation capacity to higher temperature than plants from low elevations.
• Plants from 1600, 2800 and 3600 m a.s.l. in the central Chilean Andes were collected and grown under two temperature regimes (20/16 °C and 30/26 °C day/night). The following photosynthetic traits were measured in each plant for the two temperature regimes: A_N, g_s, g_m, J_max, V_cmax, Rubisco carboxylation k_cat^c.
• Under a common growth environment, plants from the highest elevation had slightly lower CO₂ assimilation rates compared to lower elevation plants. While diffusive components of photosynthesis increased with elevation provenance, the biochemical component decreased, suggesting compensation that explains the similar rates of photosynthesis among elevation provenances. Plants from high elevations had lower photosynthetic acclimation to warmer temperatures compared to plants from lower elevations, and these responses were related to elevational changes in diffusional and biochemical components of photosynthesis.
• Plants of P. secunda from different elevations maintain photosynthetic traits when grown in a common environment, suggesting low plasticity to respond to future climate changes. The fact that high elevation plants had lower photosynthetic acclimation to warmer temperature suggests higher susceptibility to increases in temperature associated with global warming.

     

Bahiaxenidae, a "living fossil" and a new family of Strepsiptera (Hexapoda) discovered in Brazil

An adult male of a newly discovered strepsipteran species from Brazil— Bahiaxenos relictus— is described. A new family Bahiaxenidae is suggested based on cladistic analyses of comprehensive morphological data sets with a broad taxon sampling including the stem group. It is unambiguously placed as the sister group of all other extant families of Strepsiptera. Bahiaxenos relictus is the only species of basal, i.e. non-stylopidian, Strepsiptera occurring in the New World. It appears to be a relict taxon that has survived in the fossil sand dunes of the São Francisco River (Bahia State). The loss of the 8th antennomere and the greatly reduced labrum are autapomorphies of Strepsiptera s.s . excluding Bahiaxenidae. The sister group relationship between†Protoxenidae and the remaining Strepsiptera, and between † Cretostylops and a clade comprising † Mengea and Strepsiptera s.s. , is confirmed, as is the monophyly of Stylopidia and Stylopiformia.     

Effect of pH on the induction of competence and progression to the S-phase in mouse fibroblasts

The pH dependence of competence induction and progression to the S-phase in quiescent stimulated cells has been studied. The results show that: (i) induction of competence by fibroblast growth factor in these cells is relatively independent of the external pH between pH 5.6-7.6; (ii) progression of cells to the S-phase is highly sensitive to pH and shows a dramatic increase between pH 6.8-7.2. These observations suggest that the intracellular alkalinization triggered by growth factors is fundamental for progression but not for competence induction.