First record of the ichnogenus Phycodes in the Middle Ordovician of the Toledo Mounts (Central Iberian Zone, Spain)

[ES] Se presenta el primer registro español de Phycodes noha Mikuláš, un sistema horizontal de galerías en disposición flabelliforme, restringida a las facies lutíticas del Ordovícico Inferior de la República Checa y del Ordovícico Medio de la Península Ibérica. Los ejemplares españoles proceden de las pizarras del Oretaniense inferior (Darriwiliense medio basal) de la sección de la Cuesta de Valderuelo, al oeste de Navas de Estena (Ciudad Real). El análisis morfológico permite considerar a Phycodes canelensis, definido en el Oretaniense inferior de Portugal, como un sinónimo posterior de P. noha. El descubrimiento de este icnofósil incrementa la escasa icnodiversidad conocida en el Ordovícico Medio centroibérico.[EN] Phycodes noha Mikuláš, a horizontal flabellate burrow system so far restricted to the lutitic facies of the Lower Ordovician of the Czech Republic and the Middle Ordovician of Portugal, is recorded for the first time in Spain. The Spanish specimens show a complete morphological transition from typical fan-shaped passages forming a compact subtriangular body in plan view, to rarer bilateral forms ending in fanlike arrangement. The studied material comes from the lower Oretanian shales (ca. basal middle Darriwilian) outcropping at the Cuesta de Valderuelo section, west of Navas de Estena (Ciudad Real province). The morphological study concluded that Phycodes canelensis, a composite form described from the lower Oretanian beds in Portugal, could be better considered as a junior synonym of P. noha. Its description is based on incomplete specimens lacking the generating tube and stuffed with faecal pellets (Tomaculum problematicum), only hypothetically produced by the tracemaker of Phycodes. The discovery of Phycodes noha in Spain increases the very low ichnodiversity of the Middle Ordovician shales from the Central Iberian Zone of the Iberian Massif.Este artículo es una contribución a los proyectos IBEROR (CGL2012-39471) y PICG 653 de la IUGS-UNESCO.Peer reviewe

Self-adjoint oscillator operator from a modified factorization

"By using an alternative factorization, we obtain a self-adjoint oscillator operator of the form Lδ=ddx(pδ(x)ddx)−(x2pδ(x)+pδ(x)−1), where pδ(x)=1+δe−x2, with δ∈(−1,∞) an arbitrary real factorization parameter. At positive values of δ, this operator interpolates between the quantum harmonic oscillator Hamiltonian for δ=0 and a scaled Hermite operator at high values of δ. For the negative values of δ, the eigenfunctions look like deformed quantum mechanical Hermite functions. Possible applications are mentioned.

Silurian stratigraphy and paleontology of the Valongo anticline and Arouca-Tamames syncline, Central-Iberian Zone (Portugal and Spain)

2 páginas.-- Comunicación presentada en Time and Life in the Silurian: a multidisciplinary approach, Italy , June 4-11, 2009; (Subcommission on Silurian Stratigraphy Field Meeting 2009).-- Abstract.This work is a contribution to the projects CGL2006-07628/BTE (Spain) and PTDC/ CTE-GEX/64966/2006 (Portugal).Peer reviewe

Middle Ordovician harknessellid brachiopods (Dalmanellidina) from the Mediterranean margin of Gondwana

The family Harknessellidae Bancroft, 1928 (Orthida, Dalmanellidina) was designed to embrace an assemblage of species referred previously to Harknessella Reed, 1917, and included five genera known mainly from the Middle and Upper Ordovician of England. Herein, we suggest reassigning to this family the genus Cacemia Mitchell, 1974, widespread in the middle Darriwilian (upper Middle Ordovician) of the Iberian and Armorican massifs. Since its designation, Cacemia was placed among the dalmanellidin heterorthids, in spite of its strongly mucronate hinge line, which is totally unknown within this Mediterranean family. A new harknessellid has been identified from the upper Darriwilian beds of the Central Iberian Zone (Central Spain): Isabelella fascicostellata Reyes-Abril Villas gen. et sp. nov. It is similar to Horderleyella Bancroft, 1928 for its coarsely fascicostellate radial ornamentation and obtuse cardinal angles, although its convexoplane to convexoconcave profile allows discrimination from the typically dorsibiconvex Horderleyella. A phylogenetic analysis of the family places both Cacemia and Isabelella in basal positions of their clades, which fits with their early stratigraphic record. Based on our study, the family Harknessellidae appears to have originated in the high latitude Mediterranean margins of Gondwana during pre-Darriwilian times, before the detachment of Avalonia from Gondwana. The family reached its highest diversification in Avalonia throughout the Late Ordovician, keeping connections with the Mediterranean and Proto-Andean margins of Gondwana, as well as with the mid-latitude palaeocontinents of Baltica and South China