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members in both size and abundance were herbivorousdiadectids, and it was unlikely to encounterlarge predators.2008040428加 拿 大 不 列 颠 哥 伦 比 亚 晚 三 叠 世 Pardonet 组鱼 龙 一 新 属 : 架 起 三 叠 纪 - 侏 罗 纪 间 隙 的 桥 梁= A new genus of ichthyosaur from the Late TriassicPardonet Formation of British Columbia:bridging the Triassic Jurassic gap. ( 英 文 ).Nicholls E L; Manabe M. Canadian Journal ofEarth Sciences, 2001, 38(6): 983-1002Both the genus Shastasaurus and the familyShastasauridae have long been hard to definedue to the fragmentary nature of the type specimens.Consequently, recent interpretations of thegenus have been based almost entirely on Shastasaurusneoscapularis from the Late TriassicPardonet Formation of British Columbia. Twonew specimens of this taxon, from Pink Mountain,British Columbia, demonstrate that it doesnot belong in the genus Shastasaurus. This paperdescribes the new specimens, and refers the speciesto Metashastasaurus gen nov. Post-cranially,the skeleton of Metashastasaurus resembles thatof shastasaurids, differing primarily only in theshape of the scapula and fibula. However, theskull has a unique combination of characters,including large diamond-shaped frontals thatenter the supratemporal fenestrae, and very narrowposterior extensions of the nasals, whichcontact the postfrontals. It also differs from theskull of Shastasaurus in the presence of both aparietal ridge and postparietal shelf. This is acombination of derived characters previouslyknown only in Jurassic forms. The front limb hasfour proximal carpals and four digits, indicatingthat previous reconstructions were based on incompletematerial. Shastasaurus pacificus Merriam1895, the type species of the genus Shastasaurus,must be considered a nomen dubium,making the genus Shastasaurus invalid. Untilthis problem is clarified, the use of the genericname Shastasaurus should be restricted to Merriam'stype specimens, of which only Shastasaurusalexandrae and Shastasaurus osmonti arebased on adequate material.2008040429晚 白 垩 世 恐 龙 Maiasaura peeblesorum 运 动时 的 个 体 发 育 = An ontogenetic perspective onlocomotion in the Late Cretaceous dinosaurMaiasaura peeblesorum (Ornithischia: Hadrosauridae).( 英 文 ). Dilkes D W. Canadian Journalof Earth Sciences, 2001, 38(8): 1205-1227Ontogenetic growth in the forelimb andhindlimb of the dinosaur Maiasaura peeblesorum(Ornithischia: Hadrosauridae) from theUpper Cretaceous (Campanian-Maastrichtian)Two Medicine Formation of Montana is investigatedby multivariate and bivariate morphometricsand the biomechanics of beam theory. Resultssupport a hypothesis of an age-dependentselection of stance. Juveniles walked primarilyas bipeds. As an individual matured, its predominantstance shifted to quadrupedality.Within the forelimb, morphometric results showa probable allometric enlargement of posturalmuscles, an allometric increase in the lever armsof protractor muscles, and an increased robustnessof the humerus to enhance its resistance tobending stresses. In contrast, the hindlimb ischaracterized by a relative decrease in the resistanceof the femur and tibia to bending stresses.In addition, there is an allometric enlargement ofthe femoral fourth trochanter and positive allometryof the lengths of metatarsals III and IV.The most likely explanation for the differentgrowth patterns is that the hindlimb was sufficientlyrobust at a young age to accommodateincreased postural and locomotory stressesthrough largely isometric growth, whereas a behavioralshift to quadrupedality in older individualsnecessitated an allometric response inthe forelimb. Osteological adaptations forweight-bearing in the manus include metacarpalsthat are united firmly with a resultant crosssectionalshape that is resistant to bending andhyperextendable joints between the metacarpalsand first phalanges. It is probable that flexormuscles that attached to the caudal surface of themetacarpals reinforced the reduced carpus andlessened the likelihood of collapse during quadrupedality.2008040430加 拿 大 艾 伯 塔 南 部 恐 龙 公 园 组 角 龙Chasmosaurus 属 一 新 种 = A new species ofChasmosaurus (Dinosauria: Ceratopsia) from theDinosaur Park Formation of southern Alberta.( 英 文 ). Holmes R B; Forster C; Ryan M; ShepherdK M. Canadian Journal of Earth Sciences,2001, 38(10): 1423-1438Chasmosaurus irvinensis (sp. nov.) is distinguishedfrom other species of this genus by thepossession of a broad snout, absence of a browhorn (the position of which is occupied by a pitor rugosities suggestive of bone resorption),broadly rounded and open jugal notch, subrectangularsquamosal, straight posterior parietalbar bearing 10 epoccipitals, eight of which areflattened, strongly curved anterodorsally, andnearly indistinguishably coossified to theirneighbours, and small, transversely oriented parietalfenestrae restricted to the posterior portionof the frill. This species, restricted to the upperpart of the Dinosaur Park Formation, is significantlyyounger than the other recognized CanadianChasmosaurus species, C. belli and C. rus-132