Estudio comparativo de las cavidades del oído externo, medio e interno y establecimiento de la potencia sonora en Homínidos

Esta tesis se ha realizado atendiendo a dos objetivos principales: completar el estudio de las cavidades del oído de los fósiles del yacimiento de la Sima de los Huesos (SH) y extender el estudio de las cavidades del oído externo y medio (OEM) al conjunto de la subfamilia Homininae. Para ello, se han realizado las reconstrucciones tridimensionales de las cavidades del oído de 21 ejemplares de Gorilla gorilla, 9 de SH y 7 de Homo neanderthalensis. En relación con el primer objetivo, se han realizado tres trabajos que se han publicado en la revista Journal of Human Evolution. En el primero, se ha realizado el estudio comparado de los canales semicirculares del fósil mesopleistoceno Aroeira 3 (Portugal) con los ejemplares de SH. El principal resultado es el establecimiento de que, pese a su proximidad geográfica y temporal, Aroeira 3 presenta una morfología más primitiva que la de los fósiles de SH, que ya presentan rasgos de tipo neandertal. Este resultado indica el aislamiento de las poblaciones humanas de la península ibérica durante el Estadio isotópico MIS 12. El segundo trabajo publicado consiste en un detallado estudio comparativo de las cócleas de SH con muestras de Pan troglodytes, Homo sapiens y H. neanderthalensis. También se han incluido datos de Australopithecus africanus, Paranthropus robustus, y de homínidos obtenidos de la bibliografía. Las cócleas de SH muestran un patrón evolutivo en mosaico con rasgos primitivos, compartidos con P. troglodytes, y otros derivados del género Homo, compartidos con H. neanderthalensis y H. sapiens. También se ha propuesto la existencia de homoplasias entre la cóclea de los neandertales y la de nuestra especie en aquellos rasgos compartidos por ambas especies en los que los fósiles de SH presentan el estado primitivo. La inferencia realizada sobre los límites de la audición de los fósiles de SH, a partir del valor de su volumen coclear, indican que su límite superior estaba algo desplazado hacia frecuencias más altas que los de H. neanderthalensis y H. sapiens. El estudio de las capacidades auditivas del Cráneo 4 de SH constituye el tercer trabajo publicado de esta tesis. Este ejemplar había sido diagnosticado como el caso más antiguo conocido de sordera en la evolución humana por presentar exostosis bilateral de sus conductos auditivos externos. Los resultados del trabajo muestran claramente que el individuo representado por el Cráneo 4 no vio afectada su audición por las exostosis de sus conductos auditivos externos, por lo que el diagnóstico de sordera ha sido refutado. Las investigaciones efectuadas en relación con el segundo objetivo constituyen la sección inédita de esta tesis. Se ha realizado el estudio comparado de la anatomía del OEM de G. gorilla, P. troglodytes, los fósiles de SH, H. neanderthalensis y H. sapiens. Se han caracterizado los OEM de las diferentes especies y se ha hecho una propuesta de rasgos con valor para el diagnóstico taxonómico. También se ha realizado el análisis de alometrías de las distintas estructuras del oído en la subfamilia Homininae y se han propuesto rasgos con valor filogenético. Por otra parte, se han establecido los valores de transmisión de la potencia sonora y del ancho de banda ocupado en G. gorilla, lo que supone los primeros datos conocidos sobre los patrones auditivos de esta especie. Se han calculado dichos parámetros en seis nuevos ejemplares de SH, para caracterizar con más precisión los patrones auditivos de esta población. Además, se ha relacionado la longitud del ancho de banda ocupado con los cambios en las proporciones de las diferentes estructuras del OEM en la subfamilia Homininae y se ha propuesto un modelo sobre la secuencia de cambios del OEM en la evolución de la subfamilia. Finalmente, se ha contrastado la hipótesis según la cual el valor de la longitud del ancho de banda ocupado de una especie está directamente relacionado con su complejidad social y con el número y diversidad de sus vocalizaciones

