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Bryozoan fauna from the Permian (Artinskian-Kungurian) Zhongba Formation of southwestern Tibet

Andrej Ernst

Plain Language Abstract

Bryozoans are marine colonial animals and represent a phylum known from the Early Ordovician to the present. The majority of bryozoans produce a stable calcitic skeleton which has a high preservation potential. Therefore, bryozoans have multiple uses for stratigraphy, palaeogeography and palaeoecology. In the present paper an Early Permian bryozoan fauna from the Zhongba Formation of southwestern Tibet is described. The Zhongba Formation was deposited in a relatively deep marine environment of the tropical part of the Tethys. The studied bryozoan fauna includes 30 species from 25 genera. Seven species are new: Fistulipora sakagamii n. sp., Dybowskiella hupehensiformis n. sp., Etherella tibetensis n. sp., Dyscritella lii n. sp., Streblotrypa (Streblotrypa) parviformis n. sp., Timanotrypa australis n. sp., and Protoretepora irregularis n. sp. One new genus with one species is also new: Tibetiporella ornata n. gen. n. sp. The majority of species is known from other regions with faunas of late early Permian age, which is older than the previously defined age of the Zhongba Formation as stated by other fossils like brachiopods (middle – late Permian). Furthermore, the identified species are distributed in such regions as Thailand, Oman, Western Australia, Timor, central Pamir, Iran, Urals, and other Tibetan localities. So far, this fauna shows an intermixture of species from the Northern and Southern Hemispheres, and implies more extensive faunal migrations into the tropical region from both the north and south than previously known.

Resumen en Español

Fauna de briozoos del Pérmico (Artinskiano-Kunguriano) de la Formación Zhongba, sudoeste tibetano

La asociación de briozoos de la Formación Zhongba del sudoeste de Tibet incluye 30 especies de 25 géneros. Siete especies son nuevas: Fistulipora sakagamii sp. n., Dybowskiella hupehensiformis sp. n., Etherella tibetensis sp. n., Dyscritella lii sp. n., Streblotrypa (Streblotrypa) parviformis sp. n., Timanotrypa australis sp. n., y Protoretepora irregularis sp. n. Un género con una especie también es nueva: Tibetiporella ornata gen. n. sp. n. La fauna descripta implica una edad cisuraliana (artinskiana-kunguriana) para la Formación Zhongba y muestra relaciones con las faunas cisuralianas de Tailandia, Australia Occidental, Omán, Timo, Pamir central, Irán, los Urales y otras localidades tibetanas. La fauna de briozoos de la Formación Zhongba muestra una intermezcla de elementos boreales y gondwánicos e implica migraciones faunísticas más intensas hacia la región tropical tanto desde el norte como desde el sur. El análisis paleoecológico sugiere que la depositación de la Formación Zhongba ocurrió en un escenario de plataforma media a cierta distancia de la línea de costa, probablemente influenciada por corrientes locales.

Palabras clave: Bryozoa; taxonomía; paleobiogeografía; género nuevo; especie nueva

Traducción: Diana Elizabeth Fernández

Résumé en Français

La faune de bryozoaires du Permien (Artinskien-Kungurien) de la formation de Zhongba, sud-ouest du Tibet

L'assemblage de bryozoaires de la formation de Zhongba, sud-ouest du Tibet, inclut 30 espèces appartenant à 25 genres. Sept espèces classifiées dans des genres déjà connus sont nouvelles : Fistulipora sakagamii n. sp., Dybowskiella hupehensiformis n. sp., Etherella tibetensis n. sp., Dyscritella lii n. sp., Streblotrypa (Streblotrypa) parviformis n. sp., Timanotrypa australis n. sp., et Protoretepora irregularis n. sp. Une nouvelle espèce appartenant à un nouveau genre est également décrite : Tibetiporella ornata n. gen. n. sp. La faune décrite indique un âge cisuralien (artinskien-kungurien) pour la formation de Zhongba et démontre des relations avec les faunes cisuraliennes de la Thaïlande, de l'Australie occidentale, du Sultanat d'Oman, du Timor, du Pamir central, de l'Iran, de l'Oural, et d'autres localités tibétaines. La faune de bryozoaires de la formation de Zhongba montre un mélange d'éléments boréaux et gondwaniens, et indique des dispersions fauniques fortes vers les régions tropicales à la fois depuis le nord et le sud. L'analyse paléoécologique suggère que la formation de Zhongba s'est déposée dans un milieu de plateforme moyenne, à une certaine distance de la côte, probablement sous l'influence des courants locaux.

Mots-clés : Bryozoa ; taxinomie ; paléobiogéographie ; nouveau genre ; nouvelle espèce

Translator: Antoine Souron

Deutsche Zusammenfassung

Die Bryozoen-Fauna aus der permischen (Artinskium-Kungurium) Zhongba Formation von Südwest-Tibet

Die Bryozoen-Assemblage aus der Zhongba Formation von Südwest-Tibet beinhaltet 30 Arten und 25 Gattungen. Sieben Arten sind neu: Fistulipora sakagamii n. sp., Dybowskiella hupehensiformis n. sp., Etherella tibetensis n. sp., Dyscritella lii n. sp., Streblotrypa (Streblotrypa) parviformis n. sp., Timanotrypa australis n. sp. und Protoretepora irregularis n. sp. Eine Gattung mit einer Art ist ebenfalls neu: Tibetiporella ornata n. gen. n. sp. Die beschriebene Fauna weist auf ein cisurales (Artinskium-Kungurium) Alter der Zhongba Formation hin und zeigt Verwandtschaften mit den cisuralen Faunen von Thailand, Westaustralien, Oman, Timor, Zentral-Pamir, Iran, Ural und anderen tibetischen Fundstellen. Die Bryozoen-Fauna der Zhongba-Formation zeigt eine Mischung aus borealen und gondwanischen Elementen und weist auf eine stärkere Faunen-Migration, sowohl von Norden als auch von Süden, in die tropischen Gebiete hin. Paläoökologische Analysen legen nahe, dass die Zhongba Formation in einiger Entfernung zur Küste an einem mittleren Schelf abgelagert wurde und möglicherweise durch lokale Strömungen beeinflusst war.

