Early Carboniferous Ammonoids Research Articles

First record of the Early Carboniferous ammonoid genus Goniatites from the Greater Karatau (Kazakhstan palaeocontinent)

The Late Viséan ammonoid genus Goniatites had a near-global distribution within the tropical seas but was rarely reported from Central Asia. New investigations of the Early Carboniferous sedimentary succession in the Greater Karatau of Kazakhstan revealed a species-poor new assemblage with Goniatites and assists in the biostratigraphic subdivision of the section. The new species Goniatites zhankurganensis and G. abaiensis are described; these species have a morphological position at both ends of the morphological spectrum of the genus.

Early Carboniferous ammonoids from the Nanduan Formation in the Changning-Menglian Belt, western Yunnan, China

The Changning-Menglian Belt in western Yunnan, China has been interpreted as a remnant of the Paleo-Tethys. The Nanduan Formation, exposed in the eastern part of this belt, is a prominent siliciclastic succession with a thickness of more than 2000m. The age of this formation has remained poorly constrained due to the paucity of fossils. Ammonoids have been previously reported from this formation, but were neither systematically described nor properly illustrated. This study provides descriptions of ammonoids from two beds (Bed-2 and Bed-14) of the Banjiao section in the upper part of the Nanduan Formation. Specimens from Bed-2 preserve diagnostic suture patterns, facilitating generic determination, and thus five taxa are recognized, including Syngastrioceras sp., Somoholites sp., Epicanites sp., Stenopronorites sp., and Prolecanites? sp. Associated indeterminate small conchs from Bed-2 probably represent juveniles. Known ranges of these genera, and in particular, their co-occurrence, indicate a late Mississippian, and most probably a Serpukhovian age for the upper part of the Nanduan Formation. Only a single taxon, Fayettevillea sp., has been recognized from Bed-14, which also supports the Serpukhovian age.

Quantitative analysis of suture lines in Carboniferous ammonoids

Abstract. Two morphometric methods are applied and compared for the analysis of suture lines in Early Carboniferous ammonoids of the superfamilies Pericycloidea, Girtyoceratoidea and Goniatitoidea. We analysed (1) classic metric data (proportions of the width and depths or heights of lobes and saddles) using multivariate statistic methods and (2) outline data of the external lobe and the ventrolateral saddle of the same ammonoid taxa using the elliptic Fourier analysis. Both methods lead to similar results and simultaneously demonstrate ontogenetic and phylogenetic trends of these ammonoids. Our results are consistent with three previously suggested evolutionary patterns: (1) a general decrease of the amplitude of lobes and saddles, (2) a proportional widening of the external lobe and (3) a heightening of the median saddle.

The Late Devonian and Early Carboniferous ammonoids (Cephalopoda) from Milivojevića Kamenjar, Družetić (NW Serbia) and their stratigraphy.

The Late Devonian and Early Carboniferous ammonoids (Cephalopoda) from Milivojevića Kamenjar, Družetić (NW Serbia) and their stratigraphy.

Early Carboniferous ammonoids from the Chatkal River basin (Middle Tien Shan, Uzbekistan)

The Late Tournaisian ammonoids from the Kuilyuk Formation and the carbonate massifs of the Chatkal Group were studied in the lower reaches of the Chatkal River (Middle Tien Shan, Uzbekistan). Three successive ammonoid assemblages of the Late Tournaisian Pericyclus-Progoniatites and Fascipericyclus-Ammonellipsites Genozones were recognized. A new pericyclid genus, Parasiacyclus gen. nov., with the type species Parasiacyclus chatcalicus sp. nov., and the new species Eurites kuilukensis sp. nov., Habadraites kulosiensis sp. nov., and Nodopericyclus asiaticus sp. nov. are described. The genus Muensteroceratoides Popov, 1965, previously considered as a junior synonym of Dzhaprakoceras Popov, 1965 is reinstated and redescribed.

Early Carboniferous AmmonoidDombaritesfrom the Taishaku Limestone, Akiyoshi Belt, Southwest Japan

Abstract. The Early Carboniferous ammonoid Dombarites taishakuensis sp. nov. is described from the Dangyokei Formation, which is the lowermost formation of the Taishaku Limestone in the Akiyoshi Belt, Southwest Japan. This is the first described ammonoid from the Taishaku Limestone and the first record of the genus Dombarites from the Panthalassa region. The age of D. taishakuensis is probably early Serpukhovian based on the ages of morphologically similar species of Dombarites.

Patterns of ontogenetic septal spacing in Carboniferous ammonoids

Early Carboniferous ammonoids from Oued Temertasset in the Mouydir of Algeria frequently show conspicuous septal crowding at various stages in ontogeny, but particularly immediately at the end of the phragmocone. The analysis of this phenomenon suggests that closer septal spacing is probably not related to maturity in these specimens. Septal crowding occurs in different sizes, and interim septal crowding in juvenile growth stages with subsequent recovery to normal septum distances is common. Four groups of species with different modes of septal crowding can be separated. Close septal spacing is interpreted as a response to adverse ecological conditions such as depletion of oxygen, which caused deceleration of growth at the aperture.

