Histology shows that elongated neck ribs in sauropod dinosaurs are ossified tendons

The histology of cervical ribs of Sauropoda reveals a primary bone tissue, which largely consists of longitudinally oriented mineralized collagen fibres, essentially the same tissue as found in ossified tendons. The absence of regular periosteal bone and the dominance of longitudinal fibres contradict the ventral bracing hypothesis (VBH) postulated for sauropod necks. The VBH predicts histologically primary periosteal bone with fibres oriented perpendicular to the rib long axis, indicative of connective tissue between overlapping hyperelongated cervical ribs. The transformation of the cervical ribs into ossified tendons makes the neck more flexible and implies that tension forces acted mainly along the length of the neck. This is contrary to the VBH, which requires compressive forces along the neck. Tension forces would allow important neck muscles to shift back to the trunk region, making the neck much lighter.     

The phylogenetic relationships of sauropod dinosaurs

A data-matrix of 205 osteological characters for 26 sauropod taxa is subjected to cladistic analysis. Two most parsimonious trees are produced, differing only in the relationships between Euhelopus, Omeisaurus and Mamenchisaurus. The monophyly of the Euhelopodidae (including Shunosaurus) is supported by seven synapomorphies. The Cetiosauridae (Patagosaurus, Cetiosaurus and Haplocanthosaurus) is paraphyletic with respect to the Neosauropoda. The latter clade divides into two major radiations–the ‘Brachiosauria’ (Camarasaurus, brachiosaurids and titanosauroids), and the Diplodocoidea (nemegtosaurids, dicraeosaurids, diplodocids and Rebbachisaurus). Further evidence for the inclusion of Opisthocoelwaudia in the Titanosauroidea is presented. Phuwiangosaurus, a problematic sauropod from Thailand, may represent one of the most plesiomorphic titanosauroids. ‘Peg’-like teeth have evolved at least twice within the Sauropoda. The postspinal lamina, on the neural spines of middle and caudal dorsal vertebrae, represents a neomorph rather than a fusion of pre-existing structures. Forked chevrons may have evolved convergently in the Euhelopodidae and the diplodocid-dicraeosaurid clade, or they may have been acquired early in sauropod evolution and subsequently lost in the ‘Brachiosauria’. The strengths and weaknesses of the data-matrix and tree topologies are explored using bootstrapping, decay analysis and randomization tests. Several nodes are only poorly supported, but this seems to reflect the large proportion of missing data in the matrix (～46%), rather than an abnormally high level of homoplasy. The results of the randomization tests indicate that the ‘data-matrix’ probably contains a strong phylogenetic ‘signal’. The relationships of some forms, such as Haplocanthosaurus, are influenced by the inclusion or exclusion of certain taxa with unusual combinations of character states. Such a result suggests that there are dangers inherent in the view that ‘higher’ level sauropod phylogeny can be accurately reconstructed using only a small number of well-known taxa.     

Cranial biomechanics underpins high sauropod diversity in resource-poor environments

High megaherbivore species richness is documented in both fossil and contemporary ecosystems despite their high individual energy requirements. An extreme example of this is the Late Jurassic Morrison Formation, which was dominated by sauropod dinosaurs, the largest known terrestrial vertebrates. High sauropod diversity within the resource-limited Morrison is paradoxical, but might be explicable through sophisticated resource partitioning. This hypothesis was tested through finite-element analysis of the crania of the Morrison taxa Camarasaurus and Diplodocus. Results demonstrate divergent specialization, with Camarasaurus capable of exerting and accommodating greater bite forces than Diplodocus, permitting consumption of harder food items. Analysis of craniodental biomechanical characters taken from 35 sauropod taxa demonstrates a functional dichotomy in terms of bite force, cranial robustness and occlusal relationships yielding two polyphyletic functional ‘grades’. Morrison taxa are widely distributed within and between these two morphotypes, reflecting distinctive foraging specializations that formed a biomechanical basis for niche partitioning between them. This partitioning, coupled with benefits associated with large body size, would have enabled the high sauropod diversities present in the Morrison Formation. Further, this provides insight into the mechanisms responsible for supporting the high diversities of large megaherbivores observed in other Mesozoic and Cenozoic communities, particularly those occurring in resource-limited environments.     

