12 research outputs found
Thermal niche evolution and geographical range expansion in a species complex of western Mediterranean diving beetles
[Background] Species thermal requirements are one of the principal determinants of their ecology and biogeography, although our understanding of the interplay between these factors is limited by the paucity of integrative empirical studies. Here we use empirically collected thermal tolerance data in combination with molecular phylogenetics/phylogeography and ecological niche modelling to study the evolution of a clade of three western Mediterranean diving beetles, the Agabus brunneus complex.[Results] The preferred mitochondrial DNA topology recovered A. ramblae (North Africa, east Iberia and Balearic islands) as paraphyletic, with A. brunneus (widespread in the southwestern Mediterranean) and A. rufulus (Corsica and Sardinia) nested within it, with an estimated origin between 0.60-0.25 Ma. All three species were, however, recovered as monophyletic using nuclear DNA markers. A Bayesian skyline plot suggested demographic expansion in the clade at the onset of the last glacial cycle. The species thermal tolerances differ significantly, with A. brunneus able to tolerate lower temperatures than the other taxa. The climatic niche of the three species also differs, with A. ramblae occupying more arid and seasonal areas, with a higher minimum temperature in the coldest month. The estimated potential distribution for both A. brunneus and A. ramblae was most restricted in the last interglacial, becoming increasingly wider through the last glacial and the Holocene.[Conclusions] The A. brunneus complex diversified in the late Pleistocene, most likely in south Iberia after colonization from Morocco. Insular forms did not differentiate substantially in morphology or ecology, but A. brunneus evolved a wider tolerance to cold, which appeared to have facilitated its geographic expansion. Both A. brunneus and A. ramblae expanded their ranges during the last glacial, although they have not occupied areas beyond their LGM potential distribution except for isolated populations of A. brunneus in France and England. On the islands and possibly Tunisia secondary contact between A. brunneus and A. ramblae or A. rufulus has resulted in introgression. Our work highlights the complex dynamics of speciation and range expansions within southern areas during the last glacial cycle, and points to the often neglected role of North Africa as a source of European biodiversity.This work was supported by an FPI grant to AH-G and projects CGL2007-61665 and CGL2010-15755 from the Spanish government to IR. We acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).Peer reviewe
A New Species of Riama from Ecuador Previously Referred to as Riama hyposticta (Boulenger, 1902) (Squamata: Gymnophthalmidae)
We describe Riama crypta, new species, from the western slopes of the Cordillera Occidental, Ecuador. This taxon was formerly referred to as Riama hyposticta, a rare species described on the basis of an adult male from northern Ecuador and here recorded from southwestern Colombia. The new species differs principally from Riama hyposticta by an incomplete superciliary series, formed just by the anteriormost superciliary scale (superciliary series complete in R. hyposticta, formed by five or six scales), no nasoloreal suture [= loreal absent] (complete (= loreal present] in R. hyposticta), distinct dorsolateral stripes at least anteriorly (scattered brown spots dorsally without dorsolateral stripes in R. hyposticta), and ventral coloration composed of small cream or brown spots or longitudinal stripes (dark brown with conspicuous transverse white bars and spots). Additionally, we document the presence of distal filiform appendages on the hemipenial lobes of both species.American Museum of Natural HistoryCoordenadoria de Aperfeicoamento de Pessoal de Ensino Superior (CAPES)Programa de Becas para la Iniciativa de Especies Amenazadas IEA[520]Fundacao de Amparo a Pesquisa do Estado de sao Paulo (FAPESP)[2007/00811-8
FIGURE 2 in A new Petracola and re-description of P. ventrimaculatus (Squamata: Gymnophthalmidae)
FIGURE 2. Dorsal (A), lateral (B), and ventral (C) views of the head of the holotype of Petracola waka sp. nov.. Line equals 1 mm
Effects of a low-glycemic index diet during pregnancy on offspring growth, body composition, and vascular health: a pilot randomized controlled trial
Background: Elevated maternal blood glucose concentrations may contribute to macrosomia, adiposity, and poorer vascular health in the offspring. Objective: The aim was to explore the effect of a low-glycemic index (low-GI) diet during pregnancy on offspring growth, adiposity, and arterial wall thickness during infancy. Design: This was a longitudinal follow-up study in a self-selected subgroup of mother-infant pairs (n = 59) participating in a larger randomized trial comparing the effects on perinatal outcomes of a low-GI diet and a conventional high-fiber (HF) diet during pregnancy. Infant anthropometric measurements were taken every month for 6 mo and then at 9 and 12 mo of age. Adiposity was assessed at birth and at 3 mo by air-displacement plethysmography by using the Pea Pod system (Cosmed) and at 6 and 12 mo by bioimpedance analysis (Bodystat). Aortic intima-media thickness was assessed at 12 mo by high-resolution ultrasound (Philips). Results: Maternal dietary GI was lower in the low-GI group than in the HF group (51 ± 1 compared with 57 ± 1; P , 0.001). No differences in neonatal outcomes were observed in the main trial. In the self-selected subsample, birth weight and length z scores were lower in the low-GI group than in the HF group (birth weight z score: 0.2 ± 0.2 compared with 0.7 ± 0.2, respectively; P = 0.04; birth length z score: 0.3 ± 0.2 compared with 0.9 ± 0.2, respectively; P = 0.04), but adiposity from birth to 12 mo of age and growth trajectories from 1 to 12 mo of age were similar. Aortic intima-media thickness was lower in the low-GI group than in the HF group (657 612 compared with 696 ± 12 mm, respectively; P = 0.02), which was partly mediated by differences in birth weight. Conclusion: In women at risk of gestational diabetes mellitus, a low-GI diet influences offspring birth weight, birth length, and arterial wall thickness in early childhood, but not adiposity or growth trajectory during the first year of life. This trial was registered at anzctr.org.au as ACTRN12610000681055
Vicinal Diamination of Alkenes under Rh-Catalysis
The synthesis of
1,2-diamines has been achieved through a single-step,
tandem sequence involving Rh-catalyzed aziridination followed by NaI-promoted
rearrangement to an isomeric cyclic sulfamide. Facile ring opening
of these products in hot water and pyridine affords differentially
protected vicinal diamines. Demonstration of the utility of this method
for the syntheses of (±)-enduracididine and (±)-allo-enduracididine
is highlighted