Surface analysis of an eagle talon from Krapina.

The Krapina white-tailed eagle talons represent a kind of jewelry worn by Krapina Neandertals some 130,000 years ago. New inspection of one Krapina talon (386.1) revealed a fiber, sealed by a thin silicate coating, adhering to the surface within a wide cut mark, as well as concentrated traces of occasional spots of red and yellow pigment and some black stains. We analyzed the fiber and small portions of pigmented areas by non-invasive, infrared synchrotron beam. Different areas were targeted, revealing the protein nature of the fiber, identified as of animal origin. Targeted areas revealed intra- and inter-strand aggregation indicating the fiber to be collagen losing its original triple α-helix conformation, further confirming the diagenetic decay of the original collagen structure and the antiquity of the fiber. It is possible that the fiber is a remnant of the leather or sinew string binding the talons together. Spectroscopic analysis of the pigments in two isolated areas confirmed two types of ochre and that the dark spots are charcoal remnants. Applying novel non-invasive technologies provides new possibilities to further test the hypothesis of using prehistoric objects for symbolic purposes.

Over 100 years of Krapina: New insights into the Neanderthal thorax from the study of rib cross-sectional morphology.

The Krapina costal sample was studied by Gorjanovic-Kramberger in the early twentieth century. He pointed out unique features in the sample such as the rounder rib cross-section, which was recently confirmed in other Neanderthal specimens. Round rib cross-sections are characteristic of Homo ergaster, suggesting this may be plesiomorphic for Pleistocene Homo, but it is unknown whether Homo antecessor also had this rib shape. Furthermore, the influence of allometry on the cross-sectional shape of ribs is still unknown. The large costal sample from Krapina allows us to address these issues. We quantified cross-section morphology at the midshaft throughout a closed curve of one landmark and nine sliding semilandmarks in the Krapina costal remains (n = 7), as well as in other Neanderthals (n = 50), H. antecessor (n = 3) and modern humans, both fossil (n = 12) and recent (n = 160). We used principal components analysis and mean comparisons to explore interspecific differences, regression analysis to investigate allometry, and partial least squares analysis to examine covariation of cross-section shape and overall rib morphology. Neanderthal cross-sections tended to be larger than those of recent humans except for the Krapina and Tabun remains. Regarding shape, inter-group differences were found only in the diaphragmatic thorax, where Neanderthal and H. antecessor ribs were statistically significantly rounder than those of modern humans. Allometry accounted for covariation of size on shape, but the Neandertal and modern human trajectories had different slopes. While our results based on the Krapina costal sample are similar to previous findings, we also make several new insights: 1) the cross-section morphology observed in Neanderthals was probably present in H. antecessor, albeit less marked; 2) the distinct roundness of Neanderthal cross-sections is not related to size; 3) rounder cross-sections are correlated with ribs presenting less curvature in cranial view and a low degree of torsion in recent humans. These results are important for the interpretation of fragmentary Neanderthal costal remains, and the fact that the differences are marked only in the diaphragmatic thorax could have implications for breathing kinematics.

Cochlear labyrinth volume in Krapina Neandertals.

Research with extant primate taxa suggests that cochlear labyrinth volume is functionally related to the range of audible frequencies. Specifically, cochlear volume is negatively correlated with both the high and low frequency limits of hearing so that the smaller the cochlea, the higher the normal range of audible frequencies. The close anatomical relationship between the membranous cochlea and the bony cochlear labyrinth allows for the determination of cochlear size from fossil specimens. This study compares Krapina Neandertal cochlear volumes to extant taxa cochlear volumes. Cochlear volumes were acquired from high-resolution computed tomography scans of temporal bones of Krapina Neandertals, chimpanzees, gorillas, and modern humans. We find that Krapina Neandertals' cochlear volumes are similar to modern Homo sapiens and are significantly larger than chimpanzee and gorilla cochlear volumes. The measured cochlear volume in Krapina Neandertals suggests they had a range of audible frequencies similar to the modern human range.

Evidence for Neandertal jewelry: modified white-tailed eagle claws at Krapina.