On the cervical vertebrae of the Pterodactyloidea (Reptilia: Archosauria)

Within the Pterodactyloidea, the cervical vertebrae show considerable variation. These elements are also sufficiently common and contain enough anatomical information to make them taxonomically valuable. A survey of these vertebrae concludes that most known pterodactyloids fall into two groups: long-necked forms with attenuated cervical vertebrae that possess low neural spines, and tall-spined forms that possess relatively short neck vertebrae with tall neural spines. These two groups may represent natural taxonomic units. However, this is by no means conclusive and can only be tested by the study of other regions of pterodactyloid skeletons.     

Adaptive radiation in sauropod dinosaurs: bone histology indicates rapid evolution of giant body size through acceleration

The well-preserved histology of the geologically oldest sauropod dinosaur from the Late Triassic allows new insights into the timing and mechanism of the evolution of the gigantic body size of the sauropod dinosaurs. The oldest sauropods were already very large and show the same long-bone histology, laminar fibro-lamellar bone lacking growth marks, as the well-known Jurassic sauropods. This bone histology is unequivocal evidence for very fast growth. Our histologic study of growth series of the Norian Plateosaurus indicates that the sauropod sistergroup, the Late Triassic and early Jurassic Prosauropoda, reached a much more modest body size in a not much shorter ontogeny. Increase in growth rate compared to the ancestor (acceleration) is thus the underlying process in the phylogenetic size increase of sauropods. Compared to all other dinosaur lineages, sauropods were not only much larger but evolved very large body size much faster. The prerequisite for this increase in growth rate must have been a considerable increase in metabolic rate, and we speculate that a bird-like lung was important in this regard.     

No gastric mill in sauropod dinosaurs: new evidence from analysis of gastrolith mass and function in ostriches

Polished pebbles occasionally found within skeletons of giant herbivorous sauropod dinosaurs are very likely to be gastroliths (stomach stones). Here, we show that based on feeding experiments with ostriches and comparative data for relative gastrolith mass in birds, sauropod gastroliths do not represent the remains of an avian-style gastric mill. Feeding experiments with farm ostriches showed that bird gastroliths experience fast abrasion in the gizzard and do not develop a polish. Relative gastrolith mass in sauropods (gastrolith mass much less than 0.1% of body mass) is at least an order of magnitude less than that in ostriches and other herbivorous birds (gastrolith mass approximates 1% of body mass), also arguing against the presence of a gastric mill in sauropods. Sauropod dinosaurs possibly compensated for their limited oral processing and gastric trituration capabilities by greatly increasing food retention time in the digestive system. Gastrolith clusters of some derived theropod dinosaurs (oviraptorosaurs and ornithomimosaurs) compare well with those of birds, suggesting that the gastric mill evolved in the avian stem lineage.     

Retention of hemopoiesis in tail vertebrae of newborn rats

Summary In newborn rats, the marrow cavity of tail vertebrae is hemopoietic and contains no adipose tissue. The latter develops soon after birth to replace the hemopoietic tissue within the nonexpansile volume of the marrow cavity. By transposing the tail into the warmer environment of the abdomen, hemopoiesis was retained, and the development of adipose tissue was prevented in the transposed segment, when the operation was done in preweanling but not in adult animals. Systemic stimuli of erythropoiesis (phlebotomy, induced hemolysis) acted synergistically with the temperature increment to retain hemopoiesis. The findings support the concept that adipose cells in the yellow marrow are relatively stable and once developed, they are not readily mobilized. The findings may also explain the discrepancies in the results obtained by rat tail transposition.Supported by ERDA Contract EP-78-S-03-0899, NASA Grant NSG 9061 and RCDA AM16125 awarded to Mehdi Tavassoli     

Halastatic demineralization in the vertebrae of Atlantic salmon, during their spawning migration

There was a significant decrease ( c . 10%) in the mineralization of the vertebrae, determined by analysis of quantitative microradiographs, of both sexes of Atlantic salmon Salmo salar during their ascending spawning migration. The decrease was hypothesized to be the result of halastatic demineralization, i.e. the removal of mineral substance with no degradation of the organic matrix of the bone.     

