Stenolaemate bryozoans from the Geirud Formation (Upper Devonian ...

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Two bryozoan species are described from the Geirud Formation (Upper Devonian/Lower Carboniferous) of Central Alborz (Iran). Trepostome Schulgina ...
Pala¨ontol Z (2009) 83:439–447 DOI 10.1007/s12542-009-0027-3

RESEARCH PAPER

Stenolaemate bryozoans from the Geirud Formation (Upper Devonian/Lower Carboniferous) of Central Alborz (Iran) Andrej Ernst Æ Mahin Mohammadi

Received: 25 February 2009 / Accepted: 14 May 2009 / Published online: 5 June 2009 Ó Springer-Verlag 2009

Abstract Two bryozoan species are described from the Geirud Formation (Upper Devonian/Lower Carboniferous) of Central Alborz (Iran). Trepostome Schulgina mutabilis Troizkaya, 1975 is known from the Upper Devonian (Famennian) of Central Kazakhstan. The new species Ascopora geirudensis n. sp. is the earliest known representative of the rhabdomesine genus Ascopora Trautschold, 1876. Keywords Devonian  Bryozoa  Iran  Taxonomy  Palaeobiogeography Zusammenfassung Erstmals werden zwei Bryozoenarten der Geirud Formation (Oberdevon/Unterkarbon) des zentralen Elburs-Gebirges (Iran) beschrieben. Zwei Bryozoenarten werden aus der Geirud Formation (Upper Devonian/Early Carboniferous) von Zentral Alborz (Iran) beschrieben. Die trepostome Bryozoe Schulgina mutabilis Troizkaya, 1975 wurde zuvor aus dem Oberdevon (Famenne) von Zentralkasachstan bekannt. Die neue Art Ascopora geirudensis n. sp. ist der fru¨heste bekannte Vertreter der rhabdomesinen Gattung Ascopora Trautschold, 1876.

Schlu¨sselwo¨rter Devon  Bryozoa  Iran  Taxonomie  Pala¨obiogeographie

Introduction Devonian and Carboniferous Bryozoa are scarcely known in Iran. Bigey (1988) reported several bryozoans from the Upper Devonian of the eastern Alborz Mountains (northeastern Iran): trepostome Eostenopora sp., rhomboporid and rhabdomesine bryozoans. Bigey (in Mistiaen et al. 2001) mentioned a few bryozoans from the Frasnian, Upper Devonian of Chahriseh area, Esfahan province, Central Iran (Fistulipora sp. 1, F. sp. 2, Isotrypa sp.). Gorjunova (2006) described three species from the Lower Carboniferous (Vise´an) of northern Iran: Primorela iranica Gorjunova, 2006, Heloclema magnificum Gorjunova, 2006, and Worthenopora elbursensis Gorjunova, 2006. The present paper aims to offer the first overview of bryozoan fauna and a taxonomic description of two species from the Geirud Formation (Upper Devonian/Lower Carboniferous) of Central Alborz (Iran).

Geological setting

A. Ernst (&) Institut fu¨r Geowissenschaften, Christian-Albrechts-Universita¨t, Ludewig-Meyn-Str. 10, 24118 Kiel, Germany e-mail: [email protected] M. Mohammadi Geology Department, Payame Noor University, Nakhl St., Lashkarak Road, Tehran, Iran e-mail: [email protected]

The Iran plate is regarded as a part of marginal fragment of north Gondwana (Weddige 1984; Lasemi 2001; AlaviNaini 1993). The Alborz mountain system in northern Iran meanders for about 2,000 km from Caucasus and Azerbaijan in the northwest to northern Afghanistan in the east. The northern boundary of Alborz is the Paleo-Tethys collisional suture zone. This suture separates the southern part of Eurasia (Turan plate) from the Iran plate as a part of

