Diverse ophiuroid faunules from the basal Teplice Formation, of Late Turonian age, exposed at Úpohlavy in the northwestern part of the Bohemian Cretaceous Basin, northwest Bohemia, are based on only dissociated lateral arm plates, vertebrae and some other skeletal elements of the disc. The material can be ascribed to ten species, including a new taxon named Stegophiura? nekvasilovae sp. nov. Three additional species are represented in the material but these are left in open nomenclature. Relative species abundance is evaluated and discussed. • Key words: Echinodermata, Ophiuroidea, Upper Cretaceous, taxonomy, Bohemian Cretaceous Basin, Czech Republic.

ŠTORC, R. & ŽÍTT, J. 2008. Late Turonian ophiuroids (Echinodermata) from the Bohemian Cretaceous Basin, Czech Republic. Bulletin of Geosciences 83(2), 123–140 (8 figures). Czech Geological Survey, Prague. ISSN 1214-1119. Manuscript received January 3, 2008; accepted in revised form February 27, 2008; issued June 30, 2008.

Richard Štorc, Smetanova 380, CZ-251 64 Mnichovice, Czech Republic; RStorc@seznam.cz • Jiøí Žítt, Institute of Geology of the Academy of Sciences of the Czech Republic, v.v.i., Rozvojová 269, CZ-165 02 Praha 6, Czech Republic; zitt@gli.cas.cz

Tarphycerids of the suborder Barrandeocerina are striking owing to the large size of the shell and similarity with the recent Allonautilus Ward & Saunders, 1997. They are widely distributed in the Silurian rocks of Europe. They were originally classified within the genus Nautilus Linnaeus, 1758 but generic assignment remained questionable despite the detailed description and excellent illustration provided by Barrande in 1865. Species belonging to this group have been assigned to the genera Barrandeoceras Hyatt, 1884, Heracloceras Teichert, 1940, or Cumingsoceras Flower, 1950 but none of them is appropriate considering their morphology, phylogenetic trends and stratigraphic range. Therefore, a new genus Boionautilus is established here. An evolutionary trend is discerned, expressed especially in the tighter coiling of the shell – a transition from an evolute shell (gyroceracone at the beginning of the second whorl) with subelliptic cross section, to a slightly involute shell with a subtrapezoidal cross section. The dorsoventral diameter of the whorl increased
more rapidly, and septa became more densely spaced. Boionautilus tyrannus (Barrande, 1865) is now known to occur in North Africa (Algeria, the Ougarta Range). Previously-mentioned finds in peri-Gondwanan sediments of the Carnic Alps are here rejected. Differences in the colour of septa and connecting rings in one exceptionally well-preserved specimen of this taxon from Algeria and one Bohemian specimen of B. sternbergi (Barrande, 1865) are remarkable and indicate high primary content of organic matter within the connecting rings. • Key words: Cephalopoda, Nautiloidea, Tarphycerida, new taxon, Silurian, Europe, North Africa.

TUREK, V. 2008. Boionautilus gen. nov. from the Silurian of Europe and North Africa (Nautiloidea, Tarphycerida). Bulletin of Geosciences 83(2), 141–152 (7 figures). Czech Geological Survey, Prague. ISSN 1214-1119. Manuscript received February 18, 2008; accepted in revised form April 25, 2008; issued June 30, 2008.

Vojtìch Turek, National Museum, Department of Palaeontology, Václavské námìstí 68, 115 79 Praha l, Czech Republic; vojtech_turek@nm.cz

Moderate collections of fossil sponges have been recovered over a several-year period from a few scattered localities in west-central and east-central Alaska, and from westernmost Yukon Territory of Canada. Two fragments of the demosponge agelasiid cliefdenellid, Cliefdenella alaskaensis Stock, 1981, and mostly small unidentifiable additional fragments
were recovered from a limestone debris flow bed in the White Mountain area, McGrath A-4 Quadrangle in west-central Alaska. Fragments of the agelasiid actinomorph girtyocoeliids Girtyocoeliana epiporata (Rigby & Potter, 1986) and Girtyocoelia minima n. sp., plus a specimen of the vaceletid colospongiid Corymbospongia amplia Rigby, Karl, Blodgett
& Baichtal, 2005, were collected from probable Ashgillian age beds in the Livengood B-5 Quadrangle in east-central Alaska. A more extensive suite of corymbospongiids, including Corymbospongia betella Rigby, Potter & Blodgett, 1988, C. mica Rigby & Potter, 1986, and C.(?) perforata Rigby & Potter, 1986, along with the vaceletiid colospongiids
Pseudo-imperatoria minima? (Rigby & Potter, 1986), and Pseudoimperatoria media (Rigby & Potter, 1986), and with the heteractinid Nucha naucum? Pickett & Jell, 1983, were recovered from uppermost part of the Jones Ridge Limestone (Ashgillian), on the south flank of Jones Ridge, in the Sheep Mountain Quadrangle, in westernmost Yukon Territory,
Canada. The fossil sponges from the McGrath A-4 and Livengood B-5 quadrangles were recovered from attached Siberian terranes, and those from the Sheep Mountain Quadrangle were recovered from an allochthonous Laurentian terrane in the Yukon Territory. • Key words: Porifera, sponge, Ordovician, Alaska, Yukon Territory, Jones Ridge Limestone.

