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Taxonomy and species diversity of Holocene pylonioid radiolarians from surface sediments of the northeastern Indian Ocean

Lanlan Zhang and Noritoshi Suzuki

Plain Language Abstract

This paper focuses on the species of the Pylonioidea (Order Spumellaria, Class Polycystina, Infrakingdom Rhizaria) found in Holocene deposits in the northeastern Indian Ocean. Taxa of this superfamily have been regarded as particularly difficult to identify for a century, even though they are a well-known and useful group for tropical and subtropical oceanography and paleoceanography. Clear identification in the Pylonoidea to cover all the morphotypes in samples is necessary for advanced studies of radiolarians. We have found that this difficulty can be resolved with clear recognition of a specimen's orientation in terms of absolute or relative Cartesian coordinates and by improving morphological terminology. All recognizable morphotypes from our samples were photographed and divided based on morphology. To account for morphological variations within morphotypes, different ontogenetic growth stages and different orientations, a total of 34 morphotypes corresponding to species and subspecies were recognized. Based on this taxonomic framework, all pylonioid specimens illustrated in previous literature have been re-classified. Furthermore, this framework resolves the taxonomic confusion associated with the well-known Tetrapyle octacantha group and other species and reveals new information of the geographic limitations of the distribution of several species.

Resumen en Español

Taxonomía y diversidad de especies de radiolarios Pylonioidea del Holoceno de sedimentos superficiales del Océano Índico nororiental

Los radiolarios de la superfamilia Pylonioidea muestran una alta diversidad de especies en los sedimentos superficiales del Océano Índico nororiental. Pueden ser utilizados como importantes índices oceanográficos en los océanos tropicales y subtropicales, pero la identificación de los radiolarios Pylonioidea ha presentado desafíos debido a las notables diferencias en el aspecto de los especímenes en diferentes orientaciones. Se ha considerado el examen de sus estructuras internas para una identificación precisa, pero este método no es realista si se quiere examinar miles de especímenes preparados y fijados en portaobjetos para microscopía. Por lo tanto, hemos desarrollado métodos prácticos para la identificación de estos radiolarios en preparaciones de portaobjetos con el uso de microscopía de luz transmitida. Este procedimiento comienza con la confirmación de las orientaciones de los especímenes con respecto a la sombra de la combinación central. Después de que las orientaciones se determinaron bajo sistemas de coordenadas absolutos (Tipo 1) y relativos (Tipo 2), se identificaron grupos morfológicos basados en diferencias en la apariencia. Los nombres taxonómicos se asignaron a estos grupos morfológicos teniendo en cuenta las variaciones morfológicas, los cambios ontogénicos y, lo que es más importante, si los holotipos y los especímenes relevantes podrían incluirse dentro de estos grupos morfológicos. Nuestro estudio arrojó un total de 10 géneros y 34 especies/subespecies, incluidos tres nuevos géneros (Sphaeropylolena n. gen., Sphaerolarnacillium n. gen. y Qiuripylolena n. gen.) y 20 nuevas especies/subespecies en la superfamilia Pylonioidea (Larcospira teres n. sp., L. tetragonicentrum n. sp., Larcopyle buetschlii chenmuhongi n. subsp., L. buetschlii onion n. subsp., L. molle n. sp., L. eccentricanoides n. sp., L. pulchella n. sp., Sphaeropylolena laxa n. sp., S. tenellispinosa n. sp., Phorticium itakii n. sp., P. scitulum n. sp., Sphaerolarnacillium cochleatum n. sp., S. exactum n. sp., S. tanzhiyuani n. sp., Qiuripylolena chikuchik n. sp., Q. pompon n. sp., Q.? multiconcentrica n. sp., Circodiscus biorbiculus n. sp., C. pseudomicroporus n. sp., y Tholomura pilula n. sp.). Siguiendo este esquema taxonómico, confirmamos la distribución geográfica limitada de muchas especies de la superfamilia Pylonioidea.