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north Gondwana (Alavi 1991, 1996; Alavi-Naini 1972; Aghanabati 2004). Stratigraphy of Alborz shows a nearly complete succession from Precambrian to Holocene. The Palaeozoic part of the sections in Alborz begins with the Lower Cambrian Soltanieh, Barut, Zaigoon, and Lalun Formations. Alternating shales and dolomites of the Soltanieh Formation are covered by the Barut Formation, which consists of limestones and micaceous sandstones with several thin volcanic intercalations. Consequently, the Barut Formation is overlain by reddish brown siliciclastics of the Zaigoon and Lalun Formations. Middle Cambrian to Early Ordovician limestones (members 1–4 of the Mila Formation) overlay the Lower Cambrian sediments and are covered by brachiopod-bearing siltstones and shales (member 5 of Mila and Lashkarak Formation) of the Early to Middle Ordovician age. Important events in this sequence are a series of alternating transgressions and regressions (Assereto 1966; Stampfli 1978). Silurian deposits crop out only in the eastern part of Alborz and are represented by shales, limestones, and sandstones of the Niur Formation. The Devonian sequence starts with sandstones and shales with intercalated pyroclastics and lava flows, followed by the Upper Devonian to Carboniferous shales, sandstones, and limestones of Khoshyelagh and Geirud

Fig. 1 Geographical position of studied sections

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Formations, overlain by the Carboniferous Mobarak limestone. Lower to middle Devonian deposits are lacking in central Alborz. The Mobarak Formation is overlain by sandstones, conglomerates, and argillites of the Lower Permian (Dorud Formation), which is followed by limestones of the Middle Permian Ruteh Formation. The Palaeozoic section is terminated by shales and limestones of the Upper Permian Nessen Formation. Geirud Formation Assereto (1963) introduced the term Geirud Formation for the thick succession of siliciclastic, carbonate, and volcanic rocks that crop out extensively in the central Alborz of Iran (Figs. 1, 2). The name refers to the Geirud Valley, north of Tehran, where Assereto studied this succession for the first time. The Geirud Formation is 375–300 m in thickness (from west to east) and shows characteristics of a continental succession. This formation is believed to have formed in a shallow marine environment (Assereto 1966; Bozorgnia 1973; Stampfli 1978; Lasemi 2001; Alavi-Naini 1993; Weddige 1984; Gaetani 1965). The lower part of the sequence starts with quartzose sandstone and continues with nearly 30–40 m intercalation of black shales and sandstones. This unite includes layers of phosphate, especially in the type section, which is exploited as Geirud

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Fig. 2 Lithological column of the Geirud Formation with occurrence of bryozoan samples

Phosphate mine. These layers have been overlaid by alternation of siliciclastic and carbonates, sometime highly fossiliferous limestones. These strata are intercalated by pyroclastics and lava flows. The Geirud Formation corresponds to the time interval Givetian–Vise´an, which is characterized by the transgression/regression cycles of Paleotethys (Wendt et al. 2005; Weddige 1984; Lasemi 2001).

The Geirud Formation overlays unconformably on the Mila Formation (Upper Cambrian) and is conformably overlain by Mobarak Formation (Lower Carboniferous). A major gape including Ordovician, Silurian, and Lower to Middle Devonian was recognized at the base of Geirud Formation. This gape resulted because of the emergence of the Central Alborz area during the Caledonian orogeny.

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Localities Deposits of the Geiroud-Formation are cropped out in three localities in the north of Tehran (Fig. 1). The studied localities have the following coordinates: 1. 2. 3.

Geirud section (type section): 51°280 5200 E, 35°590 2400 N Lalun section: 51°340 5500 E, 35°580 2200 N Zaigun section: 51°360 1500 E, 35°580 2100 N

In all sections (Geirud, Zaigoon, and Lalun valleys), Geirud Formation progressively overlays the upper part of Mila Formation with ca. 10–12 m base white quartzitic sandstone and is covered by the Lower Carboniferous limestone Mobarak Formation with an invisible contact boundary (Wendt et al. 2005; Lasemi 2001; Alavi-Naini 1993; Weddige 1984; Gaetani 1965).