First occurrences of non-neosauropod eusauropod procoelous caudal vertebrae in the Portuguese Upper Jurassic record

The Upper Jurassic of the Lusitanian Basin (Portugal) is particularly rich in sauropod fossil remains, with four established taxa: Dinheirosaurus, Lusotitan, Lourinhasaurus and Zby. The presence of sauropod caudal procoelous vertebrae is reported for the first time in the Upper Jurassic of Portugal, with specimens described from the localities of Baleal, Paimogo, Praia da Areia Branca, Porto das Barcas, and Praia da Corva. The presence of slightly procoelous centra and fan-shaped caudal ribs with smooth prezygapophyseal centrodiapophyseal fossa in the more anterior caudal vertebrae allows for the assignment of these specimens to an indeterminate eusauropod, probably belonging to a non-neosauropod eusauropod form. The absence of several features in the Portuguese specimens that are common in diplodocids, mamenchisaurids and titanosaurs, prevents the establishment of sound relationships with these clades. The described specimens are almost identical to the anterior caudal vertebrae of the Iberian turiasaur Losillasaurus. During the Iberian Late Jurassic, Turiasauria is the only Iberian group of sauropods, which shares this type of morphology with the Baleal, Paimogo, Praia da Areia Branca, Porto das Barcas and Praia da Corva specimens. These specimens represent one of the four anterior caudal vertebral morphotypes recorded in the Upper Jurassic of the Lusitanian Basin and briefly described herein.     

Micro-CT检测中等强度跑台运动对去卵巢大鼠腰椎微结构的影响

目的用micro-CT方法,评估中等强度跑台运动对去卵巢大鼠腰椎微结构的影响。方法将30只3月龄雌性SD大鼠按体重分层后随机分为假手术、去卵巢静止和去卵巢运动三个组。运动组每周进行4次45min、速度18 m/min、坡度5°的跑台训练。正式运动处理14周时,取第2腰椎检测骨密度,取第4腰椎行micro-CT分析及三维结构重建;取第3腰椎椎体进行椎体压缩实验。结果去卵巢运动组第2腰椎骨密度、第3腰椎最大载荷、最大应力和弹性模量以及第4腰椎骨小梁体积和骨小梁数目显著高于去卵巢静止组,骨小梁分离度显著低于去卵巢静止组,而骨小梁厚度无显著变化。结论中等强度跑台运动能改善去卵巢大鼠腰椎的微结构。     

The number of vertebrae in the Southern African Negro,the American Negro and the Bushman (San)

The numbers of precoccygeal vertebrae (PCV) are compared in Southern African Negroes, Bushman (San) and American Negroes. The S.A. Negro and San males have an exceptionally high frequency of an increased total PCV number whilst the frequencies are significantly lower in a combined Caucasoid sample and the Mongoloid samples. The American Negro male, too, has a high frequency but not as high as in S.A. Negroes. The high frequency of increased PCV number in San, S.A. Negroes and American Negroes is in keeping with the view that the Khoisan peoples (here represented by the San), the Southern African Negroes and the African ancestors of American Blacks sprang from a common proto-negriform stock. Males have a significantly greater frequency of increased PCV to 30 or 31, whereas females are more likely to have a decreased number of 28 PCV. This sex difference is present in all the populations studied.     

