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opencc-zeroDec 2015View details →

Data from: Morphometrics and paleoecology of Catenipora (Tabulata) from the Xiazhen Formation (Upper Ordovician), Zhuzhai, South China

Catenipora is one of the most common tabulate coral genera occurring in various lithofacies in the Upper Ordovician Xiazhen Formation at Zhuzhai in South China. A combination of traditional multivariate analysis and geometric morphometrics is applied to a large number of specimens to distinguish and identify species. Based on three major principal components extracted from 11 morphological characters, three major groups as determined by the cluster-analysis dendrogram are considered to be morphospecies. Their validity and distinctiveness are confirmed by discriminant analysis, descriptive statistics, and bivariate plots. Tabularium area and common wall thickness are the most meaningful characters to distinguish the three morphospecies. Geometric morphometrics is adopted to compare the morphospecies with types and/or figured specimens of species previously reported from the vicinity of Zhuzhai. Despite discrepancies in corallite size, principal component analysis and discriminant analysis, as well as consideration of overall morphological characteristics, indicate that the morphospecies represent C. zhejiangensis Yu in Yu et al., 1963, C. shiyangensis Lin and Chow, 1977, and C. dianbiancunensis Lin and Chow, 1977. Catenipora occurs in seven stratigraphic intervals in the Xiazhen Formation at Zhuzhai, representing a variety of heterogeneous environments. The coralla preservation is variable due to differential compaction; coralla preserved in limestones are commonly intact and in growth position, whereas those in shales are mostly crushed or fragmentary. The size and shape of corallites are considered primarily to be species-specific characters, but are also related to the depositional environments. In all species, morphological characters, including corallite size, septal development, and shape and size of lacunae, show high variability in accordance with lithofacies and stratigraphic position. The intraspecific differences in corallite size at various localities in the Zhuzhai area may indicate responses to local environmental factors, but may also reflect genetic differences if there was limited connection among populations.

opencc-zeroDec 2014View details →

Data from: Trepostomate bryozoans from the upper Katian (Upper Ordovician) of Morocco: gigantism in high latitude Gondwana platforms

A study of the Upper Ordovician trepostomate bryozoans belonging to the families Amplexoporidae and Monticuliporidae, from the eastern Anti-Atlas of Morocco, is presented here. They occur in the marly to fine-grained limestone, intermediate unit of the Khabt-el-Hajar Formation, late Katian in age, representing outer-ramp depositional environments. They inhabited the highest paleolatitude known for a bryozoan fauna during the Ordovician, estimated at more than 65–70ºS. A total of 11 species of the genera Anaphragma, Atactoporella, Homotrypa, Monotrypa, Monticulipora, and Prasopora are described. Three species are already known from the equatorial-tropical paleocontinents of Baltica, Laurentia, and Siberia: Anaphragma mirabile, Monotrypa jewensis, and Prasopora falesi. Four new taxa are described:Anaphragma undulata, Atactoporella moroccoensis, Monticulipora globulata, and Monticulipora irregularis. The two species of Anaphragma and the one of Atactoporella display significantly larger zoarial sizes than congeneric species, representing gigantism among bryozoans. Polar gigantism is rejected for the two species of Anaphragma as is gigantism related to photosynthetic endosymbionts. An alternative proposal for their giant size is their long zoarial life span due to their well-balanced, robust branching form, with a relatively wide basal supporting surface, adapted to unconsolidated substrates in environments below wave base. Their great stability in outer-ramp environments, with infrequent storms, would allow the zoaria to grow for an extended time and reach large sizes before being overturned and buried. Atactoporella moroccoensis, has both zoaria and zooecia gigantic, suggesting a hypothesis of polar gigantism.

opencc-zeroDec 2016View details →

Data from: Disparid and hybocrinid crinoids (Echinodermata) from the Upper Ordovician (lower Katian) Brechin Lagerstätte of Ontario