Early Carboniferous ammonoid faunas and stratigraphy of the Montagne Noire (France)

The early Carboniferous (Mississippian) sedimentary succession of the Montagne Noire is subdivided into three major lithostratigraphic units, in ascending order the Montagne Noire Griotte Group (Devonian to Early Tournaisian), the Tournaisian to Viséan Saint-Nazaire Group (with the Lydiennes, Faugères, Colonnes, and Puech Capel Formations, the latter new), and the Laurens Flysch Group (late Viséan). The ammonoid assemblages in these rock units are reviewed. A total of 29 Early Carboniferous ammonoid taxa at species level are determined. The new genus <i>Nigrocyclus</i> n. gen., and the new species <i>Gattendorfia nazairensis</i> n. sp., <i>Globimitoceras albaillei</i> n. sp., and <i>Neogoniatites canovasi</i> n. sp. are described. <br><br> Die unterkarbonische Abfolge von Sedimentgesteinen in der Montagne Noire wird in drei lithostratigraphische Einheiten untergliedert, von unten nach oben die Montagne Noire Griotte Gruppe (Oberdevon bis Untertournai), die Saint-Nazaire Gruppe des Tournaisium und Viséum (mit den Lydiennes Faugères, Colonnes und Puech Capel Formationen, von denen die letzte neu ist), und der Laurens Flysch Gruppe (Oberviséum). Die Ammonoideen-Vergesellschaftungen in diesen Gesteinen werden revidiert. Insgesamt werden 29 unterkarbonische Ammonoideen-Taxa auf Artebene aufgeführt; neu beschrieben werden die Gattung <i>Nigrocyclus</i> n. gen. sowie die Arten <i>Gattendorfia nazairensis</i> n. sp., <i>Globimitoceras albaillei</i> n. sp. und <i>Neogoniatites canovasi</i> n. sp. <br><br> doi:<a href="http://dx.doi.org/10.1002/mmng.200700002" target="_blank">10.1002/mmng.200700002</a>

Early Carboniferous ammonoid faunas and stratigraphy of the Montagne Noire (France)

Abstract. The early Carboniferous (Mississippian) sedimentary succession of the Montagne Noire is subdivided into three major lithostratigraphic units, in ascending order the Montagne Noire Griotte Group (Devonian to Early Tournaisian), the Tournaisian to Viséan Saint-Nazaire Group (with the Lydiennes, Faugères, Colonnes, and Puech Capel Formations, the latter new), and the Laurens Flysch Group (late Viséan). The ammonoid assemblages in these rock units are reviewed. A total of 29 Early Carboniferous ammonoid taxa at species level are determined. The new genus Nigrocyclus n. gen., and the new species Gattendorfia nazairensis n. sp., Globimitoceras albaillei n. sp., and Neogoniatites canovasi n. sp. are described. Die unterkarbonische Abfolge von Sedimentgesteinen in der Montagne Noire wird in drei lithostratigraphische Einheiten untergliedert, von unten nach oben die Montagne Noire Griotte Gruppe (Oberdevon bis Untertournai), die Saint-Nazaire Gruppe des Tournaisium und Viséum (mit den Lydiennes Faugères, Colonnes und Puech Capel Formationen, von denen die letzte neu ist), und der Laurens Flysch Gruppe (Oberviséum). Die Ammonoideen-Vergesellschaftungen in diesen Gesteinen werden revidiert. Insgesamt werden 29 unterkarbonische Ammonoideen-Taxa auf Artebene aufgeführt; neu beschrieben werden die Gattung Nigrocyclus n. gen. sowie die Arten Gattendorfia nazairensis n. sp., Globimitoceras albaillei n. sp. und Neogoniatites canovasi n. sp. doi:10.1002/mmng.200700002

Early Carboniferous trigonoceratid nautilids from the Pitkin Formation of Arkansas, Midcontinent North America

ABSTRACT Two new species of trigonoceratid nautilids from the middle Chesterian (Early Carboniferous) Pitkin Formation of Arkansas, Midcontinent North America are described. Epistroboceras pitkinense sp. nov. is most similar to E. caneyense Niko and Mapes, 2004, but is distinguished mainly by its dorsally shifted umbilical angle. Stroboceras gordoni sp. nov. is characterized by the narrow lg 2 (second lateral groove) in the lateral grooves, the two bilaterally symmetrical lateral ridges, and the weak nodes at intersections of ridges and the growth lines. Species previously described or assigned to Stroboceras are re-examined. Similarities in the shell morphology between the trigonoceratid nautilid Stroboceras and the isochronous Early Carboniferous ammonoid Eumorphoceras probably provide an example of synchronized convergent evolution.

Early Carboniferous ammonoid Irinoceras from the Onimaru Formation in the Southern Kitakami Massif, Northeast Japan.

Early Carboniferous ammonoid Irinoceras from the Onimaru Formation in the Southern Kitakami Massif, Northeast Japan.

Late Devonian and Early Carboniferous ammonoids from the Tobigamori Formation in the Southern Kitakami Massif, Northeast Japan and their stratigraphic significance

Late Devonian and Early Carboniferous ammonoids from the Tobigamori Formation in the Southern Kitakami Massif, Northeast Japan and their stratigraphic significance