Materials and methods A total of 252 samples (3–5 kg each) were taken from carbonate layers in three sections. About 200 randomly oriented thin sections were prepared from this material at Payame Noor University in Tehran. Additionally, seven precisely oriented thin sections (Schulgina mutabilis) were prepared at Kiel University. The most important bryozoanbearing samples have been taken from the Geirud and Lalun sections (Fig. 2). Bryozoans were investigated in thin sections using a transmitted light microscope. Statistics were summarized with arithmetic mean, sample standard deviation, coefficient of variation, and minimum and maximum values. The studied material is deposited at the Geology Department of the Payame Noor University, Tehran, Iran, under collection numbers Gm 57-(1-8), Gm 38, L-6-2, L-6-4, L-15-5.

Systematic palaeontology Phylum Bryozoa Ehrenberg, 1831 Class Stenolaemata Borg, 1926 Order Trepostomata Ulrich, 1882 Suborder Halloporina Astrova, 1965 Family Atactotoechidae Duncan, 1939 Genus Schulgina Morozova, 1957 Type species: Schulgina nesterenkoae Morozova, 1957 by original designation. Upper Devonian (Frasnian and Fammenian); Russia. Diagnosis: Incrusting, massive, rarely branched colonies. Autozooecial apertures rounded-polygonal. Autozooecial walls thin, finely laminated, locally with monilae-shaped thickenings. Diaphragms thin, horizontal or inclined, abundant. Exilazooecia rare, locally accumulated in clusters.

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Fig. 3a–h Schulgina mutabilis Troizkaya, 1975. All specimens are c from the Geirud Formation (Famennian, Upper Devonian); Central Alborz, Iran. a, b Tangential section showing arrangement of autozooecial apertures, exilazooecia and tubules. GM 57-1. c Tangential section. GM 57-4. d, e Tangential section showing aggregations of tubules. GM 57-1. f, g Tangential section showing distribution of tubules in autozooecial walls. GM 57-4. h Longitudinal section showing diaphragms and monilae-shaped walls. GM 57-5

Acanthostyles of different sizes, abundant (modified after Astrova 1978). Comparison: Schulgina Morozova, 1957 is similar to Anomalotoechus Duncan, 1939 but differs in having thin autozooecial walls with monilae-shaped thickenings. Occurrence: Middle to Upper Devonian of Transcaucasia. Upper Devonian of Siberia, Russian Plate, Kazakhstan, Iran, and China. Schulgina mutabilis Troizkaya, 1975 Figs. 3a–h, 4a–c; Table 1. 1975 Schulgina mutabilis Troizkaya: 330, pl. 7 fig. 3. Described Material: Gm 57-(1-8) (eight thin sections). Description: Colonies incrusting, globular or discoid massive. Colony thickness 0.84–2.50 mm. Autozooecia growing from a thin epitheca, bending sharply in exozone and intersecting colony surface at angles of 90°. Autozooecial apertures rounded-polygonal. Diaphragms thin, horizontal, abundant. Exilazooecia rare, more abundant around maculae, three to five surrounding each autozooecial aperture, having polygonal apertures, originating at the base of exozone. Autozooecial walls finely laminated, 0.005 to 0.015 mm thick in endozone; showing reversal U-shaped lamination, with distinct monilae-shaped thickenings, 0.020 to 0.055 mm thick in exozone. Maculae indistinct, 0.90–1.20 mm in diameter, consisting of larger autozooecia, irregularly spaced. Usually the largest autozooecium in the center of a macula, surrounded by six or seven smaller autozooecia in rosette-like pattern. True acanthostyles absent. Tubules (microacanthostyles) 0.005–0.010 mm in diameter, distributed irregularly in autozooecial walls in exozone or forming rosette-shaped aggregations in junctions of autozooecia. Aggregations of tubules 0.02–0.04 mm in diameter. Comparison: Schulgina mutabilis Troizkaya, 1975 is similar to S. pustulosa Troizkaya, 1979 from the Upper Devonian (Famennian) of Central Kazakhstan, but differs from it having incrusting colony instead of branched one, smaller autozooecia (aperture width 0.14–0.25 vs. 0.21– 0.30 mm in S. pustulosa), and presence of tubules in autozooecial walls and absence of true acanthostyles. Occurrence: Upper part of sulcifer horizon (Famennian, Upper Devonian); western Central Kazakhstan. Geirud Formation, lower-middle expansa zone (Famennian, Upper Devonian); Central Alborz, Iran.