The Brechin Lagerstätte (Katian, Ordovician) from the Lake Simcoe region of Ontario, Canada, contains a diverse array of echinoderms. Here, we describe seven disparid and two hybocrinid crinoids (Subclass Pentacrinoidea, Infraclass Inadunata), including a new disparid species belonging to the Anomalocrinidae (Order Homocrinida). In total, the disparids include Anomalocrinus astrictus n. sp.; Cremacrinus guttenbergensis Kolata, 1975; Cremacrinus inaequalis Billings, E., 1859; Daedalocrinus bellevillensis Billings, W.R., 1883; Eustenocrinus springeri Ulrich, 1925; Iocrinus trentonensis Walcott, 1883; and Isotomocrinus tenuis Billings, E., 1857b; and the hybocrinids include Hybocrinus tumidus Billings, E., 1857a and Hybocystites problematicus Wetherby, 1880. Previously known from only the holotype, three additional specimens of E. springeri expand our understanding of this unusual crinoid. Nomenclatural acts include the following: the recommendation of Warn and Strimple (1977), who designated Daedalocrinus kirki as a junior synonym of Daedalocrinus bellevillensis is followed; Hybocrinus pristinus Billings, E., 1858 is designated a junior synonym of Hybocrinus tumidus; and previous decisions are followed herein to retain Hybocystites eldonensis (Parks, 1908) as a junior synonym of Hybocystites problematicus. Although probably assignable to Anomalocrinus, the aberrant crinoid Glaucocrinus falconeri is designated a nomen dubium. Iocrinus similis (Billings, E., 1857a) is also designated a nomen dubium.

opencc-zeroDec 2012View details →

Data from: Katian (Upper Ordovician) conodonts from Wales

Middle and Upper Katian conodonts are previously known in the British Isles from relatively small collections obtained from a few localities. The present study is mainly based on 17 samples containing more than 17,000 conodont elements from an approximately 14 m thick succession of the Sholeshook Limestone in a road cut near Whitland, South Wales that yielded a diverse fauna of more than 40 taxa. It is dominated by representatives of Amorphognathus, Aphelognathus/Plectodina, and Eocarniodus along with several coniform taxa. Representatives of Decoriconus, Istorinus and Sagittodontina are reported from the Ordovician of UK for the first time. The fauna is a typical representative of the British Province of the Atlantic Realm and includes a mixture of taxa of North American, Baltoscandic, and Mediterranean affinities along with pandemic species. Based on the presence of many elements of Amorphognathus ordovicicus and some morphologically advanced specimens of A. superbus, the Sholeshook Limestone is referred to the lower A. ordovicicus Zone. Most of the unit is also coeval with Zone 2 of the Cautleyan Stage in the British regional stage classification, and Stage Slice Ka3 of the middle Katian Stage in the global stratigraphical classification, an age assignment consistent with data from trilobites, graptolites, and chitinozoans. The unusually large collection of M elements of Amorphognathus provides insight into the complex morphological variation of this element of some Katian species of this genus. The Sholeshook conodont fauna is similar to those of the Crûg and Birdshill limestones but differs in several respects from the slightly older ones from the Caradocian type area in the Welsh Borderland. Although having some species in common, the Sholeshook conodont fauna clearly differs from coeval Baltoscandic faunas, and is even more different in composition compared with equivalent North American Midcontinent faunas.

opencc-zeroDec 2015View details →

Data from: Continental-scale biogeographic variation: provinces versus gradients in the Upper Ordovician of Laurentia

Although provinces are widely used to delimit large-scale variations in biotic composition, it is unknown to what extent such variations simply reflect large-scale gradients, much as has been shown at smaller scales for communities. We examine here whether four previously described Middle and Late Ordovician provinces on Laurentia are best described as distinct provinces or as biotic gradients through a combination of the Paleobiology Database and new field data. Both data sets indicate considerable overlap in faunal composition, with spatial patterns in Jaccard similarity, quantified Jaccard similarity, and nonmetric multidimensional scaling ordination structure that correspond to variations in substrate type, specifically from carbonate-dominated strata in western Laurentia to mixed carbonate–siliciclastic strata in the midcontinent to siliciclastic-dominated rocks in easternmost Laurentia. Because sampling was limited to shallow-subtidal settings, this gradient cannot be attributed to variations in water depth. Likewise, geographic distance accounts for only a quarter of the variation in faunal composition. This cross-continent faunal gradient increases in strength into the early Late Ordovician, and appears to represent increased siliciclastic influx into eastern Laurentia during the Taconic orogeny. These results raise the question of whether biogeographic provinces may be in general better interpreted and analyzed as biotic gradients rather than as discrete entities.

FIGURE 6 in The Lower Ordovician (upper Floian) bathyurid trilobite Aponileus Hu, with species from Utah, Texas, and Greenland 3293

FIGURE 6. "Acidiphorus" n. sp., from Section J 40.0 m, Wah Wah Formation (upper Floian; Blackhillsian; "Pseudocybele nasuta Zone"), southern Confusion Range, Ibex area, Millard County, western Utah, USA. This species and other undescribed species from the "Pseudocybele nasuta Zone" are closely related to the younger Psephosthenaspis Whittington, 1953. It is illustrated to facilitate comparison and will be described in detail in a forthcoming work. See text for discussion. 1, 4. Cranidium, SUI 131853, dorsal and anterior views, x7.5. 2, 3, 6. Pygidium, SUI 131854, posterior, dorsal, and right lateral views, x6. 5. Right librigena, SUI 131855, external view, x5.