RIGBY, J.K., BLODGETT, R.B. & BRITT, B.B. 2008. Ordovician sponges from west-central and east-central Alaska and western Yukon Territory, Canada. Bulletin of Geosciences 83(2), 153–168 (4 figures). Czech Geological Survey, Prague. ISSN 1214-1119. Manuscript received March 7, 2008; accepted in revised form May 20, 2008; issued June 30, 2008.

J. Keith Rigby & Brooks B. Britt, Room 165, Earth Science Museum, Department of Geological Sciences, Brigham Young University, Provo, Utah 84602-4606; rigbyjkeith@gmail.com, brooks.britt@gmail.com • Robert B. Blodgett, U.S. Geological Survey – Contractor, 4200 University Drive, Anchorage, Alaska; rblodgett@usgs.gov

The stringocephalid genus Paracrothyris Wu in Wang et al., 1974 is reported for the first time from Givetian beds of the Western Sahara (Northwest Africa). Although only dorsal shell fragments have been found, the specimens can be assigned to this genus with certainty due to a combination of preserved characters: lack of a median septum, and the presence of crural plates in combination with a typical stringocephaloid morphology. The genus Paracrothyris (type species P. distorta Wu in Wang et al., 1974) was originally described from South China and later from Nevada, U.S.A., and has only been reported from beds of Givetian age (late Middle Devonian). From the palaeogeographical distribution, it is concluded that the larvae migrated throughout the Palaeotethys along the shelf of Northern Gondwana between Nevada and South China, supporting the hypothesis of decreasing provincialism in late Middle Devonian time. • Key words: Paracrothyris, Brachiopoda, Western Sahara, Gondwana, Givetian, Middle Devonian.

SCHEMM-GREGORY, M. & JANSEN, U. 2008. First report of the stringocephalid genus Paracrothyris (Brachiopoda, Middle Devonian) from North Africa. Bulletin of Geosciences 83(2), 169–173 (3 figures, 1 table). Czech Geological Survey, Prague. ISSN 1214-1119. Manuscript received December 5, 2007; accepted in revised form January 24, 2008; issued June 30, 2008.

Mena Schemm-Gregory & Ulrich Jansen, Forschungsinstitut Senckenberg, Paläozoologie III, Senckenberganlage 25, D-60325 Frankfurt am Main, Germany; Mena.Schemm-Gregory@senckenberg.de (corresponding author), Ulrich.Jansen@senckenberg.de

An anomalous event of Ukrainian quartz-dominated dust deposited in the Czech Republic and adjacent countries on 24 March 2007 was studied with special emphasis on sedimentology, mineralogy and geochemistry. The dust deposition combined a typical eolian depositional mode with one mediated by dirty rain or drizzle. The main stage of sediment deposition was short (several tens of minutes) and synchronous with rapidly increased concentration of particles smaller than 10 µm in the atmosphere above ground. The polydisperse and multimodal sediment consisted predominantly of angular to subrounded quartz particles, of which 80–90 wt.% were silt sized (4–63 µm). A small amount of sand grains up to 0.5 mm in size was regularly observed (≤10 wt.%) and was higher than that of particles smaller than 4 µm. This relatively coarse material was transported by atmospheric flows over distances of 1400 to 2000 km. The deposited silt film was fenestrally arranged and showed various reticulate and patchy patterns of several sizes. The intensity of deposition in the main deposition areas corresponded to 2.3 g/m² of particulate solids on average. The interpreted depositional processes are based on direct observation and dust microphysics. Besides the preferentially entrained and delivered quartz, the sediment contains also perthitic feldspar, chlorite and chloritoids, and notably low amounts of mica, clay minerals and carbonate. The element content does not contradict the supposed source based on meteorological observations, i.e., from surface argillaceous and sandy soils east of Kherson, Ukraine. Particularly minor and trace element distributions are almost identical and show a nearly perfect match, closely similar to those of standards for the upper crust (not sediments). Total Fe concentrations in the sediment are about 2–3 wt.%, i.e., slightly less than those for the upper continental crust on average, yet with a large proportion of iron still bound in mineral inclusions in quartz and silicates. Smooth REE patterns correspond to the most common multi-cycle eolian material and are typical for the assumed source area. Lead isotope signatures combine a natural lithic imprint and anthropogenic contamination by petrol combustion, thereby giving a somewhat different trend compared to African sources. Palynological analysis enabled tracking of the trajectory of the dust-flow but also identified typical markers, such as ragweed pollen, from the source area. • Key words: dust, atmospheric deposition event, sedimentology, rheology, grain-size modality, pattern formation, geochemistry, lead isotopes, pollen and spores, eolian flux, climate change, Czech Republic, Ukraine, Europe, Recent/Holocene.

