Dieter Korn

Museum für Naturkunde - Leibniz Institute for Research on Evolution and Biodiversity | MFN

The species names "Tornoceras simplex" and "Tornoceras typum" have been used in a wide sense for Givetian to Famennian ammonoids. A more detailed analysis of conch shape, conch ontogeny and suture line shows that Torno ceras typus has to be restricted to middle Frasnian forms and that stratigraphically older and younger material belongs to other sp...

The ammonoids of the family Maenioceratidae from Givetian sedimentary rocks of the Anti-Atlas (Morocco) are investigated. The study is based on new collections stored in the Museum für Naturkunde, Berlin. The genera Maenioceras Schindewolf, 1933 and Afromaenioceras Göddertz, 1987 are revised; the genus Trimaenioceras is newly described. The species...

Rhachistognathus minutus (Higgins & Bouckaert) is one of the auxiliary conodont species used to define or approximate the Mid-Carboniferous boundary in the absence of the main index species, Declinognathodus noduliferus (Ellison & Graves). The stratigraphic range of R. minutus differs considerably in different areas. In North America it is known fr...

In this work, we present the preliminary results from our study on the goniatitids found in the mining area of Nerva, Huelva. The studied fossils were collected from the Culm Group of the Iberian Pyritic Belt (IPB) in the South-Portuguese Zone (SPZ), southernmost Iberian Massif. The Culm Group is the uppermost stratigraphic unit of the IPB, overlay...

The boundary between the Devonian and the Carboniferous has been drawn using ammonoids, conodonts and miospores, while geochemical data have only rarely been used. The sampling of eight sections (Aprath, Apricke, Effenberg, Wocklum, Stockum, Drewer WJ, Drewer WA, Marsberg) at the northern margin of the Rhenish Mountains demonstrates the potential o...

Viséan coiled nautiloids from North Africa are only poorly known. From the Mougoui Ayoun, Zrigat and Hamou-Rhanem formations of the eastern Anti-Atlas, we describe coiled nautiloids, which belong to the genera Rineceras, Stroboceras, Temnocheilus, Vestinautilus, Maccoyoceras, Endolobus, Epidomatoceras, Liroceras, Ephippioceras, and Solenochilus. Th...

The Late Carboniferous ammonoids Gastrioceras listeri (Sowerby, 1812) and Gastrio ceras angustum Patteisky, 1965 are reported from Ighr ou Hammoud in the vicinity of Dechra Aït Abdallah (central Moroccan Meseta). The assemblage shows very close relationships to those from the South Portuguese Zone, the British Isles and the Rhenish Mountains, sugge...

The early Tournaisian (Early Carboniferous; Mississippian) ammonoids from the classical abandoned limestone quarry of Gattendorf (Upper Franconia) are revised, using the historical collections as well as so far undescribed material. The ammonoid assemblage is composed of prionoceratid ammonoids of the six genera Mimimitoceras, Paragattendorfia, Sto...

The railway cutting near Oberrödinghausen at the northern margin of the Rhenish Mountains is the cardinal section for the investigation of Early Tournaisian (Early Carboniferous; Mississippian) ammonoids. The ammonoids from the Hangenberg Limestone (= Gattendorfia Limestone) of this and neighbouring outcrops are revised here, using the historical c...

The body size of marine ectotherms is often negatively correlated with ambient water temperature, as seen in many clades during the hyperthermal crisis of the end-Permian mass extinction (c. 252 Ma). However, in the case of ostracods, size changes during ancient hyperthermal events are rarely quantified. In this study, we evaluate the body size cha...

Fossils of Devonian ammonoids are abundant and well-preserved in the Anti-Atlas of Morocco; as such they provide an invaluable record of regional morphological disparity changes (diversity of shapes) that characterise the first steps of ammonoid evolution. However, they were rarely analysed quantitatively with respect to their morphological spectru...

Here we study the variation of the Paleozoic to Mesozoic ammonoid whorl profile shape (WPS, in previous contributions referred as the whorl cross-section shape) employing a geometric morphometric approach, virtual modelling, and statistical tools to assess possible biological phenomena. For this approach, a dataset covering 300 individuals (each be...

A single limestone bed at the top of the Hassi Sguilma Formation in the Saoura Valley in western Algeria yielded conodont and ammonoid assemblages of Late Tournaisian age (Scaliognathus anchoralis-Doliognathus latus Zone and Ammonellipsites-Merocanites Genus Zone, respectively). The conodont association is dominated by Gnathodus pseudosemiglaber Th...

Body size distributions of organisms across environments in space and time are a powerful source of information on ecological and evolutionary processes. However, most studies only focus on selected parameters of size distributions (e.g., central tendency or extremes) and rarely take into account entire distributions and how they are affected by th...