The Neandertal nature of the Atapuerca Sima de los Huesos mandibles

The recovery of additional mandibular fossils from the Atapuerca Sima de los Huesos (SH) site provides new insights into the evolutionary significance of this sample. In particular, morphological descriptions of the new adult specimens are provided, along with standardized metric data and phylogenetically relevant morphological features for the expanded adult sample. The new and more complete specimens extend the known range of variation in the Atapuerca (SH) mandibles in some metric and morphological details. In other aspects, the addition of new specimens has made it possible to confirm previous observations based on more limited evidence. Pairwise comparisons of individual metric variables revealed the only significant difference between the Atapuerca (SH) hominins and Neandertals was a more vertical symphysis in the latter. Similarly, principal components analysis of size-adjusted variables showed a strong similarity between the Atapuerca (SH) hominins and Neandertals. Morphologically, the Atapuerca (SH) mandibles show nearly the full complement of Neandertal-derived features. Nevertheless, the Neandertals differ from the Atapuerca (SH) mandibles in showing a high frequency of the H/O mandibular foramen, a truncated, thinned and inverted gonial margin, a high placement of the mylohyoid line at the level of the M3, a more vertical symphysis and somewhat more pronounced expression of the chin structures. Size-related morphological variation in the SH hominins includes larger retromolar spaces, more posterior placement of the lateral corpus structures, and stronger markings associated with the muscles of mastication in larger specimens. However, phylogenetically relevant features in the SH sample are fairly stable and do not vary with the overall size of the mandible. Direct comparison of the enlarged mandibular sample from Atapuerca (SH) with the Mauer mandible, the type specimen of H. heidelbergensis, reveals important differences from the SH hominins, and there is no morphological counterpart of Mauer within the SH sample, suggesting the SH fossils should not be assigned to this taxon. The Atapuerca (SH) mandibles show a greater number of derived Neandertal features, particularly those related to midfacial prognathism and in the configuration of the superior ramus, than other European middle Pleistocene specimens. This suggests that more than one evolutionary lineage co-existed in the middle Pleistocene, and, broadly speaking, it appears possible to separate the European middle Pleistocene mandibular remains into two distinct groupings. One group shows a suite of derived Neandertal features and includes specimens from the sites of Atapuerca (SH), Payre, l'Aubesier and Ehringsdorf. The other group includes specimens that generally lack derived Neandertal features and includes the mandibles from the sites of Mauer, Mala Balanica, Montmaurin and (probably) Visogliano. The two published Arago mandibles differ strongly from one another, with Arago 2 probably belonging to this former group, and Neandertal affinities being more difficult to identify in Arago 13. Outside of the SH sample, derived Neandertal features in the mandible only become more common during the second half of the middle Pleistocene. Acceptance of a cladogenetic pattern of evolution during the European middle Pleistocene has the potential to reconcile the predictions of the accretion model and the two phases model for the appearance of Neandertal morphology. The precise taxonomic classification of the SH hominins must contemplate features from the dentition, cranium, mandible and postcranial skeleton, all of which are preserved at the SH site. Nevertheless, the origin of the Neandertal clade may be tied to a speciation event reflected in the appearance of a suite of derived Neandertal features in the face, dentition and mandible, all of which are present in the Atapuerca (SH) hominins. This same suite of features also provides a useful anatomical basis to include other European middle Pleistocene mandibles and crania within the Neandertal clade.Depto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEBinghamton UniversityMinisterio de Ciencia e Innovación y UniversidadesJunta de Castilla y Leónpu

Early hominin auditory capacities

Studies of sensory capacities in past life forms have offered new insights into their adaptations and lifeways. Audition is particularly amenable to study in fossils because it is strongly related to physical properties that can be approached through their skeletal structures. We have studied the anatomy of the outer and middle ear in the early hominin taxa Australopithecus africanus and Paranthropus robustus and estimated their auditory capacities. Compared with chimpanzees, the early hominin taxa are derived toward modern humans in their slightly shorter and wider external auditory canal, smaller tympanic membrane, and lower malleus/incus lever ratio, but they remain primitive in the small size of their stapes footplate. Compared with chimpanzees, both early hominin taxa show a heightened sensitivity to frequencies between 1.5 and 3.5 kHz and an occupied band of maximum sensitivity that is shifted toward slightly higher frequencies. The results have implications for sensory ecology and communication, and suggest that the early hominin auditory pattern may have facilitated an increased emphasis on short-range vocal communication in open habitats

Cueva de los Torrejones revisited. New insights on the paleoecology of inland Iberia during the Late Pleistocene

34 p.The interior of the Iberian Peninsula has orographic conditions that make this territory especially vulnerable to Quaternary climate oscillations and which actually could have made it decisive for Paleolithic human populations at critical points. For this reason, the information provided by paleontological sites is important for reconstructing climatic and environmental conditions during the Late Pleistocene and understanding how they influenced the species that inhabited them, including humans. Nevertheless, the archaeo-paleontological record is scarce in central Iberia for the Late Pleistocene. A central Iberian site that is key to addressing this issue is Cueva de los Torrejones, which was discovered and excavated during the nineties. Clues indicating the presence of Neandertal populations near the cave site were announced during prior field excavations, including Neandertal remains, Middle Paleolithic artifacts, and evidence of anthropic exploitation of faunal resources at the site. Here we report the new results from the recent excavations and research, including detailed studies on stratigraphy, micromorphology, macro and microvertebrate paleontology, physical and molecular anthropology, taphonomy and zooarchaeology, and analysis of lithic and pottery remains. Our research has led to the detection of three Prehistoric chronologies recorded at the site. The oldest episode corresponds to between MIS 5 and MIS 4 in which the cave was used by carnivores. The second episode is represented by a faunal association dated to 30.0 ka cal BP and is indicative of cooler and more arid environmental conditions and, therefore, compatible with the worsening climate detected previously for MIS 3 in this area. The last episode corresponds to the Chalcolithic, directly dated to ~5000 cal BP in which humans used the cavity for funerary purposes. The DNA analysis of the human remain was assigned to mtDNA haplogroup K, which was originated in the Near East and reached western Europe through the Neolithic expansion. Human occupation during the Paleolithic has been ruled out, including Paleolithic human remains and any kind of anthropic intervention on the Hermann’s tortoise and leopard as was previously proposed at the site.European Research CouncilJunta de Comunidades de Castilla la ManchaMinisterio de Ciencia e InnovaciónCentro Nacional de Investigación sobre la Evolución Humana (CENIEH

