四川自贡大山铺蜀龙动物群——简报Ⅲ.蜥脚类

本文记述了中侏罗世蜥脚类一新属种——巴山酋龙(Datousaurus bashanensts gen. et sp. nov.)对李氏蜀龙(Shunosaurus lii)的特征进行了补充,讨论了它们在蜥脚类进化过程中的位置。     

贵州关岭海龙类一新属种——双列齿凹棘龙

简要记述了产自贵州关岭小凹组的一具基本完整的骨架,在此基础上建立了海龙类的一个新属种,双列齿凹棘龙(Concavispina biseridens)。新种最明显的鉴定特征是:上颌骨前端有两列钝的牙齿,后部无齿;脊椎神经棘背缘形成V形缺口。凹棘龙与新铺龙(Xinpusaurus)独有的衍征包括上颌骨前段背向弯曲,颈椎数目小于5枚,肱骨近端比远端宽。这些特征指示凹棘龙与新铺龙可能具有较近的亲缘关系。     

四川自贡蜥脚类一新属

记述了产自四川省自贡市的一具蜥脚类幼年个体材料。根据枢椎极短而高,颈神经棘低、上缘平直、前后延长,背神经棘呈横宽的板状,中部颈肋的前突分叉等特征将它命名为一新属新种——张氏大安龙Daanosaurus zhangi gen.etsp.nov.,并将它归入巧龙亚科Bellusaurinae。     

新疆一新蜥脚类

本文记述了新疆中侏罗世蜥脚类恐龙的克拉美丽龙新亚科的一新属种——戈壁克拉美丽龙,并对新亚科的建立及其所属地质时代进行了分析讨论。     

Zapalasaurus bonapartei, un nuevo dinosaurio saurópodo de La Formación La Amarga (Cretácico Inferior), noroeste de Patagonia, Provincia de Neuquén, Argentina

An incomplete skeleton from Puesto Morales (Neuquén Province, Argentina) is described as a new species of sauropod, Zapalasaurus bonapartei. The unit that yielded the holotype of this dinosaur is the Piedra Parada Member of the La Amarga Formation, whose age is regarded as Barremian-lower Aptian. Several characters are interpreted as autapomorphies of Zapalasaurus bonapartei: cervical vertebrae with a lamina uniting the prezygapophysis and the zygapophyseal portion of the postzygodiapophyseal lamina, cervical vertebrae with the diapophyseal portion of the postzygodiapophyseal lamina reduced, cervical vertebrae with poorly developed spinoprezygapophyseal laminae, mid and posterior caudal vertebrae with anteroposteriorly elongated neural spines, whose anterodorsal corners are higher than their posterodorsal ones, and caudal centrum length doubles over first 20 vertebrae. Zapalasaurus bonapartei is considered as the sister group of the other diplodocoids (excluding Haplocanthosaurus). Diplodocoids were abundant in the Early Cretaceous, becoming extinct by the early Late Cretaceous. The record of Zapalasaurus bonapartei shows that, at least in the Neuquina Basin, basal diplodocoids were more diverse than previously thought.     

New information on a juvenile sauropod specimen from the Morrison Formation and the reassessment of its systematic position

Abstract: Morphological changes in the ontogeny of sauropods are poorly known, making difficult to establish the systematic affinities of very young individuals. New information on an almost complete juvenile sauropod (SMA 0009) with an estimated total length of about 2 m is here presented. The specimen was described as a diplodocid owing to the presence of some putative synapomorphies of this group. However, recent further preparation revealed the absence of diplodocid characters and the presence of macronarian derived characters. To test the affinities of this specimen, a phylogenetic analysis was conducted. The strict consensus tree recovers the specimen as a basal titanosauriform, in an unresolved relation with Brachiosaurus and Giraffatitan. Nevertheless, a brachiosaurid assignment is here suggested in base of the widely accepted monophyly of this group (only recovered when SMA 0009 is placed within this group). Although the existence of a new taxon cannot be completely ruled out, the combination of derived and plesiomorphic characters in the specimen suggests its assignment to Brachiosaurus. Sixteen extra steps are needed to place this specimen within Diplodocidae. The high cost to place this specimen within this group is owing to the fact that several diplodocid characters are absent in SMA 0009, such as the absence of divided centroprezygapophyseal lamina in cervical vertebrae, procoelous anterior caudal centra, composed lateral lamina in anterior caudal vertebrae, elongated middle caudal vertebrae, short cervical ribs and caudolateral projection of distal condyle of metatarsal I. Finally, the systematic position reveals few major ontogenetic transformations. These affect the pneumatic structures (e.g. change from simple pleurocoels in the cervical vertebrae to complex pleurocoels and the development of lateral excavations in the dorsal vertebrae) but also include unrecorded transformations of the neural spine (e.g. the development of the spinodiapophyseal lamina, the widening of the neural spines in the dorsal vertebrae) and allometric growth in some limb bones.     

