Andrej Ernst

Bryozoa of the Upper Permian Zechstein Formation of Germany

The investigated bryozoan fauna of the Upper Permian Zechstein Formation includes 17 species of 9 genera, belonging mainly to the fenestellids and trepostomids and one species belonging to the tubuliporids,Corynotrypa voigtiana (King 1850). Three new species are described (Dyscritella microstoma sp. nov.,Ulrichotrypella incrustata sp. nov., andKingopora baderi sp. nov.). The Zechstein species of the generaAcanthocladia, Synocladia, Penniretepora andKalvariella display close resemblance in their internal morphology, and their derivation from a common ancestor is suggested. The distribution of the bryozoans in the Zechstein Sea was apparently controlled by factors such as lateral sedimentation, distribution of microbial mats and quality of substrates.KurzfassungDie untersuchte Fauna des Zechsteins enthält 17 Arten von 9 Gattungen, überwiegend fenestellide und trepostomide Taxa, sowie eine tubuliporide Bryozoe,Corynotrypa voigtiana (King 1850). Drei neue Arten werden beschrieben (Dyscritella microstoma sp. nov.,Ulrichotrypella incrustata sp. nov. undKingopora baderi sp. nov.). Die Arten der GattungenAcanthocladia, Synocladia, Penniretepora undKalvariella aus dem Zechstein zeigen große Ähnlichkeiten untereinander in ihrer inneren Morphologie. Ihre Abstammung von einem gemeinsamen Vorfahr wird vermutet. Die Verbreitung der Bryozoen im Zechsteinmeer wurde anscheinend von solchen Faktoren wie laterale Sedimentzufuhr, Verbreitung der mikrobiellen Matten und Substratbeschaffenheit kontrolliert.

Upper Ordovician Bryozoa from the Montagne de Noire, Southern France

Synopsis This study focuses on bryozoans from the Upper Ordovician rocks of the Montagne de Noire, southern France and additional material from contemporary rocks of the Carnic Alps. Based on museum collections, 68 bryozoan species were identified with 18 species being new: Ceramo‐porella grandis sp. nov., Crassalina fungiforme sp. nov., Lichenalia nodata sp. nov., Atactoporella magnopora sp. nov., Dekayia buttleri sp. nov., Stigmatella carnica sp. nov., Trematopora gracile sp. nov., Bythopora tenuis sp. nov., Nicholsonella divulgata sp. nov., N. recta sp. nov., Matsutrypa elegantula sp. nov., M. rogeri sp. nov., Nematotrypa punctata sp. nov., Stellatodictya valentinae sp. nov., Ptilodictya feisti sp. nov., Pseudohornera dmitrii sp. nov., Ralfinella elegantula sp. nov. and Moorephylloporina contii sp. nov. Trepostomes are the most abundant and diverse group with 40 of the total 68 species, but cyclostomes, cystoporates and cryptostomes are also present. The age of the fauna is Caradoc to Ashgill, according to the distribution of species and genera. The fauna has palaeogeographical connections to the Upper Ordovician of Wales, Estonia and North America.

Darriwilian bryozoans from the San Juan Formation (Ordovician), Argentine Precordillera

Abstract. A detailed study is carried out on the taxonomy of the bryozoan fauna from the upper levels of the San Juan Formation (Darriwilian) in the Talacasto and Cerro Viejo sections, Argentinean Precordillera. Three bryozoan genera are described and two new species are erected: Lamottopora multispinosa sp. nov., Aostiporn sanjuanensis sp. nov., and Phylloporinidae sp. indet. The paleoecological significance of the bryozoan fauna is discussed. The ramose bryozoans Lamottopora and Aostipora dominate in the Talacasto section. Some colonies probably lived attached directly to the substrate, while others occur attached to the surface of the abundant sponge fauna in the section. The majority of bryozoans at the Cerro Viejo section occur as epibionts, with bases attached to the surface of sponges. Bryozoans collected in the matrix are scarce compared to the Talacasto section, and comprise a few fragments of ramose bryozoans and two small fragments of the reticulate Phylloporinidae sp. indet were recorded exclusively in this locality. The presence of this delicate form in Cerro Viejo is further evidence of the quiet water conditions suggested for these levels. Only the laminar form Nicholsonella occurs in slightly older levels (Floian) of the San Juan Formation. The low diversity recorded here shows a slight decoupling with the global pattern. The first local radiation (three genera) is minor compared with the important radiation that the phylum experienced elsewhere.