FIGURE 4 in The Lower Ordovician (upper Floian) bathyurid trilobite Aponileus Hu, with species from Utah, Texas, and Greenland 3293

FIGURE 4. Aponileus glaber (Poulsen, 1927), from the Nunatami Formation (upper Floian), gastropod limestone member (figs 1, 4, 7) and ostracod limestone member (figs 2, 3, 5, 6, 8, 9), Nunatami, Washington Land, northwestern Greenland. 1, 4, 7. Cranidium, MGUH 2391, dorsal, right lateral, and anterior views, x6 (original of Poulsen, 1927, pl. 20, fig. 11). 2, 5, 9. Cranidium, MGUH 2390, dorsal, anterior, and oblique views, x3 (original of Poulsen, 1927, pl. 20, fig. 10). 3, 6, 8. Pygidium, lectotype, MGUH 2406, dorsal, posterior, and left lateral views, x3 (original of Poulsen, 1927, pl. 20, fig. 27).

FIGURE 1 in The Lower Ordovician (upper Floian) bathyurid trilobite Aponileus Hu, with species from Utah, Texas, and Greenland 3293

FIGURE 1. Schematic diagram of stratigraphic distribution of species of Aponileus and the outgroup species Strigigenalis plicolabeona (Young) in Blackhillsian (upper Floian) sections of the Fillmore Formation in western Utah. Measurements are in metres. Meterages are not to scale. Zonation is that established by Adrain et al. (2009), with new informal subdivisions of the "Pseudocybele nasuta Zone" discussed in text.

FIGURE 2 in The Lower Ordovician (upper Floian) bathyurid trilobite Aponileus Hu, with species from Utah, Texas, and Greenland 3293

FIGURE 2. Illustrations of states for Character 2, the presence or absence of a fine transverse ridge across the bottom of SO. 1–6, State 0, ridge present. 1. Outgroup state, Acidiphorus teretus (Young, 1973), cranidium SUI 131151, Section H 191.7 m, Fillmore Formation (upper Floian; Blackhillsian; Strigigenalis plicolabeona Zone), western Utah, x18. 2. Outgroup state, Strigigenalis plicolabeona (Young, 1973), cranidium SUI 124830, Section H 191.7 m, Fillmore Formation (upper Floian; Blackhillsian; Strigigenalis plicolabeona Zone), western Utah, x7.5. 3. Outgroup state, Acidiphorus brighti (Hintze, 1953), cranidium SUI 131152, Section H 290.4 m, Wah Wah Formation (upper Floian; Blackhillsian; "Pseudocybele nasuta Zone", Assemblage 1), western Utah, x15. 4. Aponileus belkaae n. sp., cranidium SUI 129264, Section H 294.2 m, Fillmore Formation (upper Floian; Blackhillsian; "Pseudocybele nasuta Zone"), western Utah, x22.5. 5. Aponileus strelkaae n. sp., holotype cranidium SUI 129298, Section J 28.1 m, Wah Wah Formation (upper Floian; Blackhillsian; "Pseudocybele nasuta Zone"), western Utah, x15. 6. Aponileus laikaae n. sp., holotype cranidium SUI 129234, Section H 256–261T m, Fillmore Formation (upper Floian; Blackhillsian; Presbynileus ibexensis Zone), western Utah, x18. 7–12, State 1, ridge absent. 7, 10. Aponileus ugolekae n. sp., cranidia SUI 131127 and 131130, Section J 46.3 m, Wah Wah Formation (upper Floian; Blackhillsian; "Pseudocybele nasuta Zone"), western Utah, x13.5. 8. Aponileus? veterokae n. sp., cranidium SUI 129317, Section J 48.1 m, Wah Wah Formation (upper Floian; Blackhillsian; "Pseudocybele nasuta Zone"), western Utah, x22.5. 9. Aponileus aasei n. sp., dorsal exoskeleton BYU 19975, float high in Section H, Fillmore Formation (upper Floian; Blackhillsian; probably Pseudocybele paranasuta Zone), western Utah, x9. 11. Aponileus latus Hu, 1963, holotype cranidium USNM 143342, Padre Formation (upper Floian; Blackhillsian), western Texas, x4. 12. Aponileus glaber (Poulsen, 1927), cranidium MGUH 2391, Nunatami Formation (upper Floian), gastropod limestone member, northwestern Greenland, x9.