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Integrated biostratigraphy of Upper Maastrichtian chalk at Chełm (SE Poland)

100%

Dubicka Z. , Peryt D.

tom Vol. 81, No 2

185-197

A 40-m-thick section of chalk exposed in the Chełm quarry (SE Poland) contains a rather poor assemblage of macrofauna and a well diversified assemblage of foraminifers. The planktonic foraminifer assem- blages characterized by a considerable number of representatives of Globigerinelloides and Heterohelix and the presence of Guembelitria cretacea indicate the lowest part of the Guembelitria cretacea Zone sensu Peryt (1980). Benthic foraminifers point out that the strata of the Chełm quarry section can be attributed to the lower part of the Upper Maastrichtian: i.e., the Gavelinella danica/Brotzenella preacuta Zone of the European Boreal Province or the Anomalinoides pinguis Zone distinguished in Poland (except the Carpathians). The occurrence of ammonites, such as Hoploscaphites constrictus lviviensis Machalski, Hoploscaphites schmidi (Birkelund), and Acanthoscaphites varians blaszkiewiczi Jagt & al. indicates that the Chełm succession belongs to the lower part of the Belemnitella junior Zone, i.e., to the Belemnitella junior–Spyridoceramus tegulatus Zone sensu Schulz & Schmid (1983). The correlation of the Chełm quarry section and the Middle Vistula River Valley section indicates that the equivalent interval of the former section is not exposed in the Middle Vistula River Valley and that it would occur between the Chotcza and Lucimia villages within the lower part of the Belemnitella junior Zone, i.e., within the Belemnitella junior-Spyridoceramus tegulatus Zone distinguished in NW Germany (Schulz & Schmid,1983).

Theropod teeth from the upper Maastrichtian Hell Creek Formation “Sue” Quarry: New morphotypes and faunal comparisons

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Gates T. A. , Zanno L. E. , Makovicky P. J.

nr 1

Isolated teeth from vertebrate microfossil localities often provide unique information on the biodiversity of ancient ecosystems that might otherwise remain unrecognized. Microfossil sampling is a particularly valuable tool for documenting taxa that are poorly represented in macrofossil surveys due to small body size, fragile skeletal structure, or relatively low ecosystem abundance. Because biodiversity patterns in the late Maastrichtian of North American are the primary data for a broad array of studies regarding non-avian dinosaur extinction in the terminal Cretaceous, intensive sampling on multiple scales is critical to understanding the nature of this event. We address theropod biodiversity in the Maastrichtian by examining teeth collected from the Hell Creek Formation locality that yielded FMNH PR 2081 (the Tyrannosaurus rex specimen “Sue”). Eight morphotypes (three previously undocumented) are identified in the sample, representing Tyrannosauridae, Dromaeosauridae, Troodontidae, and Avialae. Noticeably absent are teeth attributed to the morphotypes Richardoestesia and Paronychodon. Morphometric comparison to dromaeosaurid teeth from multiple Hell Creek and Lance formations microsites reveals two unique dromaeosaurid morphotypes bearing finer distal denticles than present on teeth of similar size, and also differences in crown shape in at least one of these. These findings suggest more dromaeosaurid taxa, and a higher Maastrichtian biodiversity, than previously appreciated.

Crustacean burrows from Upper Maastrichtian deposits of South-Central Cuba

80%

Pszczolkowski A.

nr 2