For the taxon comprising all Devonian to Cretaceous ammonoids, a variety of conflicting names with different authorship and taxonomic rank are available and have been repeatedly cited. Here, we review the primary literature and suggest the appropriate name, authorship and date of publication; we suggest the rank of a superorder for the ammonoids. T...

The biggest known mass extinction in the history of animal life occurred at the Permian–Triassic boundary and has often been linked to global warming. Previous studies have suggested that a geologically rapid (<40 kyr) temperature increase of more than 10°C occurred simultaneously with the main extinction pulse. This hypothesis is challenged by geo...

Coiled nautiloids of the Tournaisian and early to middle Viséan (Early Carboniferous) have so far only become known from a few regions. Here we describe material from five localities in southern Algeria; these belong to four stratigraphic horizons (two horizons in the late Tournaisian, one horizon near the Tournaisian–Viséan boundary, one horizon i...

The Permian–Triassic sedimentary succession in the Julfa region is lithostratigraphically composed of limestones and shales of the Julfa Formation, the Zal Member shales, and the Paratirolites Limestone of the Ali-Bashi Formation, as well as shales and carbonate beds of the Elikah Formation. The Lower Julfa Beds are rich in benthic organisms such a...

The ammonoids of the suborder Gephuroceratina from the Roteisenstein (Red Ironstone) Formation of the area around Dillenburg (eastern Rhenish Mountains) are revised, mainly based on historical collections stored in the Museum für Naturkunde, Berlin. The new species Ponticeras materni sp. nov. is described and the species Pseudoprobeloceras pernai (...

Animal body size provides information about the trophic position and reproductive strategies of species, and the presence of environmental stressors. The distribution of body sizes in fossils can be easily measured, making it an important tool for paleoecological studies. However, preservational and collection biases might influence the primary mea...

The ammonoids of the suborder Tornoceratina from the Middle to Late Devonian Red Ironstone Formation of the area around Dillenburg (eastern Rhenish Mountains) are revised, mainly based on historical collections stored in the Museum für Naturkunde, Berlin. The species Tornoceras typus (Sandberger & Sandberger, 1851), Tornoceras frechi Wedekind, 1918...

Ordovician ectocochleate cephalopods of the order Lituitida Starobogatov, 1983, mainly from erratics of the Orthoceratite Limestone embedded in Pleistocene glacio-fl uvial sediments in Germany, Poland and the Kaliningrad Region of Russia are revised. In total, seven genera (Rhynchorthoceras, Ancistroceras, Angelinoceras, Holmiceras, Lituites, Trila...

Early Carboniferous coiled nautiloids from North Africa are virtually unknown. An assemblage of nine species, all from the family Trigonoceratidae, from the Dalle à Merocanites (Tournaisian-Viséan boundary interval) of Timimoun in western Algeria is described, being the most diverse Carboniferous nautiloid assemblage known from North Africa but muc...

Septal crowding is widely known as a sign of maturity in conchs of ammonoids and nautiloids. However, reduced septal spacing may also occur as a consequence of adverse ecological conditions. Here, we address the question how septal spacing varied through ontogeny in representatives of some of the major clades of Devonian and Carboniferous ammonoids...

The ammonoid species Tornoceras typus (middle Frasnian, Late Devonian) is revised on the basis of the original material and material from the eastern margin of the Rhenish Mountains. The detailed investigation of the conch form and its ontogeny requires a more restrictive species diagnosis; a separation from morphologically similar forms from other...

Representatives of the Guadalupian and Lopingian ammonoid family Cyclolobidae are very rare in Transcaucasia and Iran. The new species Timorites dendroides Korn & Ghaderi n. sp. is described from the beds with Araxoceras (Julfa Formation, early Wuchiapingian) of Kuh-e-Ali Bashi (East Azerbaijan, NW Iran). It is the first record of the genus in the...

Material for the publication: Revision of Tornoceras typus (Sandberger & Sandberger, 1851) – an iconic Devonian ammonoid of a clade with slow morphological evolution. https://doi.org/10.7479/mn2v-pm95

Sections at Baghuk Mountain, 45 km NNW of Abadeh (Central Iran), have excellent exposures of fossiliferous marine Late Permian to Early Triassic sedimentary successions. Detailed bed-by-bed sampling enables the analysis of microfacies changes of three successive rock units across the Permian-Triassic boundary. The Late Permian Hambast Formation is...

The Changhsingian (Late Permian) Hambast Formation of sections at Baghuk Mountain (Central Iran) has yielded diverse ammonoid assemblages composed of the genera Pseudogastrioceras, Shevyrevites, Arasella, Dzhulfi tes, Paratirolites, Clivotirolites gen. nov., Esfahanites gen. nov., Alibashites, Lutites gen. nov., Abichites and Stoyanowites. The succ...