Vertebral pneumatic structures in the Early Cretaceous sauropod dinosaur Pilmatueia faundezi from northwestern Patagonia,Argentina

One of the diagnostic characters of dicraeosaurid sauropods is a reduction of pneumatization of dorsal and caudal vertebrae relative to their Flagellicaudata sister taxon, Diplodocidae. Here, we analyse pneumatic structures in the dicraeosaurid sauropod Pilmatueia faundezi, compare them to those of diplodocoids and report the first record of camerate chambers in a dicraeosaurid. The pneumatic structures are in a posterior cervical centrum (MLL-Pv-002) and consist of lateral pneumatic fossae on the centrum that communicate internally with large camerae. By contrast, Pilmatueia's dorsal and caudal vertebrae (MLL-Pv-005-016) lack pneumatic fossae on the centra, which is consistent with the previously reported reduced pneumaticity in dicraeosaurids. Nevertheless, the base of the neural arch and possibly the base of the bifid neural spines of a posterior dorsal vertebra (MLL-Pv-005) show pneumatic internal chambers. The pneumatic features of the Pilmatueia cervical centrum and dorsal neural arch we describe indicate that the degree of pneumatization is variable within dicraeosaurids.     

Ontogenetic influence on neural spine bifurcation in diplodocoidea (dinosauria: Sauropoda): A critical phylogenetic character

Within Diplodocoidea (Dinosauria: Sauropoda), phylogenetic position of the three subclades Rebbachisauridae, Dicraeosauridae, and Diplodocidae is strongly influenced by a relatively small number of characters. Neural spine bifurcation, especially within the cervical vertebrae, is considered to be a derived character, with taxa that lack this feature regarded as relatively basal. Our analysis of dorsal and cervical vertebrae from small‐sized diplodocoids (representing at least 18 individuals) reveals that neural spine bifurcation is less well developed or absent in smaller specimens. New preparation of the roughly 200‐cm long diplodocid juvenile Sauriermuseum Aathal 0009 reveals simple nonbifurcated cervical neural spines, strongly reminiscent of more basal sauropods such as Omeisaurus. An identical pattern of ontogenetically linked bifurcation has also been observed in several specimens of the basal macronarian Camarasaurus, suggesting that this is characteristic of several clades of Sauropoda. We suggest that neural spine bifurcation performs a biomechanical function related to horizontal positioning of the neck that may become significant only at the onset of a larger body size, hence, its apparent absence or weaker development in smaller specimens. These results have significant implications for the taxonomy and phylogenetic position of taxa described from specimens of small body size. On the basis of shallow bifurcation of its cervical and dorsal neural spines, the small diplodocid Suuwassea is more parsimoniously interpreted as an immature specimen of an already recognized diplodocid taxon. Our findings emphasize the view that nonmature dinosaurs often exhibit morphologies more similar to their ancestral state and may therefore occupy a more basal position in phylogenetic analyses than would mature specimens of the same species. In light of this, we stress the need for phylogenetic reanalysis of sauropod clades where vital characters may be ontogenetically variable, particularly when data is derived from small individuals. J. Morphol., 2012. © 2012 Wiley Periodicals, Inc.     

