A new pachyosteomorph arthrodire (Pisces: Placodermi) from the Upper Frasnian of the Central Devonian Field,Russia

A new genus and species of pachyosteomorph arthrodire, Omalosteus krutoensis gen. et sp. nov. from shallow-water marine deposits of the Evlanovo Regional Stage (Upper Frasnian, Upper Devonian) of the Central Devonian Field is described. It is tentatively referred to the family Trematosteidae Gross, 1932, which was earlier believed to be endemic to central Europe. The new genus is characterized by a rounded, dorsoventrally compressed cross section of the pectoral region and smooth head shield and postcranial membrane bones. The centrale is elongated, forming a narrow lateral lobe. The praeorbitale, postorbitale, and centrale come in contact in the center of the orbital region. The mediodorsale is wide, its carinal process projects considerably posteriorly. The anterior margin of the anterior ventrolaterale lacks articular facets for the interlaterale.     

New bryozoans (Bryozoa) from the Upper Devonian (Lower Famennian) of the Kuznetsk Basin

New bryozoans from the Upper Devonian (Famennian) of the borderlands of the Kuznetsk Coal Basin are described: Orthopora tomensis sp. nov. and Minussina incrustata sp. nov.     

Bryozoans from the Mitikha Formation (Lower Famennian, Upper Devonian) of the Kuznetsk Basin, Russia

Bryozoans from the Mitikha Formation (Lower Famennian, Upper Devonian) in the Kuznetsk depression are described for the first time. This bryozoan assemblage comprises both the well-known species Leioclema numerosum Moroz., L. ramosum Nekh., and Nicklesopora graciosa Troiz. and new taxa: L. kusmense sp. nov. and Megacanthopora glubokaensis sp. nov. The bryozoan assemblage contains some species common with the Famennian bryozoan assemblage of Kazakhstan.     

New radiolarians from the Devonian of the southern Ural Mountains: 2. Middle-Late Devonian

Middle-Late Devonian Radiolarians are recorded for the first time in the southern Ural Mountains in Bashkortostan, in a section of Kariukmas Mountain (Upper Eifelian) and on the southern slope of Argagan Mountain (Middle Frasnian). The new Late Eifelian assemblage is composed of 17 species of 11 genera, and Middle Frasnian radiolarians comprise 13 species of 7 genera of spherical, discoidal, pylomate, and spiny radiolarians. A new species, Primaritripus kariukmasensis, sp. nov., is described. The prevalence of discoidal forms in the oryctocenosis suggests shallow marine conditions in the Late Eifelian and Middle Frasnian basins. Two new biostratons, the Upper Eifelian beds with Primaritripus kariukmasensis and Middle Frasnian beds with Primaritripus chuvashovi, are established based on radiolarians.     

New radiolarians from the Devonian of the southern Ural Mountains: 1. Early-Middle Devonian (Late Emsian-Early Eifelian)

Late Emsian-Early Eifelian radiolarians from the southern Ural Mountains are recorded and described for the first time. They come from the Kamennaya Gora section on the Tanalyk River near the town of Buribay, Bashkiria. The new Late Emsian-Early Eifelian radiolarian assemblage consists of 20 species of 11 genera of spherical, discoidal, spindle-shaped, pylomate, and spiny radiolarians. Four new species, i.e., Entactinia rostriformis sp. nov., Palaeodiscaleksus tumefactus sp. nov., Primaritripus buribayensis sp. nov., and P. chuvashovi sp. nov., are described. The diagnosis of the genus Primaritripus Afanasieva, 2000 is amended. The fact that the oryctocenosis is dominated by discoidal radiolarians suggests that, in the Late Emsian-Early Eifelian, the area under study was occupied by a relatively shallow marine basin. Based on radiolarians, a new Upper Emsian-Lower Eifelian biostraton, beds with Primaritripus buribayensis-Entactinia rostriformis, is established. The history of the study of Early Devonian radiolarians is considered.     

Middle Devonian bothriolepiform antiarchs (Pisces,Placodermi) from central Kazakhstan and their implication for the antiarch system and phylogeny

The bothriolepiform antiarchs Tenizolepis asiatica (Obrucheva, 1955), Bothriolepis kassini Malinovskaja, 1988, and B. babichevi Malinovskaya, 1992 from the Givetian (Middle Devonian) of Central Kazakhstan are redescribed. Tenizolepis bychkovi Malinovskaya, 1992, known from the Konyr Formation of the Trudovoe vertebrate locality, is considered to be a synonym of B. babichevi. The history of investigation of bothriolepiforms from Kazakhstan is discussed. The system and phylogeny of antiarchs are discussed.     

Bothriolepiform antiarchs (Pisces,Placodermi) from the devonian of Central Kazakhstan

Bothriolepiform antiarchs (Placodermi, Antiarchi) are represented by two genera in the Devonian of Central Kazakhstan: Bothriolepis Eichwald (Bothriolepididae) and Tenizolepis Malinovskaja (Dianolepididae). The first includes five species: B. babichevi Malinovskaja, 1992, B. kassini Malinovskaja, 1988, B. amankonyrica Malinovskaja, 1988, B. nikitinae Malinovskaja, 1988, and B. tastenica Malinovskaja, 1988; the second includes only two valid species, T. asiatica (Obrucheva, 1955) and T. rara Malinovskaja, 1977. As type collections of bothriolepiform antiarchs of Central Kazakhstan were revised, the diagnoses were emended and the postcranial exoskeleton was reconstructed. The classification of the order is discussed and a new family, Tubalepididae fam. nov., is established.     