The Protocanites Beds of the Black Forest Massif (Germany) form an important lithostratigraphic key bed, as the index fossils contained in this formation enable correlation within large areas of the internal zone of the central Variscan Belt of Europe. Furthermore, the formation provides significant information on the geodynamic evolution of the Mo...

Die "Kulm-Tonschiefer" des Oberharzes und ihre Liegendschichten (Mississippium/Unterkarbon) H-J G , D K , C B A J Kurzfassung: Die "Kulm-Tonschiefer" bilden eine markante kartierbare unterkarbonische stratigraphische Einheit des Oberharzes. Sie entwickeln sich stratigraphisch aus den "Kieseligen Übergangsschichten". Wir beschreiben und interpretier...

The ammonoids of the suborder Pharciceratina from the Red Ironstone Formation of the area around Dillenburg (eastern Rhenish Mountains) are revised, mainly based on historical collections stored in the Museum für Naturkunde, Berlin. The genus Evopharciceras gen. nov. and the following species are newly described: Maenioceras ornatum sp. nov., Pharc...

A small ammonoid assemblage from Carboniferous-Permian boundary strata of Kuh-e-Bagh-e-Vang in the Tabas region (east-central Iran) is reported. The new species Agathiceras iranicum Korn & Ghaderi, n. sp. and Eoasianites baghevangensis Korn & Ghaderi, n. sp. are described. Ammonoids from Frasnian to Early Permian age occur in a conglomerate unit ne...

Small shelly fossils (SSFs) are highly informative of the ‘Cambrian explosion’. Their palaeobiodiversity has been documented from lower Cambrian deposits worldwide but it remains elusive in areas such as Iran, despite this region occupying a critical position on the north-western Gondwana margin during the early Cambrian. This new study of the SSFs...

A large suite of specimens belonging to the Early Bajocian Stephanoceras from Évrecy (Normandy, France) displays wide variation in conch and sculpture. The quantitative analysis of the conch geometry and its ontogeny on the basis of more than 50 sectioned specimens reveals major problems in the separation of species within the assemblage; clear mor...

Material for the publication: Revision of Tornoceras frechiWedekind, 1918 and consequences for the Late Devonian ammonoid stratigraph

Permian–Triassic boundary sections at Baghuk Mountain (Central Iran) are investigated with respect to their lithological succession, biostratigraphy (particularly conodonts, nautiloids and ammonoids) as well as chemostratigraphy (carbon isotopes). The rock successions consist of the Late Permian Hambast Formation, the youngest Permian Baghuk Member...

The ammonoid species Tornoceras frechi (middle Frasnian, Late Devonian) is revised on the basis of the original type material and material from the type locality. The detailed study of conch form and conch ontogeny requires a differentiation from records from the Anti-Atlas of Morocco, which have so far largely been referred to as Phoenixites frech...

Ammonoids suffered a diversity bottleneck during the Permian-Triassic mass extinction (PTME) and experienced a rapid diversification in the Early Triassic. However, which kinds of ammonoids were more likely to survive the PTME and fueled subsequent diversification are still poorly known. We compiled a comprehensive morphological dataset and used th...

The ammonoid genera Cancelloceras and Gastrioceras are important index fossils for the subdivision of mid-Bashkirian strata; both are represented by species in the Qilian Mountain region of Gansu and Ningxia (North China). In the Xiaoyuchuan section, four successive ammonoid assemblages were recorded, in ascending order with Cancelloceras pachygyru...

The Aras Valley section (north‐west Iran) exposes a sedimentary succession that allows the study of ostracod diversity patterns during/across the end‐Permian mass extinction. For the present study, 59 samples were investigated for their ostracod abundances, which ranged from 4 to 31 500 specimens per 500 g. In 45 sample horizons, the ostracods were...

Ammonoids reached their greatest diversity during the Triassic period. In the early Middle Triassic (Anisian) stage, ammonoid diversity was dominated by representatives of the family Ceratitidae. High taxonomic diversity can, however, be decoupled from their morphologic disparity. Due to its high phenotypic variability, the high diversity of cerati...

The Bashkirian (Late Carboniferous) ammonoid genus Bilinguites has a nearly global distribution in the tropical and subtropical zones and 25 species have been described up till now. Most of them are considered endemic, but some may have a wide geographic distribution. Our study on new and previously collected materials from North China (Gansu and N...

The neodymium isotope composition of micritic limestones from the Devonian–Carboniferous carbonate platform of the Greater Karatau (southern Kazakhstan) was investigated to test the ability of calcite micrite to archive Nd isotope signatures of seawater. The carbonate fraction that displays seawater-like rare earth element (REE + Y) signatures is o...

Gigantic representatives of the clymeniid genera Hoevelia and Protactoclymenia (Late De-vonian ammonoids) with conch sizes up to 50 cm occur in small numbers in shallow-water carbonates at Chahriseh (Central Iran). Comparison with other occurrences of gigantic clymeniids (Central Eu-rope, North Africa) suggests that taphonomic reasons rather than l...

