陕西公王岭蓝田直立人内耳迷路的复原及形态特点

1964年在陕西公王岭发现的蓝田人头骨的形态比周口店直立人和印度尼西亚爪哇直立人原始,其厚重的骨壁及较小的脑量,落入了早期人属成员的变异范围。最新测年结果将蓝田人的生存年代从原先普遍接受的距今115万年提早到大约163万年前,接近能人和南方古猿生存年代变异范围的下限,蓝田人是迄今为止我国发现的有确定年代数据的最早的古人类化石。本文采用高分辨率CT技术对蓝田人的颞骨岩部进行了扫描,对骨性内耳迷路进行了3D虚拟复原,通过与和县直立人、欧洲古老型智人、早期人属成员、南方古猿非洲种、粗壮傍人和现代人内耳迷路的21项测量项目的对比和分析,结果显示蓝田人内耳迷路的测量数据与南方古猿非洲种最接近,其次为现代人和欧洲古老型智人,而与早期人属成员和粗壮傍人相差较大。主成分分析结果显示,蓝田人内耳迷路与早期人属成员、欧洲古老型智人、南方古猿非洲种及现代人都有重叠区域,距离最近的是南方古猿非洲种Sts 5,其次为和县直立人和南方古猿非洲种Sts 19,而与粗壮傍人距离较远。本文研究提供了中更新世中国古人类内耳迷路的形态数据,为进一步探讨蓝田人体质特征演化上的意义提供了参考资料。     

New Late-Pleistocene uranium–thorium and ESR dates for the Singa hominid (Sudan)

The Singa (Sudan) calvaria has been interpreted previously as a terminal Pleistocene modern human fossil, perhaps related to the Bushman of Southern Africa. Here we report new mass-spectrometric U–Th dates for the calcrete deposit enclosing the fossil teeth and the calvaria itself and new electron spin resonance (ESR) dates for associated dental materials. The new data constrain the age of the hominid to at least 133±2 ka. Together with the preferred linear uptake (LU) ESR dates, the U–Th data confirm that the intriguing mixture of modern and archaic characteristics in the Singa specimen date from isotope stage 6. Far from being a modern human fossil, it represents a rare example of an archaic African population which may have been ancestral to all modernHomo sapiens.     

资阳人头骨化石的内部解剖结构

资阳人头骨化石,是新中国成立后首次发现的保存较为完整的人类化石,曾经引起学术界的广泛关注。由于其出土的具体位点和层位不是很清楚,对其年代目前还存有争议。长期以来,对资阳人的研究局限于传统的头骨外部形态的描述和测量。本文利用高分辨率工业CT（Computed tomography）扫描资阳人头骨,并对其内部解剖结构 (包括骨壁结构、额窦、骨内耳迷路、颞骨乳突小房、颅内模) 进行3D虚拟复原和研究,以期获得更多的形态信息。CT断层图显示资阳人头骨的骨壁板障层较厚,远大于外板层和内板层,支持以往研究认为的该头骨属于50岁以上个体的鉴定结果。额窦呈叶形,局限于两侧眼眶的内上方;左、右侧额窦的表面积分别为1780mm²和2910mm²。骨性内耳迷路半规管的大小及其比例,与尼安德特人不同,而位于晚更新世和全新世现代人变异范围之间。颞骨乳突小房为气化型,几乎占据了整个乳突部。根据复原的颅内模,资阳人的颅容量约为1250mL。颅内模的各项测量数值虽然都偏小,但脑的绝大多数形态特征、宽-高指数、顶叶-脑长指数都位于现代人的变异范围之内,而与直立人和更新世古老型人类不同。资阳人头骨内部解剖结构保留有少量原始特征,包括枕叶向后突显著、大脑窝比小脑窝大而深,这些特征不同于全新世人类,更类似于晚更新世早期现代人。     

The Bony Labyrinth in Diprotodontian Marsupial Mammals: Diversity in Extant and Extinct Forms and Relationships with Size and Phylogeny

The shape of the bony labyrinth of the inner ear was quantified using geometric morphometrics in a sample of 16 species of living marsupial diprotodontians, the extinct Diprotodon and Thylacoleo, and four outgroups. X-ray micro-computed tomography (μCT) and conventional computed tomography (CT) were used to acquire 3D data. The analyses of 22 landmarks revealed a strong body-mass related allometric pattern. A discriminant analysis on allometry-free labyrinthine shape served to evaluate the phylogenetic signal portion of the labyrinth for Macropodiformes, Phalangeroidea, Petauroidea, and Vombatiformes. The inner shape of Thylacoleo is consistent with its phylogenetic placement as a vombatiform.     

