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Xenosphinctes n. gen. (Ataxioceratidae, Lithacoceratinae), a new rare ammonite genus from the Lower Tithonian (Hybonotum Zone) of SW Germany

Scherzinger A., Schweigert G.

Volumina Jurassica

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2017

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Vol. 15, no 1

155--160

EN

The new monotypic ammonite genus Xenosphinctes (type species: Xenosphinctes berkai n. sp.) is established. It is recorded from the Upper Jurassic, Early Tithonian, Hybonotum Zone, Riedense Subzone, eigeltingense α horizon from the Talmühle, N of Engen, Baden-Württemberg, SW Germany.

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Additional Tithonian and Berriasian ammonites from the Vaca Muerta Formation in Pampa Tril, Neuquén Basin, Argentina

Parent H., Schweigert G., Scherzinger A., Garrido A. C.

Volumina Jurassica

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2017

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Vol. 15, no 1

139--154

EN

The ammonite fauna of the Tithonian–Berriasian of the Vaca Muerta Formation in Pampa Tril has been recently described in detail. New important specimens and additional information are presented in this paper. The phyletic evolution of Choicensisphinctes, passing from C. platyconus to C. erinoides is confirmed, as well as the sexual dimorphic correspondence of this latter with C. mendozanus. A microconch of the genus Krantziceras is described for the first time. New specimens of Substeueroceras koeneni identical to the paralec¬totype, along with material already described from the koeneni Hz. (Koeneni Zone), point to the fixation of this horizon as the type horizon of the species. New specimens of Subthurmannia boissieri from the Damesi Zone match clearly the range of variation of this species in Spain, thus providing an element for time-correlation with the Tethyan standard scale. Additional material from the internispinosum alpha Hz. confirms the origin of W. internispinosum from C. proximus by the inception of an evolutionary innovation in the juvenile ontogeny.

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First record of the Mediterranean zonal index Mesosimoceras cavouri (Gemmellaro, 1872) in the Upper Jurassic (Pseudomutabilis Zone, semicostatum γ horizon) of SW Germany and its stratigraphical significance

Scherzinger A., Schweigert G., Főzy I.

Volumina Jurassica

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2016

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Vol. 14, no. 1

145--154

EN

The ammonite species Mesosimoceras cavouri (Gemmellaro), the index of the Mediterranean Cavouri Zone, is recorded for the first time from the Submediterranean Upper Jurassic of SW Germany. It occurs in the Untere-Felsenkalke Formation, within a rich ammonite association of the late Pseudomutabilis Zone characterized by fine-ribbed variants of Aulacostephanus pseudomutabilis (de Loriol) and a still undescribed flexuous-ribbed variant of Aulacostephanus eudoxus (d’Orbigny). This ammonite association represents the here newly introduced Lingulaticeras semicostatum γ horizon. The record of Mesosimoceras cavouri (Gemmellaro) confirms at least a partial correlation of the Mediterranean Cavouri Zone with the Submediterranen Pseudomutabilis Zone and the Subboreal Eudoxus Zone.

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New studies on perisphinctids from the Lower Tithonian (Hybonotum Zone) of S Germany and SE France

Scherzinger A., Atrops F., Schweigert G.

Volumina Jurassica

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2006

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Vol. 4, no. 1

244-245

EN

New extensive collections from the Hybonotum Zone of Liptingen (SW Germany), Canjuers (Dpt. Var, France) and Crussol (Dpt. Ardeche, France), together with already published material from Laisacker (Franconia, S Germany, Schairer & Barthel 1981) give deep insights in ontogeny, intraspecific variation, dimorphism, and evolution of several Late Jurassic perisphinctid ammonite genera, as a basis for future revisions. In older studies perisphinctids were often problematic due to little material, erroneous interpretations of type species, incompletely or poorly preserved specimens, disregarding of dimorphism, and widespread homeomorphism. After our recent study the perisphinctids are much more diverse than previously thought. A correlation with French biohorizons established in the Paris and Aquitaine basins is possible due to the occurrence of Gravesia M+m and Tolvericeras M+m?, especially at Liptingen. Besides the two latter genera we can distinguish five other dimorphic pairs which are coupled as follows: Lithacoceras Hyatt (M) + Silicisphinctes Schweigert & Zeiss (m); group of "Virgatosphinctes" eystettensis Schneid (M) + Subplanites group A (m); Euvirgalithacoceras Zeiss, Schweigert & Scherzinger (M) + Subplanites group B, S. rueppellianus sensu Schairer & Barthel non Quenstedt (m); Hegovisphinctes Zeiss, Schweigert & Scherzinger (M) + group of "Torquatisphinctes" filiplex Schairer & Barthel non Quenstedt (m); Hoelderia Ohmert & Zeiss (M) + group of "Subdichotomoceras" sp. in Schairer & Barthel 1981, pl. 5, fig. 4 only (m). Some of these dimorphic pairs can be recognized also in SE Spain (Calanda area) and in the Balkans (Bulgaria, Croatia) and thus permit correlations across the Submediterranean Province. The rich perisphinctid fauna, together with other excellently preserved ammonites underlines the potential of the French sections as key sections for long-distance and high time-resolution correlations as well as the understanding of the Kimmeridgian-Tithonian transition.

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New data on ammonites and stratigraphy of the uppermost Kimmeridgian – lowermost Volgian of the Middle Volga region (Russia)

Mitta V., Scherzinger A.

Volumina Jurassica

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2006

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Vol. 4, no. 1

191-192

EN

New collections at the boundary of the Kimmeridgian and Volgian from the Volgian Stage lectostratotype section nearby Gorodishche (central Russia) make it possible to give a general view on the stratigraphic distribution of some of the important ammonite taxa. For the first time Sutneria eumela (d’Orbigny) and Sutneria subeumela Schneid from the Upper Kimmeridgian are illustrated, and Aulacostephanus volongensis Khudyaev is recognized. The latter is the macroconch of Aulacostephanus undorae (Pavlow). These discoveries indicate the chronostratigraphic correlation between the Eudoxus and Fallax zones of the Russian Platform and the Pseudomutabilis and Beckeri zones of the Submediterranean region. “Discosphinctoides” subborealis Kutek & Zeiss is placed in the genus Sarmatisphinctes Kutek & Zeiss and “Glochiceras (Paralingulaticeras)” efimovi Rogov belongs to a new ammonite genus. In the beginning of the Volgian a strong faunal provincialism has been perceptible which makes correlations with areas outside the Russian Plate and Central Poland more difficult. The lowermost part of the Lower Volgian (Klimovi Zone) seems to be time equivalent at least in part, if not wholly, of the Upper Kimmeridgian. Because of different interpretation of the Autissiodorensis Zone Ziegler 1962 in the localities of West Europe and the Russian Platform we give the priority to the term Fallax Zone Ilovaisky 1941. The name “Autissiodorensis Subzone” does not seem the best choice for the lowermost Subzone of the Fallax Zone of the Russian Kimmeridgian. Up to now no figured specimen of A. autissiodorensis from the Russian Platform has been indicated. According to our opinion the best index fossil for the base of the Fallax Zone in the area of study seems to be Amoeboceras volgae (Pavlow), and we recommend using the term Volgae Subzone in future. More information about results of our study are given in Scherzinger and Mitta (in press).