Palabras clave: Radiolaria; Pylonioidea; Nuevo género; Nueva especie; Océano Índico; Sedimentos superficiales tropicales

Traducción: Enrique Peñalver (Sociedad Española de Paleontología)

Résumé en Français

Taxinomie et diversité spécifique des radiolaires pylonioïdes holocènes des sédiments de surface du nord-est de l'océan Indien

Les radiolaires pylonioïdes montrent une forte diversité spécifique dans les sédiments de surface du nord-est de l'océan indien. Ils peuvent être utilisés comme d'importants marqueurs océanographiques dans les océans tropicaux et subtropicaux, mais l'identification des radiolaires pylonioïdes pose des problèmes à cause de changements majeurs d'apparence des spécimens observés sous différentes orientations. Une étude de leurs structures internes pour les identifier précisément a été envisagée, mais cette méthode n'est pas faisable pour étudier des milliers de spécimens de pylonioïdes inclus sur des lames de microscope. Nous avons donc développé des méthodes faisables pour identifier les radiolaires pylonioïdes à partir de lames minces observées sous des microscopes à lumière transmise. Cette procédure commence par l'alignement des orientations des spécimens selon l'ombre de leurs capsules centrales. Après que les orientations sont déterminées à la fois dans des systèmes de coordonnées absolues (Type 1) et relatives (Type 2), des groupes morphologiques sont identifiés d'après les différences d'apparence. Des noms taxinomiques ont été assignés à ces groupes morphologiques en prenant en compte les variations morphologiques, les changements ontogénétiques, et plus important, la possibilité d'inclure les holotypes et autres spécimens importants au sein de ces groupes morphologiques. Notre étude a livré un total de 10 genres et 34 espèces/sous-espèces, incluant trois nouveaux genres (Sphaeropylolena n. gen., Sphaerolarnacillium n. gen., et Qiuripylolena n. gen.) et 20 nouvelles espèces/sous-espèces dans la super-famille Pylonioidea (Larcospira teres n. sp., L. tetragonicentrum n. sp., Larcopyle buetschlii chenmuhongi n. subsp., L. buetschlii onion n. subsp., L. molle n. sp., L. eccentricanoides n. sp., L. pulchella n. sp., Sphaeropylolena laxa n. sp., S. tenellispinosa n. sp., Phorticium itakii n. sp., P. scitulum n. sp., Sphaerolarnacillium cochleatum n. sp., S. exactum n. sp., S. tanzhiyuani n. sp., Qiuripylolena chikuchik n. sp., Q. pompon n. sp., Q.? multiconcentrica n. sp., Circodiscus biorbiculus n. sp., C. pseudomicroporus n. sp., et Tholomura pilula n. sp.). En utilisant ce schéma taxinomique, nous avons confirmé la distribution géographique limitée de nombreuses espèces de pylonioïdes.

Mots-clés : Radiolaria ; Pylonioidea ; nouveau genre ; nouvelle espèce ; océan Indien ; sédiments tropicaux de surface

Translator: Antoine Souron

Deutsche Zusammenfassung

Taxonomie und Artenvielfalt der holozänen pylonioiden Radiolarien aus Oberflächensedimenten des nordöstlichen Indischen Ozeans

Pylonioide Radiolarien weisen in Oberflächensedimenten des nordöstlichen Indischen Ozeans eine hohe Artenvielfalt auf. Sie können als wichtige ozeanografische Indizes in tropischen und subtropischen Ozeanen angewandt werden, jedoch ist die Bestimmung pylonioider Radiolarien wegen gravierender Veränderungen der Stücke in unterschiedlichen Orientierungen schwierig. Es wurden Untersuchungen ihrer internen Struktur für eine präzisen Identifikation angedacht, jedoch ist diese Methode unrealistisch, wenn tausende pylonioider Stücke auf Objektträgern untersucht werden sollen. Daher haben wir praktische Methoden zur Radiolarienbestimmung mittels Durchlicht-Mikroskopie mit gerahmten Objektträgern entwickelt. Anfangs wird die Orientierung des Stückes in Bezug auf den Schatten der zentralen Kombination bestätigt. Nachdem die Orientierung sowohl unter dem absoluten (Typ 1) als auch unter dem relativen (Typ 2) Koordinatensystem festgelegt wurde, wurden morphologische Gruppen aufgrund von Unterschieden im Erscheinungsbild identifiziert. Diesen morphologischen Gruppen wurden taxonomische Namen zugeteilt unter Berücksichtigung morphologischer Variationen, ontogenetischer Veränderung und, am wichtigsten, ob die Holotypen und relevanten Stücke in diese morphologische Gruppen einbezogen werden könnten. Unsere Untersuchung erbrachte insgesamt 10 Gattungen und 34 Arten/Subarten, inklusive dreier neuer Gattungen (Sphaeropylolena n. gen., Sphaerolarnacillium n. gen. und Qiuripylolena n. gen.) und 20 neue Arten/Subarten innerhalb der Subfamilie Pylonioidea (Larcospira teres n. sp., L. tetragonicentrum n. sp., Larcopyle buetschlii chenmuhongi n. subsp., L. buetschlii onion n. subsp., L. molle n. sp., L. eccentricanoides n. sp., L. pulchella n. sp., Sphaeropylolena laxa n. sp., S. tenellispinosa n. sp., Phorticium itakii n. sp., P. scitulum n. sp., Sphaerolarnacillium cochleatum n. sp., S. exactum n. sp., S. tanzhiyuani n. sp., Qiuripylolena chikuchik n. sp., Q. pompon n. sp., Q.? multiconcentrica n. sp., Circodiscus biorbiculus n. sp., C. pseudomicroporus n. sp. und Tholomura pilula n. sp.). Indem wir diesem taxonomischen Schema folgen, bestätigten wir die limitierte geografische Verbreitung vieler pylonioider Arten.