New endothyrids (Foraminifera) from the Upper Visean of the northern Ural Mountains

New endothyrids from the Upper Visean of the western slope of the northern Ural Mountains are described and assigned to the new species Eoendothyranopsis (Ninella) extremus and E. (N.) poststaffelliformis.     

Upper Devonian Sponges from the Holy Cross Mountains, Central Poland

The rich fauna of Late Devonian (Late Frasnian) siliceous sponges from the Holy Cross Mountains, Poland is composed of 15 species and 11 genera. Both astylospongid demosponges (lithistids) and hexactinosan hexactinellids are present. The following new genera and/or species are proposed: D regulara Rigby and Pisera sp. nov., Jazwicella media Rigby and Pisera gen. et sp. nov., Astyloscyphia irregularia Rigby and Pisera gen. et sp. nov., A. turbinata Rigby and Pisera gen. et sp. nov., Astylotuba modica Rigby and Pisera gen. et sp. nov., Paleoregulara cupula Rigby and Pisera gen. et sp. nov., Paleoramospongia bifurcata Rigby and Pisera gen. et sp. nov., Cordiospongia conica Rigby and Pisera gen. et sp. nov., Paleocraticularia elongata Rigby and Pisera gen. et sp. nov., P gigantia Rigby and Pisera gen. et sp. nov., Polonospongiadevonica Rigby and Pisera gen. et sp. nov., P fistulata Rigby and Pisera gen. et sp. nov., Urnospongia modica Rigby and Pisera gen. et sp. nov., and Conicospongia annulata Rigby and Pisera gen. et sp. nov. The investigated fauna contains the youngest astylospongiids known and the oldest well-preserved, and most diversified Palaeozoic hexactinosans. The sponge fauna constituted a significant element of a brachiopod-coral-sponge assemblage that inhabited a deep slope of the local Dyminy Reef structure, during its final phase of growth, in a clearly hemipelagic setting. This fauna is limited to the intrashelf depression within an incipiently drowned carbonate platform.     

A new camuropiscid arthrodire (Pisces: Placodermi) from Gogo, Western Australia

A new camuropiscid arthrodire, Latocamurus coulthardi gen. et sp. nov., is described from the Upper Devonian Gogo Formation, Western Australia. Latocamurus , known from two complete specimens, is recognized as a camuropiscid by its narrow, spindle-shaped armour, deep postnasal plates participating in the orbits, preorbital plates which meet mesially, cheek unit firmly sutured to skull roof, posterior check plates tightly interconnected and much reduced, and the robust durophagous dentition. It is characterized by its downturned snout, broad, flat rostral plate, and narrow, deep parasphenoid. It is placed phyletically as the plesiomorphic sister taxon to all other camuropiscids which are more derived in having, inter alia , an anterior lateral plate which anteriorly contacts the anterior ventrolateral plate and pointed rostral plates. The family Camuropiscidae Dennis & Miles 1979b is redefined to incorporate features of the new genus. Camuropiscids and Incisoscutum are closely related by features of the postnasal plate and cheek.     

Middle-late devonian placoderms (Pisces: Antiarchi) from Central and northern Asia

Antiarch placoderms (Pisces, Placodermi, Antiarchi) from the Middle-Upper Devonian of Central and northern Asia (Asian part of the former Soviet Union) are described. Available antiarch specimens belong to 28 species (eight of which are described in open nomenclature), of 9 genera, 5 subfamilies, 6 families, 2 orders. The main localities of Middle-Late Devonian antiarchs are listed and provided with the data on stratigraphic distribution. The morphological structure of antiarchs and history of their study in Central and northern Asia are briefly considered. The principles of systematics and phylogeny of antiarchs, feature of their historical development in the Middle and Late Devonian of this area, and their paleozoogeographic relationships are discussed.     

Devonian antiarchs (Pisces,Antiarchi) from central and Southern European Russia

Antiarchi (Pisces, Placodermi) from the Devonian of central and southern European Russia (Central Devonian Field) are studied. Antiarchs belong to three families, the Asterolepididae, Remigolepididae (suborder Asterolepidoidei), and Bothriolepididae (suborder Bothriolepidoidei). The diagnoses of the order, two suborders, three families, and five genera (two of which are new) are given. Sixteen species, including one new, are described; ten taxa are determined in open nomenclature. Morphological structures of representatives of these families are considered in detail. Classifications of antiarchs and their position in the system of the lower vertebrates are discussed. Devonian vertebrate localities of central and southern European Russia that have yielded antiarchs are listed. Each locality is characterized by its ichthyoassemblage.     

