abderaz formation is one of the upper cretaceous formations in the kopet-dagh sedimentary basin. a stratigraphic section from the mentioned formation is selected for detailed systematic description with regard to echinoids. numerous well preserved representatives of the families mircrasteridae wright, 1857 and echinocorythidae lambert, 1920 are described from the ghaleh-zoo stratigraphic sectio...

Based on a review of troodontid specimens from the territories of the former Soviet Union, including new discoveries from Uzbekistan, two dental morphotypes can be distinguished among Troodontidae from the Cretaceous of Asia: (1) unserrated teeth, present in Mei from Lujiatun (China; Early Cretaceous: Hauterivian-Barremian), an unnamed taxon from Hövöör (Mongolia; Early Cretaceous: Aptian-Albia...

The oxygen isotope composition of fossil fish teeth, a paleoupper ocean temperature proxy exceptionally resistant to diagenetic alteration, provides new insight on the evolution of the lowto middlelatitude thermal gradient between the middle Cretaceous climatic optimum and the cooler latest Cretaceous period. The new middle Cretaceous low to middle latitude thermal gradient agrees with that pre...

Metatherians, which comprise marsupials and their closest fossil relatives, were one of the most dominant clades of mammals during the Cretaceous and are the most diverse clade of living mammals after Placentalia. Our understanding of this group has increased greatly over the past 20 years, with the discovery of new specimens and the application of new analytical tools. Here we provide a review...

large benthic foraminifera and dasycladalean green algae are the most common and important (micro) fossils in lower cretaceous shallow-water sediments of the tethyan realm. in this paper, we introduced such taxa and their importance in age dating of lower cretaceous strata in the kopet-dagh sedimentary basin. also, according to determinations of index taxa (fauna and flora) in this period, the ...

Chelonians are ectothermic, with an extensive fossil record preserved in diverse palaeoenvironmental settings: consequently, they represent excellent models for investigating organismal response to long-term environmental change. We present the first Mesozoic chelonian taxic richness curve, subsampled to remove geological/collection biases, and demonstrate that their palaeolatitudinal distribut...

BACKGROUND The origin of hadrosaurid dinosaurs is far from clear, mainly due to the paucity of their early Late Cretaceous close relatives. Compared to numerous Early Cretaceous basal hadrosauroids, which are mainly from Eastern Asia, only six early Late Cretaceous (pre-Campanian) basal hadrosauroids have been found: three from Asia and three from North America. METHODOLOGY/PRINCIPAL FINDINGS...

Recent model-based phylogenetic approaches have expanded upon the incorporation of extinct lineages and their respective temporal information for calibrating divergence date estimates. Here, model-based methods are explored to estimate divergence dates and ancestral ranges for titanosaurian sauropod dinosaurs, an extinct and globally distributed terrestrial clade that existed during the extensi...

Detrital zircon U-Pb ages for 30 Late Jurassic and Cretaceous sandstones from the Eastern Province of eastern New Zealand, combined with previously-published geochronological and palaeontological data, constrain the time of deposition in the Pahau and Waioeka terranes of the Cretaceous accretionary margin of Zealandia, and their adjacent cover strata. The zircon age patterns also constrain poss...

The fossil record of Aponogeton (Aponogetonaceae) is scarce and the few reported macrofossil findings are in need of taxonomic revision. Aponogeton pollen is highly diagnostic and when studied with light microscopy (LM) and scanning electron microscopy (SEM) it cannot be confused with any other pollen types. The fossil Aponogeton pollen described here represent the first reliable Cretaceous and...