Schlüsselwörter: Bryozoa; Taxonomie; Paläobiogeographie; neue Gattung; neue Art

Translator: Eva Gebauer

Arabic

585 arab

Translator: Ashraf M.T. Elewa

 

 

TABLE 1. Measurements of Fistulipora enodata Gorjunova, 1970. Abbreviations: N = number of measurements; X = mean; SD = standard deviation; CV = coefficient of variation; MIN = minimal value; MAX = maximal value.

  N X SD CV MIN MAX
Autozooecial aperture width, mm 35 0.30 0.032 10.87 0.24 0.38
Autozooecial aperture spacing, mm 35 0.58 0.067 11.47 0.45 0.75
Vesicle diameter, mm 35 0.13 0.034 27.24 0.07 0.21
Vesicle spacing, mm 35 0.11 0.025 21.80 0.08 0.17
Vesicles per aperture 20 12.6 1.188 9.43 11.0 15.0
Lunarium length, mm 20 0.14 0.024 17.26 0.10 0.18
Lunarium width, mm 20 0.25 0.028 11.30 0.20 0.29

TABLE 2. Measurements of Fistulipora guttata Trizna and Klautzan, 1961. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Autozooecial aperture width, mm 30 0.28 0.038 13.89 0.23 0.38
Autozooecial aperture spacing, mm 30 0.66 0.073 11.04 0.55 0.80
Vesicle diameter, mm 30 0.11 0.030 28.08 0.05 0.19
Vesicle spacing, mm 25 0.10 0.022 21.78 0.05 0.13
Vesicles per aperture 30 12.0 1.564 13.07 9.0 16.0
Lunarium length, mm 15 0.14 0.037 26.91 0.08 0.23
Lunarium width, mm 15 0.21 0.030 14.18 0.17 0.29
Lunarium thickness, mm 15 0.08 0.031 40.31 0.03 0.13

TABLE 3. Measurements of Fistulipora sakagamii n. sp. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Autozooecial aperture width, mm 13 0.15 0.014 9.39 0.14 0.19
Autozooecial aperture spacing, mm 7 0.42 0.034 8.20 0.36 0.46
Vesicle diameter, mm 10 0.12 0.021 17.78 0.09 0.16
Vesicles per aperture 4 8.5 1.000 11.76 8.0 10.0
Lunarium length, mm 7 0.13 0.030 23.01 0.09 0.16
Lunarium width, mm 7 0.14 0.023 16.55 0.10 0.18
Lunarium thickness, mm 7 0.07 0.015 21.35 0.05 0.09

TABLE 4. Measurements of Dybowskiella hupehensiformis n. sp. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Autozooecial aperture width, mm 30 0.30 0.019 6.43 0.26 0.33
Autozooecial aperture spacing, mm 30 0.57 0.056 9.75 0.45 0.67
Vesicle diameter, mm 30 0.11 0.026 22.76 0.06 0.18
Vesicle spacing, mm 30 0.09 0.013 15.18 0.06 0.11
Vesicles per aperture 10 13 1.563 12.03 11.0 15.0
Lunarium length, mm 30 0.19 0.021 11.06 0.15 0.24
Lunarium width, mm 30 0.21 0.021 10.28 0.17 0.28
Lunarium thickness, mm 30 0.12 0.024 20.27 0.07 0.18

TABLE 5. Measurements of Fistuliramus xianzaensis Liu and Wang, 1987. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch diameter, mm 6 7.4 0.928 12.49 5.9 8.3
Exozone width, mm 6 1.7 0.417 24.76 1.1 2.3
Endozone width, mm 6 4.1 0.613 15.04 3.3 5.1
Autozooecial aperture width, mm 50 0.29 0.031 10.58 0.23 0.34
Autozooecial aperture spacing, mm 50 0.51 0.072 14.13 0.35 0.65
Vesicle diameter, mm 50 0.12 0.029 24.54 0.05 0.19
Vesicles per aperture 16 11.7 0.873 7.47 10.0 13.0
Vesicle spacing, mm 50 0.12 0.033 26.52 0.07 0.24
Lunarium length, mm 29 0.16 0.042 26.36 0.08 0.24
Lunarium width, mm 29 0.24 0.036 15.28 0.16 0.31
Lunarium thickness, mm 29 0.11 0.025 23.33 0.06 0.15

TABLE 6. Measurements of Eridopora uncata Yang and Lu, 1983. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Autozooecial aperture width, mm 31 0.26 0.046 17.72 0.18 0.37
Autozooecial aperture spacing, mm 31 0.47 0.068 14.39 0.33 0.62
Vesicle diameter, mm 31 0.09 0.024 25.76 0.05 0.15
Vesicles per aperture 10 13.7 1.703 12.43 11.0 16.0

