Ignacio Martínez

Intrapopulational Body Size Variation and Cranial Capacity Variation in Middle Pleistocene Humans: The Sima de los Huesos Sample (Sierra de Atapuerca, Spain)

A sexual dimorphism more marked than in living humans has been claimed for European Middle Pleistocene humans, Neandertals and prehistoric modern humans. In this paper, body size and cranial capacity variation are studied in the Sima de los Huesos Middle Pleistocene sample. This is the largest sample of non-modern humans found to date from one single site, and with all skeletal elements represented. Since the techniques available to estimate the degree of sexual dimorphism in small palaeontological samples are all unsatisfactory, we have used the bootstraping method to asses the magnitude of the variation in the Sima de los Huesos sample compared to modern human intrapopulational variation. We analyze size variation without attempting to sex the specimens a priori. Anatomical regions investigated are scapular glenoid fossa; acetabulum; humeral proximal and distal epiphyses; ulnar proximal epiphysis; radial neck; proximal femur; humeral, femoral, ulnar and tibial shaft; lumbosacral joint; patella; calcaneum; and talar trochlea. In the Sima de los Huesos sample only the humeral midshaft perimeter shows an unusual high variation (only when it is expressed by the maximum ratio, not by the coefficient of variation). In spite of that the cranial capacity range at Sima de los Huesos almost spans the rest of the European and African Middle Pleistocene range. The maximum ratio is in the central part of the distribution of modern human samples. Thus, the hypothesis of a greater sexual dimorphism in Middle Pleistocene populations than in modern populations is not supported by either cranial or postcranial evidence from Sima de los Huesos.

The Atapuerca sites and the ibeas hominids

The Atapuerca railway Trench and Ibeas sites near Burgos, Spain, are cave fillings that include a series of deposits ranging from below the Matuyama/Bruhnes reversal up to the end of Middle Pleistocene. The lowest fossil-bearing bed in the Trench contains an assemblage of large and small Mammals includingMimomys savini, Pitymys gregaloides, Pliomys episcopalis, Crocuta crocuta, Dama sp. and Megacerini; the uppermost assemblage includesCanis lupus, Lynx spelaea, Panthera (Leo) fossilis, Felis sylvestris, Equus caballus steinbeimensis, E.c. germanicus, Pitymys subterraneus, Microtus arvalis agrestis, Pliomys lenki, and alsoPanthera toscana, Dicerorbinus hemitoechus, Bison schoetensacki, which are equally present in the lowest level. The biostratigraphic correlation and dates of the sites are briefly discussed, as are the paleoclimatic interpretation of the Trench sequences. Stone artifacts are found in several layers; the earliest occurrences correspond to the upper beds containingMimomys savini. A set of preserved human occupation floors has been excavated in the top fossil-bearing beds. The stone-tool assemblages of the upper levels are of upper-medial Acheulean to Charentian tradition. The rich bone breccia SH, in the Cueva Mayor-Cueva del Silo, Ibeas de Juarros, is a derived deposit, due to a mud flow that dispersed and carried the skeletons of many carnivores and humans. The taxa represented are:Ursus deningeri (largely dominant),Panthera (Leo) fossilis, Vulpes vulpes, Homo sapiens var. Several traits of both mandibular and cranial remains are summarized. Preliminary attempts at dating suggest that the Ibeas fossil man is older than the Last Interglacial, or oxygen-isotope stage 5.

The human remains from Cova Negra (Valencia, Spain) and their place in European Pleistocene human evolution

Abstract The phylogenetic and chronological positions of the Cova Negra human remains are discussed. These remains include an adult right parietal bone, a juvenile right mandibular body fragment with a deciduous second molar, and an isolated permanent upper central incisor. There are 40 levels in the Cova Negra sedimentary sequence, ranging from the Riss-Wurm to the beginning of the Wurm III. The Cova Negra A phase (Riss-Wurm) is faunally and industrially sterile. Several variants of the Mousterian (Charentian type) are known from the beginning of the Wurm (Cova Negra B phase) to the end of the sequence (Cova Negra E and F phases). All human remains are assigned to the Wurm. On the basis of the parietal bone, uni- and bivariate analyses show that the Cova Negra biparietal vault was very broad. The cluster analysis groups Cova Negra with the biggest Neandertal neurocrania (specimens generally sexed as males). Also, this parietal bone exhibits a subcircular profile in posterior view, a trait considered as a Neandertal autapomorphy. The mandibular fragment shows three foramina mentalia and a steep linea mylohyoidea. These and other traits lead us to include this specimen in the Neandertal group. The crown dimensions and the morphology of the deciduous molar are consistent with this taxonomic attribution. The comparative study of the crown and root dimensions of the permanent incisor, as well as the presence of traits such as a strong tuberculum linguale, well developed marginal ridges (shovelling), and the marked lingual inclination of the buccal face, lead us to attribute this tooth to the Neandertal group.

Label free localization of nanoparticles in live cancer cells using spectroscopic microscopy

Gold nanoparticles (GNPs) have become essential tools used in nanobiotechnology due to their tunable plasmonic properties and low toxicity in biological samples. Among the available approaches for imaging GNPs internalized by cells, hyperspectral techniques stand out due to their ability to simultaneously image and perform spectral analysis of GNPs. Here, we present a study utilizing a recently introduced hyperspectral imaging technique, live-cell PWS, for the imaging, tracking, and spectral analysis of GNPs in live cancer cells. Using principal components analysis, the extracellular or intracellular localization of the GNPs can be determined without the use of exogenous labels. This technique uses wide-field white light, assuring minimal toxicity and suitable signal-to-noise ratio for spectral and temporal resolution of backscattered signal from GNPs and local cellular structures. The application of live-cell PWS introduced here could make a great impact in nanomedicine and nanotechnology by giving new insights into GNP internalization and intracellular trafficking.