“Lucy” (A.L. 288‐1) had five sacral vertebrae

A “long‐backed” scenario of hominin vertebral evolution posits that early hominins possessed six lumbar vertebrae coupled with a high frequency of four sacral vertebrae (7:12‐13:6:4), a configuration acquired from a hominin‐panin last common ancestor (PLCA) having a vertebral formula of 7:13:6‐7:4. One founding line of evidence for this hypothesis is the recent assertion that the “Lucy” sacrum (A.L. 288‐1an, Australopithecus afarensis) consists of four sacral vertebrae and a partially‐fused first coccygeal vertebra (Co1), rather than five sacral vertebrae as in modern humans. This study reassesses the number of sacral vertebrae in Lucy by reexamining the distal end of A.L.288‐1an in the context of a comparative sample of modern human sacra and Co1 vertebrae, and the sacrum of A. sediba (MH2). Results demonstrate that, similar to S5 in modern humans and A. sediba, the last vertebra in A.L. 288‐1an exhibits inferiorly‐projecting (right side) cornua and a kidney‐shaped inferior body articular surface. This morphology is inconsistent with that of fused or isolated Co1 vertebrae in humans, which either lack cornua or possess only superiorly‐projecting cornua, and have more circularly‐shaped inferior body articular surfaces. The level at which the hiatus' apex is located is also more compatible with typical five‐element modern human sacra and A. sediba than if only four sacral vertebrae are present. Our observations suggest that A.L. 288‐1 possessed five sacral vertebrae as in modern humans; thus, sacral number in “Lucy” does not indicate a directional change in vertebral count that can provide information on the PLCA ancestral condition. Am J Phys Anthropol 156:295–303, 2015. © 2014 Wiley Periodicals, Inc.     

腰椎管狭窄症脊椎融合术适应症研究进展

腰椎管狭窄症主要由腰椎关节强硬引起。腰椎狭窄症的临床表现分为两类:一类为局域性症状,如下腰痛,僵硬等,一类为神经根症状,如神经性跛行。适当保护性治疗可以改善这些症状,但是一些顽固病例仍需手术治疗。单纯腰椎管减压术适用于以神经根症状为初发表现并且脊椎生物力学稳定的患者。术前评估时如出现背部手术失败综合征,退行性不稳定,严重畸形,有症状的椎骨脱离,难治性退行性椎间盘疾病,以及邻近节段病的患者可行腰椎融合术。术中评估出现广泛椎体压缩合并椎间隙大或者骨储存量不足的患者可行腰椎融合术。     

不同垂直骨面型错合畸形患者颈椎姿势差异的研究

目的：研究不同垂直骨面型错合畸形患者颈椎姿势的特点及差异,为正畸矫治错合畸形获得较好的临床效果及颅面、颈部生长发育的研究提供一定的参考依据。方法：采用计算机辅助X线头影测量技术,对226例不同垂直骨面型的儿童、成人在自然头位时拍摄的头颅定位侧位片进行测量研究,分别比较儿童以及成人不同垂直骨面型间颈椎姿势的差异。结果：儿童：CVT-OPT、SN-CP、SN-OPT及SN-CVT在低、均、高角各组间的差别均无统计学意义。成人：CVT-OPT在低角组与高角组间、均角组与高角组间的差别有统计学意义,高角组低于低角组和均角组,在低角组与均角组间的差别无统计学意义;SN-CP在低、均、高角各组间的差别有统计学意义,低角组〈均角组〈高角组;SN-OPT及SN-CVT在低角组与高角组间的差别有统计学意义,低角组〈高角组,在低角组与均角组间、均角组与高角组间的差别无统计学意义。结论：不同垂直骨面型错合畸形患者的颈椎姿势在儿童无显著差异,在成人差异显著。     

THE FIRST NEOCERATOPSIAN DINOSAUR REMAINS FROM EUROPE

Abstract:  Shallow marine, nearshore strata of earliest Campanian ( Gonioteuthis granulataquadrata belemnite Zone) and latest Early Campanian (informal Belemnellocamax mammillatus belemnite zone) age in the Kristianstad Basin, southern Sweden, have yielded isolated leptoceratopsid teeth and vertebrae, representing the first record of horned dinosaurs from Europe. The new leptoceratopsid occurrence may support a European dispersal route for the Leptoceratopsidae, or may represent an entirely endemic population. The presence of leptoceratopsid teeth in shallow marine deposits contradicts previous hypotheses suggesting that basal neoceratopsians mainly preferred arid and/or semi-arid habitats far from coastal areas.     

