Trunk elongation and ontogenetic changes in the axial skeleton of Triturus newts

Body elongation in vertebrates can be achieved by lengthening of the vertebrae or by an increase in their number. In salamanders, longer bodies are mostly associated with greater numbers of vertebrae in the trunk or tail region. However, studies on the relative contribution of the length of single vertebra to body elongation are lacking. In this study, we focus on evolutionary and ontogenetic changes in differentiation of the trunk vertebrae and the relative contribution of individual vertebrae to trunk lengthening in Triturus newts, a monophyletic group of salamanders that shows remarkable disparity in body shape. We compared juveniles and adults of the most elongated T. dobrogicus , which has 17 trunk vertebrae, with juveniles and adults of two closely related species (T. ivanbureschi and T. anatolicus belonging to the T. karelinii species complex) representing a stout and robust morphotype with thirteen trunk vertebrae. We show that trunk vertebrae are uniform in size at the juvenile stage of both analyzed morphotypes. In adults, the trunk vertebrae of the elongated T. dobrogicus are largely uniform, while in those of T. anatolicus , the first two vertebrae differ from the remaining trunk vertebrae. There was no difference in the relative contribution of individual vertebrae to body lengthening between species or stages. We conclude that body elongation in Triturus newts is achieved by increasing the number of vertebrae but not their length.     

The Postcranial Skeleton of an Exceptionally Complete Individual of the Plated Dinosaur Stegosaurus stenops (Dinosauria: Thyreophora) from the Upper Jurassic Morrison Formation of Wyoming,U.S.A.

Although Stegosaurus is one of the most iconic dinosaurs, well-preserved fossils are rare and as a consequence there is still much that remains unknown about the taxon. A new, exceptionally complete individual affords the opportunity to describe the anatomy of Stegosaurus in detail for the first time in over a century, and enables additional comparisons with other stegosaurian dinosaurs. The new specimen is from the Red Canyon Ranch Quarry, near Shell Wyoming, and appears to have been so well preserved because it was buried rapidly in a pond or body of standing water immediately after death. The quarry is probably located in the middle part of the Morrison Formation, which is believed to be Tithonian in age in this area. The specimen is referable to Stegosaurus stenops based on the possession of an edentulous anterior portion of the dentary and elevated postzygapophyses on the cervical vertebrae. New information provided by the specimen concerns the morphology of the vertebrae, the iliosacral block and dermal armor. Several aspects of its morphology indicate the individual was not fully skeletally mature at the time of death, corroborating a previous histological study.     

Cercopithecoid cervical vertebral morphology and implications for the presence of Theropithecus in early Pleistocene Europe

While it is recognized that the overall configuration of the vertebral column, as well as the size and shape of individual vertebrae, differ within and between primate taxa, relatively little is known about the degree to which vertebral morphology reflects a phylogenetic signal or the degree to which vertebral elements can be used in accurate taxonomic classification. Isolated vertebrae are occasionally found in fossil assemblages, and proper taxonomic identification is necessary to make inferences about the animal's biology and place it in a broader phylogenetic and evolutionary context. Recently, three large primate cervical vertebrae (C3, C5, and C6) from Pirro Nord, Italy (early Pleistocene, late Villafranchian) were attributed to the genus Theropithecus based on size comparisons with extant cercopithecoid primates (Rook et al., 2004, J. Hum. Evol. 47, 267-277). These fossils were suggested to indicate an early dispersal of this genus out of Africa around 1.6-1.3 Ma possibly co-incident with early Pleistocene dispersals of Homo. Because of the potential importance of these fossils for interpreting Theropithecus evolution and the relatively few morphological data on primate cervical vertebral morphology, we examined the size and shape of cervical vertebrae in a large sample of extant cercopithecoid taxa (n=106). Specifically, we evaluated whether subfamily and genus level assignments can be made on the basis of isolated cervical elements. Discriminant analyses reveal that scaled shape variables are good discriminators of taxonomic affinity at the subfamily level but are poor discriminators at the genus level. Least-squares regressions show that raw linear dimensions of cervical vertebral morphology are good predictors of body mass in the extant sample. Our regression results produce a likely body mass estimate of 22-38 kg for the Pirro Nord cervical vertebrae. Based on these regression estimates, the poor ability to discriminate cervical vertebrae at the genus level, and paleoenvironmental reconstructions of Pirro Nord, it is unlikely that the Pirro Nord fossils can be confidently attributed to the genus Theropithecus. These findings have important implications for recent interpretations of the nature of Theropithecus dispersal out of Africa.     