Schlüsselwörter: Radiolaria; Pylonioidea; neue Gattung; neue Art; Indischer Ozean; tropische Oberflächensedimente

Translator: Eva Gebauer

Arabic

Translator: Ashraf M.T. Elewa

 

 

FIGURE 1. Location of the sampling sites in the northeastern Indian Ocean. The surface current (thick arrows) is modified from Peng et al. (2015); the deep circulation (thin arrows) is modified from Kawagata et al. (2006); the isohaline showing surface salinity during June (mean of 93 years) is modified from Gupta et al. (2002). Abbreviations are as follows: AABW, Antarctic Bottom Water; CPDW, Circumpolar Deep Water; NIHSIW, North Indian High-salinity Intermediate Water; NMC, Northeast Monsoon Current; SMC, Southwest Monsoon Current.

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FIGURE 2. Morphological terminology under a transmitted light microscope. 1-2, for gate and girdle; 3-8, for different pylonioid systems.

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FIGURE 3. The absolute and relative orientations of specimens under the pylonioid system. The symbol “*” indicates Type 2 Relative Cartesian Coordinates.

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FIGURE 4. The diagrams of the absolute Cartesian coordinate (Type 1) and the relative Cartesian coordinate (Type 2). 1, Type 1; 2, Type 2.

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FIGURE 5. The structure of central combination in genera Tetrapyle (1-3), Larcopyle (4) and Circodiscus (5). 1, Sg-view at Type 1, Fr-view at Type 2; 2, Pl-view at Type 1, Fr-view at Type 2; 3, Lt-view at Type 1, Pr-view at Type 2. G1, G2, S1a, and S1a-girdle are the morphological terminology, of which the definitions have been shown in Table 1.

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FIGURE 6. Photographs of the encountered morphotypes of Tetrapyle octacantha Müller 1859 sensu stricto. All are Pl-view at Type 1, Fr-view at Type 2. Scale bar equals 0.1 mm. The arrow marks indicate the major portal-spines. All specimens are from YDY05-01.

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FIGURE 7. The typical Tetrapyle octacantha specimens from the surface water from the southern Villefranche-sur-Mer. 1 and 6, Ug-view at Type 2; 2-3 and 8, Pr-view at Type 2; 4-7, Fr-view at Type 2. Scale bar equals 0.1 mm. The arrow marks indicate the major portal-spines.

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FIGURE 8. Photographs of the encountered morphotypes of Tetrapyle circularis Haeckel, 1887. All are Pl-view at Type 1, Fr-view at Type 2. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 9. Photographs of the encountered morphotypes of Tetrapyle circularis Haeckel, 1887. All are Pl-view at Type 1, Fr-view at Type 2. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 10. Photographs of the encountered morphotypes of Tetrapyle fruticosa (Tan and Chen, 1990) new combination. All are Pl-view at Type 1, Fr-view at Type 2. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 11. Photographs of the encountered morphotypes of Tetrapyle spp. (juvenile form). 1-2 and 9, Lt-view at Type 1, Fr-view at Type 2; 3-5, 7-8, 11-12, Sg-view at Type 1, Fr-view at Type 2; 6 and 10, Pl-view at Type 1, Fr-view at Type 2; 13-14, Pl-view at Type 1, Ug-view at Type 2; 15-16, Sg-view at Type 1, Fr-view at Type 2; 17-18, Sg-view at Type 1, Ug-view at Type 2. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 12. Photographs of the encountered morphotypes of Larcospira quadrangula Haeckel, 1887 sensu stricto. All are Pl-view at Type 1. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 13. Photographs of the encountered morphotypes of Larcospira teres n. sp. All are Pl-view at Type 1. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 14. Photographs of the encountered morphotypes of Larcospira tetragonicentrum n. sp. All are Pl-view at Type 1. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 15. Photographs of the encountered morphotypes of Pylodiscus spinulosus (Chen and Tan, 1989). All are Fr-view at Type 2. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 16. Photographs of the encountered morphotypes of Larcopyle cervicornis (Haeckel, 1887) sensu stricto. All are Pl-view at Type 1. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 17. The topotypes from the H.M.S. Challenger station 271. 1-6, Larcopyle cervicornis (Haeckel, 1887); 7-12, Larcopyle buetschlii buetschlii Dreyer, 1889. All are Pl-view at Type1. Scale bar equals 0.1 mm. All specimens are from H.M.S. Challenger Station 271 sample