TABLE 7. Measurements of Cyclotrypa alexanderi Sakagami, 1963. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Autozooecial aperture width, mm 50 0.20 0.017 8.71 0.17 0.25
Autozooecial aperture spacing, mm 50 0.39 0.050 12.86 0.27 0.50
Vesicle diameter, mm 50 0.13 0.029 22.74 0.07 0.18
Vesicles per aperture 22 7.64 1.432 18.76 5.0 11.0
Maculae diameter, mm 11 0.6 0.163 26.67 0.4 0.9
Macrozooecial aperture width, mm 7 0.31 0.041 13.25 0.25 0.36

TABLE 8. Measurements of Hexagonella kobayashii Sakagami, 1968. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Autozooecial aperture width, mm 22 0.22 0.016 7.15 0.19 0.25
Autozooecial aperture spacing, mm 22 0.53 0.047 8.81 0.42 0.60
Vesicle diameter, mm 30 0.12 0.031 25.96 0.04 0.19
Vesicles per aperture 10 9.0 0.667 7.41 8.0 10.0
Vesicle spacing, mm 13 0.10 0.023 23.09 0.07 0.14

TABLE 9. Measurements of Goniocladia aff. indica Waagen and Pichl, 1885. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch width, mm 6 1.22 0.405 33.36 0.88 2.00
Branch thickness, mm 10 0.99 0.220 22.34 0.63 1.26
Fenestrule width, mm 8 3.2 0.412 13.04 2.4 3.7
Fenestrule length, mm 8 5.8 0.989 17.03 4.3 6.9
Distance between branch centres, mm 8 6.5 0.316 4.82 6.0 7.0
Distance between dissepiment centres, mm 6 7.7 0.359 4.67 7.2 8.1
Autozooecial aperture width, mm 20 0.19 0.022 11.29 0.15 0.22
Autozooecial aperture spacing, mm 20 0.60 0.097 16.37 0.42 0.70
Lunarium length, mm 6 0.08 0.018 21.29 0.06 0.10
Lunarium width, mm 6 0.14 0.019 14.03 0.10 0.15
Lunarium thickness, mm 5 0.03 0.009 36.19 0.02 0.04

TABLE 10. Measurements of Liguloclema meridianus (Etheridge, 1926). Abbreviations as for Table 1.

  N X SD CV MIN MAX
Autozooecial aperture width, mm 30 0.14 0.012 8.54 0.12 0.16
Autozooecial aperture spacing, mm 30 0.65 0.105 16.17 0.52 0.95
Aperture spacing diagonally, mm 30 0.47 0.045 9.59 0.37 0.55
Vesicle diameter, mm 30 0.08 0.018 22.51 0.05 0.12

TABLE 11. Measurements of Etherella tibetensis n. sp. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch width, mm 10 3.60 0.790 21.99 2.8 5.1
Fenestrule width, mm 20 2.33 0.477 20.50 1.6 3.3
Fenestrule length, mm 20 3.2 0.376 11.75 2.1 4.0
Autozooecial aperture width, mm 30 0.17 0.025 14.40 0.12 0.21
Autozooecial aperture spacing along branch, mm 30 0.53 0.066 12.52 0.45 0.66
Autozooecial aperture spacing diagonally, mm 30 0.50 0.056 11.15 0.4 0.6
Vesicle diameter, mm 20 0.09 0.030 32.88 0.05 0.15

TABLE 12. Measurements of Tabulipora xinjiangensis Yang and Lu, 1983. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Autozooecial aperture width, mm 12 0.30 0.027 9.19 0.25 0.35
Autozooecial aperture spacing, mm 7 0.40 0.060 15.08 0.32 0.50
Exozonal wall thickness, mm 7 0.094 0.014 14.50 0.075 0.120

TABLE 13. Measurements of Dyscritella lii n. sp. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Autozooecial aperture width, mm 29 0.24 0.030 12.28 0.18 0.30
Autozooecial aperture spacing, mm 22 0.38 0.057 15.06 0.26 0.48
Acanthostyle diameter, mm 20 0.08 0.022 28.54 0.04 0.12
Acanthostyles per aperture 14 10.1 1.657 16.34 8.0 14.0

TABLE 14. Measurements of Ulrichotrypa omanica Ernst et al., 2008. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Autozooecial aperture width, mm 17 0.28 0.048 17.11 0.21 0.38
Autozooecial aperture spacing, mm 13 0.47 0.076 16.33 0.38 0.67
Exozone width, mm 6 0.10 0.023 23.29 0.06 0.12
Aktinotostyle diameter, mm 10 0.06 0.012 21.43 0.04 0.07
Exozonal wall thickness, mm 8 0.11 0.031 28.22 0.07 0.15

TABLE 15. Measurements of Neoeridotrypella astrica (Linskaya, 1951). Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch width, mm 4 4.66 0.550 11.79 4.10 5.40
Exozone width, mm 4 0.65 0.136 20.94 0.54 0.82
Endozone width, mm 4 3.36 0.305 9.07 3.02 3.76
Autozooecial aperture width, mm 30 0.22 0.024 11.00 0.17 0.26
Autozooecial aperture spacing along branch, mm 30 0.47 0.051 10.85 0.40 0.57
Macroacanthostyle diameter, mm 21 0.16 0.028 17.42 0.10 0.22
Microacanthostyle diameter, mm 30 0.07 0.013 17.64 0.04 0.10

TABLE 16. Measurements of Streblotrypa (Streblotrypa ) parviformis n. sp. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch width, mm 20 0.68 0.091 13.45 0.51 0.92
Exozone width, mm 19 0.13 0.027 20.66 0.09 0.17
Endozone width, mm 19 0.42 0.066 15.84 0.31 0.58
Axial bundle width, mm 17 0.15 0.039 25.61 0.10 0.26
Autozooecial aperture width, mm 25 0.10 0.011 11.15 0.08 0.12
Autozooecial aperture spacing along branch, mm 4 0.53 0.059 11.20 0.48 0.61
Autozooecial aperture spacing diagonally, mm 3 0.25 0.026 10.58 0.22 0.27
Metazooecia width, mm 15 0.02 0.006 28.30 0.01 0.03