A comparison of the structure,composition and mechanical properties of anosteocytic vertebrae of medaka (O. latipes) and osteocytic vertebrae of zebrafish (D. rerio)

Medaka (O. latipes) and zebrafish (D. rerio) are two teleost fish increasingly used as models to study human skeletal diseases. Although they are similar in size, swimming pattern and many other characteristics, these two species are very distant from an evolutionary point of view (by at least 100 million years). A prominent difference between the skeletons of medaka and zebrafish is the total absence of osteocytes in medaka (anosteocytic), while zebrafish bone contains numerous osteocytes (osteocytic). This fundamental difference suggests the possibility that the bony elements of their skeleton may be different in a variety of other aspects, structural, mechanical or both, particularly in heavily loaded bones like the vertebrae. Here we report on the results of a comparative study that aimed to determine the similarities and differences in medaka and zebrafish vertebrae in terms of their macro- to nanostructure, composition and mechanical properties. Our results reveal many similarities between medaka and zebrafish vertebrae, making the lack or presence of osteocytes the only major difference between the bones of these two species.     

Chemical evidence of preserved collagen in 54-million-year-old fish vertebrae

Collagens are the most abundant proteins in the animal kingdom. They form the structural framework of connective tissues such as bones, tendons and skin, and play important biomechanical role in supporting tissue functions. The preservation of collagen in deep time is a topic of intense debate. Here we provide indisputable evidence for the presence of collagen in early Eocene fish vertebrae using online pyrolysis comprehensive two dimensional gas chromatography time-of-flight mass spectrometry (py-GC×GC-TOFMS) and immunofluorescence analysis. The presence of cyclic dipeptides such as diketodipyrrole, 2,5-diketopiperazine of proline-proline and 2,5-diketopiperazine of proline-glycine along with other nitrogen-bearing molecules in the pyrolysis products of the studied fossils unequivocally demonstrate that collagen can withstand degradation and diagenetic alteration. Immunofluorescence study also confirms the presence of collagen-I in the fossilized fish vertebrae. Contrary to common opinion, the present findings suggest that the preservation of collagen in fossilized soft tissues is not rare. We propose that one of the essential factors controlling preservation of collagen is the establishment of a suitable microenvironment within the fossil, inhibiting diagenetic alteration including microbial decay.     

Morphological and biochemical analyses of original and regenerated lizard tails reveal variation in protein and lipid composition

Caudal autotomy, or voluntary self-amputation of the tail, is a common and effective predator evasion mechanism used by most lizard species. The tail contributes to a multitude of biological functions such as locomotion, energetics, and social interactions, and thus there are often costs associated with autotomy. Notably, relatively little is known regarding bioenergetic costs of caudal autotomy in lizards, though key morphological differences exist between the original and regenerated tail that could alter the biochemistry and energetics. Therefore, we investigated lizard caudal biochemical content before and after regeneration in three gecko and one skink species. Specifically, we integrated biochemical and morphological analyses to quantify protein and lipid content in original and regenerated tails. All lizards lost significant body mass, mostly protein, due to autotomy and biochemical results indicated that original tails of all species contained a greater proportion of protein than lipid. Morphological analyses of two gecko species revealed interspecific differences in protein and lipid content of regenerated lizard tails. Results of this study contribute to our understanding of the biochemical consequences of a widespread predator evasion mechanism.     

Feeding ecology of the armored shrew, from the north-eastern Democratic Republic of Congo

The diet of Scutisorex somereni (Soricomorpha: Soricidae) from forests in the Democratic Republic of Congo was investigated to elucidate its feeding ecology in the context of its unique spinal modifications. It ate a wide range of small and large invertebrates, including representatives of Coleoptera, Formicidae, Lepidoptera and Diptera larvae, Chilopoda, Diplopoda and Araneae, but the principal prey was Oligochaeta. All diet samples contained Oligochaeta and these contributed 38–45% of prey volume. While 64% of prey occurrences were <10 mm in length, 56% of prey volume comprised invertebrates >26 mm, mostly large Oligochaeta (some of >50 mm). Soil-dwelling prey comprised 46% by composition (59% by volume) of the diet. Besides its peculiar skeletal modifications, it has an exceptionally long intestine relative to its body size. It was concluded that S. somereni is primarily an earthworm-eating shrew and partially subterranean rather than truly fossorial in foraging mode. Its diet and foraging mode cannot explain the unique vertebral modifications of this zoological curiosity.     

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.