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FIGURE 18. Photographs of the encountered morphotypes of Larcopyle. 1-6, Larcopyle variabile (Dreyer, 1889) sensu emend.; 7-12, Larcopyle molle n. sp.; 13-18, Larcopyle eccentricanoides n. sp.; 19-22, Larcopyle pulchella n. sp. All are Fr-view at Type 2. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 19. Photographs of the encountered morphotypes of Larcopyle buetschlii buetschlii Dreyer, 1889, sensu stricto. All are Fr-view at Type 2. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 20. Photographs of the encountered morphotypes of Larcopyle buetschlii chenmuhongi n. subsp. All are Fr-view at Type 2. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 21. Photographs of the encountered morphotypes of Larcopyle buetschlii orion n. subsp. All are Fr-view at Type 2. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

 

FIGURE 22. Photographs of the encountered morphotypes of Sphaeropylolena laxa n. sp. All are Fr-view at Type 2. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 23. Photographs of the encountered morphotypes of Sphaeropylolena tenellispinosa n. sp. All are Fr-view at Type 2. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 24. Photographs of the encountered morphotypes of Phorticium multispinum Popofsky, 1912 sensu emend. (1-3) and Phorticium itakii n. sp. (4-6). All are Pl-view at Type 1, Fr-view at Type 2. Scale bar equala 0.1 mm. All specimens are from YDY05-01.

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FIGURE 25. Photographs of the encountered morphotypes of Phorticium polycladum Tan and Tchang, 1976. 1-10, Sg-view at Type 1; 11-14, Pl-view at Type 1. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 26. Photographs of the encountered morphotypes of Phorticium scitulum n. sp. 1-23, Sg-view at Type 1. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 27. Photographs of the encountered morphotypes of Sphaerolarnacillium cochleatum gen. et n. sp. All are Fr-view at Type 2. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 28. Photographs of the encountered morphotypes of Sphaerolarnacillium exactum n. sp. All are Fr-view at Type 2. Scale bar equala 0.1 mm. All specimens are from YDY05-01.

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FIGURE 29. Photographs of the encountered morphotypes of Sphaerolarnacillium tanzhiyuani n. sp. All are Fr-view at Type 2. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 30. Photographs of the encountered morphotypes of Qiuripylolena. 1-10, Qiuripylolena chikuchik n. sp.; 11-22, Qiuripylolena pompon n. sp.; 23-34, Qiuripylolena ? multiconcentica n. sp. All are Sg-view at Type 1. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 31. Photographs of the encountered morphotypes of Circodiscus. 1-2, Circodiscus amphitrites (Ehrenberg, 1854b); 3-4, Circodiscus biorbiculus n. sp.; 5-14, Circodiscus microporus (Stöhr, 1880); and 15-16, Circodiscus pseudomicroporus n. sp. All are Sg-view at Type1, Fr-view at Type 2. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

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FIGURE 32. Photographs of the encountered morphotypes of Tholomura. 1-11, Tholomura hexonia (Haeckel, 1887); 12-23, Tholomura pilula n. sp.; 24-32, Tholomura polystyla (Chen, 1987). 1-16, 19-23, 26-32, Pl-view at Type 1; 17-18, 24-25, Lt-view at Type 1. Scale bar equals 0.1 mm. All specimens are from YDY05-01.

figure32

 

 

TABLE 1. Morphological terminology for pylonioids.