A Hirnantian (latest Ordovician) reefal bryozoan fauna from Anticosti Island, eastern Canada: taxonomy and chemostratigraphy

The Natiscotec outcrop on Anticosti Island, Canada (Ellis Bay Formation, Laframboise Member, Hirnantian, Late Ordovician), exposes a patch reef some 20–30 m in diameter, 2–3 m thick, with abundant rugose corals, as well as favositids and heliolitids. Reef capping and flanking sediments include typical Hirnantian brachiopods, such as Hirnantia, Hindella, and Eospirigerina. Within the reef peloidal microbialites encrusting bryozoan colonies are common. The bryozoan fauna includes three cystoporates, seven trepostomes, and three phylloporines. Two genera and two species are new: the cystoporate Natiscotecella tenuis n. gen. and n. sp. and the phylloporine Dilaminocladia natiscotecensis n. gen. and n. sp. Three more species are also new: the cystoporates Ceramopora clara n. sp. and Acanthoceramoporella spinigera n. sp. and the trepostome Revalotrypa honguedensis n. sp. Furthermore, we identify the three trepostomes Atactoporella aff. ortoni (Nicholson, 1874), Hallopora elegantula (Hall, 1852), and Monotrypell...

Permian bryozoans of the NW-tethys

SummaryPermian bryozoan faunas from the Lower Permian sequences of the Carnic Alps (UpperPseudoschwagerina Formation and Trogkofel Formation) and from some other Permian units of the NW-Tethys (Sicily, Tunisia) include cystoporid, trepostomid, fenestellid, rhabdomesid, and timanodictyid taxa. Fenestellids and cystoporids species dominate. The Lower Permian bryozoan fauna of the Carnic Alps displays close relations to faunas of Sakmarian-Artinskian age of the Russian Platform and Pamir as well as of the Lower Permian of Australia. Bryozoans from Permian sequences of Sicily and Tunisia display relations to the Permian faunas of Indonesia and Australia.

A new Middle Devonian cystoporate bryozoan from Germany containing a new symbiont bioclaustration

An unusual cystoporate bryozoan from the Middle Devonian (Givetian) Ahbach Formation of the Hillersheim Syncline (Eifel, Rhenish Massif, Germany) is described as Stellatoides muellertchensis gen. et sp. nov. The lamellar colonies have elongate stellate maculae with depressed centres consisting of vesicular skeleton. All colonies collected contain vertical axial tubular holes, which are embedment structures formed by the bryozoan around a soft-bodied symbiont and lined by bryozoan skeleton. These bioclaustrations are referred to the ichnogenus Chaetosalpinx, previously known in Ordovician—Devonian corals and sponges, and are described as Chaetosalpinx tapanilai ichnosp. nov. Ecological analogues to Chaetosalpinx tapanilai can be found in modern bryozoans in which tubes formed of bryozoan calcite are occupied by spionid polychaetes, or less often tanaidacean crustaceans.

BRYOZOAN FAUNA FROM THE KONEPRUSY LIMESTONE (PRAGIAN, LOWER DEVONIAN) OF ZLATÝ KŮN NEAR KONEPRUSY (CZECH REPUBLIC)

