Sucesión de Polygnátidos (Conodontos) del Emsiense (Devónico Inferior) en los Pirineos Centrales Españoles

Abstract

A comprehensive conodont study of five sections of Emsian age, carried out in the Spanish Central Pyrenees, has revealed an important succession of polygnathids that can be used for identifying basal boundaries of globally recognized biozones.This succession consists of Polygnathus excavatus excavatus, Po. gronbergi, Po. nothoperbonus, Po. mashkovae, Po. laticostatus, and the new species Polygnathus luciae that allows the identification of the excavatus, nothoperbonus and laticostatus Zones. The nothoperbonus Zone is further subdivided into Lower and Upper nothoperbonus subzones, relying upon the lowest occurrence of Po. mashkovae. These biostratigraphic data from the Spanish Central Pyrenees corroborate the succession of conodont indexes in other regions of Europe (north-western France and southern Italy), North Africa (Morocco), Central Asia, Australia, and North America (Alaska, Nevada and Canada).Keywords: Conodonts; Lower Devonian; Emsian; nothoperbonus Zone; Spanish Central Pyrenees ResumenEl estudio exhaustivo de cinco secciones de edad Emsiense en el Pirineo Central Español ha proporcionado una importante sucesión de especies de conodontos del género Polygnathus que puede usarse para reconocer los límites de diferentes biozonas de aplicación global.

Upper Frasnian and Lower Famennian (Upper Devonian) conodonts of the Compte section (Spanish Central Pyrenees)

“…Later, Boersma (1973), confi rmed the presence of Givetian to Lower Carboniferous rocks based on a biostratigraphic analysis using conodonts. Subsequently, the sampling program developed by Valenzuela-Ríos and his team has demonstrated the international relevance of this section for the Lower, Middle and lower Upper Devonian: Valenzuela-Ríos et al (2005,2015,2017), Valenzuela-Ríos and Liao (2012), Liao (2014), Liao andValenzuela-Ríos (2008, 2017), Martínez-Pérez (2010a, 2010b, Martínez-Pérez et al (2011), Martínez-Pérez and Valenzuela-Ríos (2014), Gouwy et al (2016) and Slavík et al (2016). The compiled bio-chronostratigraphic succession is composed of two sections (Valenzuela-Ríos et al, 2005: the Compte-I (CP-I) section, corresponding to the Lower Devonian sequence; and the Compte (CP) section, corresponding to the Middle and Upper Devonian sequence.…”

New Lower Devonian Polygnathids (Conodonta) from the Spanish Central Pyrenees, with comments on the early radiation of the group

“…It is worldwide distributed (see Martínez-Pérez et al, 2011 for a recent list of occurrences). 114 Carls and Valenzuela-Ríos, 2002 (Figs.…”

“…For specific time intervals, some groups of conodonts have demonstrated to be extremely good biomarkers. In that sense, Devonian polygnathid species have been extensively used in establishing boundaries between different stages and substages, being especially useful for the Emsian conodont-based zonal subdivision (see for example Klapper and Johnson, 1975;Klapper, 1977;Weddige and Ziegler, 1977;Lane and Ormiston, 1979;Yolkin et al, 1994;Mawson, 1995;Bardashev et al, 2002, Martínez-Pérez et al, 2011.…”