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

The ear of the Sima de los Huesos hominins (Atapuerca, Spain)

Previous studies on the morphology of the inner ear (semicircular canals and cochlea) in the Sima de los Huesos hominin sample have provided important results on the evolution of these structures in the Neandertal lineage. Similarly, studies of the anatomy of the external and middle ear cavities of the Sima de los Huesos hominins have also provided important data on the auditory capacities of this European Middle Pleistocene population. The present contribution provides unpublished data on three new middle ear variables from the Sima de los Huesos fossils and compares these data with values from samples of Pan troglodytes, Homo neanderthalensis and Homo sapiens. The results of this analysis are combined with those obtained in previous studies to characterize the anatomy of the outer, middle and inner ear in the Sima de los Huesos fossils, as well as to establish the order of appearance of the features that characterize Neandertal ears. As in other cranial structures, the ear region in the Sima de los Huesos show a mosaic evolutionary pattern that includes primitive traits, others shared exclusively with Neandertals, and others that are specific to the Sima de los Huesos hominins. Neandertals and Sima de los Huesos hominins share two exclusive features of the middle ear that are among the first characteristics of the Neandertal lineage: a long tympanic cavity and a large entrance and exit of the mastoid antrum. Along with these traits, the Sima de los Huesos hominins present two specialized features: large volumes of the tympanic cavity and the mastoid antrum. Finally, the middle ear of the Neandertals is characterized by the presence of small angles between the tympanic axis and the plane of the oval window.MCIN/AEI/10.13039/501100011033/FEDERUniversidad de AlcaláDepto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

Fusion of the occipitomastoidal synchondrosis as a developmental marker in the Sima de los Huesos Crania (Atapuerca, Spain)

The basicranium contains multiple synchondroses potentially informative for estimating the developmental stage of individuals. The basilar synchondrosis has been routinely used for this purpose in bioarchaeological, forensic and paleoanthropological research, and studies carried out in modern human populations have shown a close relationship between the fusion of the occipitomastoidal synchondrosis and developmental processes. This synchondrosis articulates the jugular process of the occipital bone with the jugular surface of the temporal bone. As the process of fusion of the synchondrosis progresses, the jugular surface undergoes a series of alterations whose study allows to establish the state of fusion of the synchondrosis when the individual died. The extraordinary preservation of the jugular surface in a large number of individuals represented in the fossil hominin sample from the middle Pleistocene site of the Sima de los Huesos (SH) has made it possible to carry out the first systematic study to assess the usefulness of occipitomastoidal synchondrosis in the establishment of the state of development in fossil hominins. Our results show that the complete closure of the occipitomastoidal synchondrosis occurred toward the end of the growth period in the SH fossils. This result opens up the possibility of using it to determine the developmental stage of fossil hominins for which no other information is available, such as the state of the dentition or the degree of closure of the basilar synchondrosis. This has allowed us to infer a state of development for three SH crania where it could not previously be established with certainty.MCIN/AEI/10.13039/501100011033/FEDER UEUniversidad de AlcaláBinghamton UniversityDepto. de Geodinámica, Estratigrafía y PaleontologíaFac. de Ciencias GeológicasTRUEpu

Geometric morphometric analysis of the bony labyrinth of the Sima de los Huesos hominins

The bony labyrinth contains phylogenetic information that can be used to determine interspecific differences between fossil hominins. The present study conducted a comparative 3D geometric morphometric analysis on the bony labyrinth of the Middle Pleistocene Sima de los Huesos (SH) hominins. The findings of this study corroborate previous multivariate analyses of the SH hominin bony labyrinth. The analysis of the semicircular canals revealed the SH hominin canal morphologies appear closer to those of the Neandertals than to those of Homo sapiens. This is attributable to a Neandertal-like ovoid anterior canal, and mediolaterally expanded, circular posterior canal. However, the SH hominins lack the increased torsion in the anterior canal and the inferior orientation of the lateral canal seen in Neandertals. The results of the cochlear analysis indicated that, although there is some overlap, there are notable differences between the SH hominins and the Neandertals. In particular, the SH hominin cochlea appears more constricted than in Neandertals in the first and second turns. A principal component analysis of the full bony labyrinth separated most SH hominins from the Neandertals, which largely clustered with modern humans. A covariance ratio analysis found a significant degree of modularity within the bony labyrinth of all three groups, with the SH hominins and Neandertals displaying the highest modularity. This modular signal in the bony labyrinth may be attributable to different selective pressures related to locomotion and audition. Overall, the results of this study confirm previous suggestions that the semicircular canals in the SH hominins are somewhat derived toward Neandertals, while their cochlea is largely primitive within the genus Homo

The cochlea of the Aroeira 3 Middle Pleistocene cranium—a comparative study

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