Cranial thickening in an Australian hominid as a possible palaeoepidemiological indicator

This paper describes the cranial thickening of a late Pleistocene hominid (Willandra Lakes Hominid 50) from Australia. The unusual development of the vault structures in this individual has few, if any, equals among other hominids or more recent populations from around the world. The vault morphology is, therefore, described in terms of a pathologically related condition associated with the modern haemolytic blood dyscrasias, typical of sickle cell anamia and thalassemia. A possible palaeoepidemiology for these genetic adaptations among early Australasian populations is proposed together with a discussion of similar changes observed in the vault of the Singa calvarium from the Sudan. It is tentatively suggested that the cranial thickening of the Australian hominid has its origins in some form of genetic blood disease and that if this diagnosis is correct, this individual provides a rare glimpse of human biological adaptation in the late Upper Pleistocene.     

The bony labyrinth of Neanderthals

This paper presents a comprehensive comparative analysis of the Neanderthal bony labyrinth, a structure located inside the petrous temporal bone. Fifteen Neanderthal specimens are compared with a Holocene human sample, as well as with a small number of European Middle Pleistocene hominins, and early anatomically modern and European Upper Palaeolithic humans. Compared with Holocene humans the bony labyrinth of Neanderthals can be characterized by an anterior semicircular canal arc which is smaller in absolute and relative size, is relatively narrow, and shows more torsion. The posterior semicircular canal arc is smaller in absolute and relative size as well, it is more circular in shape, and is positioned more inferiorly relative to the lateral canal plane. The lateral semicircular canal arc is absolutely and relatively larger. Finally, the Neanderthal ampullar line is more vertically inclined relative to the planar orientation of the lateral canal. The European Upper Palaeolithic and early modern humans are most similar, although not fully identical to Holocene humans in labyrinthine morphology. The European Middle Pleistocene hominins show the typical semicircular canal morphology of Neanderthals, with the exception of the arc shape and inferiorly position of the posterior canal and the strongly inclined ampullar line. The marked difference between the labyrinths of Neanderthals and modern humans can be used to assess the phylogenetic affinities of fragmentary temporal bone fossils. However, this application is limited by a degree of overlap between the morphologies. The typical shape of the Neanderthal labyrinth appears to mirror aspects of the surrounding petrous pyramid, and both may follow from the phylogenetic impact of Neanderthal brain morphology moulding the shape of the posterior cranial fossa. The functionally important arc sizes of the Neanderthal semicircular canals may reflect a pattern of head movements different from that of modern humans, possibly related to aspects of locomotor behaviour and the kinematic properties of their head and neck.     

Digital Reconstruction of the Otic Region and Inner Ear of the Non-Mammalian Cynodont Brasilitherium riograndensis (Late Triassic, Brazil) and Its Relevance to the Evolution of the Mammalian Ear

The external anatomy of the petrosal, the bony labyrinth of the inner ear, and the stapes of Brasilitherium riograndensis (specimen UFRGS-PV-1043-T) were investigated by digital 3D reconstructions based on μCT scan images. Brasilitherium is the most basal taxon bearing a distinct promontorium, although less inflated than that of Morganucodon and still lacking a flat medial facet. A bony wall formed by the petrosal separates the cochlear canal and the vestibule from the brain cavity, with an internal acoustic meatus bearing distinct foramina for the facial nerve (VII) and vestibulocochlear nerve (VIII). The semicircular canals are irregular in shape, the anterior canal being the largest and the lateral one the smallest. Brasilitherium has an elongated but straight cochlear canal. The stapes resembles the morphology of derived non-mammaliaform cynodonts, such as Probainognathus and Pachygenelus, and differs from Thrinaxodon. By the allometric relationship of the cochlear canal and the estimated body mass, Brasilitherium can be grouped with Yunnanodon and Morganucodon in a regression line, which is below the line of mammals and above the line of non-avian reptiles. Brasilitherium fits in a sequence of gradual elongation of the cochlear canal associated with the enhancement in the capacity to hear higher frequencies. Among the constraints that might have triggered these transformations in small, insectivorous, and possibly nocturnal Mesozoic cynodont taxa is the improvement of detecting acoustically active insects.     