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Order Cryptostomata Vine, 1884 Suborder Rhabdomesina Astrova & Morozova, 1956 Family Rhabdomesidae Vine, 1884 Genus Ascopora Trautschold, 1876 Type species: Ceriopora nodosa Fischer von Waldheim, 1837 (designated by P. Wyse Jackson, International Commission on Zoological Nomenclature 1994. Opinion 1786). Carboniferous; Russia. Diagnosis: Branched colonies. Apertural arrangement rhombic. Axial region formed by weakly to well-defined axial bundle of 4–30 axial zooecia. Axial zooecia polygonal in cross-section, autozooecia in endozone initially triangular in cross-section, becoming hexagonal. Superior hemisepta usually present, strong, single, or multiple; inferior hemisepta rarely present or absent. Autozooecial diaphragms rare or absent. One or two acanthostyles proximal to each autozooecial aperture. Paurostyles common to densely spaced, arranged in single or double row, or forming aggregations. Mural spines rarely occurring (modified after Blake 1983). Comparison: Ascopora Trautschold, 1876 differs from Rhabdomeson Young & Young, 1874 in having a bundle of axial zooecia instead of a single axial cylinder. Occurrence: Carboniferous—Permian; worldwide. Ascopora geirudensis sp. n. Fig. 4d–i; Table 2. Derivation of the name: The species is named after the Geirud Formation, from which it was identified. Holotype: Gm-38. Paratypes: L-6-2, L-6-4, L-15-5. Locus typicus: Central Alborz, Iran. Stratum typicum: Geirud Formation, lower-upper expansa zone (Famennian, Upper Devonian). Description: Ramose branched colonies. Branches 0.75–2.00 mm in diameter. Axial bundle indistinct, 0.30– 1.05 mm in diameter, consisting of eight or nine axial zooecia. Autozooecia tubular-prismatic, rhombic in crosssection in endozones. Autozooecial apertures oval, arranged in regular diagonal rows around branches. Single long superior hemisepta in each autozooecium, slightly curved proximally. Six macroacanthostyles surrounding each autozooecial aperture, two arranged longitudinally between apertures; paurostyles scattered between them, 0.010– 0.015 mm in diameter. Autozooecial walls granular, 0.005–0.010 mm thick in endozone; regularly thickened, laminated in exozone. Comparison: The present species is similar to Ascopora worthenoides McKinney, 1972 from the Mississippian of Alabama in colony and aperture sizes, character of axial bundle, and presence of superior hemisepta. However, the new species differs in having two macroacanthostyles

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A. Ernst, M. Mohammadi Fig. 4a–i Schulgina mutabilis Troizkaya, 1975. All specimens are c from the Geirud Formation (Famennian, Upper Devonian); Central Alborz, Iran. a–c Longitudinal section showing diaphragms and monilae-shaped walls. GM 57-5. Ascopora geirudensis sp. n. d, e Branch cross-section. Paratype L-15-5. f Longitudinal section showing superior hemisepta. Paratype L-6-2. g Longitudinal section. Paratype L-6-1. h, i Tangential section showing apertures, macroacanthostyles and paurostyles

between autozooecial apertures instead of one in Ascopora worthenoides.

