Ammonoid Biostratigraphy in the Jurassic

Schweigert, Günter

doi:10.1007/978-94-017-9633-0_14

Cited by 4 publications

(2 citation statements)

References 19 publications

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“…From a palaeontological point of view the macrofaunal assemblage can be assigned to the Jurassic Mediterranean Province of the Western Tethyan Realm ("alpin-mediterrane Juraprovinz" in Trauth, 1923a;see Fernández-López et al, 2009;Schweigert, 2015;Pavia and Fernández-Lopez, 2019). The cephalopod fauna is almost identical with isochronic assemblages from other localities of Austria (Northern Calcareous Alps; Krystyn, 1970, 1971, 1972Fernandez-Lopez, 1985;Fernández-López et al, 2009;Sandoval, 2016), southeast France (southern Subalpine Chains; Pavia, 1983;Fernández-López, 2007;De Baets et al, 2008;Pavia et al, 2008;Fernández-López et al, 2009), northern France (Pavia et al, 2013), from Italy (Apennine Mountains and Sicily; Cresta and Galácz, 1990), southern Germany (Scheurlen, 1928;Schlegelmilch, 1985;Schweigert and Dietze, 1998;Dietze et al, 2007;Schweigert et al, 2007), Slovakia (Western Carpathians; Schlögl et al, 2009), Hungary (Bakony and Mecsek Montains; Galácz, 1980Galácz, , 1991Cresta and Galácz, 1990;Galácz and Kassai, 2012;Galácz et al, 2015), Poland (Polish Jura Chain; Zatoń, 2010;Birkenmajer and Gedl, 2017), and Bulgaria (Western and Central Balkan Mountains;Metodiev, 2019).…”

Section: Palaeogeography and Provincialismmentioning

confidence: 99%

“…One Early Jurassic (late Hettangian-Sinemurian) with the indicative ammonites Arnioceras ceratitoides (early Sinemurian) and Echioceras cf. quenstedti (late Sinemurian, Raricostatum Zone; Schlegelmilch, 1985;Blau, 1998;Lukeneder and Lukeneder, 2018;zonations according to Ogg et al, 2012;Schweigert, 2015) accompanied by the Early Jurassic bivalve Gryphaea arcuata (Hettangian to Sinemurian).…”

Section: Biostratigraphymentioning

confidence: 99%

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The St. Veit Klippen Unit in Vienna (Austria) – Jurassic to Cretaceous biostratigraphy and facies based on historical fossil collections

Lukeneder

Harzhauser

2020

Austrian Journal of Earth Sciences

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Historical fossil assemblages from the Lower Jurassic to Lower Cretaceous of the Sankt Veit Klippen Unit (SVK) on the western outskirts of Vienna were re-evaluated. Collections of the material from the St. Veit Klippen Unit comprise 3497 specimens. An appropriate nomenclature was used, and the taxonomy was partly revised. Historical collections from Franz Toula (1845–1920) and Friedrich Trauth (1883–1967) were investigated in the collections of the Natural History Museum Vienna, the Geological Survey Vienna, the Department of Geology and the Department of Palaeontology (both University Vienna). Additional collections were studied in the district museums Hietzing (13th district Vienna) and Liesing (23rd district Vienna), in the district municipal office of Hietzing and in the Wienerwald Museum (Eichgraben, Lower Austria). The study area is situated in the easternmost part of the St. Veit Klippen Unit in the Wienerwald (Vienna Woods), part of the 13th Viennese district Hietzing. New data allowed a revision of the biostratigraphy of several lithological units of the SVK. Two main fossil complexes could be distinguished: 1) the Hohenauer Wiese assemblage from the wildlife park Lainz (= “Lainzer Tiergarten”) and 2) the Glasauer quarry assemblage from St. Veit.