A new species of eastmanosteid arthrodire (Pisces: Placodermi) from Gogo, Western Australia

A new species of Eastmanosteus Obruchev is described from the Upper Devonian Gogo Formation of Western Australia as E. calliaspis sp. nov. It is at the pachyosteomorph level of organization having no contact between the plates of the flank and those of the ventral shield behind the pectoral fin. Well preserved material of the parasphenoid and scapulocoracoid throws further light on the structure of these elements in arthrodires. The genus Eastmanosteus is reviewed.     

Microfossils in stromatolitic cherts from the upper proterozoic Min'yar formation, southern Ural Mountains, USSR

A diverse assemblage of exceptionally well-preserved microorganisms, including several previously unknown taxa, has been discovered in stromatolitic black chert from the ca. 680-790 Ma-old Min'yar Formation (Suite) of the southern Ural Mountains, USSR. Like most ancient and modern stromatolitic communities, the Min'yar microflora is dominated by filamentous and unicellular cyanobacteria. Geologic evidence indicates that the microbial community inhabited a shallow water, presumably marine environment. The microfossils occur in two interlaminated and thinly interbedded sedimentary fabrics: 1, fact to wavy-laminated Stratifera-like stromatolitic laminae that presumably were deposited during periods of little wave action; and 2, intraclast grainstone that formed as a result of desiccation and (or) wave agitation. Microfossils are both better preserved and more abundant in the intraclasts than in the Stratifera-like laminae. The occurrence of probable pseudomorphs after replacement of sulfate minerals provides additional evidence for a shallow water, periodically emergent depositional environment for the Min'yar microbial mats. Kerogenous microfossils are three-dimensionally preserved, permineralized in fine-grained silica of primary or early diagenetic origin. In many aspects the Min'yar assemblage is comparable to that of the well-known ca. 850 Ma-old Bitter Springs Formation of central Australia. The following taxa are herein described: Division? Schizomycophyta or ? Cyanophyta, Biocatenoides sp.; Family Oscillatoriaceae, Eomycetopsis robusta Schopf emend. Knoll and Golubic, Rhicnonema antiquum Hofmann, Entosphaeroides? sp., Palaeolyngbya? sp., Siphonophycus capitaneum n. gen., n. sp.; Family? Oscillatoriaceae or? Rivulariaceae, Caudiculophycus? sp.; Family? Scytonemataceae or? Stigonemataceae, Ramivaginalis uralensis n. gen., n. sp.; Family Chroococcaceae, Sphaerophycus medium Horodyski and Donaldson, Eosynechococcus amadeus Knoll and Golubic, Gloeodiniopsis lamellosa Schopf emend. Knoll and Golubic, Gloeodiniopsis magna n. sp., Eoaphanocapsa oparinii n. gen., n. sp.; Division? Chlorophycophyta or? Rhodophycophyta, Glenobotrydion majorinum Schopf and Blacic. Also discussed in the taxonomic section, but not formally described, are intermediate-diameter tubular sheaths (Oscillatoriaceae), small tubular sheaths enclosed by larger tubular sheaths (Oscillatoriaceae?), and undifferentiated spheroidal unicells.     

New Upper Devonian brachiopod genus <Emphasis Type="Italic">Paraimbrexia</Emphasis> (Order Spiriferida) from the Abyshevo Horizon of the Kuznetsk Basin

A new spiriferid genus Paraimbrexia with the type species Imbrexia topkensis Besnossova, 1959 is established within the family Imbrexiidae Carter, 1992 from the Abyshevo Horizon, Famennian, Upper Devonian of the Kuznetsk Basin. Revision of the type material of I. topkensis revealed that this species strongly differs from the other species of Imbrexia Nalivkin, 1937 in details of shell exterior and interior.     

Possible evidence of predation in placoderms (Pisces) of the Evlanovo basin of central Russia

Two placoderms of different orders from a concretion of the Zyabrevo locality (Evlanovo Regional Stage, Frasnian) in central Russia are described. Five plates of the ventral and lateral sides of the trunk armor are assigned to a plourdosteid arthrodire. Three bones located in the region of its stomach are determined as a juvenile ptyctodontid, Ctenurella sp. Records providing actual evidence of predation in Devonian vertebrates are extremely scarce. Finds of this kind are listed for the first time.     

Frasnian bryozoans (Late Devonian) from the Khoshyeilagh Section,Alborz Mountains (northern Iran)

A bryozoan fauna containing seven species is described from the Upper Frasnian (Upper Devonian) rocks in the Khoshyeilagh Section, Alborz Mountains (northern Iran). The studied bryozoan assemblage includes one new trepostome species, Eridotrypella alborzensis sp. nov., an additional four species identified at species level: two trepostomes, Minussina akkayaensis Volkova, 1974 and Leptotrypella inaudita Morozova, 1961, and two rhabdomesine cryptostomes, Bigeyella mariae (Morozova, 1961) and Saffordotaxis multispinata (Morozova, 1955). Furthermore, two species are described in open nomenclature: the trepostome Schulgina sp. and the rhabdomesine cryptostome Nicklesopora sp. The studied fauna shows a close similarity at the species level between northern Iran and the Altai-Sayan Folded Belt (Russia), south China, and Transcaucasia.