Discussion Devonian and Carboniferous Bryozoa are scarcely known in Iran. Only a few species have been reported from there (see the ‘‘Introduction’’ section). During the Upper Devonian, significant changes in the bryozoan faunas occurred worldwide. These changes resulted in increasing of importance of fenestrate and rhabdomesine bryozoans in comparison to trepostomes and fistuliporines. Furthermore, the generic composition of existing families was renewed. However, our knowledge about these events is scarce, especially because of missing data from different regions such as Iran. The Devonian part of the Geirud Formation (lowerupper expansa zone) in Central Alborz, Iran, contains relatively abundant bryozoan fauna. Unfortunately, these are mainly small fragments, which are difficult to identify. The two described species, Schulgina mutabilis Troizkaya, 1975 and Ascopora geirudensis sp. n., occur in large numbers. Schulgina mutabilis is restricted to the level of Gm 57 (lower-middle expansa zone), whereas Ascopora geirudensis has wider distribution (lower-upper expansa zone). Schulgina mutabilis is known from the upper part of sulcifer horizon (Famennian) of the western Central Kazakhstan. The short-living genus Schulgina Morozova, 1957 is restricted with 17 species mainly in the Upper Devonian of Siberia, Russian Plate, Kazakhstan, Iran and China. Single species is known from the Middle Devonian of Transcaucasia (Lavrentjeva 2001). The finding of Schulgina mutabilis Troizkaya, 1975 in the Geirud Formation delivers good support for the preliminary conodont data and maintains a palaeobiogeographic connection to the Central Kazakhstan. The earliest previously known species of the genus Ascopora Trautschold, 1876 come from the Lower Carboniferous (Vise´an) of the United States (Utah) and Russia: Ascopora macella Karklins, 1986 and Ascopora primitiva Schulga-Nesterenko, 1955. This genus includes about 50 species and persisted until the Middle Permian, being mainly distributed in the Tethian Realm. Ascopora

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Table 1 Descriptive statistics for Schulgina mutabilis Troizkaya, 1975 N

X

SD

CV

Min

Max

Aperture width

30 0.19

0.022 11.6 0.14

0.25

Aperture spacing

30 0.23

0.019

0.28

8.2 0.18

Aperture width (macular area) 25 0.27

0.027

9.8 0.24

0.32

Aperture spacing (macular area)

0.019

6.1 0.29

0.36

20 0.31

Exilazooecia width

30 0.08

0.019 25.2 0.05

0.12

Diaphragm spacing

20 0.14

0.032 22.7 0.08

0.19

Monilae length

20 0.06

0.016 25.0 0.04

0.11

Wall thickness in exozone

30 0.035 0.010 28.8 0.015 0.055

All measurements are in millimeters N Number of measurements, X mean, SD sample standard deviation, CV coefficient of variation, Min minimum value, Max maximum value

Table 2 Descriptive statistics for Ascopora geirudensis sp. n N

X

SD

CV

Min

Max

Branch width

7

1.08

0.447 41.3 0.75

2.00

Aperture width

35 0.07

0.017 23.0 0.05

0.11

Aperture spacing along branch 15 0.45

0.043

9.7 0.36

0.52

Aperture spacing across branch

15 0.18

0.012

6.9 0.16

0.19

Macroacanthostyle diameter

15 0.039 0.005 13.9 0.035 0.050

All measurements are in millimeters Abbreviations as for Table 1

geirudensis sp. n. represents the earliest known species of the genus Ascopora, identified from the Upper Devonian (Famennian) of Iran. Acknowledgments The study is undertaken with the support of the Isfehan University of Iran. We thank to Prof. Zdzislaw Belka who has contributed conodont data (in preparation). Many thanks to Mr. H. Dashtban, field geologist of National Iranian Oil Company, and Mr. Sina Farshidi for their kind assistance in field investigation and sampling.

References Aghanabati, M. 2004. Geology of Iran (in Farsi). Tehran: Geological Survey of Iran. Alavi, M. 1991. Sedimentary and structural characteristics of the Paleo-Tethys remnants in northeastern Iran. Geological Society of America Bulletin 103: 983–992. doi:10.1130/0016-7606 (1991)103\0983:SASCOT[2.3.CO;2. Alavi, M. 1996. Tectonostratigraphic synthesis and structural style of the Alborz Mountain system in northern Iran. Journal of Geodynamics 21(1): 1–33. doi:10.1016/0264-3707(95)00009-7. Alavi-Naini, M. 1972. Etude geologique de la ergion de djam. Geological Survey of Iran Reports 23: 1–45.

