Zhou et al., 2003 (Jehol exceptional preservation) Flashcards
Fieldwork in the … … Jehol Group in northeastern China has revealed an abundance of exceptionally well-preserved fossils, including … … dinosaurs and early …, which provide additional, indisputable support for the dinosaurian ancestry of …, and new evidence on the evolution of … and ….
Early Cretaceous, feathered theropod, birds, birds, feathers, flight
Specimens of putative … and primitive … are clarifying details of the early radiations of these major clades too.
angiosperms (proposed as the oldest flowering plants), mammals
Detailed …-… preservation of the organisms from the Jehol … is providing palaeontology insights that would not normally be accessible from the fossil record
soft-tissue, Biota
Soft tissues and associated … structures are exceptionally well-preserved in many of the theropod, bird and mammal specimens from the Jehol Biota
integumentary
The Jehol Biota includes representatives of almost all major clades of … … … and … vertebrates, a wide variety of … and a diverse ….
lower cretaceous terrestrial, aquatic, invertebrates, flora
The Jehol Biota provides a rare, incredibly detailed picture of an … Early Cretaceous terrestrial ….
intact, ecosystem
Composed of deposits of weakly … to finely bedded … sediments, mainly low-energy … and …, intercalated with extrusive … and …. The deposits are associated with freshwater … rather than rivers or deltas, which are more laterally variable, or marine environments. There was increased … and … activity during the time of the Jehol formation.
laminated, siliciclastic, sandstones, shales, basalts, tuffs (volcanic), lake, tectonic, volcanic
The regional …, in combination with the presence of numerous … …, provided ideal environments for the … … of the Jehol Biota.
volcanism, shallow lakes, exceptional preservation
Preservation of complete … shells, arthropod …, vertebrate … and terrestrial plant stems with associated structures indicates that all of these specimens originated in … … to low-energy lacustrine depositional sites and were not … over extensive …. Individual elements are generally unbroken and display little or no abrasion.
articulated, exoskeletons, skeletons, close proximity, transported, distances
Dead organisms entered the lakes, were buried … and encased in …-… sediments.
rapidly, fine-grained
Tuff layers are strongly correlated with … … events, from pyroclastic flows and ash tuff falls. These conditions sealed the organisms and promoted … conditions ideal for preserving the detail and soft tissues of specimens. Additionally, these conditions prevent … from … organisms.
mass mortality, anoxic, bioturbation, burrowing
These types of conditions are known as …-… conditions
Konzervat-Lagerstatten
… structures (filaments, feathers and fur) are known from …, …, … and …
pterosaur, dinosaur, bird, mammal
Other soft tissues commonly preserved include keratinous …, … impressions and cartilaginous elements…. contents is also common.
beaks, skin, stomach
The three-dimensionally preserved whole specimens often lack … …, suggesting they were preserved in a single, catastrophic mass mortality event
bedding planes
Jehol’s diverse theropod fauna spans the phylogenetic transition phylogenetic transition from basal … to … …
coelurosaurian, ornithurine birds
The basal coelurosaur … possesses and extensive covering of filamentous integumentary structures, considered to be the precursors of true feathers
Sinosauropteryx
The coelurosaur …, for example, bears feathers of modern appearance (central rachis supports a branching patten of barbs)
Protarchaeopteryx
All of these animals lacked … specialisations and most were …-dwelling cursorial animals, indicating that the selective pressures responsible for initiating the development of feathers were imposed before the origin of …
flight, ground, flight
- e.g. sexual display, camouflage, species recognition, thrust generation during running/jumping, providing insulation due to evolution of endothermy
… size and … differences between sympatric Jehol taxa indicate that a rapid … diversification of … taxa occurred during the early Cretaceous.
Body, locomotory, ecological, avian
… possessed an advanced flight apparatus, including and elongated, deeply … … and a “modern” bird-like appearance - indicate … capability.
Yanornis, keeled sternum, flight
… exhibits a mosaic of therian and non-therian character states
Jeholodens
Differences in body size and locomotory features indicate that … had diversified into a number of … roles by the late Early Cretaceous.
mammals, ecological
The discovery of brachycerna flies with …, … mouhparts suggests the presence of …-… angiosperms in the Jehol flora - provides support for the suggestion that … insects might have had an important role in the origin and early evolution of … plants.
long, tubular, nectar-producing, pollinating, flowering
… are the most abundant elements of the biota, but much of the … material has yet to be described in detail and remains poorly known
invertebrates, invertebrate
It is hypothesised that East Asia acted as a … fro some typically “…” taxa in the Lower Cretaceous (dating suggests from Early cretaceous but others suggest biota looks more similar to Jurassic biota. This would help explain this). East Asia seems to have been isolated from the rest of Laurasia during Mid-Jurassic to Early Cretaceous, which also supports this idea.
refugia, jurassic
The region may also have been a centre for … of these taxa, as there are many … representatives of dinosaur clades more often associated with Upper Cretaceous biomes (e.g. Tyrannosauroids, oviraptorosaurian theropods)
diversification, basal
