Historically, the foramen magnum (FM) has been an integral component of studies on skull ontogeny and evolutionary transformations of cranial form. Although this foramen has been considered a single entity, we hypothesize that it comprises two functional matrices, a ventral matrix and a dorsal matrix. In general, the ventral matrix is related to locomotor functions, whereas the dorsal matrix is related to neurological functions and fluid flow dynamics. To test our hypothesis, we used a large ontogenetic sample of modern human crania (seventh fetal month to adult) to (1) delineate bony size and shape ontogeny for both the foramen and its dorsal and ventral units; (2) delineate the role of synchondroses in the observed growth patterns and rates; and (3) explore the relationship between FM and cranial size, shape, and growth. Detailed growth patterns and rates are established for the bony FM and its ventral and dorsal skeletal units. These data are supplemented by literature and observational data on embryonic and fetal FM ontogeny, soft tissue relationships, anomalous/pathological extremes of size, and craniocervical anatomy and locomotor functions. The hypothesis that the FM is composed of a ventral and a dorsal functional matrix is supported by observed ontogenetic differences between ventral and dorsal skeletal units, as well as by the soft tissue anatomy of these matrices. Further documentation of these matrices has the potential to significantly enhance our understanding of the ontogenetic and evolutionary transformations of skull base morphology. Anat Rec, 294:199-216, 2011. V V C 2010 Wiley-Liss, Inc.Key words: foramen magnum; ontogeny; human variation; functional matricesThe basicranium forms in a zone of interaction between structures with neural, skeletomotor, respiratory, auditory, masticatory, digestive, and visual functions. Because of the complex structural-functional relationships, the morphology of the basicranium reflects compromises resulting from the competing demands of multiple soft tissue units that are responding to essential functions.During basicranial development, the structures traversing the endocranial-ectocranial boundary become encircled by cartilage and, eventually, by bone. The resulting bony foramina of the basicranium respond in Additional Supporting Information may be found in the online version of this article.

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Objectives We provide the first comparative description of the Guercy 1 cranium and isolated cranial fragments from Baume Moula‐Guercy and examine their affinities to European Preneanderthals, Neanderthals, and Homo sapiens. Materials and Methods The Moula‐Guercy hominins derive from deposits chronostratigraphically and biostratigraphically dated to the Eemian Interglacial (MIS 5e). For comparisons we compiled a sample of European and Southwest Asian subadult‐adult Middle‐to‐Late Pleistocene hominins (≈MIS 14–MIS 2; N = 184). This sample represents a Preneanderthal–Neanderthal group and a H. sapiens group, both of which were further divided into three time‐successive subgroups defined by associated marine isotope stages (MIS). Metric and morphological observations were made on the original fossils and a virtual reconstruction of Guercy 1. Developmental age and sex and the minimum–maximum number of individuals were assessed. Results Guercy 1 represents the remains of a late stage adolescent (≈15–16.0 years) female. Morphological and metric data combine to associate the total morphological pattern expressed in Guercy 1 with our MIS 7–MIS 5e (“Early Neanderthal”) subgroup. Some features, especially those related to the frontal, suggest linkage to a paleodeme comprising the Moula‐Guercy, Artenac, La Chaise Abri Suard and, possibly, the Biache‐Saint‐Vaast samples. Discussion Remains of MIS 7–MIS 5e Neanderthals are rare and fragmentary, especially those dated to the Last Interglacial. The Baume Moula‐Guercy sample provides new insights into the total morphological pattern expressed in MIS 5e Neanderthals. Further, our results support earlier suggestions that MIS 7–MIS 5e European hominins represent a morphotype that is distinct from both earlier and later members of the Preneanderthal–Neanderthal group.

Studies using synchrotron microtomography have shown that this radiographic imaging technique provides highly informative microanatomical data from modern and fossil bones and teeth without the need for physical sectioning. The method is considered to be nondestructive; however, researchers using the European Synchrotron Radiation Facility have reported that color changes sometimes occur in teeth during submicron scanning. Using the Advanced Light Source, we tested for color changes during micron-level scanning and for postexposure effects of ultraviolet light. We exposed a 2.0-mm wide strip (band) to synchrotron light in 32 specimens, using multiple energy levels and scan durations. The sample included modern and fossilized teeth and bone. After scanning, the specimens were exposed to fluorescent and direct ultraviolet light. All teeth showed color changes caused by exposure to synchrotron radiation. The resulting color bands varied in intensity but were present even at the lowest energy and shortest duration of exposure. Color bands faded during subsequent exposure to fluorescent and ultraviolet light, but even after extensive ultraviolet exposure, 67% (8/12) of UV-exposed teeth retained some degree of induced color. We found that the hydroxyapatite crystals, rather than the organic component, are the targets of change, and that diagenesis appears to impact color retention. Color changes have significance beyond aesthetics. They are visible indicators of ionization (chemical change) and, therefore, of potential physical damage. It is important for researchers to recognize that synchrotron microtomography may damage specimens, but adopting suitable safeguards and procedures may moderate or eliminate this damage.

The hand and foot remains from Moula-Guercy cave (Ardèche, France) comprise 24 specimens of Eemian age (ca. 120 ka). The specimens include primarily complete elements, which are rare among the Moula-Guercy postcrania. The hand remains have several characteristic Neanderthal traits including a laterally facing (parasagittally oriented) second metacarpal-capitate articulation, a short styloid process, a wide proximal articular surface on the third metacarpal, and absolutely expanded apical tuberosities on the distal hand phalanges relative to modern humans. The foot remains include several incomplete elements along with an antimeric pair of naviculars, a medial cuneiform and cuboid, and a single complete element from each of the distal segments (one each: metatarsal, proximal foot phalanx, intermediate foot phalanx, distal foot phalanx). Consistent among the specimens are relatively wide diaphyses for length in the metatarsals and phalanges and large and prominent muscle attachments, both consistent with previously published Neanderthal morphology. The hand and foot collection from Moula-Guercy is an important dataset for future studies of Neanderthal functional morphology, dexterity, and behavior as it represents a previously undersampled time period for European Neanderthals.