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Alavi-Naini, M. 1993. Paleozoic stratigraphy of Iran. Treatise on the geology of Iran. Tehran: Geological Survey of Iran. Assereto, R. 1963. The Paleozoic formations in Central Elburz (Iran) (preliminary note). Rivista Italiana di Paleontologia e Stratigrafia 69: 503–543. Assereto, R. 1966. Explanatory notes on geological map of upper Djadjerud and Lar valleys (central Elburz, Iran), scale 1: 50 000. Instituto di Geologia dell, Universita di Millano, Serie G, Pubblicazione 232: 1–86. Astrova, G.G. 1965. Morphology, history of development and system of the Ordovician and Silurian Bryozoa (in Russian). Trudy Paleontologicheskogo Instituta Akademii Nauk SSSR 106: 1–432. Astrova, G.G. 1978. The history of development, system, and phylogeny of the Bryozoa: Order Trepostomata (in Russian). Trudy Paleontologicheskogo Instituta Akademii Nauk SSSR 169: 1–240. Astrova, G.G., and I.P. Morozova. 1956. K sistematike mshanok otryada Cryptostomata [About systematics of the Order Cryptostomata] (in Russian). Doklady Akademii Nauk SSSR 110: 661–664. Bigey, F.P. 1988. Devonian Bryozoa and global events: the Frasnian/ Famenian extinction. In The Devonian of the world, Proceedings of the Second International Symposium of the Devonian System (Calgary, Canada), eds. N.J. McMillan, A.F. Embry, and D.J. Glass. Canadian Society of Petroleum Geology, Calgary, Memoir 14, vol. 3: 53–62. Blake, D.B. 1983. Systematic descriptions for the Suborder Rhabdomesina. In Treatise on Invertebrate Paleontology, Part G (1): Bryozoa (revised), ed. R.A. Robison, 550–592. Boulder: Geological Society of America and University of Kansas Press. Borg, F. 1926. Studies on recent cyclostomatous Bryozoa. Zoologiska Bidrag fran Uppsala 10: 181–507. Bozorgnia, F. 1973. Paleozoic foraminiferal biostratigraphy of central and east Alborz Mountains, Iran. National Iranian Oil Company, Geological Laboratories 4: 1–185. Duncan, H. 1939. Trepostomatous Bryozoa from the Traverse Group of Michigan. University of Michigan Paleontology Contributions 5(10): 171–270. Ehrenberg, C.G. 1831. Symbolae Physicae, seu Icones et descptiones Corporum Naturalium novorum aut minus cognitorum, quae ex itineribus per Libyam, Aegiptum, Nubiam, Dongalaam, Syriam, Arabiam et Habessiniam, studia annis 1820–25, redirent. Pars Zoologica 4, Animalia Evertebrata exclusis Insectis: 831 p. Berlin: Mittler. Fischer von Waldheim, J.G. 1837. Oryctographie du gouvernement de Moscou, 203 pp. Moscow: Socie´te´ Impe´riale des Naturalistes de Moscou. Gaetani, M. 1965. Brachiopods and molluscs from Geirud Formation, Member A (Upper Devonian and Tournaisian). Rivista Italiana di Paleontologia e Stratigrafia 71: 679–770. Ghasemi, M.R. 1990. Stratigraphy and structural geology of GgaharDeh area, eastern Alborz (in Farsi). M.S. Thesis, the Department of Geology, Tehran University, 109 p. Gorjunova, R.V. 2006. New bryozoans from the Devonian of Afghanistan and the Carboniferous of Iran (in Russian). Paleontologicheskii Zhurnal 6: 43–51. International Commission on Zoological Nomenclature. 1994. Opinion 1786. Ascopora Trautschold, 1876 (Bryozoa, Cryptostomata): Ceriopora nodosa Fischer von Waldheim, 1837 designated as a type species. Bulletin of Zoological Nomenclature 51: 285. Karklins, O.L. 1986. Chesterian (Late Mississippian) bryozoans from the upper Chainman Shale and the lowermost Ely Limestone of western Utah. Paleontological Society Memoir 17: 48 pp. Lasemi, Y. 2001. Facies analysis, depositional environment and sequence stratigraphy of the upper Pre-Cambrian and Palaeozoic rocks of Iran (in Farsi). Geological Survey of Iran: 1–181.

