Forty-four selected organic-walled dinoflagellate cyst species have been used for biozonation of the Bathonian, Callovian, and Upper Jurassic in North Bulgaria. The dinocysts were collected from 49 borehole sections two exposures. following dinocyst zones are herein introduced described: Lithodinium valensii–Gongylodinium erymnoteichos Concurrent-range Zone (lower–middle Bathonian); Ellipsoidic...

Abstract Mudstones from the Argiles de Châtillon Formation exposed in Boulonnais region of Northern France represent a proximal lateral equivalent organic-rich Kimmeridge Clay Formation. The is composed two subunits that straddle Kimmeridgian–Tithonian boundary. Each subunit contains an interval. conspicuous intervals have been linked to either periods high sea level or greenhouse warming. Here...

The Jurassic–Cretaceous boundary transition is widely distributed within the West Cameros Basin. This horizon constituted by Tera Group, consisting of two depositional sequences (DS1 and DS2) comprising four geological formations spanning Tithonian to Berriasian. Here, a combined sedimentological palynostratigraphic study was made covering Group. results for DS 1 differentiate three facies asso...

Colymbosaurus is a genus of long-necked plesiosaurian represented by two valid species: C. megadeirus from the Upper Kimmeridge Clay Formation (Kimmeridgian–Tithonian) of the United Kingdom and C. svalbardensis from the Slottsmøya Member of the Agardhfjellet Formation (Tithonian–Berriasian) of Svalbard, Norway. Due to the lack of complete and articulated skeletons and a near absence of cranial ...

The non-avian saurischians that have associated eggshells and embryos are represented only by the sauropodomorph Massospondylus and Coelurosauria (derived theropods), thus missing the basal theropod representatives. We report a dinosaur clutch containing several crushed eggs and embryonic material ascribed to the megalosaurid theropod Torvosaurus. It represents the first associated eggshells an...

Pterosaurs were a unique clade of flying reptiles that were contemporaries of dinosaurs in Mesozoic ecosystems. The Pterodactyloidea as the most species-diverse group of pterosaurs dominated the sky during Cretaceous time, but earlier phases of their evolution remain poorly known. Here, we describe a 160 Ma filter-feeding pterosaur from western Liaoning, China, representing the geologically old...

Sphenodontians were a successful group of rhynchocephalian reptiles that dominated the fossil record of Lepidosauria during the Triassic and Jurassic. Although evidence of extinction is seen at the end of the Laurasian Early Cretaceous, they appeared to remain numerically abundant in South America until the end of the period. Most of the known Late Cretaceous record in South America is composed...