Macroevolución y claves de homología profunda en la organización fenotípica del cráneo amniota

Tesis Doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Ciencias, Departamento de Biología. Fecha de Lectura: 13-06-2024Esta tesis doctoral ha sido financiada por el Proyecto de Generación de Conocimiento PID2019-105546GB-I00 del Ministerio de Ciencia e Innovación de España (co-IPs: Jesús Marugán Lobón y Ángela Delgado Buscalioni

Quantitative analysis of morphometric data of pre-modern birds: phylogenetic versus ecological signal

Birds are one of the most diverse clades of extant terrestrial vertebrates, a diversity that first arose during the Mesozoic as a multitude of lineages of pre-neornithine (stem) birds appeared but did not survive into the Cenozoic Era. Modern birds (Neornithes) inhabit an extensive array of ecologically distinct habitats and have specific and varied foraging strategies. Likewise, the morphological disparity among Mesozoic lineages appears to underscore a significant degree of ecological diversity, yet attempts to determine lineage specific ecologies have mainly been limited to superficial narratives. In recent years, numerous studies have used various morphometric proxies to interpret the paleoecology of Mesozoic bird lineages, but largely without evaluating the interplay between ecological and phylogenetic signals. Moreover, most studies of this sort transform the original data into logarithms to control dimensionality, underestimating the biases induced upon such transformations. The goal of this study is to quantitatively address the ecomorphology of crown-group Neornithes using a dense sample of raw forelimb and hindlimb measurements, and to examine if such results can be used to infer the ecologies of Mesozoic bird lineages. To that end, scaling of limb measurements and ecological data from modern birds was assessed statistically using phylogenetic comparative methods, followed by the inclusion of fossil taxa. A strong relationship was recovered between humerus and hindlimb allometric scaling and phylogeny. Our results indicate that while some ecological classes of modern birds can be discriminated from each other, phylogenetic signature can overwhelm ecological signal in morphometric data, potentially limiting the inferences that can be made from ecomorphological studies. Furthermore, we found differential scaling of leg bones among Early Cretaceous enantiornithines and ornithuromorphs, a result hinting that habitat partitioning among different lineages could be a pervasive phenomenon in avian evolutio

A new enantiornithine specimen from the Lower Cretaceous of Las Hoyas: avifaunal diversity and life-history of a wetland Mesozoic bird

The Lower Cretaceous fossil site of Las Hoyas (Cuenca, Spain) has yielded the richest Cretaceous avifauna of the European continent. We describe a new fossil (MUPA-LH-33333) of an enantiornithine bird from this locality. This specimen consists of a partially articulated skeleton preserving portions of the vertebral column, both girdles and limbs, ribs and sternum; it also preserves patches of soft tissues including remigial feathers and integumentary structures belonging to the postpatagium. MUPA-LH-33333 shares dimensions and some anatomical features with the holotype of Concornis lacustris, a species previously described from Las Hoyas. However, the new specimen shows differences especially in the coracoid and the sternum, suggesting the presence of a different morpho-type closely related to C. lacustris. Nevertheless, the poor preservation prevents asserting that it represents a new species. Histological evidence from its long bones indicates that is subadult or adult and that early fast rates followed by slower and protracted cyclical phases took place during its growth, a previously unnoticed pattern in Lower Cretaceous enantior-nithines. This new finding supports the hypothesis that enantiornithines regularly inhabited the Las Hoyas wetland, making this site a hotspot for enhancing our understanding of the evolution and life history of these Cretaceous birdsThis study has been funded by the 2021 call of the grant program ‘Ayudas a Jóvenes Investigadores de la Sociedad Española de Paleontología’. SMN is supported by a FPIUAM 2019 predoctoral grant from the Universidad Autónoma de Madrid. SMN, GN, ADB and JM-L are supported by the PID2019-105546GB-I00 project from the Ministerio de Ciencia e Innovación de España. GN is funded by UKRI grant MR/S032177/1. This work is a contribution of the CIPb-UAM research grou