 

TABLE 17. Measurements of Streblotrypa (Streblascopora ) delicatula Sakagami, 1961. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch width, mm 4 1.68 0.288 17.14 1.30 2.00
Axial bundle width, mm 4 0.58 0.092 15.97 0.45 0.67
Autozooecial aperture width, mm 19 0.16 0.010 6.53 0.13 0.17
Autozooecial aperture spacing along branch, mm 15 0.45 0.055 12.15 0.37 0.55
Autozooecial aperture spacing diagonally, mm 15 0.29 0.034 11.50 0.24 0.35
Metazooecia width, mm 15 0.03 0.009 27.91 0.02 0.05
Metazooecia per aperture 7 7.4 0.976 13.14 6.0 9.0

 

TABLE 18. Measurements of Streblotrypa (Streblascopora ) marmionensis (Etheridge, 1926). Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch width, mm 12 1.25 0.198 15.88 1.00 1.55
Axial bundle width, mm 12 0.38 0.077 20.26 0.26 0.54
Exozone width, mm 12 0.19 0.034 17.95 0.14 0.26
Endozone width, mm 12 0.87 0.165 18.88 0.65 1.15
Autozooecial aperture width, mm 12 0.11 0.010 9.22 0.10 0.13
Metazooecia width, mm 11 0.02 0.006 30.05 0.01 0.03

TABLE 19. Measurements of Rhabdomeson bretnalli Crockford, 1957. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch width, mm 7 2.45 0.610 24.91 1.60 3.30
Axial tube diameter, mm 7 0.53 0.158 29.76 0.27 0.80
Autozooecial aperture width, mm 18 0.17 0.021 12.58 0.12 0.20
Autozooecial aperture spacing along branch, mm 10 0.41 0.068 16.60 0.36 0.56
Autozooecial aperture spacing diagonally, mm 12 0.27 0.028 10.44 0.22 0.31

TABLE 20. Measurements of Primorella rotunda Gorjunova, 1975. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Autozooecial aperture width, mm 30 0.17 0.026 15.98 0.12 0.22
Autozooecial aperture spacing along branch, mm 5 0.53 0.050 9.33 0.48 0.61
Autozooecial aperture spacing diagonally, mm 5 0.36 0.050 14.02 0.32 0.44
Aktinotostyle diameter, mm 20 0.027 0.007 25.38 0.010 0.038

TABLE 21. Measurements of Timanotrypa australis n. sp. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch width, mm 4 4.9 1.458 29.76 3.2 6.7
Branch thickness, mm 5 1.7 0.415 24.69 1.1 2.2
Autozooecial aperture width, mm 35 0.16 0.012 7.60 0.13 0.19
Autozooecial aperture spacing along branch, mm 8 0.79 0.044 5.55 0.72 0.85
Autozooecial aperture spacing diagonally, mm 30 0.44 0.051 11.57 0.37 0.55
Node diameter, mm 5 0.08 0.015 18.05 0.06 0.10

TABLE 22. Measurements of Spinofenestella sp. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch width, mm 15 0.30 0.020 6.67 0.28 0.34
Dissepiment width, mm 15 0.15 0.009 6.05 0.14 0.17
Fenestrule width, mm 15 0.23 0.019 8.01 0.20 0.27
Fenestrule length, mm 15 0.41 0.018 4.26 0.38 0.45
Distance between branch centres, mm 15 0.51 0.032 6.27 0.45 0.56
Distance between dissepiment centres, mm 15 0.56 0.025 4.38 0.52 0.61
Autozooecial aperture width, mm 20 0.07 0.007 9.13 0.06 0.09
Autozooecial aperture spacing along branch, mm 20 0.26 0.015 5.72 0.24 0.29
Autozooecial aperture spacing diagonally, mm 20 0.30 0.014 4.51 0.27 0.33
Maximum chamber width, mm 20 0.12 0.008 6.62 0.11 0.14
Keel node diameter, mm 15 0.06 0.008 12.94 0.05 0.08
Node spacing, mm 15 0.13 0.011 8.35 0.10 0.14
Node diameter, reverse side, mm 20 0.11 0.020 18.01 0.08 0.15

TABLE 23. Measurements of Spinofenestella subquadratopora (Schulga-Nesterenko, 1952). Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch width, mm 10 0.32 0.023 7.16 0.29 0.36
Dissepiment width, mm 10 0.12 0.022 18.00 0.10 0.17
Fenestrule width, mm 10 0.33 0.047 14.42 0.25 0.39
Fenestrule length, mm 10 0.46 0.036 7.82 0.40 0.50
Distance between branch centres, mm 10 0.62 0.094 15.21 0.48 0.80
Distance between dissepiment centres, mm 10 0.59 0.041 7.03 0.53 0.68
Autozooecial aperture width, mm 10 0.10 0.007 7.45 0.09 0.11
Autozooecial aperture spacing along branch, mm 10 0.29 0.018 6.03 0.27 0.32
Autozooecial aperture spacing diagonally, mm 10 0.31 0.023 7.50 0.28 0.35
Maximum chamber width, mm 10 0.17 0.018 10.70 0.14 0.19
Keel node diameter, mm 20 0.11 0.017 15.88 0.08 0.14
Node spacing, mm 20 0.30 0.021 7.03 0.25 0.34