A new long-necked ‘sauropod-mimic’ stegosaur and the evolution of the plated dinosaurs

Stegosaurian dinosaurs have a quadrupedal stance, short forelimbs, short necks, and are generally considered to be low browsers. A new stegosaur, Miragaia longicollum gen. et sp. nov., from the Late Jurassic of Portugal, has a neck comprising at least 17 cervical vertebrae. This is eight additional cervical vertebrae when compared with the ancestral condition seen in basal ornithischians such as Scutellosaurus. Miragaia has a higher cervical count than most of the iconically long-necked sauropod dinosaurs. Long neck length has been achieved by ‘cervicalization’ of anterior dorsal vertebrae and probable lengthening of centra. All these anatomical features are evolutionarily convergent with those exhibited in the necks of sauropod dinosaurs. Miragaia longicollum is based upon a partial articulated skeleton, and includes the only known cranial remains from any European stegosaur. A well-resolved phylogeny supports a new clade that unites Miragaia and Dacentrurus as the sister group to Stegosaurus; this new topology challenges the common view of Dacentrurus as a basal stegosaur.     

Association between the dopamine D4 receptor gene exon III variable number of tandem repeats and political attitudes in female Han Chinese

Twin and family studies suggest that political attitudes are partially determined by an individual''s genotype. The dopamine D4 receptor gene (DRD4) exon III repeat region that has been extensively studied in connection with human behaviour, is a plausible candidate to contribute to individual differences in political attitudes. A first United States study provisionally identified this gene with political attitude along a liberal–conservative axis albeit contingent upon number of friends. In a large sample of 1771 Han Chinese university students in Singapore, we observed a significant main effect of association between the DRD4 exon III variable number of tandem repeats and political attitude. Subjects with two copies of the 4-repeat allele (4R/4R) were significantly more conservative. Our results provided evidence for a role of the DRD4 gene variants in contributing to individual differences in political attitude particularly in females and more generally suggested that associations between individual genes, and neurochemical pathways, contributing to traits relevant to the social sciences can be provisionally identified.     

Evolution of the sacrum in hominoids

In order to study the formation of the sacrum during the primate evolution, a new way of numbering mammalian vertebrae is presented; this demonstrates that the thoracolumbosacral complex is fixed at 22 vertebrae in 80% and at 22 +/- 1 in 100% of the cases. The shift of a vertebra from one type to another occurs either at the thoracolumbar or at the lumbosacral junction and not at the cervicothoracic junction. Rarely does the shift take place at the sacrococcygeal junction. Data from 318 primates reveal that the seven original lumbar vertebrae of the Old World monkeys are reduced in the great apes by a caudad "thoracization" of one to two lumbar vertebrae and a cephalad sacralization of one to four lumbar vertebrae. In the apes, sacralization is not total and different stages that are intermediate between lumbar and sacral are described. In Homo sapiens there is a total sacralization of the last two original lumbar vertebrae. In addition, development of the sacral wings (alae) is minimal in apes and reaches its maximum in hominids. The tendency of the hominoid sacrum to incorporate the last lumbar vertebrae and to widen markedly provides for an enhanced articulation of the sacrum with the ilium and offers a firm base of support for the trunk during erect posture. This is necessary for the support of the weight of the trunk above the sacrum and for the stabilization of the body during bipedal posture and locomotion. Encephalization did not play any major role in the widening of the sacrum since the former by far preceded the latter.     