HLADIL, J., STRNAD, L., ŠÁLEK, M., JANKOVSKÁ, V., ŠIMANDL, P., SCHWARZ, J., SMOLÍK, J., LISÁ, L., KOPTÍKOVÁ, L., ROHOVEC, J., BÖHMOVÁ, V., LANGROVÁ, A., KOCIÁNOVÁ, M.,MELICHAR, R. & ADAMOVIÈ, J. 2008. An anomalous atmospheric dust deposition event over Central Europe, 24 March 2007, and fingerprinting of the SE Ukrainian source. Bulletin of Geosciences 83(2), 175–206 (18 figures, 5 tables). Czech Geological Survey, Prague. ISSN 1214-1119. Manuscript received November 25, 2007; accepted in revised form February 25, 2008; issued June 30, 2008.

Jindøich Hladil, Lenka Lisá, Leona Koptíková, Jiøí Adamoviè, Jan Rohovec, Vlasta Böhmová & Anna Langrová, Institute of Geology AS CR, v.v.i., Rozvojová 269, 165 00 Prague 6 – Suchdol, Czech Republic; hladil@gli.cas.cz • Milan Šálek, Czech Hydrometeorological Institute, Brno Regional Office, Kroftova 43, 616 67 Brno – Žabovøesky, Czech Republic; salek@chmi.cz • Pavel Šimandl, Czech Hydrometeorological Institute, Central Forecasting Office, Na Šabatce 17, 143 06 Prague 4 – Komoøany; simandl@chmi.cz • Jaroslav Schwarz & Jiøí Smolík, Institute of Chemical Process Fundamentals of the AS CR, v.v.i., Rozvojová 2, 165 00 Prague 6 – Suchdol, Czech Republic; schwarz@icpf.cas.cz • Ladislav Strnad, Laboratories of Geological Institutes, Faculty of Science, Charles University, Albertov 6, 128 43 Prague 2, Czech Republic; lada@natur.cuni.cz • Vlasta Jankovská, Department of Ecology, Institute of Botany AS CR, v.v.i., Poøíèí 3b, 603 00 Brno, Czech Republic; jankovska@brno.cas.cz • Milena Kociánová, Krkonoše Museum in Vrchlabí, Krkonoše National Park Administration, Husova 213, 54 301 Vrchlabí, Czech Republic; mkocianova@krnap.cz • Rostislav Melichar, Department of Geological Sciences, Faculty of Science, Masaryk University in Brno, Kotláøská 2, 611 37 Brno, Czech Republic; melda@sci.muni.cz

Dinoflagellate cysts are reported from 20 Upper Cretaceous claystone samples from the Godula and Istebna formations of the Silesian unit. Age-assessment of the sediments based on 150 species suggests a Late Campanian to probably earliest Maastrichtian age for the middle and upper part of the Godula Formation and a Early Maastrichtian age for the basal
part of the Istebna Formation. Key biotic events are especially the first occurrence datums of Areoligera senonensis, Cerodinium diebelii, Palaeocystodinium golzowense and Trithyrodinium evittii, and the last occurrence datums of Odontochitina, Palaeohystrichophora infusorioides, Raeteiaedinium truncigerum, Trihyrodinium suspectum and Xenascus ceratioides. Palynofacies analysis shows deposition in an offshore marine environment subjected to influxes of terrestrial material. Organic matter is dominated by phytoclasts and contains very little amorphous organic material. The succession is also characterized by a low percentage of dinoflagellate cysts and a very low percentage of spores and pollen grains. The presence of thermophilitic dinoflagellate cysts points to a warm-temperate to subtropical climate during Late Campanian to Early Maastrichtian. • Key words: Silesian Unit, Cretaceous, Campanian, Maastrichtian, dinoflagellate cysts, palynofacies, Carpathians.