TABLE 24. Measurements of Polypora consanguinea Bassler, 1929. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch width, mm 5 1.27 0.180 14.21 1.08 1.45
Dissepiment width, mm 2 0.54 0.014 2.62 0.53 0.55
Fenestrule width, mm 4 1.24 0.159 12.79 1.08 1.40
Fenestrule length, mm 2 2.05 0.071 3.45 2.00 2.10
Autozooecial aperture width, mm 9 0.13 0.005 4.20 0.12 0.13
Autozooecial aperture spacing along branch, mm 7 0.41 0.059 14.50 0.36 0.53
Autozooecial aperture spacing diagonally, mm 7 0.28 0.025 8.99 0.25 0.32
Maximum chamber width, mm 9 0.21 0.011 4.99 0.20 0.23

TABLE 25. Measurements of Polypora brouweri Bassler, 1929. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch width, mm 6 0.91 0.151 16.55 0.72 1.13
Dissepiment width, mm 3 0.48 0.035 7.27 0.45 0.52
Fenestrule width, mm 4 1.1 0.200 18.18 1.0 1.4
Fenestrule length, mm 3 3.1 0.814 26.56 2.5 4.0
Distance between branch centres, mm 6 1.94 0.191 9.83 1.80 2.25
Autozooecial aperture width, mm 20 0.14 0.009 6.91 0.12 0.16
Autozooecial aperture spacing along branch, mm 20 0.51 0.065 12.68 0.40 0.60
Autozooecial aperture spacing diagonally, mm 20 0.32 0.035 11.02 0.25 0.38
Maximum chamber width, mm 20 0.21 0.009 4.14 0.20 0.23

TABLE 26. Measurements of Polypora aff. voluminosa Trizna and Klautzan, 1961. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch width, mm 8 0.85 0.153 17.92 0.67 1.02
Dissepiment width, mm 7 0.56 0.052 9.25 0.50 0.65
Fenestrule width, mm 6 0.62 0.066 10.77 0.53 0.70
Fenestrule length, mm 3 1.25 0.218 17.44 1.10 1.50
Distance between branch centres, mm 6 1.26 0.143 11.36 1.10 1.50
Distance between dissepiment centres, mm 7 1.90 0.312 16.44 1.63 2.38
Autozooecial aperture width, mm 30 0.11 0.006 5.57 0.10 0.12
Autozooecial aperture spacing along branch, mm 30 0.42 0.038 8.98 0.36 0.56
Autozooecial aperture spacing diagonally, mm 30 0.33 0.032 9.80 0.27 0.40
Maximum chamber width, mm 15 0.22 0.015 6.65 0.20 0.25
Node diameter, obverse side, mm 29 0.10 0.022 23.60 0.06 0.15
Node diameter, reverse side, mm 10 0.10 0.015 15.89 0.07 0.12

 

TABLE 27. Measurements of Mackinneyella obesa (Crockford, 1957). Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch width, mm 18 1.83 0.121 6.58 1.70 2.10
Dissepiment width, mm 23 0.86 0.112 13.00 0.67 1.08
Fenestrule width, mm 21 0.88 0.200 22.84 0.55 1.20
Fenestrule length, mm 25 1.96 0.219 11.20 1.50 2.30
Distance between branch centres, mm 16 2.55 0.297 11.63 1.75 3.00
Distance between dissepiment centres, mm 20 2.97 0.294 9.93 2.30 3.45
Autozooecial aperture width, mm 40 0.17 0.021 11.89 0.14 0.23
Autozooecial aperture spacing along branch, mm 40 0.45 0.041 9.00 0.36 0.51
Autozooecial aperture spacing diagonally, mm 40 0.30 0.034 11.53 0.24 0.38
Maximum chamber width, mm 40 0.23 0.017 7.25 0.20 0.27
Node diameter, reverse side, mm 20 0.16 0.028 17.32 0.12 0.20
Node diameter, obverse side, mm 10 0.08 0.018 22.05 0.05 0.10

TABLE 28. Measurements of Protoretepora irregularis n. sp. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch width, mm 20 1.8 0.332 18.21 1.2 2.5
Fenestrule width, mm 12 1.4 0.310 21.88 0.9 2.0
Fenestrule length, mm 7 3.9 1.212 31.19 2.0 5.5
Autozooecial aperture width, mm 40 0.18 0.017 9.94 0.14 0.20
Autozooecial aperture spacing along branch, mm 40 0.33 0.037 11.18 0.26 0.40
Maximum chamber width, mm 40 0.26 0.018 6.85 0.23 0.30
Node diameter, reverse side, mm 20 0.18 0.036 20.10 0.14 0.25

TABLE 29. Measurements of Tibetiporella ornata n. gen. n. sp. Abbreviations as for Table 1.

  N X SD CV MIN MAX
Branch width, mm 30 1.06 0.157 14.73 0.78 1.38
Branch thickness 10 1.87 0.308 16.42 1.40 2.25
Dissepiment width, mm 30 1.29 0.165 12.78 1.00 1.60
Fenestrule width, mm 30 0.60 0.090 15.01 0.45 0.79
Fenestrule length, mm 30 1.20 0.151 12.64 0.77 1.63
Distance between branch centres, mm 30 1.68 0.195 11.60 1.25 2.13
Distance between dissepiment centres, mm 30 2.54 0.123 4.84 2.40 2.85
Autozooecial aperture width, mm 30 0.14 0.011 7.70 0.12 0.16
Autozooecial aperture spacing along branch, mm 30 0.36 0.046 12.79 0.26 0.43
Autozooecial aperture spacing diagonally, mm 30 0.22 0.025 11.31 0.17 0.26
Apertures per fenestrule length 10 5.8 0.789 13.60 5.0 7.0
Maximum chamber width, mm 30 0.21 0.017 8.12 0.18 0.25
Node diameter, mm 30 0.09 0.018 20.85 0.05 0.12
Heteromorph width, mm 30 0.30 0.045 15.07 0.24 0.41

TABLE 30. Matrix of occurrences of bryozoan species from the Zhongba Formation used for the numerical plots in the Figure 23 (1 - present, 0 - absent). Thailand and Western Australia share the hightest number of species with the Zhongba area (five and four species, respectively), whereas other regions share three or fewer species with the studied area.