Cranial discrete traits in the middle pleistocene humans from Sima de los Huesos (Sierra de Atapuerca, Spain). Does hypostosis represent any increase in "ontogenetic stress" along the Neanderthal lineage?

Cranial discrete traits may be regarded as markers of dynamic responses to general and local perturbations of the morphogenetic pattern, particularly when they are viewed and examined in terms of hypostosis vs. hyperostosis. There are indications, in fact, that the variation between these two opposite conditions relates to mechanical stress suffered by the bony structures during early stages of growth and development. In a previous comparison between Neanderthals and modern humans, variable degrees and contrasting distribution patterns of hypostosis were found [Manzi et al. (1996), JHE30: 511-527]. In the present paper, the occurrence, expression and cranial distribution of 20 hypo-hyperostotic traits are examined in the Middle Pleistocene sample from Atapuerca - Sima de los Huesos (Spain), with the principal aim being to test whether or not the degree of cranial hypostosis increases during the evolution of the Neanderthals. Other Middle Pleistocene representatives of the genus Homo (Kabwe and Petralona), the Italian Neanderthals, and a large recent European sample are also considered. A general consistency between the gradual appearance and stabilization of the Neanderthal cranial features and the results of the present analysis is found and is interpreted as an indication that hypostosis does mark the occurrence of "ontogenetic stress". As suggested more than half a century ago by S. Sergi, an increase in "ontogenetic stress" in the Neanderthal lineage could result from the relationship between intracranial pressures and other (heterochronic) effects produced by the growth of a large brain (encephalization) and the ossification of an archaic (platycephalic) cranial vault.     

Computed tomography of the temporal bones in children with developmental anomalies of the external and middle ear]

Computed polypositional high-resolution tomography (CT) was provided to 45 children with dysplasia of the external acoustic meatus (EAM). The computed tomograms were analyzed in accordance with the scheme which included the evaluation of the following structures: atresia or stenosis area, pneumatized mastoid process, tympanic cavity, ant rum, osteal opening of the Eustachian tube, chain of auditory ossicles, windows of the labyrinth, internal ear, facial nerve canal, and large vessels. Preoperative CT of the temporal bones allows for the evaluation of the above-listed structures, which is of paramount importance for the planning of the patient management policy. Also, CT enables the assessment of the risk of surgical intervention associated with a potential injury to the facial nerve, large vessels, and temporomandibular articulation. CT is to be an indispensable diagnostic modality for examination of children presenting with EAM dysplasia.     

Potentialities of temporal bone computed tomography in the identification of causes of hypoacusis of postinflammatory genesis

Temporal bone computed tomography (CT) was used to examine 64 patients with impaired hearing due to inflammatory diseases of the middle year. In 21 patients, the pathological process was bilateral. A total of 85 series of temporal bone CT scans were analyzed. The patients' age ranged from 2 to 66 years. CT verified adhesive otitis media in 62 cases, otosclerosis in 7, local malformation of the auditory ossicles and/or the labyrinthine fenestrae in 11. No CT changes were revealed in 5 cases. The CT symptoms of adhesive otitis media were identified. These included soft tissue bands and/or soft tissue-density portions that fix the auditory ossicles or block the niches of the labyrinthine fenestrae (31 temporal bones); sclerosis or ossification of the ligaments and tendons of the middle ear (7 temporal bones); calcification foci in the tympanic cavity (9 cases); osteosclerotic changes in the epitympanus (2 cases); cicatricial changes in the tympanic membrane (24 cases); destructive changes in the auditory ossicles (19 temporal bones). There has been evidence that CT may be used for the differential diagnosis of adhesive otitis media from otosclerosis and congenital malformations of the structures of the middle ear.     

