A bizarre Cretaceous theropod dinosaur from Patagonia and the evolution of Gondwanan dromaeosaurids

Fossils of a predatory dinosaur provide novel information about the evolution of unenlagiines, a poorly known group of dromaeosaurid theropods from Gondwana. The new dinosaur is the largest dromaeosaurid yet discovered in the Southern Hemisphere and depicts bizarre cranial and postcranial features. Its long and low snout bears numerous, small-sized conical teeth, a condition resembling spinosaurid theropods. Its short forearms depart from the characteristically long-armed condition of all dromaeosaurids and their close avian relatives. The new discovery amplifies the range of morphological disparity among unenlagiines, demonstrating that by the end of the Cretaceous this clade included large, short-armed forms alongside crow-sized, long-armed, possibly flying representatives. The new dinosaur is the youngest record of dromaeosaurids from Gondwana and represents a previously unrecognized lineage of large predators in Late Cretaceous dinosaur faunas mainly dominated by abelisaurid theropods.     

A new small theropod dinosaur from the Judith River Formation (Campanian) of Alberta Canada.

A new small theropod dinosaur, documented by an incomplete skeleton and three frontals, is described from the Judith River Formation (Upper Cretaceous: Campanian) of south-central Alberta.
It is distinguished from both Stenonychosaurus and Dromaeosaurus by the structure of the frontal and by the marginal dentition.
It resembles Stenonychosaurus in the structure of the frontal and the Dromaeosauridae in the shape of the endocranial cavity and other skeletal features.
The material is referred to a new genus and species of the Dromaeosauridae.     

辽宁西部早白垩世义县组一新驰龙类

我国辽西早白垩世义县组底部陆家屯层近年来产出大量恐龙和其他脊椎动物化石 ,其中包括兽脚类恐龙当中的伤齿龙类和窃蛋龙类 (Xu ,2 0 0 2 )。本文报道该层位产出的一件驰龙类化石标本。通过对比研究 ,我们确认这一标本不同于热河群已知的其他 3种驰龙类 ,并建立了驰龙类的一个新属种 :陆家屯纤细盗龙 (Graciliraptorlujiatunensisgen .etsp .nov .)。驰龙类最初发现于北美晚白垩世地层中 (MatthewandBrown ,1 92 2 ) ,随后在蒙古晚白垩世地层中也有发现 (Osborn ,1 92 4 ) ;现在已知驰龙类的化石记录主要集中在北美和中亚地区的白垩纪地层中 (Xu ,2 0 0 2 )。千禧中国鸟龙 (Sinornithosaurusmillenii)曾代表最早的确定无疑的驰龙属种 (Xuetal.,1 999) ,其生存时代大约为 1 2 5Ma (Swisheretal.,1 999)。陆家屯纤细盗龙正型标本产于义县组底部陆家屯层 ,其上覆和下伏岩层的同位素年代分别为 1 2 8Ma和 1 39Ma (Swisheretal.,2 0 0 1 )。因此 ,陆家屯纤细盗龙代表已知最早的驰龙属种。陆家屯纤细盗龙和其他驰龙类共享以下近裔特征 :尾椎前关节突和脉弧极度加长、上颌齿后缘锯齿明显大于前缘锯齿和指节III- 2明显缩短。陆家屯纤细盗龙的以下近裔特征区别于其他驰龙类 :中部尾椎有一板状结构连接左右后关节     

Theropod dinosaur teeth from the lowermost Cretaceous Rabekke Formation on Bornholm, Denmark

The dinosaur fauna of the palynologically dated lower Berriasian Skyttegård Member of the Rabekke Formation on the Baltic island of Bornholm, Denmark, is represented by isolated tooth crowns. The assemblage is restricted to small maniraptoran theropods, assigned to the Dromaeosauridae incertae sedis and Maniraptora incertae sedis. The dromaeosaurid teeth are characterized by their labiolingually compressed and distally curved crowns that are each equipped with a lingually flexed mesial carina and a distinctly denticulated distal cutting edge. A morphologically aberrant tooth crown (referred to as Maniraptora incertae sedis) has triangular denticles of uneven width, a feature occasionally found in Upper Cretaceous hesperornithiform toothed diving birds, but also in premaxillary teeth of the velociraptorine Nuthetes from the Lower Cretaceous of England.     

晚白垩世精美临河盗龙(Linheraptor exquisitus)的分类位置及其对驰龙科系统学的意义（英文）

驰龙类的精美临河盗龙(Linheraptor exquisitus)于2010年基于一件近完整骨架命名,化石采自内蒙古西部巴彦满达呼大门地点上白垩统乌兰苏海组。然而,最近三项研究认为精美临河盗龙是蒙古乌哈托喀地点上白垩统捷达克赫塔组发现的白魔龙(Tsaagan mangas)的晚出异名。本文依据61个形态学特征区分精美临河盗龙和白魔龙,否认了上述观点。许多特征来自对精美临河盗龙正型标本先前未修理部分,特别是头骨左侧的观察。这些新观察支持和加强了我们先前认为的精美临河盗龙和白魔龙属于两个不同属种的观点。精美临河盗龙具有的一些特征之前被认为是白魔龙或者其他驰龙类的自近裔特征,这表明进步的骨骼特征在驰龙类中的分布异常复杂。认为精美临河盗龙和白魔龙为同物异名的观点实际上忽略了很多微小的形态变异。增加分类取样可以将那些看似显著的鉴定特征转化为更加细微的形态变异,而这些形态变异对于精细的系统发育分析具有潜在的重要意义。在未来的研究中,利用连续数据的严格定量方法,有助于处理类似信息。     

辽西下白垩统热河群一新微型驰龙类恐龙和热河生物群驰龙类的生态位分化

早白垩世热河生物群的驰龙类恐龙在分类和形态上多样化程度很高,其中的赵氏小盗龙曾被认为是已知体型最小的非鸟兽脚类恐龙之一.然而这个观点依据的标本都处于相对早期的生长发育阶段,因此热河生物群驰龙类恐龙的体型下限仍不明确.本文依据一件产白辽宁省凌源县四合当下白垩统义县组(热河群中部)的标本,描述驰龙类一新种,杨氏钟健龙.这一新种可归入小盗龙类,但它在很多特征上不同于其他小盗龙类,其中最明显的区别是其相对长的钩状突愈合于背肋上,肱骨具有强烈内倾的近端,肱骨三角嵴上有一窗孔,尺骨略长于肱骨,并具有窄跖型的足.最重要的是,已为成年个体的杨氏钟健龙正模估计体重约为0.31 kg,这证实了热河生物群的一些驰龙类恐龙属于已知体型最小的非鸟恐龙.初步分析显示热河生物群驰龙类恐龙有生态位分化的情况,这一现象在中生代恐龙动物群中报道很少.