DR全脊柱成像技术应用探讨

目的探讨DR全脊柱成像技术在脊柱侧弯畸形诊断及测量中的价值,研究不同检查方法对成像质量及测量精度的影响。方法利用PHIIAPS公司Digital Diagnost DR系统和具有全脊柱拼接功能的SUN后处理工作站,对分次所摄的脊柱正位、侧位、左、右侧屈位影像进行拼接处理后作必要的测量,并打印成像。结果经上述处理后的全脊柱正位、侧位及左、右侧屈位均能将颈、胸、腰、骶椎完整联接,显示在1张14＋17的X光片上,其测量的数据真实可靠。结论DR全脊柱成像技术克服了以往颈、胸、腰、骶椎单独成像后测量上的误差,为临床手术提供了更精确的数据。     

Evidence of Spondyloarthropathy in the Spine of a Phytosaur (Reptilia: Archosauriformes) from the Late Triassic of Halberstadt,Germany

Pathologies in the skeleton of phytosaurs, extinct archosauriform reptiles restricted to the Late Triassic, have only been rarely described. The only known postcranial pathologies of a phytosaur are two pairs of fused vertebrae of “Angistorhinopsis ruetimeyeri” from Halberstadt, Germany, as initially described by the paleontologist Friedrich von Huene. These pathologic vertebrae are redescribed in more detail in this study in the light of modern paleopathologic methods. Four different pathologic observations can be made in the vertebral column of this individual: 1) fusion of two thoracic vertebral bodies by new bone formation within the synovial membrane and articular capsule of the intervertebral joint; 2) fusion and conspicuous antero-posterior shortening of last presacral and first sacral vertebral bodies; 3) destruction and erosion of the anterior articular surface of the last presacral vertebra; and 4) a smooth depression on the ventral surface of the fused last presacral and first sacral vertebral bodies. Observations 1–3 can most plausibly and parsimoniously be attributed to one disease: spondyloarthropathy, an aseptic inflammatory process in which affected vertebrae show typical types of reactive new bone formation and erosion of subchondral bone. The kind of vertebral shortening present in the fused lumbosacral vertebrae suggests that the phytosaur acquired this disease in its early life. Observation 4, the smooth ventral depression in the fused lumbosacral vertebrae, is most probably not connected to the spondyloarthropathy, and can be regarded as a separate abnormality. It remains of uncertain origin, but may be the result of pressure, perhaps caused by a benign mass such as an aneurysm or cyst of unknown type. Reports of spondyloarthropathy in Paleozoic and Mesozoic reptiles are still exceptional, and our report of spondyloarthropathy in fossil material from Halberstadt is the first unequivocal occurrence of this disease in a Triassic tetrapod and in a phytosaur.     

Current methodological refinements for the acquisition of life history information in fishes: paradigms from pan-oceanic billfishes.

1. Many factors contribute to hinder progress in estimating and verifying age, growth, and life history strategies of billfishes. It is necessary to discern growth of an individual fish to circumvent problems in substantiating age, growth, longevity and age at maturity. These biological characteristics allow us to discover what life history periods are critical to survival and reproduction. 2. Two theoretical approaches may be considered for studying the age of billfish: Age may be delineated in terms of the passage of time (chronological age), or may be examined as the progression of physiological development (physiological age). 3. Hard tissues such as otoliths, spines, vertebrae and post-mitotic tissues contain a plethora of biological and ecological information documenting a fish's chronological and physiological age and individual life history. In calcified tissues, this information can be obtained when the proper techniques are used to investigate the structural and chemical components of billfish hard parts. Chemical analyses of stable isotopes and elemental concentrations in calcified tissues suggest that calcified tissues contain hydrographic, nutritional and migrational information--life history information. 4. Utilization of structural and chemical analyses of billfish otoliths, vertebrae, and other hard parts, enables specific phases of growth to be linked to environmental occurrences. Measurement of the metabolically accumulated cellular pigment, lipofuscin, in post-mitotic tissue may make it possible to define physiological age or readiness. Internal and external structural and chemical analyses of otoliths, vertebrae, and other hard parts, combined with biochemical assays of post-mitotic tissue will greatly enhance studies of life history. The methods presented provide insights into means by which life history knowledge can be obtained.     

