Rare and little-known ammonites from the Lower and Middle Jurassic of the Western and Central Balkan Mts (Bulgaria)

Abstract

This paper presents insufficiently or previously unknown Jurassic ammonites from 21 localities and sections of the Western and Central Balkan Mts (Bulgaria). The total stratigraphical range of the studied fauna corresponds to a broad interval, from the Pliensbachian (Lower Jurassic) to the Callovian (Middle Jurassic), with emphasis on the ammonites from the Bajocian–Callovian interval. These ammonites belong to 36 species and 23 genera that are affiliated to 12 ammonite families: Polymorphitidae, Acanthopleuroceratidae, Amaltheidae, Hildoceratidae, Graphoceratidae, Strigoceratidae, Sonniniidae, Stephanoceratidae, Oppeliidae, Tulitidae, Parkinsoniidae, and Perisphinctidae. Of them, 13 species have been left in open nomenclature. This account comprises both newly recorded ammonite taxa and redefined ammonite species from older collections. The new evidence also includes the upper Bathonian species Siemiradzkia mangoldi sp. n., which was recorded from south-eastern France as well. Although being represented mainly by single specimens, often with no other supporting material, the newly discovered taxa have high stratigraphical significance, being both valuable additions to well-known Bulgarian ammonite zonal associations and new indications of ammonite successions that have quite poorly been identified in Bulgaria to date. In this regard, they are useful for better dating of the sedimentary successions in Bulgaria and are valuable for the purposes of correlation outside Bulgaria.

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

“…The occurring taxa and biostratigraphy are mainly matched to well-known and described faunas from Austrian localities (e.g. Hödl-Kritsch; Krystyn, 1970Krystyn, , 1971Krystyn, , 1972, Spain (Fernández-López et al, 2009;Sandoval, 2016), France (Pavia, 1983;Pavia and Fernández-López, 2008;Pavia et al, 2008), S Germany (Schlegelmilch, 1985;Dietze et al, 2007;Schweigert et al, 2007), Switzerland (Scheurlen, 1928), and Bulgaria (Metodiev, 2019).…”

“…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). Especially the Middle Jurassic Bajocian to Bathonian sections yield the same ammonite families and partly even the identical species.…”