The first well-preserved Early Cretaceous brachiosaurid dinosaur in Asia

A new genus and species of brachiosaurid sauropods, Qiaowanlong kangxii gen. et sp. nov., is reported, representing the first well-preserved Early Cretaceous brachiosaurid in Asia and expanding the distribution of brachiosaurids undoubtedly into the Asian continent. The new taxon was recovered from the late Early Cretaceous Xinminpu Group of Yujingzi Basin in northwestern Gansu Province, China, and is represented by a series of eight mid-cervical vertebrae, a right pelvic girdle and some unidentified bones. The existence of deeply excavated cervical neural spines and a rising transition in the neural spine height among mid-cervical vertebrae clearly show the affinity of Qiaowanlong as a member of brachiosaurids. Among brachiosaurids, Qiaowanlong shares a derived feature with the North American Early Cretaceous brachiosaurid Sauroposeidon: the lack of cranial centrodiapophyseal lamina. However, Qiaowanlong is unique in possessing a suite of features, such as a low central length/cotyle height ratio, bifurcated cervical neural spines and a much reduced ischium. The discovery of Qiaowanlong and other new material indicates a diverse and abundant sauropod assemblage in China during the Early Cretaceous.     

蜥脚类骨质尾锤之发现

自贡大山铺恐龙化石坑中出土的李氏蜀龙(Shunosaurus lii)和天府峨眉龙(Omeisaurustianfuensis)均发现由尾端脊椎愈合膨大而成之纺锤形骨质尾锤。这一特征在蜥脚类中尚属首次记述。骨质尾锤是一种适应陆地生活之特殊构造。它作为一种防御武器,主要起防卫身体的作用。它的存在说明R.T.Bakker提出的蜥脚类是一类营陆地生活的恐龙的观点是正确的。     

The theropod dinosaur Elaphrosaurus bambergi Janensch, 1920, from the Late Jurassic of Tendaguru,Tanzania

Theropod dinosaurs from the Late Jurassic of Gondwana are still poorly known, with Elaphrosaurus bambergi Janensch, 1920, from the late Kimmeridgian of Tendaguru, Tanzania, being the only taxon represented by more than isolated remains from Africa. Having long been considered a coelurosaurian, more specifically an ornithomimosaur, Elaphrosaurus is currently regarded as a basal ceratosaur. Here, we revise the osteology and phylogenetic position of this important taxon. Elaphrosaurus shows many unusual osteological characters, including extremely elongated and constricted cervical vertebrae, an expansive shoulder girdle with strongly modified forelimbs, a relatively small ilium, and elongate hindlimbs with a very small ascending process of the astragalus that is fused to the tibia. We found this taxon to share many derived characters with noasaurids, such as: strongly elongate cervical and dorsal vertebrae; low, rectangular neural spines in the mid‐caudal vertebrae; presence of only an anterior centrodiapophyseal lamina in anterior caudal vertebrae; presence of a wide, U–shaped notch between the glenoid and the anteroventral hook in the coracoid; a laterally flared postacetabular blade of the ilium; a flat anterior side of the distal tibia; and a reduced shaft of metatarsal II. Our analysis placed Elaphrosaurus within a dichotomous Noasauridae as part of a Jurassic subclade, here termed Elaphrosaurinae, that otherwise includes taxa from eastern Asia. These results underscore the long and complex evolutionary history of abelisauroids, which is still only beginning to be understood.     

A Small Short-Necked Hupehsuchian from the Lower Triassic of Hubei Province,China

Hupehsuchia is a group of enigmatic Triassic marine reptiles that is known exclusively from two counties in Hubei Province, China. One of the common features of the group was a modestly long neck with nine to ten cervical vertebrae. We report a new species of Hupehsuchia, Eohupehsuchus brevicollis gen. et sp. nov., which for the first time shows a short neck in this group, with six cervicals. The configuration of the skull roof in Eohupehsuchus is also unique among Hupehsuchia, with narrow frontals and posteriorly shifted parietals, warranting recognition of a new species. The taxon superficially resembles Nanchangosaurus in retaining hupehsuchian plesiomorphies, such as low neural spines and small body size. However, its limbs are well-developed, unlike in Nanchangosaurus, although the latter genus is marginally larger in body length. Thus, the individual is unlikely to be immature. Also, Eohupehsuchus shares a suite of synapomorphies with Hupehsuchus, including the second and third layers of dermal ossicles above the dorsal neural spines. A phylogenetic analysis suggests that the new species is not the most basal hupehsuchian despite its short neck, and instead forms the sister taxon of Hupehsuchidae. Until recently, Hupehsuchia contained only two monotypic genera. Now there are at least four genera among Hupehsuchia, and the undescribed diversity is even higher. The left forelimb of the only specimen is incomplete, ending with broken phalanges distally. The breakage could only have occurred pre-burial. The individual may have been attacked by a predator and escaped, given that scavenging is unlikely.     

