Origin and evolutionary trends of the Neogene genera Amaurolithus and Nicklithus (calcareous nannofossils)

Sediment samples from Ocean Drilling Program (ODP) Sites 999 and 1237 in the Caribbean Sea and Eastern Pacific Ocean were studied to monitor the evolution of ceratoliths from 7.4 Ma to 6 Ma. Orthorhabdus rugosus shows high variability at the end of the Tortonian to the Early Messinian (7.35 Ma to 6.91 Ma), resulting in the Amaurolithus (7.354 Ma) and Nicklithus branches (6.985 Ma). Orthorhabdus rugosus is an ortholith with three blades (sinistral, median, and dextral). The first ceratholith, A. primus, has two arms and a horseshoe shape with marked laths, and is stable and concave upwards. Its sinistral arm is formed from the sinistral blade of O. rugosus and the right arm is formed from the other blades. Early robust A. primus evolved into stylised forms and then to A. delicatus (7.226 Ma), an almost plain horseshoe ceratolith with two arms. The left arm, usually the longer one, comes from the sinistral wing of A. primus and has a characteristic flattened omega section (Ω) without laths. There is a distribution overlap between A. primus and A. delicatus; the highest occurrence of the first one, at 6.282 Ma, is a newly proposed bioevent for the Messinian. After this, Amaurolithus does not have laths in its longer left arm and should be included in A. delicatus. The second branch has only one species, Nicklithus amplificus, which became extinct at 6.049 Ma. In addition, the dextral and median blades of O. rugosus form N. amplificus dextral arm and the sinistral arm, which has the characteristic beak, hook, or hawk's bill, which is the main difference between the development of this horseshoe and that of the previous one. The descriptions of A. primus, A. delicatus, and N. amplificus were specified based on the proposed evolutionary genesis.This work was supported by projects RTI2018-099489-B-I00 and PID2020-114381GB-I00 (Spanish Ministry of Science, Innovation and Universities). This study was funded by the European Union NextGenerationEU project GVA-THINKINAZUL/2021/039

Origin and evolution of the Neogene calcareous nannofossil Ceratolithus

Sediment samples of deep marine oceanic ODP boreholes from sites 999 in the Caribbean Sea and 1237 in the Eastern Pacific Ocean covering the period between 6 and 4.5 Ma have been studied with a focus on ceratolith evolution. Orthorhabdus rugosus is a nannolith with three blades (sinistral, median, and dextral) that first appeared during the Serravallian, it is not-birefringent in its stable orientation. It shows a high morphological variability time-interval at the end of the Messinian to the basal Pliocene (5.5 to 5 Ma) during which Ceratolithus (5.484 Ma) evolved. Changes occurred in the sinistral and median blades, whilst the dextral blade was reduced. Ceratolithus finifer n. comb is the first species of the evolutionary line. The nannolith stable position changed during its evolution, resulting in the older forms showing low birefringence and the younger ones moderate to high birefringence in the most stable orientation. Ceratolithus acutus, with an arrowhead shape, Ceratolithus armatus, and the morphologically distinct C. larrymayeri evolved from C. finifer with all three species showing high birefringence. The previous O. rugosus and C. finifer continued. Finally, C. armatus gives rise to C. cristatus. Ceratolithus atlanticus and C. tricorniculatus also evolved from C. finifer. All the species mentioned become extinct during the Pliocene except Ceratolithus cristatus that lives today. Detailed observations permit the analysis of the evolutionary trends of the group, possible mechanisms, patterns, and processes of speciation, and establish new criteria to define the species that, by their relative abundance and short geologic range, have permitted adjustment of biostratigraphic markers for this period.This work was supported by the projects RTI2018-099489-B-I00 and PID2020-114381GB-I00 (Spanish Ministry of Science, Innovation, and Universities). This study was funded by the European Union NextGenerationEU (PRTR-C17.I1) project GVA-THINKINAZUL/2021/039

The Pliocene Mediterranean infilling of the Messinian Erosional Surface: New biostratigraphic data based on calcareous nannofossils (Bajo Segura Basin, SE Spain)

The Bajo Segura Basin (eastern Betic Cordillera) is a Mediterranean marginal basin where the Messinian Erosional Surface (MES), formed during the Messinian Salinity Crisis sea-level fall, is well developed. Overlying this major discontinuity the lower Pliocene transgressive sediments record the reflooding of the Mediterranean and the return to an open marine environment, the continental shelf being rebuilt after the Messinian erosion. The stratigraphic and biostratigraphic study of six sections allows two transgressive-regressive sequences filling the MES to be distinguished, correlated with the previously distinguished Mediterranean offshore seismic units. Ten calcareous nannofossil bioevents have been identified. The lower sequence can be dated according to nannofossil biozones NN12 to NN14 and the upper sequence by NN15 to NN16. The boundary between both lower Pliocene sedimentary sequences occur after the first common occurrence (FCO) of Discoaster asymmetricus found in the uppermost sediments of the lower sequence and before the first occurrence (FO) of Discoaster tamalis in the lowermost part of the upper sequence. Thus this sequence boundary can be estimated at between 4.1 and 4.0Ma ago.This work has been supported by projects: CGL2007-65832/BTE Ministerio de Educación y Ciencia, CGL2009-07830/BTE Ministerio de Ciencia e Innovación, and PASUR.CGL2009-08651 Ministerio de Ciencia e Innovación Projects and BEST/2010/068 Generalitat Valenciana