Morphing the feature-based multi-blocks of normative/healthy vertebral geometries to scoliosis vertebral geometries: development of personalized finite element models

Personalized Finite Element (FE) models and hexahedral elements are preferred for biomechanical investigations. Feature-based multi-block methods are used to develop anatomically accurate personalized FE models with hexahedral mesh. It is tedious to manually construct multi-blocks for large number of geometries on an individual basis to develop personalized FE models. Mesh-morphing method mitigates the aforementioned tediousness in meshing personalized geometries every time, but leads to element warping and loss of geometrical data. Such issues increase in magnitude when normative spine FE model is morphed to scoliosis-affected spinal geometry. The only way to bypass the issue of hex-mesh distortion or loss of geometry as a result of morphing is to rely on manually constructing the multi-blocks for scoliosis-affected spine geometry of each individual, which is time intensive. A method to semi-automate the construction of multi-blocks on the geometry of scoliosis vertebrae from the existing multi-blocks of normative vertebrae is demonstrated in this paper. High-quality hexahedral elements were generated on the scoliosis vertebrae from the morphed multi-blocks of normative vertebrae. Time taken was 3 months to construct the multi-blocks for normative spine and less than a day for scoliosis. Efforts taken to construct multi-blocks on personalized scoliosis spinal geometries are significantly reduced by morphing existing multi-blocks.     

Studies on the appearance of skeletal anomalies in red porgy: effect of culture intensiveness,feeding habits and nutritional quality of live preys

Despite the great interest of red porgy as a new species for Mediterranean aquaculture, its commercial production is constrained by the high incidence of skeletal deformities occurring in this species under culture conditions. Several studies have been conducted to better understand the origin of these anomalies in this species, using different system intensiveness, rotifers enrichment products or rotifers docosahexaenoic acid content. The first study showed that culture intensification increased the number of fish with an extra vertebrae, what was probably related to the different nutritional quality of live preys employed in each treatment, since water temperature, salinity and genetic background were identical for the different batches of fish studied. Total incidence of skeletal abnormalities was higher in the intensive system, particularly cranial abnormalities and kyphosis in the cephalic vertebrae. In both rearing systems the most common skeletal anomalies were vertebral column disorders, lordosis and fused vertebrae, their localization along the column being affected by the culture intensiveness. Rotifer enrichment, predominantly its docosahexaenoic acid content significantly affected deformities occurrence. A marked positive effect of rotifer docosahexaenoic acid content was found on larval survival. X‐ray studies denoted elevated levels of bone abnormalities associated, in both trials, to low docosahexaenoic acid content in live preys. Among different anomalies, the presence of fused vertebrae was the most frequent deformity for both rearing trials. A 50% reduction in the number of deformed fish for each type of deformity was obtained when the larvae were fed higher docosahexaenoic acid levels, denoting the important role of this fatty acid in bone development. Further studies are needed to elucidate the importance of essential fatty acids on the development of bone deformities in fish, since the functions of these fatty acids differ among them and can lead to very different effects in fish metabolism, including bone formation.     

Watching the components of photosynthetic bacterial membranes and their in situ organisation by atomic force microscopy

The atomic force microscope has developed into a powerful tool in structural biology allowing information to be acquired at submolecular resolution on the protruding structures of membrane proteins. It is now a complementary technique to X-ray crystallography and electron microscopy for structure determination of individual membrane proteins after extraction, purification and reconstitution into lipid bilayers. Moving on from the structures of individual components of biological membranes, atomic force microscopy has recently been demonstrated to be a unique tool to identify in situ the individual components of multi-protein assemblies and to study the supramolecular architecture of these components allowing the efficient performance of a complex biological function.Here, recent atomic force microscopy studies of native membranes of different photosynthetic bacteria with different polypeptide contents are reviewed. Technology, advantages, feasibilities, restrictions and limits of atomic force microscopy for the acquisition of highly resolved images of up to 10 Å lateral resolution under native conditions are discussed. From a biological point of view, the new insights contributed by the images are analysed and discussed in the context of the strongly debated organisation of the interconnected network of membrane-associated chlorophyll-protein complexes composing the photosynthetic apparatus in different species of purple bacteria.     