A NEW TITANOSAUR FROM WESTERN SÃO PAULO STATE, UPPER CRETACEOUS BAURU GROUP, SOUTH-EAST BRAZIL

Abstract: Material from a new titanosaur from the Bauru Basin (Bauru Group), Brazil is described and compared with well‐known titanosaurs. Adamantisaurus mezzalirai gen. et sp. nov. is based on six articulated anterior caudal vertebrae and two haemapophyses collected from the Adamantina Formation, which is considered to be Campanian–Maastrichtian? in age. Adamantisaurus mezzalirai is characterized by the following combination of characteristics: anterior caudal vertebrae with straight or slightly backwardly‐projecting neural spines with strongly expanded distal ends, stout prespinal lamina, very wide pre‐ and postzygapophyseal articular facets, and concave postzygapophyseal articular facets on anterior caudal vertebrae. Although our cladistic analysis has produced equivocal results, Adamantisaurus mezzalirai shares with DGM ‘Series B’ (Peirópolis titanosaur) and Aeolosaurus the presence of postzygapophyses with concave articular facets, and shares with DGM ‘Series B’ the presence of laterally expanded neural spines and stout prespinal lamina. Additionally, A. mezzalirai shares with DGM ‘Series’ C (other titanosaur from Peirópolis) the presence of short neural spines.     

The lambeosaurine dinosaur Magnapaulia laticaudus from the late cretaceous of Baja California, Northwestern Mexico

The taxonomy, osteology, phylogenetic position, and historical biogeography of the lambeosaurine hadrosaurid Magnapaulia laticaudus (new combination) are revised. The diagnosis of this species is amended on the basis on two autapomorphies (i.e., longest haemal arches of proximal caudal vertebrae being at least four times longer than the height of their respective centra; base of prezygapophyses in caudal vertebrae merging to form a bowl-shaped surface) and a unique combination of characters (i.e., downturned cranioventral process of the maxilla; tear-shaped external naris with length/width ratio between 1.85 and 2.85; neural spines of dorsal, sacral, and proximal caudal vertebrae being at least four times the height of their respective centra). A maximum parsimony analysis supports a sister taxon relationship between M. laticaudus and Velafrons coahuilensis. Both taxa constitute a clade of southern North American lambeosaurines, which forms a sister relationship with the diverse clade of helmet-crested lambeosaurines from northern North America that includes well-known genera like Corythosaurus, Lambeosaurus, and Hypacrosaurus. According to the results of a Dispersal-Vicariance analysis, southern North American lambeosaurines split from the northern forms via vicariance from a common ancestor that lived in both the northern and southern regions of the continent.     

Structural features of neural spines of the caudal vertebrae of protoceratopoids (Ornithischia: Neoceratopsia)

The structure of caudal neural spines of protoceratopoids displays adaptation for aquatic and terrestrial mode of life. The increasing height of caudal neural spines in the series Leptoceratops, Udanoceratops, Protoceratops, Bagaceratops is connected with the extent of adaptation for swimming and changes in inclination of neural spines are connected with the mechanical balance of the lever. Thus, the anterior caudal vertebrae (1cd–15cd) of Protoceratops and Bagaceratops show an anticliny, which promotes extension (rise) of a heavy tail in terrestrial conditions. In the middle part of the tail (16cd–23cd), with the greatest height of neural spines, a decrease in width and increase in thickness counteract transverse loads accompanying movements on land. At the same time, the supraspinal ligament prevents divergence of neural spines caused by curvature of the tail as it is raised above the ground.     

A revision of the akysid catfish genus Breitensteinia Steindachner with descriptions of two new species

The highly specialized akysid catfish genus Breitensteinia is revised; two new species are described. Breitensteinia cessator is described from Sumatra and western Borneo. It can be distinguished by its large, wide-set eyes and evenly scattered brown spots on the dorsal and pectoral fins. Breitensteinia hypselurus is described from western Borneo. It can be distinguished by its relatively tall neural spines on caudal vertebrae, smooth posterior edge of dorsal spine, short caudal peduncle, and fewer vertebrae. Breitensteinia insignis is sexually dimorphic.     