The Hadropithecus conundrum reconsidered, with implications for interpreting diet in fossil hominins

The fossil 'monkey lemur' Hadropithecus stenognathus has long excited palaeontologists because its skull bears an astonishing resemblance to those of robust australopiths, an enigmatic side branch of the human family tree. Multiple lines of evidence point to the likelihood that these australopiths ate at least some 'hard', stress-limited food items, but conflicting data from H. stenognathus pose a conundrum. While its hominin-like craniofacial architecture is suggestive of an ability to generate high bite forces, details of its tooth structure suggest that it was not well equipped to withstand the forces imposed by cracking hard objects. Here, we use three-dimensional digital reconstructions and finite-element analysis to test the hard-object processing hypothesis. We show that Archaeolemur sp. cf. A. edwardsi, a longer-faced close relative of H. stenognathus that lacked hominin convergences, was probably capable of breaking apart large, stress-limited food items, while Hadropithecus was better suited to processing small, displacement-limited (tougher but more compliant) foods. Our suggestion that H. stenognathus was not a hard-object feeder has bearing on the interpretation of hominin cranial architecture; the features shared by H. stenognathus and robust australopiths do not necessarily reflect adaptations for hard-object processing.     

A new turtle from the La Colonia Formation (Campanian–Maastrichtian), Patagonia,Argentina, with remarks on the evolution of the vertebral column in turtles

Abstract: Patagoniaemys gasparinae gen. et sp. nov. is a new stem turtle found in central Patagonia, Chubut Province, Argentina, in outcrops of the La Colonia Formation (Campanian–Maastrichtian). This is a turtle of relatively large size (carapace length c. 70 cm), and the preserved remains of the holotype consist of skull fragments and several postcranial elements including a nearly complete vertebral column. A phylogenetic analysis shows Patagoniaemys gasparinae gen. et sp. nov. forming a monophyletic group with Otwayemys cunicularius and Mongolochelys efremovi, as a sister group to Meiolaniidae. A comprehensive review confirms that formed cervical vertebrae appeared independently several times during turtle evolution: in the clade that includes Patagoniaemys gasparinae gen. et sp. nov. and Meiolaniidae, in some baenids, in the total group Pleurodira and in crown group Cryptodira. Likewise, formed caudal vertebrae appeared several times in turtle evolution.     

Some implications of relative biomechanical neck length in hominid femora

Demonstration of a size-based influence on relative biomechanical neck length of the femur predicts relatively longer necks for smaller femurs. Fossil hominids through the middle Pleistocene appear to have relatively longer femur necks than expected from this relation, excepting the two small australopithecine females. It is suggested that this variation results from smaller crania at birth in the fossils, and the possibility is raised that australopithecine populations were characterized by marked brain size differences at birth.     

Moa diet fits the bill: virtual reconstruction incorporating mummified remains and prediction of biomechanical performance in avian giants

The moa (Dinornithiformes) are large to gigantic extinct terrestrial birds of New Zealand. Knowledge about niche partitioning, feeding mode and preference among moa species is limited, hampering palaeoecological reconstruction and evaluation of the impacts of their extinction on remnant native biota, or the viability of exotic species as proposed ecological ‘surrogates''. Here we apply three-dimensional finite-element analysis to compare the biomechanical performance of skulls from five of the six moa genera, and two extant ratites, to predict the range of moa feeding behaviours relative to each other and to living relatives. Mechanical performance during biting was compared using simulations of the birds clipping twigs based on muscle reconstruction of mummified moa remains. Other simulated food acquisition strategies included lateral shaking, pullback and dorsoventral movement of the skull. We found evidence for limited overlap in biomechanical performance between the extant emu (Dromaius novaehollandiae) and extinct upland moa (Megalapteryx didinus) based on similarities in mandibular stress distribution in two loading cases, but overall our findings suggest that moa species exploited their habitats in different ways, relative to both each other and extant ratites. The broad range of feeding strategies used by moa, as inferred from interspecific differences in biomechanical performance of the skull, provides insight into mechanisms that facilitated high diversities of these avian herbivores in prehistoric New Zealand.     