Coexistence of Abies alba (Mill.) - Fagus sylvatica (L.) and climate change impact in the Iberian Peninsula: A climatic-niche perspective approach

Abies alba Mill. (European silver fir) and Fagus sylvatica L. (beech) are Eurosiberian species dispersed over the Iberian Peninsula. Climate change predictions indicate a rise in temperature and a decrease in precipitation in this region, threatening the future existence of these species. In the present study we analyzed the future topo-climatic suitability of Abies alba and Fagus sylvatica and the mixed forests of these two species, using the General Linear Models technique and data from the third National Forest Inventory (Ministerio de Agricultura PyA, 2007). We considered two modeling approaches based on niche theory: modeling community (Abieti-Fagetum) and overlapping individual species models. General trends showed an overall decrease in both species’ topo-climatic suitability and indicated that the Pyrenees will play a crucial role as a climatic refuge. The modeling approaches markedly differed, however, in their current and future spatial agreement. Despite good accuracy results, community modeling through co-occurrence does not encompass the environmental space of individual species prejudicing future assessments in new environmental situations, suggesting a need for future studies in community modeling.     

Wernerius inyoensis, an elusive new scorpion from the Inyo Mountains of California (Scorpiones, Vaejovidae)

A new scorpion species is described from the Inyo Mountains of California (USA). The presence of a strong subaculear spine, along with other characters, places the new species within Wernerius, an incredibly rare genus that until now consisted of only two species. Wernerius inyoensissp. n. can be most easily distinguished from the other members of the genus by smaller adult size, femur and pedipalp dimensions, and differences in hemispermatophore morphology. Previous studies have suggested that the elusive nature of this genus may be attributed to low densities and sporadic surface activity. Herein, we provide another hypothesis, that Wernerius are primarily subterranean. Mitochondrial sequence data are provided for the holotype.     

Reproducible reference frame for in vitro testing of the human vertebrae

Definition of an anatomical reference frame is necessary for in vitro biomechanical testing. Nevertheless, there is neither a clear recommendation, nor consensus in the literature concerning an anatomical reference frame for in vitro testing of the human vertebrae. The scope of this work is to define a reference frame for the human vertebrae for in vitro applications. The proposed anatomical reference frame relies on alignment of well-defined points on the endplates, and on two landmarks on the posterior wall. The repeatability of the proposed alignment procedure has been tested in vitro by 5 operators, on 7 specimens. Furthermore, the feasibility and repeatability of the proposed procedure was assessed in silico, using CT-scans of the same specimens.     

Occurrence of Theropithecus sp. in the Late Villafranchian of Southern Italy and implication for Early Pleistocene "out of Africa" dispersals

Three cervical vertebrae of a large primate have been identified in the revision of the faunal assemblage collected during the late '70s from fissure fillings in the area known as Pirro Nord in southern Italy. By size the three vertebrae are comparable to the large fossil species Theropithecus oswaldi, however we prefer here to attribute the remains to Theropithecus sp. The Pirro Nord Theropithecus represents the second finding outside of Africa of this genus in association with Megantereon whitei, after the site of 'Ubeidiya. The biochronology of Pirro Nord faunal assemblage demonstrates that the arrival into Europe of Theropithecus occurred earlier than thought: in the range of approx 1.6-1.3 Ma. The identification of an European "African assemblage" (Theropithecus associated with Megantereon whitei) has consequences for interpretation of an "out of Africa" (genus Homo) event around the Plio-Pleistocene transition.