We describe eight, mostly complete white-tailed eagle (Haliaëtus [Haliaeetus] albicilla) talons from the Krapina Neandertal site in present-day Croatia, dating to approximately 130 kyrs ago. Four talons bear multiple, edge-smoothed cut marks; eight show polishing facets and/or abrasion. Three of the largest talons have small notches at roughly the same place along the plantar surface, interrupting the proximal margin of the talon blade. These features suggest they were part of a jewelry assemblage, --- the manipulations a consequence of mounting the talons in a necklace or bracelet. An associated phalanx articulates with one of the talons and has numerous cut marks, some of which are smoothed. These white-tailed eagle bones, discovered more than 100 years ago, all derive from a single level at Krapina and represent more talons than found in the entire European Mousterian period. Presence of eight talons indicates that the Krapina Neandertals acquired and curated eagle talons for some kind of symbolic purpose. Some have argued that Neandertals lacked symbolic ability or copied this behavior from modern humans. These remains clearly show that the Krapina Neandertals made jewelry well before the appearance of modern humans in Europe, extending ornament production and symbolic activity early into the European Mousterian.

Brief communication: Investigation of the semicircular canal variation in the Krapina Neandertals.

Previous studies comparing bony labyrinth morphology in geographically-dispersed samples of Neandertals and modern Homo sapiens (H. sapiens) showed that Neandertals generally have smaller semicircular canals than modern H. sapiens (Hublin et al., ; Spoor et al., ; Glantz et al., ). Here we analyze the morphology of a single group of Neandertal specimens from one locale, the Krapina site, to determine the intraspecific variation in Neandertal semicircular canal sizes. Dimensions of the semicircular canals were collected from computed tomography scans of nine temporal bones. With the rare exception, the dimensions of the semicircular canals in the Krapina sample are similar to those previously reported across a geographically-dispersed sample of Neandertals, further supporting previous studies that suggest low levels of variation in the semicircular canals for Neandertals.

Fibrous dysplasia in a 120,000+ year old Neandertal from Krapina, Croatia.

We describe the first definitive case of a fibrous dysplastic neoplasm in a Neandertal rib (120.71) from the site of Krapina in present-day Croatia. The tumor predates other evidence for these kinds of tumor by well over 100,000 years. Tumors of any sort are a rare occurrence in recent archaeological periods or in living primates, but especially in the human fossil record. Several studies have surveyed bone diseases in past human populations and living primates and fibrous dysplasias occur in a low incidence. Within the class of bone tumors of the rib, fibrous dysplasia is present in living humans at a higher frequency than other bone tumors. The bony features leading to our diagnosis are described in detail. In living humans effects of the neoplasm present a broad spectrum of symptoms, from asymptomatic to debilitating. Given the incomplete nature of this rib and the lack of associated skeletal elements, we resist commenting on the health effects the tumor had on the individual. Yet, the occurrence of this neoplasm shows that at least one Neandertal suffered a common bone tumor found in modern humans.

Variation in enamel thickness within the genus Homo.

Recent humans and their fossil relatives are classified as having thick molar enamel, one of very few dental traits that distinguish hominins from living African apes. However, little is known about enamel thickness in the earliest members of the genus Homo, and recent studies of later Homo report considerable intra- and inter-specific variation. In order to assess taxonomic, geographic, and temporal trends in enamel thickness, we applied micro-computed tomographic imaging to 150 fossil Homo teeth spanning two million years. Early Homo postcanine teeth from Africa and Asia show highly variable average and relative enamel thickness (AET and RET) values. Three molars from South Africa exceed Homo AET and RET ranges, resembling the hyper thick Paranthropus condition. Most later Homo groups (archaic European and north African Homo, and fossil and recent Homo sapiens) possess absolutely and relatively thick enamel across the entire dentition. In contrast, Neanderthals show relatively thin enamel in their incisors, canines, premolars, and molars, although incisor AET values are similar to H. sapiens. Comparisons of recent and fossil H. sapiens reveal that dental size reduction has led to a disproportionate decrease in coronal dentine compared with enamel (although both are reduced), leading to relatively thicker enamel in recent humans. General characterizations of hominins as having 'thick enamel' thus oversimplify a surprisingly variable craniodental trait with limited taxonomic utility within a genus. Moreover, estimates of dental attrition rates employed in paleodemographic reconstruction may be biased when this variation is not considered. Additional research is necessary to reconstruct hominin dietary ecology since thick enamel is not a prerequisite for hard-object feeding, and it is present in most later Homo species despite advances in technology and food processing.