Taxonomic specification Terms Definition Reference
Key skeletal elements microsphere (S1a) The innermost shell (< 50 μm in diameter) in Spumellaria. Microsphere is considered to form at the initial skeletogenesis. It differs from the macrosphere by its size only. This corresponds to S1a. De Wever et al. (2001); Dumitrica (1989)
girdle One of pylonioid multiple shells. A girdle looks like an encircled band, a triangle outline composed of mutually oriented circular tests, or a set of large vaulted dome-shaped tests which are orthogonally arranged. For example, a girdle is constituted with two caps or two wings in Tetrapyle, with six cupolas in the Tholoniidae. De Wever et al. (2001)
cap Portion of a girdle that develops from a previous skeletal part. The “circular test”, “dome-shaped test” and cupolar is a kind of cap. Dumitrica (19895)
wing An incomplete cap. Haeckel (1887)
half girdle An abstract word when it is not necessary to differentiate between “cap” and “wing”. Haeckel (1887)
cupola Large vaulted dome of a cap. This is also termed as “dome-shaped test.” Dumitrica (1989)
gate Gate is defined by the disclosed large space between part of a girdle and the previous skeleton, in the case of the Pylonioidea. This term is an abstract noun if it is not necessary to concern on the orientation of a gate. “Aperture” and “Tunnel” are used when one needs to explain about gates in consideration with its orientation. Redefined herein
aperture An appearance of a gate that one can see an opening. New
tunnel An appearance of a gate that one can see the wall that forms a gate. New
Pylonioid system A set of one to four successive outer girdles. One set of the lateral, transverse and sagittal girdles in the sense of Jørgensen (1905). This term may be written simply as “system.” Dumitrica (1989)
S1a-girdle The pylonioid system that directly develops from the microsphere (S1a). This corresponds to S1a-girdle. Dumitrica (1989)
central combination The skeletal structure comprised with a microsphere and the S1a-girdle. The development pattern of the a-girdle with the S1a is a key to specify family or subfamily position in Pylonioidea. New
band girdle An encircle girdle to form a ring. New
joint part The connection where two or more caps share. New
ring One of Circodiscus multiple shells. A ring is encircled. New
di-clade corner/junction A corner resulting from bending of a microspheric bar. Dumitrica (1989)
tri-clade corner/junction A kind of a triple-junction on pore frame. An edged corner or a nodal point where three bars of pore frame unit. Dumitrica (1989)
pillar A kind of bar, beam, rod and spine that are arisen from cupolas of an inner girdle. Dumitrica (1989)
Skeletal frame and structures primary ray/spine (RB) A kind of bar, beam, rod and spine that directly extends from a tri-clade corner. RL-primary ray (spines) originating in a di-clade bar corresponding to one of the lateral edges of the hypothetical prism. Dumitrica (1991)
dimensive beams/rods/spines (DR) A kind of beam, rod and spine that orthogonally extends from the S1a. The term DR is mainly used if its orientation is not concerned. If its orientation is concerned under some coordinates, they are called like “a sagittal beam”. Dumitrica (1989)
polar beam/rod/spine (PN) The straight heavy beam/rod/spine on the top of a cap. A PN is not always connected to a DR. This term includes “a sagittal septum” in the concept of Haeckel (1887, p. 650) Benson (1966)
pseudo-concentric shell This term is named for “concentric appearance” of girdles under transmitted light microscope. Although pyloniid skeleton is made of one or more systems of girdles, the skeleton looks like having “concentric” structure. The quick recognition of “pseudo-concentric shell” without regard to the number of a system and the orientation of the central combination is useful in observing mounted slides New
portal-main spines Generally, eight long and thin cylindrical radial spines from the edges of girdle, lying in two crossed diagonal planes, opposite direction. New

 

 

TABLE 2. The definitions of the Type 1 absolute Cartesian coordinate systems for pylonioids.

Newly defined three coordinate systems Terms Sub-terms Definition Reference
Absolute Cartesian coordinates

(Type 1 coordinates)

Origin   The center of the microsphere (S1a). This origin is critical when inner pylonioid systems are concerned. New
Axis polar axis (Pl-axis) The axis that crosses the longest orientation of the central combination. Sugiyama et al. (1992)
lateral axis (Lt-axis) The axis in parallel to the maximum width of S2a girdle. Sugiyama et al. (1992)
sagittal axis (Sg-axis) The axis which orthogonally crosses both the Pl-axis and Lt-axis. Sugiyama et al. (1992)
Plane polar plane (Pl-plane) The plane vertical to Pl-axis includes both Sg-axis and Lt-axis. Sugiyama et al. (1992)
lateral plane (Lt-plane) The plane vertical to Lt-axis includes Pl-axis and Sg-axis. Sugiyama et al. (1992)
sagittal plane (Sg-plane) The plane vertical to Sg-axis includes both Pl-axis and Lt-axis. Sugiyama et al. (1992)
View polar view (Pl-view) The view that one can see Pl-plane. Defined here
lateral view (Lt-view) The view that one can see Lt-plane. Defined here
sagittal view (Sg-view) The view that one can see Sg-plane. Defined here

 

 

TABLE 3. The definitions of the Type 2 relative Cartesian coordinate systems for pylonioids.

