Early-diverging Titanosauriform(Dinosauria,Sauropoda)Teeth from the Lower Cretaceous Yixian Formation of Southeastern Inner Mongolia,Northeast China

Three eusauropod teeth(SDUST-V1064,PMOL-AD00176,PMOL-ADt0005)are reported from the Lower Cretaceous Yixian Formation of Ningcheng,southeastern Inner Mongolia,China.Two of them(SDUST-V1064,PMOL-AD00176)are assigned to early-diverging titanosauriforms in having slightly mesiodistal expansion at the base of the tooth crown,a slenderness index value>2.0 and<4.0,and D-shaped cross section.Furthermore,SDUST-V1064 and PMOL-AD00176 are referred as an Euhelopus-like titanosauriform on the basis of having a sub-circular boss on the lingual surface and an asymmetrical crown-root margin which slants apically,respectively.CT scan data of SDUST-V1064 reveals new dental information of early-diverging titanosauriforms,for example,the enamel on the labial side thicker than that on the lingual side,an enamel/dentine ratio of 0.26 and a boss present on the lingual side of the dentine of the crown.

Characteristics of the basement reformed volcanic edifice in Bohai Sea and its implication for hydrocarbon enrichment

The intact volcanic edifice had been formed and finalized during the depositional stage of Mesozoic Yixian Formation in the Bohai Sea.The residual body of the intact volcanic edifice after reformation was defined as the basement reformed volcanic edifice.Based on drilling,seismic,well logging and microscopic data in the study area,characteristics of the basement reformed volcanic edifice were well discussed,and its control on oil and gas was also investigated.Results showed that the basement reformed volcanic edifice was jointly controlled by magmatic property,paleo-geomorphology and late reformation,and the late fault cutting and differential denudation were major reformation ways of the volcanic edifice;strong and weak volcanic eruption patterns developed in the study belonged to the invertedsequence eruption,and the explosive facies and the intermediate-acidic or acidic effusive facies were the favorable reservoir facies;weathering,cycles and period boundaries controlled vertical distribution of high-quality lithofacies,and coupling between each periodic interface at different levels and residual high-quality lithofacies was the key to oil and gas enrichment.Major exploration targets of volcanic rocks were to find periodic interfaces in the volcanic edifice with the residual high-quality lithofacies within 150 m from the weathering crust or eruption surface.

Insect herbivory immediately before the eclipse of the gymnosperms:The Dawangzhangzi plant assemblage of Northeastern China

The Early Cretaceous terrestrial revolution involved global shifts from gymnosperm-to angiosperm-dominated floras.However,responses of insect herbivores to these changes remain unexamined.We evaluated 2176 highly sampled plant specimens representing 62 species/morphotypes from the 126 Ma Dawangzhangzi plant assemblage of Northeastern China.Our study consisted of horsetails,ferns,ginkgoaleans,czekanowskialeans,conifers,and an angiosperm.Their herbivory was evaluated by the functional feeding groups of hole feeding,margin feeding,and surface feeding(ectophytic feeders);piercer and suckers,and ovipositing insects(ectoendophytic feeders);mining,galling,and borings(endophytic feeders);and pathogens,collectively constituting 65 damage types(DTs).The plant assemblage was assessed for herbivory richness by DT richness,component community structure,and DT specialization on plant hosts;for herbivory intensity,it was evaluated for DT frequency,herbivorized surface area,and feeding event occurrences.Using feeding event occurrences,the data supported seven species/morphotypes as most intensely herbivorized:Liaoningocladus boii(76.6%),Czekanowskia sp.1(8.4%),Czekanowskia rigida(4.10%),Lindleycladus lanceolatus(3.5%),Ginkgoites sp.2(2.0%),Podozamites sp.1(1.1%),and Solenites sp.1(0.9%).The most herbivorized taxa were pinaleans(conifers),then czekanowskialeans,and lastly ginkgoaleans;the monodominant component community was the conifer Liaoningocladus boii.DT host specialization levels were low.The plant assemblage had an overall low 0.86%of foliage removed by herbivores,explained by physical and chemical antiherbivore defenses,and parasitoid attack.Although Paleozoic,gymnosperm-dominated assemblages had greater herbivory,component community structure of the three most herbivorized taxa are more similar to modern bracken fern and willow than modern gymnosperm taxa.