Oscar Cambra-Moo

Multidisciplinary characterization of the long-bone cortex growth patterns through sheep’s ontogeny

Bone researches have studied extant and extinct taxa extensively trying to disclose a complete view of the complex structural and chemical transformations that model and remodel the macro and microstructure of bone during growth. However, to approach bone growth variations is not an easy task, and many aspects related with histological transformations during ontogeny remain unresolved. In the present study, we conduct a holistic approach using different techniques (polarized microscopy, Raman spectroscopy and X-ray diffraction) to examine the histomorphological and histochemical variations in the cortical bone of sheep specimens from intrauterine to adult stages, using environmentally controlled specimens from the same species. Our results suggest that during sheep bone development, the most important morphological (shape and size) and chemical transformations in the cortical bone occur during the first weeks of life; synchronized but dissimilar variations are established in the forelimb and hind limb cortical bone; and the patterns of bone tissue maturation in both extremities are differentiated in the adult stage. All of these results indicate that standardized histological models are useful not only for evaluating many aspects of normal bone growth but also to understand other important influences on the bones, such as pathologies that remain unknown.

PALEOENVIRONMENTAL RECONSTRUCTION OF THE ''LO HUECO'' FOSSIL SITE (UPPER CRETACEOUS, CUENCA, SPAIN): PRELIMINARY STABLE ISOTOPE ANALYSES ON CROCODILIANS AND DINOSAURS

ABSTRACT Stable isotope analyses (&dgr;18OPO4, &dgr;18OCO3, and &dgr;13C) are reported for the first time on crocodilian, theropod, and sauropod teeth from two stratigraphic levels (G1 and G2) from the late Campanian–early Maastrichtian “Lo Hueco” fossil site (Cuenca, Spain) in order to better understand paleoclimatic and paleoenvironmental conditions existing in the Iberian Peninsula during the Late Cretaceous. Diagenetic alteration was evaluated using three tests: (1) consistent differences in enamel and dentine &dgr;18OPO4 values, (2) crocodilian &dgr;18OPO4 values consistently lower than dinosaur &dgr;18OPO4 values in agreement with the proposed latitudinal distribution between ectotherms and endotherms, and (3) a &Dgr;&dgr;18OCO3-PO4 value of 9.1 ± 1.7‰ for dinosaurs in accordance with the expected equilibrium fractionation between carbonate and phosphate in unaltered modern mammalian bioapatite. Calculated &dgr;18OH2O values are slightly higher in crocodilians compared to dinosaurs since semiaquatic ectothermic taxa &dgr;18OH2O represents local meteoric waters in a brief window of time when the conditions are favorable for apatite synthesis, whereas terrestrial endothermic taxa &dgr;18OH2O records ingested water year-round. Mean air temperature calculated using crocodilian and dinosaur &dgr;18OH2O values shows an increase between G1 and G2, which may be related to differences in the sedimentological setting and/or to a shift toward warmer conditions over time. Finally, the sauropod mean &dgr;13C value (−11.1 ± 0.2‰, VPDB) is in the predicted range for C3 vegetation.

Fossil assemblages and palaeoenvironments in the Cenomanian vertebrate site of Nazaré (West Central Portugal)

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External and internal ontogenetic changes in the first rib

OBJECTIVES First ribs bear information about thorax morphology and are usually well preserved, compared to other ribs, in bone/fossil samples. Several studies have addressed ontogeny of the first rib by studying changes in bone microanatomy and rib morphology separately, but no studies have combined both approaches to study how internal and external changes covary during ontogeny. The aim of this project is to fill this gap in our knowledge. MATERIALS AND METHODS We applied 3D geometric morphometrics of sliding semilandmarks to 14 first ribs of Homo sapiens to quantify rib curvature and mid-shaft cross-section outline. Ontogenetic variation was addressed throughout a principal component analysis (PCA). Additionally, we made histological sections at the mid-shaft of the same ribs and studied tissue matrix composition and compartmentalization. Finally, we performed partial least squares (PLS) and regression analyses to study covariation between rib morphology and compartmentalization variables. RESULTS PCA shows that first ribs increase their curvature over the course of ontogeny and the rib midshaft becomes less rounded during ontogeny. In addition, the sternal end becomes more medially oriented during ontogeny and the relative head-tubercle distance becomes longer. Compartmentalization shows a decrease in the area occupied by mineralized tissues and an increase in the area occupied by non-mineralized tissues over the course of ontogeny, which covaries with mid-shaft cross-section shape. CONCLUSIONS Our results show detailed variation in rib morphology along with histological changes in bone tissue compartmentalization and, for the first time, the correlation between the two. This could be related to muscle attachments on the 1st rib and also to changes in breathing mode, from diaphragmatic in perinatals to pulmonary in adults, which could also have implications for understanding thorax evolution.

Geometric morphometrics reveals restrictions on the shape of the female os coxae

The methodology for sex determination in human skeletal remains depends on the different bone morphologies presented by men and women. Due to their direct implications in reproduction, the whole pelvis, particularly the os coxae, shows different characteristics in either sex. The sacrum and the os coxae constitute the birth canal. In this research study, the os coxae shape is analyzed using geometric morphometrics, providing information on morphology, regardless of size or any other factor beyond the geometry itself. A total of 46 adult ossa coxae from a Spanish archaeological collection were studied using geometric morphometrics. The results show that there is a restriction on the shape of female os coxae. In contrast, male os coxae presents a greater range of variation. The biological reason for this difference is the obstetrical dilemma; a concept defined as the anatomical conflict between bipedalism and the full‐term birth of a neonate whose large head requires greater dimensions in the pelvic cavity. Our experimental data reinforce the validity of the obstetrical dilemma as source of the restriction on the shape of female ossa coxae. Additionally, according to the results obtained, size itself does not represent a condition for belonging to one sex or another.