Newly defined three coordinate systems Terms Sub-terms Definition Reference
Relative Cartesian coordinates

(Type 2 coordinates)

Origin   The origin of Type 2 coordinates is virtually defined by the “center” of the outermost pylonioid system. This leads that the origin of type 2 coordinates may or may not be the same with that of type 1 coordinates. This origin is not critical in order to describe something with type 2 coordinates. New
Axis Profile axis (Pr-axis) The axis of the shortest direction of a girdle where one can see a large gate aperture. Haeckel (1887); redefined here
Upright axis (Ug-axis) The axis of the widest direction of a girdle where one can see a large gate aperture. Haeckel (1887); redefined here
Front axis (Fr-axis) The axis vertical to both Pr-axis and Ug-axis. Haeckel (1887); redefined here
Plane Front plane (Fr-plane) The plane vertical to the Fr-axis includes both Ug-axis and Pr-axis. New
Profile plane (Pr-plane) The plane vertical to the Pr-axis includes both Ug-axis and Fr-axis. New
Upright plane (Ug-plane) The plane vertical to the Ug-axis includes both Pr-axis and Fr-axis. New
View Front view (Fr-view) The view that one can see Fr-plane. If the girdle is a ribbon-like girdle, the large aperture of gate is visible. New
Profile view (Pr-view) The view that one can see Pr-plane. If the girdle is a ribbon-like girdle, a single tunnel of gate is visible on the same focus of an S1a. New
Upright view (Ug-view) The view that one can see Ug-plane. If the girdle is a ribbon-like girdle, twin tunnels of gate is visible in both sides of the previous system on the same focus of an S1a. New

 

 

TABLE 4. The counting rules for pylonioids.

Terms Definition Reference
Gn [n = 1, 2, 3...] The distinguishing code of a gate in a pylonioid system (Gn) [n = 1, 2, 3...]: G1, G2, and G3 are coded from the inner gate to outer gate. Definition herein
x ring [x = 1st, 2nd, 3rd...] The distinguishing code of a ring in a Circodiscus system (x ring) [x = 1st, 2nd, 3rd...]: 1st ring, 2nd ring, and 3rd ring are coded from the inner ring to outer ring. Definition herein
Sn [n = 1, 2, 3...] The numbering system for the pylonioid system (Sn) [n = 1, 2, 3...]: From the first system, systems are coded as S1, S2, and S3... Dumitrica (1989)
k-girdle [k = a, b, c...] The distinguishing code of a girdle in a pylonioid system (k-girdle) [k = a, b, c, d...]: a-girdle, b-girdle, c-girdle, and d-girdle are coded from the inner (or early developmental) girdle to outer (or later developmental) girdle in the same system Dumitrica (1989)
Snk girdle The combination of Sn and k-girdle (Snk girdle): The code Snk-girdle is defined as the k (k = a, b, c...) girdle of Sn (n = 1, 2, 3). For example, the second girdle of the 3rd system is coded as “S3b girdle”. The microsphere is coded as “S1a.” Dumitrica (1989)
 

author1Lanlan Zhang. CAS Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China. This email address is being protected from spambots. You need JavaScript enabled to view it.

Lanlan Zhang is associate professor at South China Sea Institute of Oceanology, Chinese Academy of Sciences. She is mainly interested in the ecology and biology of modern radiolarians, and the sedimentary and preservation of radiolarian shells.

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author2Noritoshi Suzuki. Department of Earth Sciences, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan. This email address is being protected from spambots. You need JavaScript enabled to view it.

Noritoshi Suzuki is assistant professor at Tohoku University. He is interested in the diversity change of radiolarians through the Phanerozoic, the ecology and biology of radiolarians, and advanced paleontologic studies based on modern radiolarians.
Further information on his contributions can be found here:
https://scholar.google.com/citations?user=K1FDz5wAAAAJ&hl=en