Differential scaling patterns of vertebrae and the evolution of neck length in mammals

Almost all mammals have seven vertebrae in their cervical spines. This consistency represents one of the most prominent examples of morphological stasis in vertebrae evolution. Hence, the requirements associated with evolutionary modifications of neck length have to be met with a fixed number of vertebrae. It has not been clear whether body size influences the overall length of the cervical spine and its inner organization (i.e., if the mammalian neck is subject to allometry). Here, we provide the first large‐scale analysis of the scaling patterns of the cervical spine and its constituting cervical vertebrae. Our findings reveal that the opposite allometric scaling of C1 and C2–C7 accommodate the increase of neck bending moment with body size. The internal organization of the neck skeleton exhibits surprisingly uniformity in the vast majority of mammals. Deviations from this general pattern only occur under extreme loading regimes associated with particular functional and allometric demands. Our results indicate that the main source of variation in the mammalian neck stems from the disparity of overall cervical spine length. The mammalian neck reveals how evolutionary disparity manifests itself in a structure that is otherwise highly restricted by meristic constraints.     

A tall-spined ornithopod dinosaur from the Early Cretaceous of Salas de los Infantes (Burgos, Spain)

A tall-spined ornithopod dinosaur from the Pinilla de los Moros Formation (Upper Hauterivian-Lower Barremian) of Salas de los Infantes (Burgos, Spain) is described. The material consists of seven associated axial remains, including five middle dorsal vertebrae, a fragmentary neural spine and a dorsal rib, from a single medium-sized individual. This material was previously referred to Iguanodon cf. fittoni. It is characterised by having a high dorsal neurapophysis that is approximately 4.5 times the height of the centrum. The elongation and vertical orientation of the dorsal neural spines allow it to be distinguished from other ornithopods from the Wealden of Europe, including Hypselospinus and Barilium from the Valanginian, and Iguanodon and Mantellisaurus from the Barremian-Aptian. The material is here referred to Iguanodontia indet. because it is so incomplete, but it is potentially a distinct taxon. Among the ornithopods, only Ouranosaurus and the hadrosaurid Hypacrosaurus possess higher dorsal neural spines.     

应用反向滤过及迭代重建方法评估标准放射剂量与低剂量颈椎 CT图像质量的对比研究

目的：利用反向滤过重建（filtered back-projection,FBP）及迭代重建（iterative reconstruction,IR）方法评估标准剂量及低剂量 对颈椎CT 图像质量的影响。方法：40 例受检对象行颈椎CT 检查,将其随机分为两组：标准剂量组（SD,120 kVp, 275 mAs）及低 剂量组（LD,120 kVp,150 mAs）,随机选择管电流值,所有数据均行FBP 及IR 重建。测量C3 C4 及C6 C7 椎间盘水平椎间盘、脊 神经、脊髓、韧带以及周围软组织的图像噪声值（Image noise,IN）,信噪比（signal-to-noise,SNR）及对比信噪比（contrast-to-noise, CNR）。结果：在测量的各椎间盘水平,迭代重建的信噪比及对比噪声比要明显高于反向滤过重建方法,并有效的降低了图像噪 声。低剂量迭代重建图像与标准剂量反向滤过图像相比无明显统计学意义。排除剂量及扫描层面的影响,椎间盘、脊神经及韧带 的图像质量,迭代重建评分要明显高于反向滤过重建,结果具有统计学差异;而低剂量迭代重建图像质量评分与标准剂量反向滤 过重建相比无明显差异。软组织及椎体的图像质量,迭代重建图像质量评分要低于反向滤过重建方法,结果具有统计学差异;而 低剂量迭代重建图像质量评分与标准剂量反向滤过重建相比无明显差异。整体病例图像质量评分,迭代重建方法要高于反向滤 过重建方法,低剂量迭代重建方法要高于标准剂量反向滤过重建方法。结论：应用低剂量扫描方式以及迭代重建方法进行颈椎 CT 检查可以为临床提供较好的图像质量,对于椎间盘、脊神经、脊髓显示较好,对于周围软组织以及椎体来说,图像质量相对较 差,同时可以降低大约40%的放射剂量。