More than 500,000 years of right-handedness in Europe.

Considerable research supports the high frequency of right-handedness in living Homo sapiens, with worldwide rates of approximately nine right- for every one left-hander. Right-handedness appears to be a uniquely human trait, as no other primate species, no matter how proficient in tool use, shows frequencies even close to the strong right bias typical of humans (Cashmore, Uomini, & Chapelain, 2008; McGrew & Marchant 1997; Steele & Uomini, 2009). Here we review our research on human fossils from Sima de los Huesos (Atapuerca, Spain) and their likely descendants, the European Neandertals. We document hand preference in fossils by scratch patterns that occur on the labial (lip) face of incisors and canines, and contend that these patterns provide a reliable means for identifying predominant hand use in these samples. Manipulatory marks on the anterior teeth show a persistent pattern of right-handed actions, implying that the modern human pattern of dominant right-handedness extends deep into the European past.

Dental evidence for ontogenetic differences between modern humans and Neanderthals.

Humans have an unusual life history, with an early weaning age, long childhood, late first reproduction, short interbirth intervals, and long lifespan. In contrast, great apes wean later, reproduce earlier, and have longer intervals between births. Despite 80 y of speculation, the origins of these developmental patterns in Homo sapiens remain unknown. Because they record daily growth during formation, teeth provide important insights, revealing that australopithecines and early Homo had more rapid ontogenies than recent humans. Dental development in later Homo species has been intensely debated, most notably the issue of whether Neanderthals and H. sapiens differ. Here we apply synchrotron virtual histology to a geographically and temporally diverse sample of Middle Paleolithic juveniles, including Neanderthals, to assess tooth formation and calculate age at death from dental microstructure. We find that most Neanderthal tooth crowns grew more rapidly than modern human teeth, resulting in significantly faster dental maturation. In contrast, Middle Paleolithic H. sapiens juveniles show greater similarity to recent humans. These findings are consistent with recent cranial and molecular evidence for subtle developmental differences between Neanderthals and H. sapiens. When compared with earlier hominin taxa, both Neanderthals and H. sapiens have extended the duration of dental development. This period of dental immaturity is particularly prolonged in modern humans.

Right handed Neandertals: Vindija and beyond.

Seven Vindija (Croatia) Neandertal teeth, dated about 32,000 years ago, were analyzed to determine patterning of scratches on the anterior teeth. Oblique scratches exclusively on the labial faces of incisors and canines represent a distinctive pattern, characteristic of hand directed, non-masticatory activities. At Vindija and elsewhere these scratches reveal activities, which were performed primarily with the right hand. The late Neandertals from Vindija, combined with other studies, show that European Neandertals were predominately right-handed with a ratio 15:2 (88.2%), a frequency similar to living people. Studies of teeth from Atapuerca extend this modern ratio to more than 500,000 years ago and increase the frequency of right- handers in the European fossil record to almost 94%. Species-wide, preferential right-handedness is a defining feature of modern Homo sapiens, tied to brain laterality and language with the 9:1 ratio of right- to left- handers - a reflection of the link between left hemispheric dominance and language. Up-to-date behavioral and anatomical studies of Neandertal fossils and the recent discovery of their possession of the FOXP2 gene indicate Neandertals (and, very likely, their European ancestors) had linguistic capacities similar to living humans.

Brief communication: Contributions of enamel-dentine junction shape and enamel deposition to primate molar crown complexity.

Molar crown morphology varies among primates from relatively simple in some taxa to more complex in others, with such variability having both functional and taxonomic significance. In addition to the primary cusps, crown surface complexity derives from the presence of crests, cuspules, and crenulations. Developmentally, this complexity results from the deposition of an enamel cap over a basement membrane (the morphology of which is preserved as the enamel-dentine junction, or EDJ, in fully formed teeth). However, the relative contribution of the enamel cap and the EDJ to molar crown complexity is poorly characterized. In this study we examine the complexity of the EDJ and enamel surface of a broad sample of primate (including fossil hominin) lower molars through the application of micro-computed tomography and dental topographic analysis. Surface complexity of the EDJ and outer enamel surface (OES) is quantified by first mapping, and then summing, the total number of discrete surface orientation patches. We investigate the relative contribution of the EDJ and enamel cap to crown complexity by assessing the correlation in patch counts between the EDJ and OES within taxa and within individual teeth. We identify three patterns of EDJ/OES complexity which demonstrate that both crown patterning early in development and the subsequent deposition of the enamel cap contribute to overall crown complexity in primates.

