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New Romanian Cretaceous vertebrate site
From: Ben Creisler
A new paper:
Mátyás Vremir, Ramona Balc, Zoltán Csiki-Sava, Stephen L. Brusatte,
Gareth Dyke, Darren Naish & Mark A. Norell (2014)
Petresti-Arini--An important but ephemeral Upper Cretaceous
continental vertebrate site in the southwestern Transylvanian Basin,
Cretaceous Research 49: 13-38
The Transylvanian region of Romania preserves some of the most unusual
and iconic dinosaurs in the global fossil record, including dwarfed
herbivores and aberrant carnivores that lived during the very latest
Cretaceous (Maastrichtian) in an ancient island ecosystem (the Hateg
Island). A series of artificial outcrops recently exposed during a
hydroelectric project, the Petresti-Arini section near Sebes in the
Transylvanian Basin, records a 400+ meter sequence documenting the
transition from fully marine to terrestrial environments during the
Campanian-Maastrichtian. Calcareous nannofossil biostratigraphy
indicates that the lower marine beds in this section, part of the
uppermost Bozes Formation, can be assigned to the CC22 biozone,
corresponding to the lower-mid upper Campanian. These beds smoothly
transition, via a brackish-water unit, into the fully continental
Maastrichtian Sebes Formation. Dinosaur and pterosaur fossils from the
uppermost Bozes Formation can be assigned a late Campanian age making
them the oldest well-dated terrestrial fossils from the Hateg Island,
and indicating that the classic Hateg dinosaur fauna was becoming
established by this time, coincident with the first emergence of
widespread land areas. Vertebrate fossils occur throughout the
overlying Sebes Formation at the site and are dominated by the
small-bodied herbivorous dinosaur Zalmoxes. The dominance of Zalmoxes,
and the absence of many taxa commonly seen elsewhere in Maastrichtian
sites in Romania, suggests the possibility that either the
Petresti-Arini section preserves a somewhat unusual near-shore
environment, or the earliest Hateg Island dinosaur communities were
structured differently from the more diverse communities later in the
Maastrichtian. Alternatively, due to the limited sample size available
from the studied succession, it is also conceivable that sampling
biases give an incomplete portrayal of the Petresti-Arini local fauna.
Support for any one of these alternative hypotheses requires further
data from Petresti-Arini as well as from the larger Transylvania area.
Romania boasts some of the most unusual, insular dinosaurs in the fossil record.
A new site preserves a unique late Campanian-earliest Maastrichtian
Dinosaurs and pterosaurs from this site are the oldest from the Hateg Island.
The Hateg Island fauna was becoming established by the late Campanian.
The site may suggest the earliest Hateg faunas were somewhat distinct
from later ones.