The petrosal and inner ear of the Late Jurassic cladotherian mammal Dryolestes leiriensis and implications for ear evolution in therian mammals

Dryolestes leiriensis is a Late Jurassic fossil mammal of the dryolestoid superfamily in the cladotherian clade that includes the extant marsupials and placentals. We used high resolution micro‐computed tomography (µCT) scanning and digital reconstruction of the virtual endocast of the inner ear to show that its cochlear canal is coiled through 270°, and has a cribriform plate with the spiral cochlear nerve foramina between the internal acoustic meatus and the cochlear bony labyrinth. The cochlear canal has the primary bony lamina for the basilar membrane with a partially formed (or partially preserved) canal for the cochlear spiral ganglion. These structures, in their fully developed condition, form the modiolus (the bony spiral structure) of the fully coiled cochlea in extant marsupial and placental mammals. The CT data show that the secondary bony lamina is present, although less developed than in another dryolestoid Henkelotherium and in the prototribosphenidan Vincelestes. The presence of the primary bony lamina with spiral ganglion canal suggests a dense and finely distributed cochlear nerve innervation of the hair cells for improved resolution of sound frequencies. The primary, and very probably also the secondary, bony laminae are correlated with a more rigid support for the basilar membrane and a narrower width of this membrane, both of which are key soft‐tissue characteristics for more sensitive hearing for higher frequency sound. All these cochlear features originated prior to the full coiling of the therian mammal cochlea beyond one full turn, suggesting that the adaptation to hearing a wider range of sound frequencies, especially higher frequencies with refined resolution, has an ancient evolutionary origin no later than the Late Jurassic in therian evolution. The petrosal of Dryolestes has added several features that are not preserved in the petrosal of Henkelotherium. The petrosal characters of dryolestoid mammals are essentially the same as those of Vincelestes, helping to corroborate the synapomorphies of the cladotherian clade in neural, vascular, and other petrosal characteristics. The petrosal characteristics of Dryolestes and Henkelotherium together represent the ancestral morphotype of the cladotherian clade (Dryolestoidea + Vincelestes + extant Theria) from which the extant therian mammals evolved their ear region characteristics. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 166 , 433–463.     

How and why humans grow thin skulls: Experimental evidence for systemic cortical robusticity

To what extent is cranial vault thickness (CVT) a character that is strongly linked to the genome, or to what extent does it reflect the activity of an individual prior to skeletal maturity? Experimental data from pigs and armadillos indicate that CVT increases more rapidly in exercised juveniles than in genetically similar controls, despite the low levels of strain generated by chewing or locomotion in the neurocranium. CVT increases in these individuals appear to be a consequence of systemic cortical bone growth induced by exercise. In addition, an analysis of the variability in vault thickness in the genus Homo demonstrates that, until the Holocene, there has been only a slight, general decrease in vault thickness over time with no consistent significant differences between archaic and early anatomically modern humans from the Late Pleistocene. Although there may be some genetic component to variation in CVT, exercise-related, non-genetically heritable stimuli appear to account for most of the variance between individuals. The thick cranial vaults of most hunter-gatherers and early agriculturalists suggests that they may have experienced higher levels of sustained exercise relative to body mass than the majority of recent, post-industrial humans. © 1996 Wiley-Liss, Inc.     

Occipital bunning among later pleistocene hominids

Occipital bunning is a posterior projection of the occipital squama, which occurs in varying frequencies in samples of archaic Homo sapiens, Upper Pleistocene anatomically modern humans, and recent humans. It can be best interpreted as a product of the timing of posterior cerebral growth relative to the growth of the cranial vault bones. It is not a feature that was unique to the Neandertals.     

Tissue origins and interactions in the mammalian skull vault.

During mammalian evolution, expansion of the cerebral hemispheres was accompanied by expansion of the frontal and parietal bones of the skull vault and deployment of the coronal (fronto-parietal) and sagittal (parietal-parietal) sutures as major growth centres. Using a transgenic mouse with a permanent neural crest cell lineage marker, Wnt1-Cre/R26R, we show that both sutures are formed at a neural crest-mesoderm interface: the frontal bones are neural crest-derived and the parietal bones mesodermal, with a tongue of neural crest between the two parietal bones. By detailed analysis of neural crest migration pathways using X-gal staining, and mesodermal tracing by DiI labelling, we show that the neural crest-mesodermal tissue juxtaposition that later forms the coronal suture is established at E9.5 as the caudal boundary of the frontonasal mesenchyme. As the cerebral hemispheres expand, they extend caudally, passing beneath the neural crest-mesodermal interface within the dermis, carrying with them a layer of neural crest cells that forms their meningeal covering. Exposure of embryos to retinoic acid at E10.0 reduces this meningeal neural crest and inhibits parietal ossification, suggesting that intramembranous ossification of this mesodermal bone requires interaction with neural crest-derived meninges, whereas ossification of the neural crest-derived frontal bone is autonomous. These observations provide new perspectives on skull evolution and on human genetic abnormalities of skull growth and ossification.     

