North Andean environmental and climatic change at orbital to submillennial time-scales: vegetation, waterlevels and sedimentary regimes from Lake Fúquene from 284 to 130 ka

We present a record of environmental and climatic changes in the northern Andes during the penultimate interglacial-glacial cycle based on integrated information from pollen and grain size distributions (GSDs). The record reflects the 58.33-26.21 m interval of a new sediment core from Lake Fúquene (2540 m elevation; 5°N) in the Colombian Andes. The age model is mainly based on cyclostyratigraphy and shows that this core interval reflects the period from 284 to 130 ka. The 1 cm sample increments yield a resolution of ~ 60 yr. In 2553 samples we analyzed 66 selected pollen and spore taxa with the best known ecological ranges. We reconstructed upper forest line (UFL) positions between ~ 2000 and ~ 3400 m elevation and the most abrupt temperature shifts ranged up to 10 °C/100 yr at Terminations II and III. Regional vegetation change is mainly driven by eccentricity (100 kyr) and obliquity (41 kyr) cycles, while changes in local aquatic vegetation show variability in the obliquity and precession (21 kyr) bands. Millennial-scale climate variability reflecting Dansgaard-Oeschger (DO) climate cycles in the upper part of the record, continues in this penultimate intergalcial-glacial cycle strongly suggesting that this variability has a persistent character in Pleistocene vegetation and climate dynamics. Short-lived upslope excursions of the UFL reflect 20 DO-style cycles during marine isotope stages (MIS) 7 and 6. Changes in species composition of montane forest are evident, and trees with most pioneer qualities (Alnus, Morella, Quercus and Weinmannia) migrated at the forefront. Other arboreal taxa like Podocarpus, Miconia, and Hedyosmum mostly followed later. Changes in regional vegetation distribution and forest composition, as well as in local aquatic vegetation and GSD of sediments supplied to the lake, allowed the development of an integrated reconstruction of the biotic and abiotic environments in the drainage basin

Pindaro a Tebe: studi sulle odi pindariche di contesto tebano.

La tesi si propone un’analisi trasversale delle odi (epinicie e cultuali) composte dal poeta tebano Pindaro per la propria città o per propri concittadini: Pitica 11, Istmica 1,3,4,7; Inno 1; Peana 1,7,9; Ditirambo 2; Partenio, 1,2; Iporchema 110-109. Visto il numero dei componimenti presi in considerazione, si è deciso di articolare l’indagine e l’esposizione per quattro temi fondamentali: il mito di Eracle come esempio del trattamento del mito tebano; la guerra come rappresentata dal poeta a confronto con le ricostruzioni storico-militari fornite di volta in volta dagli studiosi; Apollo e la sua centralità nei culti epicorici e tebani; infine la discussa questione dell’io pindarico. Di ciascun carme, allo stesso tempo, è stata fornita un’analisi sufficientemente dettagliata per affrontarne i principali problemi interpretativi. Anche la possibile interazione intertestuale tra le odi è stata via via rilevata, sottolinerando eventuali richiami da un componimento all’altro e permettendo così di delineare l’immagine di un corpus potenzialmente conchiuso

Pollen morphology of Sabinaria magnifica (Cryosophileae, Coryphoideae, Arecaceae)

Sabinaria magnifica is so far the only known species in the recently discovered tropical palm genus Sabinaria (Arecaceae). Here we present a complete description of the pollen morphology of this palm species based on light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). We also made SEM-based comparisons of Sabinaria with other genera within the tribe Cryosophileae. Pollen grains of Sabinaria magnifica resemble the other genera in the heteropolar, slightly asymmetric monads, and the monosulcate and tectate exine with perforate surface. Nevertheless, there are some clear differences with Thrinax, Chelyocarpus and Cryosophila in terms of aperture and exine. S. magnifica differs from its closest relative, Itaya amicorum, in the exine structure. This study shows that a combination of microscope techniques is essential for the identification of different genera within the Cryosophileae and may also be a necessary when working with other palynologically less distinct palm genera