  Zhongba Fm. Xainza Pamir Thailand W-Australia Timor Urals Oman Xinjiang Iran
Fistulipora enodata 1 1 1 0 0 0 0 0 0 0
Fistulipora guttata 1 0 0 0 0 0 1 0 0 0
Fistulipora sakagamii 1 0 0 1 0 0 0 0 0 0
Dybowskiella hupehensiformis 1 0 0 0 0 0 0 0 1 0
Fistuliramus xianzaensis 1 1 0 0 0 0 0 0 0 0
Eridopora uncata 1 0 0 0 0 0 0 0 1 0
Cyclotrypa alexanderi 1 0 0 0 1 0 0 0 0 0
Hexagonella kobayashii 1 0 0 1 0 0 0 1 0 0
Liguloclema meridianus 1 1 0 1 1 0 0 0 0 0
Tabulipora xinjiangensis 1 0 0 0 0 0 0 0 1 0
Ulrichotrypella omanica 1 0 0 0 0 0 0 1 0 0
Neoeridotrypella astrica 1 0 0 0 0 0 1 0 0 0
S.(S.) delicatula 1 0 0 1 0 0 0 1 0 0
S. (S.) marmionensis 1 0 1 0 1 0 0 1 0 1
Rhabdomeson bretnalli 1 0 0 0 1 0 0 0 0 0
Primorella rotunda 1 0 1 0 0 0 0 1 0 1
Timanotrypa australis 1 0 0 1 0 0 0 0 0 0
Spinofenestella subquadratopora 1 0 0 0 0 0 1 0 0 0
Polypora consanguinea 1 0 0 0 0 1 0 0 0 0
Polypora brouweri 1 0 0 0 0 1 0 0 0 0
Mackinneyella obesa 1 0 0 0 0 1 0 0 0 0

TABLE 31. Distribution of bryozoan growth forms in the Zhongba Formation.

Species Growth form
Fistulipora enodata encrusting
Fistulipora guttata encrusting
Fistulipora sakagamii encrusting
Dybowskiella hupehensiformis encrusting
Eridopora uncata encrusting
Tabulipora xinjiangensis encrusting
Dyscritella lii encrusting
Cyclotrypa alexanderi encrusting/branched
Hexagonella kobayashii branched/bifoliate/lenticular
Liguloclema meridianus branched/bifoliate/lenticular
Timanotrypa australis branched/bifoliate/lenticular
Fistuliramus xianzaensis branched/cylindrical
Ulrichotrypella omanica branched/cylindrical
Neoeridotrypella astrica branched/cylindrical
Streblotrypa (Streblotrypa) parviformis branched/cylindrical
Streblotrypa (Streblascopora) delicatula branched/cylindrical
Streblotrypa (Streblascopora) marmionensis branched/cylindrical
Rhabdomeson bretnalli branched/cylindrical
Rhabdomeson sp. branched/cylindrical
Primorella rotunda branched/cylindrical
Spinofenestella sp. reticulate/connected/biserial
Spinofenestella subquadratopora reticulate/connected/biserial
Polypora consanguinea reticulate/connected/multiserial
Polypora brouweri reticulate/connected/multiserial
Polypora aff. voluminosa reticulate/connected/multiserial
Mackinneyella obesa reticulate/connected/multiserial
Goniocladia aff. indica reticulate/fused/bifolate/multiserial
Etherella tibetensis reticulate/fused/bifoliate/lenticular
Protoretepora irregularis reticulate/fused/multiserial
Tibetiporella ornata reticulate/fused/multiserial
 

FIGURE 1. Position of the sampling area and tectonic setting of the Tibetan Plateau and Southern China (simplified after Dai et al., 2011). GCT: Great Counter thrust; ZGT: Zhongba-Gyangze thrust.

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FIGURE 2. Lithological characteristics of the limestones from the Zhongba Formation. 1, limestone sample with abundant bryozoans (SMF 23.262); 2, rudstone containing crinoids, cystoporate (Fistulipora enodata Gorjunova, 1970) and fenestrate bryozoans (SMF 23.263); 3, bindstones with Fistulipora guttata Trizna and Klautzan, 1961 (SMF 23.264); and 4, grain- to packstones with bryozoan and crinoid fragments (SMF 23.265).

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FIGURE 3. Thin section photographs of Fistulipora enodata Gorjunova, 1970, SMF 23.014 (1-4); Fistulipora guttata Trizna and Klautzan, 1961, SMF 23.025 (5-8); and Fistulipora sakagamii n. sp., holotype SMF 23.028 (9 and 10). 1 and 5, longitudinal section showing autozooecial chambers and vesicular skeleton; and 2-4, 6-8, 9, and 10, tangential sections showing autozooecial apertures and vesicles.

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FIGURE 4. Thin section photographs of Fistulipora sakagamii n. sp., holotype SMF 23.028 (1 and 2); Dybowskiella hupehensiformis n. sp., holotype SMF 23.030 and paratype SMF 23.032 (3-7); and Fistuliramus xianzaensis Liu and Wang, 1987, SMF 23.037 (8). 1, 2, 5-7, tangential section showing autozooecial apertures and vesicles; 3 and 4, longitudinal section showing autozooecial chambers and vesicular skeleton; and 8, branch transverse section.

