Embryos of an early Jurassic prosauropod dinosaur and their evolutionary significance

Articulated embryos from the Lower Jurassic Elliot Formation of South Africa are referable to the prosauropod Massospondylus carinatus and, together with other material, provide substantial insights into the ontogenetic development in this early dinosaur. The large forelimbs and head and the horizontally held neck indicate that the hatchlings were obligate quadrupeds. In contrast, adult Massospondylus were at least facultatively bipedal. This suggests that the quadrupedal gait of giant sauropods may have evolved by retardation of postnatal negative allometry of the forelimbs. Embryonic body proportions and an absence of well-developed teeth suggest that hatchlings of this dinosaur may have required parental care.     

A theropod dinosaur embryo and the affinities of the flaming cliffs dinosaur eggs

An embryonic skeleton of a nonavian theropod dinosaur was found preserved in an egg from Upper Cretaceous rocks in the Gobi Desert of Mongolia. Cranial features identify the embryo as a member of Oviraptoridae. Two embryo-sized skulls of dromaeosaurids, similar to that of Velociraptor, were also recovered in the nest. The eggshell microstructure is similar to that of ratite birds and is of a type common in the Djadokhta Formation at the Flaming Cliffs (Bayn Dzak). Discovery of a nest of such eggs at the Flaming Cliffs in 1923, beneath the Oviraptor philoceratops holotype, suggests that this dinosaur may have been a brooding adult.     

Cardiovascular evidence for an intermediate or higher metabolic rate in an ornithischian dinosaur

Computerized tomography scans of a ferruginous concretion within the chest region of an ornithischian dinosaur reveal structures that are suggestive of a four-chambered heart and a single systemic aorta. The apparently derived condition of the cardiovascular system in turn suggests the existence of intermediate-to-high metabolic rates among dinosaurs.     

Tyrannosaur life tables: an example of nonavian dinosaur population biology

The size and age structures for four assemblages of North American tyrannosaurs-Albertosaurus, Tyrannosaurus, Gorgosaurus, and Daspletosaurus-reveal a pronounced, bootstrap-supported pattern of age-specific mortality characterized by relatively high juvenile survivorship and increased mortality at midlife and near the maximum life span. Such patterns are common today in wild populations of long-lived birds and mammals. Factors such as predation and entrance into the breeding population may have influenced tyrannosaur survivorship. This survivorship pattern can explain the rarity of juvenile specimens in museum collections.     

A new skull of early Homo from Dmanisi,Georgia

Another hominid skull has been recovered at Dmanisi (Republic of Georgia) from the same strata in which hominid remains have been reported previously. The Dmanisi site dated to approximately 1.75 million years ago has now produced craniofacial portions of several hominid individuals, along with many well-preserved animal fossils and quantities of stone artifacts. Although there are certain anatomical differences among the Dmanisi specimens, the hominids do not clearly represent more than one taxon. We assign the new skull provisionally to Homo erectus (=ergaster). The Dmanisi specimens are the most primitive and small-brained fossils to be grouped with this species or any taxon linked unequivocally with genus Homo and also the ones most similar to the presumed habilis-like stem. We suggest that the ancestors of the Dmanisi population dispersed from Africa before the emergence of humans identified broadly with the H. erectus grade.     

A basal dinosaur from the dawn of the dinosaur era in southwestern Pangaea

Upper Triassic rocks in northwestern Argentina preserve the most complete record of dinosaurs before their rise to dominance in the Early Jurassic. Here, we describe a previously unidentified basal theropod, reassess its contemporary Eoraptor as a basal sauropodomorph, divide the faunal record of the Ischigualasto Formation with biozones, and bracket the formation with (40)Ar/(39)Ar ages. Some 230 million years ago in the Late Triassic (mid Carnian), the earliest dinosaurs were the dominant terrestrial carnivores and small herbivores in southwestern Pangaea. The extinction of nondinosaurian herbivores is sequential and is not linked to an increase in dinosaurian diversity, which weakens the predominant scenario for dinosaurian ascendancy as opportunistic replacement.     

A giant sauropod dinosaur from an Upper Cretaceous mangrove deposit in Egypt

We describe a giant titanosaurid sauropod dinosaur discovered in coastal deposits in the Upper Cretaceous Bahariya Formation of Egypt, a unit that has produced three Tyrannosaurus-sized theropods and numerous other vertebrate taxa. Paralititan stromeri is the first tetrapod reported from Bahariya since 1935. Its 1.69-meter-long humerus is longer than that of any known Cretaceous sauropod. The autochthonous scavenged skeleton was preserved in mangrove deposits, raising the possibility that titanosaurids and their predators habitually entered such environments.     

鲜食糯玉米无公害早熟栽培配套技术

糯玉米又称粘玉米、蜡质玉米，是玉米中的特用玉米，鲜食具有鲜嫩柔软细腻，清香粘糯微甜、皮薄无渣等特点，已越来越受消费者的青睐。近年来，随着市场需求量的不断增加，鲜食玉米的种植面积也逐年扩大，特别是早春鲜食玉米以产量高、品质优、效益好而快速发展，因此我们为了顺应发展需要．在试验示范的基础上，通过调查研究，整理出此项配套技术。     

A giant European dinosaur and a new sauropod clade

Fossils of a giant sauropod dinosaur, Turiasaurus riodevensis, have been recovered from terrestrial deposits of the Villar del Arzobispo Formation (Jurassic-Cretaceous boundary) of Riodeva (Teruel Province, Spain). Its humerus length (1790 millimeters) and estimated mass (40 to 48 metric tons) indicate that it may have been the most massive terrestrial animal in Europe and one of the largest in the world. Phylogenetic analysis indicates that the fossil represents a member of a hitherto unrecognized group of primitive European eusauropods that evolved in the Jurassic.     