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Section: Palaeogeography and Provincialismmentioning

confidence: 99%

Section: Biostratigraphymentioning

confidence: 99%

The St. Veit Klippen Unit in Vienna (Austria) – Jurassic to Cretaceous biostratigraphy and facies based on historical fossil collections

Lukeneder

Harzhauser

2020

Austrian Journal of Earth Sciences

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Nautiloid Biostratigraphy of the Jurassic of Kutch, India: An Exploration of Bio- and Chrono-stratigraphic Potential of Nautiloids

Halder

2021

Mesozoic Stratigraphy of India

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Another lesson from beautiful monsters: the case of 'sex reversals' in the Ammonoidea and their significance

Frau

Boursicot²

2021

BMC Ecol Evo

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Background Expression of sexual dimorphism is recognised in various fossil groups of molluscs such as the Ammonoidea, an extinct group of shelled cephalopods. During the Mesozoic, the best-documented sexual dimorphic examples are seen in the Jurassic superfamily Perisphinctoidea. It is usually expressed by distinct adult size and apertural modifications between the antidimorphs. Putative males (otherwise referred to as microconch) are small in size and develop lappets at the end of the shell while the females (macroconch) are larger and bear a simple peristome. Dubious cases are, however, known in that superfamily, which often relate to taxonomic biases or lack of diagnostic characters, and some others expose ontogenetic anomalies illustrated by ‘sex reversals’ in the shell morphology and ornamentation. Results The discovery of two specimens of the Callovian Aspidoceratidae Peltoceras athleta (Phillips), having both female and male features, questions the significance and causes of ‘sex reversals’ in the Ammonoidea. The two specimens have started with the macroconch ontogeny of Peltoceras athleta and show an apparent change toward maleness in the adult, as illustrated by their rounded whorl section, ribs retroversion, fading of the tubercles and lappets typical of the microconchs. Few other cases of female-to-male, as well as male-to-female ‘sex reversal’, are known in the fossil record, all belonging to the Jurassic Perisphinctoidea (families Perisphinctidae or Aspidoceratidae). Since all Jurassic Perisphinctoidea are strictly gonochoristic, these ‘sex reversals’ are pathological in nature and are herein referred to as a new forma-type pathology: namely “forma hermaphrodita”. Conclusions In the absence of any clear evidence of injury or parasitism, we hypothesize that such “forma hermaphrodita” individuals illustrate pathologic cases of intersexuality. Little is known about the ammonoid soft parts, and it is not possible to determine which internal sexual organs occur in specimens having both male and female external shell features. Abnormal feminisation and/or masculinisation also occur in modern cephalopods, the latter also grouping only gonochoric species. This phenomenon is similarly illustrated by a change in the adult body size and a mixing of both female and male structures. In that case, intersexuality is either advantageous in the population or caused sterility. The causes of intersexuality are not clearly established but environmental pollutants are evoked in modern cephalopods because they act as endocrine disrupters. ‘Sex reversals’ and/or non-functional reproductive abnormalities have also been caused by endocrine disrupters in various gonochoric gastropods species, but infestation, genetic abnormalities, temperature fluctuations or viruses are multiple causes, which can stimulate or inhibit neural-endocrinal activity by direct gonadal influence, and ultimately lead to feminisation or masculinisation in fishes, isopods, crustaceans, and gastropods as well. Regardless of whether “forma hermaphrodita” is due to an exogenic or endogenic cause, the record of intersex Perisphinctoidea in the Jurassic can be explained by the ready recognition of dimorphic pairs, and the easy collection of large and sufficiently preserved fossil palaeopopulations in which intersex specimens have statistically more chance to be found.

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Ammonoid Biostratigraphy in the Jurassic

Cited by 4 publications

References 19 publications

The St. Veit Klippen Unit in Vienna (Austria) – Jurassic to Cretaceous biostratigraphy and facies based on historical fossil collections

The St. Veit Klippen Unit in Vienna (Austria) – Jurassic to Cretaceous biostratigraphy and facies based on historical fossil collections

Nautiloid Biostratigraphy of the Jurassic of Kutch, India: An Exploration of Bio- and Chrono-stratigraphic Potential of Nautiloids

Another lesson from beautiful monsters: the case of 'sex reversals' in the Ammonoidea and their significance

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