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FIGURE 5. Thin section photographs of Fistuliramus xianzaensis Liu and Wang, 1987, SMF 23.042 (1) and SMF 23.038 (2 and 3); and Eridopora uncata Yang and Lu, 1983, SMF 23.052 (4 and 6) and SMF 23.051 (5). 1, longitudinal section; and 2-6, tangential section showing autozooecial apertures and vesicles.

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FIGURE 6. Thin section photographs of Eridopora uncata Yang and Lu, 1983, SMF 23.052 (1-3); Cyclotrypa alexanderi Sakagami, 1963 SMF 23.056 (4-5), SMF 23.061 (6), and SMF 23.056 (7); and Hexagonella kobayashii Sakagami, 1968, SMF 23.069 (8-9) and SMF 23.070 (10 and 11). 1-3, tangential section showing autozooecial apertures with lunarial ends indenting into the aperture (arrow); 7, tangential section showing autozooecia and macrozooecia (arrow); 8 and 9, branch transverse section showing autozooecial chambers and vesicular skeleton; and 10 and 11, longitudinal section showing autozooecial chambers and vesicular skeleton.

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FIGURE 7. Thin section photographs of Hexagonella kobayashii Sakagami, 1968, SMF 23.067 (1-3) and SMF 23.072 (4); and Goniocladia aff. indica Waagen and Pichl, 1885, SMF 23.266 (5), SMF 23.077 (6), and SMF 23.073 (7). 1-3 and 6, tangential section; 7, mid-tangential section showing autozooecial chamber; 4, transverse section showing mesotheca with median tubules (arrow); and 5, external view of the colony form the reverse side.

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FIGURE 8. Thin section photographs of Goniocladia aff. indica Waagen and Pichl, 1885, SMF 23.076 (1 and 2), SMF 23.077 (3-5), and SMF 23.073 (6 and 7); and Liguloclema meridianus (Etheridge, 1926), SMF 23.093 (8). 1-2, and 6, branch transverse sections showing autozooecia chambers, mesotheca and hemisepta (arrow); 3-5, tangential sections showing autozooecial apertures; 7, longitudinal section showing autozooecial chamber with superior hemisepta (arrow); and 8, branch oblique section showing mesotheca, autozooecial chambers with hemisepta and vesicular skeleton.

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FIGURE 9. Thin section photographs of Liguloclema meridianus (Etheridge, 1926), SMF 23.093 (1), SMF 23.085 (2), and SMF 23.083 (3-5); and Etherella tibetensis n. sp., paratype SMF 23.217 (6). 1 and 2, branch oblique section showing mesotheca, autozooecial chambers with hemisepta and vesicular skeleton; 3 and 4, mid-tangential section showing autozooecial chambers with hemisepta; 5, tangential section showing autozooecial apertures; and 6, transverse section showing extrazooecial skeleton and sparse vesicles.

figure9

FIGURE 10. Thin section photographs of Etherella tibetensis n. sp., paratype SMF 23.267 (1), paratype SMF 23.216 (2), paratype SMF 23.219 (3 and 4), holotype SMF 23.214 (5-7), and paratype SMF 23.230 (8 and 9). 1, external view of the colony (split along mesotheca); 2-4, tangential section showing arrangement of autozooecia and wall microstructure; 5-7, oblique section showing hemisepta and mesotheca (arrows); and 8 and 9, branch transverse section showing autozooecial chambers and extrazooecial skeleton.

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FIGURE 11. Thin section photographs of Tabulipora xinjiangensis Yang and Lu, 1983, SMF 23.233 (1 and 2); Dyscritella lii n. sp., holotype SMF 23.235 (3, 4, and 6) and paratype SMF 23.236 (5); and Ulrichotrypella omanica Ernst et al., 2008, SMF 23.242 (7 and 8). 1, longitudinal section showing ring septa; 2, oblique section showing macroacanthostyles and tubules; 3 and 4, oblique section through the colony; 5 and 6, tangential section showing autozooecial apertures and acanthostyles; and 7 and 8, oblique section.

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FIGURE 12. Thin section photographs of Ulrichotrypella omanica Ernst et al., 2008, SMF 23.242 (1); Neoeridotrypella astrica (Linskaya, 1951), SMF 23.245 (2 and 3), SMF 23.246 (4-6), and SMF 23.249 (7); and Streblotrypa (Streblotrypa) parviformis n. sp., holotype SMF 23.251 (8-10). 1, 6, 7, and 10, tangential section; 2-5, oblique branch section; and 8 and 9, longitudinal section.

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FIGURE 13. Thin section photographs of Streblotrypa ( Streblotrypa) parviformis n. sp., paratype SMF 23.260 (1) and paratype SMF 23.256 (2 and 3); Streblotrypa (Streblascopora) delicatula Sakagami, 1961, SMF 23.205 (4, 6, and 7), SMF 23.206 (5), and SMF 23.143 (8); and Streblotrypa (Streblascopora) marmionensis (Etheridge, 1926), SMF 23.145 (9). 1 and 8, branch transverse section; 2, 3, 5, and 9, longitudinal section; 4, branch oblique section; and 6 and 7, tangential section.

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FIGURE 14. Thin section photographs of Streblotrypa ( Streblascopora) marmionensis (Etheridge, 1926), SMF 23.145 (1 and 2), and SMF 23.148 (3); and Rhabdomeson bretnalli Crockford, 1957, SMF 23.155 (4-6) and SMF 23.157 (7-9). 1, longitudinal section; 2 and 7, tangential section; 3 and 4, branch transverse section; and 5, 6, 8 and 9; branch oblique section.