Abstract This paper presents an overview of the bryozoan fauna from the upper Koněprusy Limestone (kindlei Conodont Zone, middle Pragian, Lower Devonian) exposed in two quarries at Zlatý Kůň near Koněprusy in Central Bohemia, and discusses its paleoecology and paleobiogeography. The studied fauna is dominated by encrusting fistuliporine and trepostome bryozoans (eight species), accompanied mainly by reticulate fenestrates (four species), branching ramose trepostomes and cryptostomes (three species), and one massive trepostome species. The richest bryozoan association comes from reef core/margin facies (13 species), followed by crinoid-bryozoan facies of the ramp (eight species). The reef-terrace facies and the crinoid-bryozoan-algal facies contain three and two species respectively. Seven species are described taxonomically, three fistuliporines and four trepostomes. The following taxa are new: Koneprusiella armata n. gen. n. sp., Fistulipora rarivesiculata n. sp., Fistulipora hladili n. sp. and Leptotrypa varia n. sp. Paleobiogeographic patterns of the bryozoan fauna from the Koněprusy Limestone are similar to those of stromatoporoids, comprising widely distributed genera but mainly endemic species. This supports a relative geographic isolation of the Koněprusy reef. The bryozoan fauna from the Koněprusy Limestone shows paleogeographic affinities with that from the Lower Devonian (Pragian) of Morocco and the Middle Devonian of Michigan (USA).

Bryozoan fauna from the Mississippian (Visean) of Roque Redonde (Montagne Noire, southern France)

ABSTRACT A bryozoan fauna from the Mississippian (Visean) of Roque Redonde (Montagne Noire, southern France), contains 38 species (12 cystoporates, 2 trepostomes, 6 cryptostomes [rhabdomesines], and 18 fenestrates). Of them 9 are new: Fistulipora tolokonnikovae n. sp., Dybowskiella rotunda n. sp., Dybowskiella piriforme n. sp., Eridopora suarezi n. sp., Volgia deftera n. sp., Cystodictya gallensis n. sp., Megacanthopora enodata n. sp., Fabifenestella macrofenestrata n. sp., and Baculopora redondensis n. sp. Beside them, one new genus with a new species is established: Gorjunopora gallica n. gen., n. sp. Furthermore, 23 species characteristic of the Mississippian of Eurasia and North America were identified. The bryozoan species show various palaeobiogeographic connections. The closest connections are to the Mississippian (Visean) of the British Isles and the Russian Platform. Moreover, some connections to the Mississippian of Germany, Ukraine, Spain, Kuznets Basin, North America and Kazakhstan can be traced. The studied bryozoan assemblage is represented mainly by delicate growth forms and suggests a calm water environment.

Dianulites (Trepostomata, Bryozoa) from the Early Ordovician of Severnaya Zemlya, Arctic Russia

Trepostome bryozoan Dianulites borealis Astrova, 1965, the earliest known member of this genus, has been identified from the Early Ordovician of Severnaya Zemlya, Arctic Russia. This species developed hemispherical colonies which indicate that it lived on a relatively soft substrate with moderately low rates of sedimentation and erosion. The new record from Severnaya Zemlya expands the palaeogeographical distribution of Dianulites , known before from the Early Ordovician of Novaya Zemlya, Arctic Russia.

Chapter 12 A review of the Early Palaeozoic biogeography of bryozoans

Abstract The palaeogeographical distributions of Early Palaeozoic bryozoan faunas are reviewed. Previous studies are examined and new databases have been assembled of the stratigraphical and geographical distribution of Ordovician and Silurian taxa. Analysis was carried out using cluster analysis based on Jaccard’s coefficient and paired group method, as well as principal coordinate analysis based on Jaccard’s coefficient, to examine the relationships between different localities. Bryozoan faunas increased in diversity throughout the Ordovician peaking with 133 genera during the Katian. In the earliest Ordovician provincialism is difficult to determine, but by the Darriwilian five distinct provinces developed, decreasing to four in the Sandbian. There was a decrease in provinciality throughout the Katian as faunas became less endemic, caused by the reduction of geographical barriers. Following the extinction of many genera at the end of the Ordovician, early Silurian faunas contain remnant taxa. Subsequently fenestrates began to dominate faunas. During the Llandovery bryozoans began to show distinct provincialism, but this declined during the Wenlock, only to re-emerge during the Ludlow. Late Silurian (Pridoli) faunas are sparse but nevertheless show possible division into two provinces.