Reevaluation of ‘endocostal ossifications’ on the Kebara 2 Neanderthal ribs

This research was funded by the Ministerio de Economia y Competitividad (project numbers: CGL2015-63648-P, MAT2013-48426-C2-1-R and HAR2016-78036-P) and the Leakey Foundation (Project 29027). D.G.M. was funded by the European Commissions Research Infrastructure Action via the Synthesys Projects (DK-TAF-3494, BE-TAF-5639, DE-TAF-6404 and SE-TAF-6406) and also by the American Museum of Natural History via a collection study grant. D.G.M. thanks Spanish INEM (Instituto Nacional de Empleo) for its funding support via unemployment benefits.

Características paleodemográficas de la población recuperada del cementerio de Marialba de la Ribera (Villaturiel, León, España) (S. IV-XIII)

The Archaeology and Physical Anthropology represent a multidisciplinary approach from which human past researchers could enrich their archaeological sites interpretations. The interaction of both disciplines permit overpass the analysis of isolated individuals in a specific archaeological context, and to reach a holistic understanding of the entire osteological remains recovered. Paleodemography deals with the study of demographic structure in this archaeological populations and their diachronic evolution, and is an essential starting point for any investigation that involve inferences related with the biology and behaviour of past populations. Taking into account the particular historical context, being an important Early-Christian monument founded in the 4th century and used as a cemetery until the 13th century, and due to the exceptional stage of preservation presented by the skeletal material, Marialba de la Ribera is (1) Laboratorio de Poblaciones del Pasado, Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid. 28049 – Madrid. mnieves.candelas@titulado.uam.es alvaro.nunnez@estudiante.uam.es; josefina.rascon@predoc.uam.es; oscar.cambra@uam.es; armando.gonzalez@uam.es (2) Grupo de Investigación en Arqueología Antigua y Medieval, Universidad de Oviedo. 33011 –Oviedo. (3) TALACTOR, S.L Arqueología y Patrimonio. fernando@talactor.com; emilio@talactor.com (4) Departamento de Historia. Facultad de Geografía e Historia. Universidad de Oviedo. Campus de Humanidades. 33071 – Oviedo. avelino@ uniovi.es Correspondencia: Armando González Martín. Dirección postal: Departamento de Biología. Facultad de Ciencias. Universidad Autónoma de Madrid. 28049 – Madrid. España. Tfno.: +34 914 978 150. Fax: +34 914 978 344. E-mail: armando.gonzalez@uam.es doi: 10.21630/maa.2016.67.07 Características paleodemográficas de la población recuperada del cementerio de Marialba de la Ribera (Villaturiel, León, España) (S. IV-XIII) Recibido: 2016-07-05 Aceptado: 2016-09-23 Paleodemographic data from the Marialba de la Ribera cemetery (Villaturiel, León, Spain) (4th-13th centuries AD) PALABRAS CLAVES: estructura por edad y sexo, Demografía, Paleocristiano, Antigüedad Tardía, Edad Media. GAKO-HITZAK: adinaren eta sexuaren araberako egitura, demografia, Paleokristianoa, Antzinatasun Berantiarra, Erdi Aroa.

Seasonality and Paleoecology of the Late Cretaceous Multi-Taxa Vertebrate Assemblage of “Lo Hueco” (Central Eastern Spain)

Isotopic studies of multi-taxa terrestrial vertebrate assemblages allow determination of paleoclimatic and paleoecological aspects on account of the different information supplied by each taxon. The late Campanian-early Maastrichtian “Lo Hueco” Fossil-Lagerstätte (central eastern Spain), located at a subtropical paleolatitude of ~31°N, constitutes an ideal setting to carry out this task due to its abundant and diverse vertebrate assemblage. Local δ18OPO4 values estimated from δ18OPO4 values of theropods, sauropods, crocodyliforms, and turtles are close to δ18OH2O values observed at modern subtropical latitudes. Theropod δ18OH2O values are lower than those shown by crocodyliforms and turtles, indicating that terrestrial endothermic taxa record δ18OH2O values throughout the year, whereas semiaquatic ectothermic taxa δ18OH2O values represent local meteoric waters over a shorter time period when conditions are favorable for bioapatite synthesis (warm season). Temperatures calculated by combining theropod, crocodyliform, and turtle δ18OH2O values and gar δ18OPO4 have enabled us to estimate seasonal variability as the difference between mean annual temperature (MAT, yielded by theropods) and temperature of the warmest months (TWMs, provided by crocodyliforms and turtles). ΔTWMs-MAT value does not point to a significantly different seasonal thermal variability when compared to modern coastal subtropical meteorological stations and Late Cretaceous rudists from eastern Tethys. Bioapatite and bulk organic matter δ13C values point to a C3 environment in the “Lo Hueco” area. The estimated fractionation between sauropod enamel and diet is ~15‰. While waiting for paleoecological information yielded by the ongoing morphological study of the “Lo Hueco” crocodyliforms, δ13C and δ18OCO3 results point to incorporation of food items with brackish influence, but preferential ingestion of freshwater. “Lo Hueco” turtles showed the lowest δ13C and δ18OCO3 values of the vertebrate assemblage, likely indicating a diet based on a mixture of aquatic and terrestrial C3 vegetation and/or invertebrates and ingestion of freshwater.