Dental tissue proportions and enamel thickness in Neandertal and modern human molars.

The thickness of dental enamel is often discussed in paleoanthropological literature, particularly with regard to differences in growth, health, and diet between Neandertals and modern humans. Paleoanthropologists employ enamel thickness in paleodietary and taxonomic studies regarding earlier hominins, but variation in enamel thickness within the genus Homo has not been thoroughly explored despite its potential to discriminate species and its relevance to studies of growth and development. Radiographic two-dimensional studies indicate that Neandertal molar enamel is thin relative to the thick enamel of modern humans, although such methods have limited accuracy. Here we show that, measured via accurate high-resolution microtomographic imaging, Neandertal molar enamel is absolutely and relatively thinner than modern human enamel at most molar positions. However, this difference relates to the ratio of coronal dentine volume to total crown volume, rather than the quantity of enamel per se. The absolute volume of Neandertal molar enamel is similar to that of modern humans, but Neandertal enamel is deposited over a larger volume of coronal dentine, resulting in lower average (and relative) enamel thickness values. Sample sizes do not permit rigorous intragroup comparisons, but Neandertal molar tissue proportions evince less variation than the modern human sample. Differences in three- and two-dimensional enamel thickness data describing Neandertal molars may be explained by dimensional reduction. Although molar tissue proportions distinguish Neanderthals from recent Homo sapiens, additional study is necessary to assess trends in tissue proportions in the genus Homo throughout the Pleistocene.

Variation and modalities of growth and development of the temporal bone pneumatization in Neandertals.

The temporal bone is used frequently to determine taxonomic affinities as it contains several features that differentiate Neandertals from anatomically modern Homo sapiens. However, only little information is available about temporal bone pneumatization in Neandertals. This study provides descriptions and comparisons of the disposition and the extensiveness of the pneumatization of the temporal bone in large samples of Neandertal specimens of different geological and developmental ages (25 individuals and 33 temporal bones from the sites of Engis, Krapina, La Chapelle aux Saints, La Ferrassie, La Quina, Pech de l'Azé, and Spy). Although temporal bone pneumatization shows some individual variability, a similar pattern of distribution is found in all adult Neandertal individuals from Krapina and Western Europe. Pneumatization is restricted mainly to most parts of the petromastoid areas. We also retrace for the first time the modalities of growth and development of this pneumatization in Neandertals. Finally, this study provides new information about possible correlations between the extension and position of temporal bone pneumatization and some of the morphological features used to characterize the temporal bone of the Neandertals. These latter features include the relatively low and short temporal squama, the robust zygomatic process with a relatively marked lateral projection, the strong supramastoid crest, the significant thickness of the tympanic part of the temporal bone, and the relatively small mastoid process and large juxtamastoid eminence. Our results suggest that the development of pneumatization in Neandertals is related to available space and to temporal bone morphology. Moreover, it appears that the development of pneumatization does not play an active role in determining the morphology of the apomorphic features of the temporal bone in Neandertals.

New reconstruction of Krapina 5, a male Neandertal cranial vault from Krapina, Croatia.

The Neandertals from Krapina, Croatia represent some of the geologically oldest Neandertals known, and they comprise the largest Neandertal collection from a single site in the world. However, comparisons of the Krapina material with other, later Neandertals have been limited both because of their fragmentary condition and because the sample has a disproportionate number of females and/or young individuals. This paper presents a preliminary description of our new reconstruction of Krapina 5, an adult male, and provides comparisons with females from Krapina and with later Neandertal males from Western Europe. Like other hominid sites with large samples, there is considerable cranial variation at Krapina; we believe that some, but clearly not all of it is due to sexual dimorphism. Although Krapina 5 differs from the later males in a number of features, such as cranial thickness, cranial height, and sagittal curvature, it fits well within the male Neandertal range for most other metric variables, including cranial capacity.