Stenolaemate Bryozoans from the Geirud Formation Lavrentjeva, V.D. 2001. New bryozoan species of the family Atactotoechidae from the Devonian of Transcaucasia. Paleontologicheskii Zhurnal 35(2): 45–49. Mistiaen, B., H. Gholamalian, R. Gourvennec, Y. Plusquellec, F. Bigey, D. Brice, M. Feist, R. Feist, P. Ghobadi, and E.-M. Kebria. 2001. Preliminary data on the Upper Devonian (Frasnian, Famennian) and Permian fauna and flora from the Chahriseh area (Esfahan Province, central Iran). In New systematic and palaeobiogeographic data from Palaeozoic of central Iran, eds. R. Feist, and J.-A. Talent. Annales de la Societe Geologique du Nord 8 (2): 93–102. Morozova, I.P. 1957. First representatives of the bryozoan family Atactotoechidae from the Devonian of Kuzbass (in Russian). Materialy k osnovam paleontologii Akad Nauk SSSR 1: 17–20. Sandberg, C.A., and R. Dressen. 1984. Late Devonian icriodontid biofacies models and alternate shallow water conodont zonation. Geological Society of America, Special Paper 196: 179–194. Schulga-Nesterenko, M.I. 1955. Kamennougol’nye mshanki Russkoi platformy [Carboniferous Bryozoa of the Russian Platform] (in Russian). Trudy Paleontologicheskogo Instituta Akademiya Nauk SSSR 57: 1–207. Stampfli, G. 1978. Etude ge´ologique ge´ne´rale de l’Alburz oriental au S du Gonbad-e-Qabus, Iran NE. The`se presentee a la faculte des Science de l’Universite de Geneve, No. 1868, Univ. Gene`ve, 328 p.

447 Trautschold, H. 1876. Bryozoa. Nouveaux Me´moires de la Socie´te´ Impe´riales des Naturalistes de Moscou 13 (5): 367 p. Troizkaya, T.D. 1975. Main features of the development of bryozoans in central Kazakhstan at the boundary between the Devonian and the Carboniferous. Paleontological Journal 9: 323–339. Troizkaya, T.D. 1979. Bryozoans of the meistorovi horizon of central Kazakhstan. Paleontological Journal 12: 415–423. Ulrich, E.O. 1882. American Paleozoic Bryozoa. The Journal of the Cincinnati Society of Natural History 5: 121–175, 233–257. Vine, G.R. 1884. Fourth report of the Committee consisting of Dr. H. R. Sorby and Mr. G. R. Vine, appointed for the purpose of reporting on fossil Polyzoa. Reports of the 53rd Meeting of the British Association for the Advancement in Sciences, 161–209. Weddige, K. 1984. Externally controlled Late Paleozoic events of the Iran Plate. Neues Jahrbuch fu¨r Geologie und Pala¨ontologie, Abhandlungen 168: 278–286. Wendt, J., B. Kaufmann, Z. Belka, N. Farsan, and A.K. Bavandpur. 2005. Devonian/Lower carboniferous stratigraphy, facies patterns and palaeogeography of Iran. Part P. North and central Iran. Acta Geologica Polonica 55(1): 31–97. Young, J., and I. Young. 1874. On a new genus of Carboniferous Polyzoa. Annals and Magazine of Natural History 13(4): 335– 339.

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