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[ES] Se presentan diversos yacimientos españoles y portugueses con conservación excepcional de trilobites ordovícicos. En la Zona Cantábrica, el Túnel Ordovícico del Fabar proporcionó niveles de obrucción con trilobites en posición de vida y evidencia de hábitos gregarios en estadios juveniles de Placoparia, así como la detallada conservación de larvas, huevos e improntas orgánicas. En la Zona Centroibérica, el yacimiento portugués de Arouca contiene formas gigantes de trilobites y congregaciones monoespecíficas para la muda o la reproducción, en niveles similares a los de algunas localidades de los Montes de Toledo. Otra localidad portuguesa (Mação) destaca por la buena conservación y variedad de trilobites del Ordovícico Superior. Finalmente, en dos localidades de la Zona de Ossa- Morena se localizan los únicos ciclopígidos (trilobites pelágicos) conocidos en la península Ibérica. Gran parte de los yacimientos reseñados se halla en una fase inicial de estudio., [EN] Several Spanish and Portuguese fossil localities with exceptionally-preserved Ordovician trilobites are briefly examined herein. The El Fabar Ordovician Tunnel in the Cantabrian Zone includes obrution beds with trilobites in life-position and monospecific groups indicating gregarious habits in juvenile stages of Placoparia. Another horizons show fine preservation of trilobite larvae, eggs (possibly of trilobites) and organic impressions on cephala and pygidia of some illaenids and asaphids. In the Central-Iberian Zone, the Portuguese locality of Arouca yielded giant trilobites related probably to “polar gigantism”, as well as large concentrations of individuals of certain species for mating or molting. All these phenomena have been also recorded in trilobites from the same beds in the Toledo Mountains of central Spain. A second Portuguese locality (Mação) enhanced good preservation and displays a remarkable diversity of Upper Ordovician trilobites. Finally, two trilobite localities placed in the Ossa-Morena Zone contain the only cyclopygids (pelagic forms) so far recognized in the Iberian Peninsula. Most of these localities still remain partially studied.

Illaenid trilobites were relatively scarce in south-polar peri-Gondwanan areas during the Ordovician, with all their African occurrences restricted to the Middle and Upper Ordovician of Morocco. At a specific level, only the Bohemian form Ectillaenus benignensis (Novák) has been positively identified from the Middle Ordovician of that region. In the present work we add the discovery of the new form Caudillaenus nicolasi gen. et sp. nov., occurring in a single bed of late Darriwilian 2 age within the Taddrist Formation of the Rahiat region (south of Alnif), in the central Moroccan Anti-Atlas. The new genus is characterized by a large and subtriangular pygidium, a cephalon with relatively large eyes, a broad rostral plate with a short upwardly and forwardly turned posterior flange, and a globose hypostome. It shows a spheroidal enrolment type previously unknown in illaenids, with the pygidium protruding beyond the cephalon, and the cephalic margin fitting into a shallow and wide coaptative furrow on the pygidial doublure.