A long-snouted predatory dinosaur from africa and the evolution of spinosaurids

Fossils discovered in Lower Cretaceous (Aptian) rocks in the Tenere Desert of central Niger provide new information about spinosaurids, a peculiar group of piscivorous theropod dinosaurs. The remains, which represent a new genus and species, reveal the extreme elongation and transverse compression of the spinosaurid snout. The postcranial bones include blade-shaped vertebral spines that form a low sail over the hips. Phylogenetic analysis suggests that the enlarged thumb claw and robust forelimb evolved during the Jurassic, before the elongated snout and other fish-eating adaptations in the skull. The close phylogenetic relationship between the new African spinosaurid and Baryonyx from Europe provides evidence of dispersal across the Tethys seaway during the Early Cretaceous.     

不同营养水平全颗粒饲粮对乳羔的育肥效果

按同质原则将24只早期断奶杂交羔羊(陶♂×滩寒♀)分为3组,采用单因子随机分组设计,研究3个营养水平(Ⅰ—0.9×NRC、Ⅱ—1.0×NRC、Ⅲ—1.1×NRC)条件下,高比例精料饲粮对1月龄早期断奶乳羔的肥育效果.试验表明:3个处理组日增重依组次为217.05、267.60、275.33 g,Ⅱ、Ⅲ组的日增重显著高于Ⅰ组(P<0.05),Ⅱ与Ⅲ组之间差异不显著;各组间干物质采食量和料肉比差异不显著;各组羔羊只育肥收入都在25元以上,其中以Ⅱ、Ⅲ组较好,为Ⅰ组的135.46%和130.83%.综合考虑乳羔的生产性能及经济效益,采用1.0×NRC营养水平较为适宜.     

A pair of shelled eggs inside a female dinosaur

An oviraptosaurian specimen (Dinosauria, Theropoda) from an Upper Cretaceous formation in China retains a pair of shelled eggs in the pelvis, providing direct evidence that oviraptorosaurian dinosaurs laid paired elongatoolithid eggs. The presence of the paired eggs suggests that theropod dinosaurs had two functional oviducts (like crocodiles) but that each oviduct produced only one egg at a time and that an entire egg clutch was laid through multiple ovipositions (like birds). The orientations of the eggs inside the skeleton and in clutches indicate that the mother came to the center of the nest to lay eggs.     

无齿相手蟹的幼体发育

无齿相手蟹的幼体发育经过4个sou状幼体和1个大眼幼体期。大水温25－26℃，盐度15，光照度200－200Lx的条件下，从第一期sou状幼体出膜到大眼幼体出现历时12d；大眼幼体至第一期幼蟹出现为4－5d。作者观察的无齿相手蟹各期幼体的形态与Baba所描述的有些不同，尤其是各期sou状幼体第1，2颚足的刚体数本文结果均分别为不变的10根和4根，且按2，2，3，3和1，1，1，1有规律的排列，本文还对相手蟹属的幼体形态特征进行讨论和简要总结。     

无齿相手蟹的幼体发育

无齿相手蟹的幼体发育经过4个sou状幼体和1个大眼幼体期。大水温25－26℃，盐度15，光照度200－200Lx的条件下，从第一期sou状幼体出膜到大眼幼体出现历时12d；大眼幼体至第一期幼蟹出现为4－5d。作者观察的无齿相手蟹各期幼体的形态与Baba所描述的有些不同，尤其是各期sou状幼体第1，2颚足的刚体数本文结果均分别为不变的10根和4根，且按2，2，3，3和1，1，1，1有规律的排列，本文还对相手蟹属的幼体形态特征进行讨论和简要总结。     

Developmental plasticity in the life history of a prosauropod dinosaur

Long-bone histology indicates that the most common early dinosaur, the prosauropod Plateosaurus engelhardti from the Upper Triassic of Central Europe, had variable life histories. Although Plateosaurus grew at the fast rates typical for dinosaurs, as indicated by fibrolamellar bone, qualitative (growth stop) and quantitative (growth-mark counts) features of its histology are poorly correlated with body size. Individual life histories of P. engelhardti were influenced by environmental factors, as in modern ectothermic reptiles, but not in mammals, birds, or other dinosaurs.     

A diverse assemblage of Late Cretaceous dinosaur and bird feathers from Canadian amber

The fossil record of early feathers has relied on carbonized compressions that lack fine structural detail. Specimens in amber are preserved in greater detail, but they are rare. Late Cretaceous coal-rich strata from western Canada provide the richest and most diverse Mesozoic feather assemblage yet reported from amber. The fossils include primitive structures closely matching the protofeathers of nonavian dinosaurs, offering new insights into their structure and function. Additional derived morphologies confirm that plumage specialized for flight and underwater diving had evolved in Late Cretaceous birds. Because amber preserves feather structure and pigmentation in unmatched detail, these fossils provide novel insights regarding feather evolution.