DNA quantification is technically feasible and of value in cervical smear samples: possible applications for determination of progression in low grade dyskaryosis

This study evaluates the feasibility of DNA analysis of cervical intraepithelial neoplasia III (CIN III) lesions on cervical smear and formalin-fixed paraffin-embedded tissue (FFPET) blocks with a view to extending this type of analysis to milder grades of dyskaryosis. DNA ploidy was determined by image analysis using a CAS 200 Image Analyser. Seventeen patients with a diagnosis of CIN III were studied. Results show that all smear and tissue samples were non-diploid with nine aneuploid and eight tetraploid lesions. In 6/7 patients whose smears and corresponding biopsies were examined there was complete agreement as to the DNA profile. We conclude that DNA quantification is technically feasible in archival, routinely prepared cervical smears. This technique should now be applied to CINI and CINII cervical smears to determine if it is of value in identifying those lesions that will progress to CIN III. This study is particularly timely with the possibility in the near future of estimation of ploidy by image analysis using instruments such as the Highly Optimized Microscope Environment (HOME) system.     

Seasonal variation of mass, condition and gonadosomatic index in fourhorn sculpin (Myoxocephalus quadricornis) with normal and malformed vertebrae in the Gulf of Bothnia

It may be expected that vertehral anomaties would reduer the viability and reproductive success of fish. In the present study. the relationship of vertebral defects to body mass. Iength, age, condition, gonadosomatic index and growth in fourhorn sculpin, Myoxocephalus quadricornis , in the Gulf of Bothnia was studied. There were no differences in growth between normal and defective lish, for either males or females. While normal and defectives males were similar in age and length. defective females were older and longer than normal females. Defective males and females had a significantly greater somatic mass that normal fish. However defective females may be later than in normal fish. Hence, vertebral defects do not necessarly reduce the reproductive potential of fourhorn sculpin.     

Investigation of pediatric neck response and muscle activation in low-speed frontal impacts

Pediatric necks present different responses and injury patterns compared with those of adults in motor vehicle crashes (MVCs). To evaluate the effect of different muscle modeling methodologies, three muscle models were developed and simulated under low-speed frontal impact conditions with an average peak acceleration of 3g's. The muscle activation curve for the curve-guided model, the muscle segment was curved using guiding nodes, was further optimized based on experimental data. The pediatric neck model was also simulated under more severe frontal impact conditions with an average peak acceleration of 8g's. Simulation results revealed that the curve-guided model needed more muscle force than the straight-guided model, in which the muscle segment was straight with guiding nodes, and the curve-constrained model, in which the muscle segment was curved without guiding nodes and which imposes more constraints on the head and neck than the curve-guided model. The predicted head responses for the child finite element neck model were within or close to the experimental corridors of 3- and 8-g's frontal impacts. The neck injuries for a 10-year-old child commonly occurred at the interspinous ligament in the C7–T1 segment. The model could be used to analyze the responses and injuries of pediatric neck and head in low-speed frontal impacts.     

Cervical cancer: cytological cervical screening in Iceland and implications of HPV vaccines

K. Sigurdsson
Cervical cancer: cytological cervical screening in Iceland and implications of HPV vaccines This paper reviews the Icelandic experience regarding the age‐specific effectiveness, optimal targeted age range and intervals in cervical cancer screening and the screening implications of the HPV16/18 vaccines. The background material is based on data from a screening programme with centralized records dating back to 1964, as well as from population‐based studies on the distribution of oncogenic HPV types in cancer and histologically verified CIN2‐3 lesions and from the Icelandic arm of the Future II trial with Gardasil^®. The findings confirm significant increased rates in the screened population of CIN2‐3, stage IA (microinvasive) cancer since 1979, mainly in the age group 20–34 years. These lesions start to accumulate within 3 years of a normal smear. Studies on the distribution of HPV types indicate that the marketed vaccines could lower the incidence of cancer and CIN2‐3 by about 67% and 53%, respectively, after taking into account reported cross‐protection. About 65% of women below 25 years of age had lesions related to the non‐vaccine types and after the last normal smear these cases accumulated at the same frequency as cases with vaccine‐included types. Cases with combined vaccine and non‐vaccine types accumulated at a slower rate. We conclude that screening should continue to start at age 20 years, with invitations at 2‐year intervals up to age 39 years and thereafter at 4‐year intervals up to age 65–69 years. Current data support the conclusion that the optimal age for catch‐up HPV vaccination should be considered in the context of sexual practices and the data do not support changes in the lower age limit or screening intervals for the vaccinated women.