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FIGURE 15. Thin section photographs of Rhabdomeson sp. SMF 23.160 (1-4) and SMF 23.158 (5); and Primorella rotunda Gorjunova, 1985, SMF 23.163 (6) and SMF 23.162 (7-9). 1-3, branch oblique section; 4 and 5, longitudinal section; 6, tangential section; and 7-9, oblique section.

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FIGURE 16. Thin section photographs of Timanotrypa australis n. sp., holotype SMF 23.165 (1), paratype SMF 23.166 (2 and 3), paratype SMF 23.169 (4), and paratype SMF 23.171 (5). 1, oblique section of the pinnate branch; 2 and 3, tangential section showing autozooecial apertures, nodes (arrows) and microstyles; and 4 and 5, branch transverse section.

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FIGURE 17. Thin section photographs of Spinofenestella sp., SMF 23.178 (1-5); and Spinofenestella subquadratopora (Schulga-Nesterenko, 1952), SMF 23. 179 (6-8). 1-3, tangential section of the reverse side; 4-7, tangential section of the obverse side; and 8, mid- tangential section.

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FIGURE 18. Thin section photographs of Polypora consanguinea Bassler, 1929, SMF 23.182 (1-4); and Polypora brouweri Bassler, 1929, SMF 23.183 (5-9). 1, oblique section; 2-5, tangential section showing autozooecial apertures, nodes and autozooecial chambers; 6, reverse side of the colony; and 7-9, tangential section showing autozooecial apertures and chambers.

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FIGURE 19. Thin section photographs of Polypora aff. voluminosa Trizna and Klautzan, 1961, SMF 23.187 (1-3, and 5) and SMF 23.185 (4 and 6); and Mackinneyella obesa (Crockford, 1957), SMF 23.191 (7) and SMF 23.192 (8). 1 and 2, tangential section branches and fenestrules; 3, tangential section of the reverse side showing nodes; 4, tangential section showing autozooecial apertures and chambers with hemisepta (arrow); 5, tangential section showing autozooecial apertures, chambers and heteromorph (arrow); 6, tangential section showing autozooecial apertures and nodes; and 7 and 8, tangential section showing autozooecial apertures and chambers.

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FIGURE 20. Thin section photographs of Mackinneyella obesa (Crockford, 1957), SMF 23.194 (1, 3), SMF 23.191 (2), and SMF 23.189 (4); and Protoretepora irregularis n. sp., paratype SMF 23.198 (5), SMF 23.268 (6), and SMF 23.195 (7). 1-3, and 7, tangential section showing autozooecial chambers; 4, branch transverse section; 5, branch longitudinal section; and 6, external view of the reverse side of the colony.

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FIGURE 21. Thin section photographs of Protoretepora irregularis n. sp., paratype SMF 23.201 (1, 3, and 4), paratype SMF 23.202 (2), and holotype SMF 23.195 (5); and Tibetiporella ornata n. gen. n. sp., paratype SMF 23.224 (6 and 7) and holotype SMF 23.227 (8). 1, tangential section showing autozooecial apertures and chambers; 2, mid-tangential section showing autozooecial chambers; 3, 4, 7, and 8, tangential section showing autozooecial apertures, microstyles and nodes; 5, tangential section of obverse colony side with nodes; and 6, tangential section of the reverse side of the colony.

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FIGURE 22. Thin section photographs of Tibetiporella ornata n. gen. n. sp., holotype SMF 23.227 (1 and 2), paratype SMF 23.211 (3 and 4), paratype SMF 23.210 (5 and 6), paratype SMF 23.213 (7 and 8), and paratype SMF 23.225 (9). 1 and 2, tangential section showing autozooecial apertures, nodes and heteromorphs; 3 and 4, mid-tangential section showing autozooecial chambers; 5 and 6, tangential section showing autozooecial apertures, nodes and heteromorphs; 7 and 8, longitudinal section showing autozooecial chambers and heteromorphs; and 9, transverse section showing autozooecial chambers.

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FIGURE 23. Palaeobiogeographical affinities of the bryozoan assemblage from the Zhongba Formation (Zhongba). Top: dendrogram of the cluster analysis using Jacquard's similarity index (unweighted pair-group average algorithm), and bottom: plot of non-metric MDS analysis made with Jacquard's similarity index. Areas: Pamir (Tajikistan), Oman (Batain Coast), Iran (central Iran, Chili Formation), Xainza (southwestern Tibet, Xiala Fm.), Thailand, Urals, Western Xinjiang (Baliqliq Group), and W. Australia (Noonkanbah Fm.). Japan, Malaysia, and Rutog (southwestern Tibet) were omitted as sharing only one species with Zhongba assemblage.

figure23

 

authorAndrej Ernst. Institut für Geologie, Universität Hamburg, Bundesstr. 55, 20146 Hamburg, Germany. This email address is being protected from spambots. You need JavaScript enabled to view it.

Dr. Andrej Ernst is a specialist for bryozoan taxonomy, evolution, biogeography and ecology, as well as for carbonate sedimentology. His PhD at the University of Kiel (1999) was devoted Permian bryozoans of Zechstein Basin and NW Tethys. After a short post-doc project he spent one year at the Geological Museum in Oslo (2002-2003), then acted at the University of Kiel. In 2013 Andrej Ernst has moved to Hamburg. The range of his research includes study of Palaeozoic and some post-Palaeozoic bryozoans faunas worldwide.