A theropod trackway providing evidence of a pathological foot from the exceptional locality of Las Hoyas (upper Barremian, Serrania de Cuenca, Spain)

We describe a trackway (LH-Mg-10-16) occurring in laminated carbonated limestones of the Las Hoyas locality, Serranı´a de Cuenca, Spain. It is unmistakably a large theropod dinosaur trackway encompassing two unusual aspects, namely, wide-steps, and a set of equally deformed left footprints (with a dislocated digit). The layer also preserves other vertebrate trails (fish Undichna) and different impressions in the sediment. To address these complex settings, we devised a multidisciplinary approach, including the ichnological and taphonomical descriptions, characterisation of the rock lithofacies using thin-sections, 3D structuredlight digitalisation with a high precision of 200–400 μm, and a geometric morphometric comparison with a large sample of bipedal dinosaur trackways. Sedimentary analyses showed that the trackway was produced in a humid, benthonic microbial mat, the consistency and plasticity of which enabled the preservation of the details of the movement of the animal. The results of the geometric analysis indicate that the “wide-steps” of the trackway is not unusual compared to other trackways, providing evidence that it was made by a single individual with an estimated hip height approximately 2 m. Analogous pathologies in extant archosaurs that yield the combination of wide steps and deformed digits in the same trackway were considered. All results mutually support the hypothesis that a large theropod dinosaur, with a pathological foot, generated the trackway as it crossed an area of shallow water while slowly walking towards the main water source, thus stepping steadily over the benthonic mat over which multiple fish were swimmin

Evolución morfológica de los ‘módulos locomotores’ en dinosaurios manirraptores: disparidad e integración

Las extremidades son unas de las estructuras más estudiadas en dinosaurios manirraptores, dada su particular importancia en la locomoción y la evolución del vuelo. La gran mayoría de trabajos al respecto se han llevado a cabo desde un punto de vista funcional, aplicándolo al entendimiento de las tendencias de transformación de los módulos locomotores. Sin embargo, las relaciones de transformación y covariación de las extremidades anteriores y posteriores, desde el marco de la integración morfológica, pueden haber tenido una relevancia fundamental en la capacidad evolutiva de los distintos grados del linaje. A pesar de ello, la evolución de las extremidades nunca ha sido estudiada bajo esta perspectiva. En el presente trabajo, se propone una nueva aproximación morfométrica para investigar la evolución de dicha integración en Maniraptora. Para ello, sobre una amplia muestra de 150 especímenes, procedentes tanto de restos fósiles como de esqueletos de representantes actuales, se han transformado medidas morfométricas tradicionales en coordenadas Procrustes para así poder aplicar la estadística multivariante de la Morfometría Geométrica, bajo una estructura filogenética. Con ello, se ha buscado determinar patrones de variación y covariación en las extremidades anteriores y posteriores, relacionándolos además con variables alométricas y ecomorfológicas. Los resultados más relevantes muestran una integración morfológica para todo el linaje manirraptor, mediante la cual extremidades anteriores y posteriores han evolucionado de manera coordinada y bajo una fuerte inercia filogenética a lo largo de la transición dinosaurio-ave, modificando mayormente el autopodio. Sin embargo, dicha integración se reduce a un nivel macroevolutivo menor, modularizándose y mostrando distintas relaciones de covariación en los diversos grados evolutivos estudiados. De esta manera, formas manirraptoras no avianas y aves basales no ornitotoracinas presentan una relación en la cual la disparidad morfológica de las (proto)alas es mucho mayor que la de las patas, al contrario que en aves enantiornitinas y ornituromorfas (incluyendo al grupo corona). La particular relación de éstas últimas se presenta de manera destacada en aves neornitas, cuya disparidad morfológica en las patas se incrementa en gran medida. Por otro lado, se ha encontrado que tanto el tamaño como las diferentes variables ecomorfológicas explican, aunque de manera significativa, un porcentaje muy bajo de los cambios de forma en las extremidades. Con todo esto, se interpreta que tanto la historia evolutiva del linaje como la morfogénesis común de las extremidades podrían haber influido en su integración y en su consecuente transformación morfológica, siendo la función locomotora principal la que ha podido estar relacionada con la evolución de dicha integración y con la modularización de las extremidades en los distintos grados, ya que el desarrollo del vuelo parece estar asociado al desacoplamiento morfológico de ambas estructuras y a la integración de las alas en sí mismas.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEsubmitte

p38alpha regulates actin cytoskeleton and cytokinesis in hepatocytes during development and aging.