SKUPIEN, P. & MOHAMED, O. 2008. Campanian to Maastrichtian palynofacies and dinoflagellate cysts of the Silesian Unit, Outer Western Carpathians, Czech Republic. Bulletin of Geosciences 83(2), 207–224 (11 figures, 3 tables). Czech Geological Survey, Prague. ISSN 1214-1119. Manuscript received November 2, 2007; accepted in revised form April 25, 2008; issued June 30, 2008.

Petr Skupien, Institute of Geological Engineering, VŠB – Technical University, 17. listopadu 15, Ostrava-Poruba, Czech Republic; petr.skupien@vsb.cz • Omar Mohamed, Geology Department, Faculty of Science, Elminia University, Elminia, Egypt; omaraosman@yahoo.com

Analyses of the characteristic structural Schreger pattern in the dentine of tusks of numerous fossil proboscidean Mammuthus primigenius (Blumenbach, 1799) from five Upper Palaeolithic (Gravettian) Moravian localities (35–25 cal. ka BP) [Pøedmostí, Pavlov, Dolní Vìstonice, Milovice and Napajedla] and one Würmian Croatian locality Viljevacki
cret (Donji Miholjac) reveal the microstructure within the dentine. Values of the Schreger angles, the qualitative appearance of the pattern, and the wavelengths in transverse and longitudinal sections of the tusks were determined showing that Schreger angles can reach around 25–40° near the pulp cavity, begin to increase towards the tusk surface (cement-
dentine junction – CDJ), and reach a maximum of around 125°. Wavelengths reach maximal values of around 2,175 µm at low Schreger angles, towards the tusk surface becoming shorter and measuring around 1,100 µm. The qualitative pattern appearance depends mainly on the Schreger angle with a so-called ‘V’ pattern occurring at low angles, that is between 25–70°. At a maximal angle value (approximately from 80° to 125°) the so-called ‘C’ pattern occurs near the tusk surface. An ‘X’ pattern occurs with angle values around 70–80° lying between ‘V’ and ‘C’ patterns. • Key words: Schreger pattern, Mammuthus primigenius, tusks, microscopic study, histology, vertebrate palaeontology.

ÁBELOVÁ, M. 2008. Schreger pattern analysis of Mammuthus primigenius tusk: analytical approach and utility. Bulletin of Geosciences 83(2), 225–232 (6 figures, 3 tables). Czech Geological Survey, Prague. ISSN 1214-1119. Manuscript received May 9, 2007; accepted in revised form March 4, 2008; issued June 30, 2008.

 
Martina Ábelová, Masaryk University, Faculty of Science, Institute of Geological Sciences, Kotláøská 2, 611 37 Brno, Czech Republic; abelova.m@mail.muni.cz; State Geological Institute of Dionyz Stur, Mlynská dolina 1, 817 04 Bratislava 11, Slovak Republic; martina.abelova@geology.sk

A unique cluster of pentactine spicules has been observed in the lower part of the Olešná Member of the Klabava Formation (Upper Tremadocian or earliest Floian) in the Prague Basin. Some 100 pentactines of uniform size are arranged in one layer of regular quadrules. Although the general shape of the sponge is not preserved, the orientation of the pentactines in the quadrules is consistent with attribution to Cyathophycus Walcott, 1879. • Key words: Porifera, Cyathophycus, Ordovician, Tremadocian, Floian, Klabava Formation, Prague Basin, Czech Republic.

MERGL, M. 2008. The hexactinellid sponge Cyathophycus from the Lower Ordovician Klabava Formation of the Prague Basin, Czech Republic. Bulletin of Geosciences 83(2), 233–236 (2 figures). Czech Geological Survey, Prague. ISSN 1214-1119. Manuscript received September 3, 2007; accepted in revised form January 24, 2008; issued June 30, 2008.

Michal Mergl, University of West Bohemia, Faculty of Education, Department of Biology, Klatovská 51, 306 19 Plzeò, Czech Republic; mmergl@kbi.zcu.cz