The Bajo Segura Basin (SE Spain): implications for the Messinian salinity crisis in the Mediterranean margins

The analysis of the Messinian and Pliocene stratigraphy of the Bajo Segura Basin (a marginal basin of the western Mediterranean) has revealed three synthems deposited in a high sea-level context: T-MI (late Tortonian-Messinian), MII (Messinian), and P (early Pliocene), bounded by two lowstand erosional surfaces (intra-Messinian and end-Messinian unconformities). With respect to the salinity crisis, we propose the following series of events: 1) pre-evaporitic or pre-crisis phase (T-MI synthem); 2) first sea-level fall and subaerial exposure (intra-Messinian unconformity), possibly related to the precipitation of the Lower Evaporites; 3) syn-evaporitic phase (MII synthem), recorded both by selenitic gypsum (Upper Evaporites) as well as by lagoon deposits (Lago-Mare); 4) second sea-level fall and subaerial exposure (end-Messinian unconformity), characterized by deeply incised palaeovalleys; and 5) postevaporitic or post-crisis phase (P synthem), which coincides with the definitive restoration of open marine conditions in the basin. A combined biostratigraphic and magnetostratigraphic study revealed that all the events linked to the salinity crisis (from the end of the pre-evaporitic phase to the beginning of the post-evaporitic phase) occurred within the chron C3r (c. 5.9-5.2 Ma).Financial aid was provided by Research Projects BTE2003-05047, CGL2005-06224BTE (MEC), CGL2007-65832/BTE (MEC), GV04B-629 (Generalitat Valenciana) and “Paleoenvironmental Changes” Group (UA)

Resúmenes de comunicaciones y excursiones del Simposio Homenaje a D. Daniel Jiménez de Cisneros y Hervás

Libro de resúmenes y excursiones del simposio homenaje a D. Daniel Jiménez de Cisnero

INVES: Docencia en Iniciación a la Investigación en Biología

Un equipo multidisciplinar de profesores y profesoras que imparten docencia en la asignatura Iniciación a la Investigación en Biología, constituyen la Red Docente INVES con el fin de desarrollar una metodología propia de trabajo en equipo, en coordinación con el profesorado de la asignatura Estadística, con la que se comparten objetivos de aprendizaje comunes. Durante el desarrollo de la asignatura, el alumnado diseña y ejecuta un proyecto de investigación bibliométrico de temática biológica sobre un tema actual y de interés. Con ello se favorece la adquisición de competencias transversales del módulo básico del título de grado. La dinámica de trabajo en grupo culmina en la edición de unas Jornadas Científicas, donde los estudiantes exponen los trabajos realizados. Se han consensuado modificaciones en las metodologías y actividades de aprendizaje, mejorando en la eficiencia de la experiencia de enseñanza-aprendizaje

Excursión por los alrededores de Agres. Estudio del medio físico y biótico de la Sierra de Mariola (Alicante)

In order to keep up the tradition initiated in our school by Professor Daniel Jiménez de Cisneros in 1904, we intended to initiate students into field studies, and knowledge of their natural environment. In this work we present a pool of activities related with the study of the natural environment of the Alicante Province (Spain), performed with students from first level of BA. It was conducted by teachers from the Department of Biology and Geology of the "Jorge Juan" High school (Alicante) and other centres, together with other Biologists and Geologists. Our general goal was to achieve a progressive learning and to enhance the interest of students in Science. This didactic experience started with practical as well as theoretical activities in the laboratory and in the botanical garden of our centre that lasted 25 hours distributed in seven sessions, and was completed with field studies in Mariola mountain during a period of three days.El presente trabajo ha sido financiado en parte por la A.P.A. del Instituto de Educación Secundaria Jorge Juan de Alicante, la Caja de Ahorros del Mediterráneo (CAM), y la Editorial Santillana

A new centrifugation/filtration technique to improve the observation of calcareous nannofossils under the scanning electron microscope

A new sediment sample preparation procedure for observing calcareous nannofossils using a scanning electron microscope (SEM) is described. The new preparation technique is a moderately time-consuming technique that allows observation of the finest structural details of specimens in the SEM. It has two separate steps: 1) disaggregation employing H2O2 and an ultrasound bath, keeping the pH stable through the use of a NaCO3-HCO3 buffer solution; and 2) a filtration process that concentrates and cleans the nannofossils through use of a vacuum pump. To do this, previous techniques for improving the quality of SEM images were combined, aimed at avoiding dissolution in the process, for which a slow digestion of the organic matter was carried out using a buffered solution, adding centrifugation and controlled vacuum pumping in order to retain the coccoliths without affecting their preservation.This work was supported by Projects RTI2018-099489-B-I00 and PID2020-114381GB-I00, granted by the Spanish Ministry of Science and Innovation, and also by the European Union Next-GenerationEU Project GVA-THINKINAZUL/2021/039

El material científico y didáctico del Gabinete de Historia Natural del Instituto Nacional y Técnico de Alicante (actual I.E.S. Jorge Juan)

The Department of Biology and Geology of the I.E.S. Jorge Juan (Alicante), the only Institute of the province of Alicante during more than a century, counts between his heritage with an excellent scientific and didactic material, like the result of the different collections and instruments that have been compiled since his foundation, in 1845. One of the main authors of the existing collections was D. Daniel Jiménez de Cisneros y Hervás, who was professor of Natural History of the I.E.S. Jorge Juan during 30 years and his Director in several stages