AMT was recipient of a fellowship from the Ministry of Economy and Competitiveness. PR was recipient of a postdoctoral contract Juan de la Cierva (MINECO, Spain)Background Hepatocyte poliploidization is an age-dependent process, being cytokinesis failure the main mechanism of polyploid hepatocyte formation. Our aim was to study the role of p38α MAPK in the regulation of actin cytoskeleton and cytokinesis in hepatocytes during development and aging. Methods Wild type and p38α liver-specific knock out mice at different ages (after weaning, adults and old) were used. Results We show that p38α MAPK deficiency induces actin disassembly upon aging and also cytokinesis failure leading to enhanced binucleation. Although the steady state levels of cyclin D1 in wild type and p38α knock out old livers remained unaffected, cyclin B1- a marker for G2/M transition- was significantly overexpressed in p38α knock out mice. Our findings suggest that hepatocytes do enter into S phase but they do not complete cell division upon p38α deficiency leading to cytokinesis failure and binucleation. Moreover, old liver-specific p38α MAPK knock out mice exhibited reduced F-actin polymerization and a dramatic loss of actin cytoskeleton. This was associated with abnormal hyperactivation of RhoA and Cdc42 GTPases. Long-term p38α deficiency drives to inactivation of HSP27, which seems to account for the impairment in actin cytoskeleton as Hsp27-silencing decreased the number and length of actin filaments in isolated hepatocytes. Conclusions p38α MAPK is essential for actin dynamics with age in hepatocytes.Spanish Ministry of Economy and Competitiveness (MINECO, Spain

DocStories: @foto_historias_ The Photo Stories exhibition and intergenerational meetings

A partir de las fotografías recogidas en Instagram (@foto_historias_ ) se organizará una exposición fotográfica itinerante comisariada por el alumnado y se llevarán a cabo encuentros intergeneracionales entre estudiantes y escuelas de adultos.Unidad Deptal. de Biblioteconomía y DocumentaciónFac. de Ciencias de la InformaciónFALSEsubmitte

Quorum sensing network in clinical strains of A. baumannii : AidA is a new quorum quenching enzyme

Acinetobacter baumannii is an important pathogen that causes nosocomial infections generally associated with high mortality and morbidity in Intensive Care Units (ICUs). Currently, little is known about the Quorum Sensing (QS)/Quorum Quenching (QQ) systems of this pathogen. We analyzed these mechanisms in seven clinical isolates of A. baumannii. Microarray analysis of one of these clinical isolates, Ab1 (A. baumannii ST-2-clon-2010), previously cultured in the presence of 3-oxo-C12-HSL (a QS signalling molecule) revealed a putative QQ enzyme (α/β hydrolase gene, AidA). This QQ enzyme was present in all nonmotile clinical isolates (67% of which were isolated from the respiratory tract) cultured in nutrient depleted LB medium. Interestingly, this gene was not located in the genome of the only motile clinical strain growing in this medium (A. baumannii strain Ab421-GEIH-2010 [Ab7], isolated from a blood sample). The AidA protein expressed in E. coli showed QQ activity. Finally, we observed downregulation of the AidA protein (QQ system attenuation) in the presence of HO (ROS stress). In conclusion, most of the A. baumannii clinical strains were not surface motile (84%) and were of respiratory origin (67%). Only the pilT gene was involved in surface motility and related to the QS system. Finally, a new QQ enzyme (α/β hydrolase gene, AidA protein) was detected in these strains