Ultrastructural observations on the maturation of the placental labyrinth of the golden hamster (days 10 to 16 of gestation).

Morphogenesis of the labyrinthine part of the chorioallantoic placenta of the golden hamster between day 10 of gestation and term (day 16) was studied by light and electron microscopy. During this period the labyrinth increases greatly in both size and complexity. Trabeculae of the labyrinth, thin partitions composed of trophoblastic tissue and fetal capillaries which delimit the maternal blood spaces, apparently proliferate both by appositional and interstitial growth. From the time of its formation (day 9 of gestation) until term the labyrinth is hemotrichorial in organization (i.e. three layers of trophoblast separate maternal blood from fetal capillaries). Both the inner and intermediate layers of trophoblast (layers III and II, respectively) are syncytial. The outer trophoblastic layer (III), which is in direct contact with maternal blood, remains cellular, although many of its component cells grow to giant cell dimensions ("labyrinthine giant cells"). Between the tenth and fourteenth days of gestation the anatomical barrier to diffusion between maternal and fetal blood is progressively reduced. This is accomplished both by gradual attenuation of the trophoblastic layers and fetal capillary endothelium and by the formation of discontinuities (gaps) in layer I, and diaphragmed fenestrae in fetal capillary endothelium. The labyrinthine placental barrier is fully developed and probably attains maximal functional efficiency by the fourteenth day of gestation. Late in the fifteenth day of gestation, a few hours before parturition, distinct degenerative changes are apparent in the trophoblastic layers and fetal capillaries of the trabeculae. The factors responsible for initiation these degenerative changes and the onset of parturition are still controversial.     

An Enlarged Parietal Foramen in the Late Archaic Xujiayao 11 Neurocranium from Northern China,and Rare Anomalies among Pleistocene Homo

We report here a neurocranial abnormality previously undescribed in Pleistocene human fossils, an enlarged parietal foramen (EPF) in the early Late Pleistocene Xujiayao 11 parietal bones from the Xujiayao (Houjiayao) site, northern China. Xujiayao 11 is a pair of partial posteromedial parietal bones from an adult. It exhibits thick cranial vault bones, arachnoid granulations, a deviated posterior sagittal suture, and a unilateral (right) parietal lacuna with a posteriorly-directed and enlarged endocranial vascular sulcus. Differential diagnosis indicates that the perforation is a congenital defect, an enlarged parietal foramen, commonly associated with cerebral venous and cranial vault anomalies. It was not lethal given the individual’s age-at-death, but it may have been associated with secondary neurological deficiencies. The fossil constitutes the oldest evidence in human evolution of this very rare condition (a single enlarged parietal foramen). In combination with developmental and degenerative abnormalities in other Pleistocene human remains, it suggests demographic and survival patterns among Pleistocene Homo that led to an elevated frequency of conditions unknown or rare among recent humans.     

Atresia of the external acoustic meatus in prehistoric populations

A case of atresia of the external acoustic meatus is presented from a prehistoric Late Woodland site in Iowa. The affected individual was a female aged 30 to 40 years. The left temporal bone displayed a thin bony plate occluding the external acoustic canal. No evidence of middle ear or inner ear malformation was observed on the axial tomographs, although the external canal was shortened. The individual is diagnosed as having a mild case of congenital atresia. The report extends the geographical and temporal distributions of this archaeologically rare condition.     

Early development of the primitive cranial vault in the chick embryo.

The calcified tissues involved in the early morphogenesis of the cranial vault were studied by microradiographic analysis and histological techniques in 12 chick embryos on the 9th, 12th, and 14th days of incubation. On the 9th day, the frontal, parietal, and squamosal bones are comprised of a thin lamina of chondroid tissue deposited at a short distance from the fibers of the dura mater. Woven bone formation takes place in the calvarial mesenchyme only after the 12th day of incubation and occurs mainly on the external side of the chondroid primordium. The present data obviously indicate that the primitive desmocranium of the chick embryo, which is usually known to be formed by intramembranous ossification, consists first of chondroid tissue. This tissue represents thus the initial modality of skeletogenic differentiation within the cephalic mesenchyme of the cranial vault.