Ammonoids of the subfamily Paratornoceratinae are characterised by disc-shaped adult conchs; furthermore they display a wide range of ontogenetic pathways leading to a similar adult conch morphology. The subfamily Paratornoceratinae occurs in the late early Famennian shelf sediments of various regions from the Anti-Atlas of Morocco to the Canning B...

The Late Devonian ammonoid species Acrimeroceras falcisulcatum and A. stella have similar-shaped discoidal adult conchs. Their conch morphology and its ontogenetic development are described and analysed. Despite great similarities in their adult conch morphology, they can be clearly distinguished by differences in the shape of their juvenile whorl...

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...

Representatives of the family Kosmoclymeniidae belong to the most abundant ammonoids in the late Famennian seccessions of various regions, but they are much less common in the North African occurrences. In the following, the two new kosmoclymeniid species Kosmoclymenia ebbighau seni and Muessenbiaergia bockwinkeli are described from the Anti-Atlas...

The impact of mass extinctions on the body sizes of animals has received considerable attention and debate, as to whether the reduced size of post-extinction organisms is due to the selective extinction of large species, absence of large species as a stochastic effect of low-diversity faunas, or a size decrease within surviving genera and species....

The Permian–Triassic boundary section in the Aras Valley in NW Iran is investigated with respect to carbonate microfacies, biostratigraphy (particularly conodonts, nautiloids, and ammonoids), chemostratigraphy (carbon isotopes), and environmental setting. Correlation of the data allows the establishment of a high-resolution stratigraphy based on co...

Reproductive strategies of extinct organisms can only be recognised indirectly and hence, they are exceedingly rarely reported and tend to be speculative. Here, we present a mass-occurrence with common preservation of pairs of late Givetian (Middle Devonian) oncocerid cephalopods from Hamar Laghdad in the Tafilalt (eastern Anti-Atlas, Morocco). We...

In the Carnic Alps there are four sections exposing rocks across the Devonian–Carboniferous boundary: the Grüne Schneid and the Kronhofgraben sections in Austria, the Plan di Zermula A and the Sentiero per Cresta Verde sections in Italy. All of them are mainly composed of limestone and span from the late Famennian through the Tournaisian. In the Kr...

In the Carnic Alps there are four sections exposing rocks across the Devonian–Carboniferous boundary: the Grüne Schneid and the Kronhofgraben sections in Austria, the Plan di Zermula A and the Sentiero per Cresta Verde sections in Italy. All of them are mainly composed of limestone and span from the late Famennian through the Tournaisian. In the Kr...

The Early Pennsylvanian Xiaheyan entomofauna (Ningxia, China) is among the earliest assemblages of winged insects known so far, and therefore provides an essential input on deciphering the early diversification of this group. Despite its evolutionary significance, both the age and depositional environment remained poorly constrained. Here, we prese...

Ammonoidea are cephalopods that provide an exceptionally high-resolution marine biostratigraphic scale from Devonian through Cretaceous. In some stratigraphic intervals , such as across the JurassicÀCretaceous boundary, they displayed considerable endemism that is a challenge for interregional correlation.

During the earliest Triassic microbial mats flourished in the photic zones of marginal seas, generating widespread microbialites. It has been suggested that anoxic conditions in shallow marine environments, linked to the end-Permian mass extinction, limited mat-inhibiting metazoans allowing for this microbialite expansion. The presence of a diverse...

Advanced gonioclymeniids comprise two families, Gonioclymeniidae and Sphenoclymeniidae. These are the phylogenetic end-members of the order Clymeniida, and are usually rarely represented in the Late Famennian ammonoid assemblages of Central Europe. The two families include the latest Famennian genera Finiclymenia, Medioclymenia and Sphenoclymenia....

The new genera and species of the early late Famennian (Late Devonian) ammonoids Hoevelia schindewolfi n. gen. n. sp. and Beulia wunderlichi n. gen. n. sp. are described from material collected in the Rhenish Mountains and attributed to the new family Hoeveliidae. The genus Falciclymenia Schindewolf, 1923 is revised with the description of the prop...

The devastating end-Permian mass extinction (252 my ago) is regarded as the most severe biotic crisis of the last 500 million years. Profound and rapid greenhouse gas release by Siberian magmatism led to a tropical seawater temperature increase of eight to ten degrees led to a complete reworking of the biosphere (e.g. Joa-chimski et al. 2012; Schob...

The end-Permian mass extinction event as the most se-vere biotic crises in Earth history is still a matter of de-bate regarding the responsibility of several environmen-tal factors, such as ocean acidification, widespread ma-rine anoxia and global temperature rise. In our study, we focus on the detailed reconstruction of a possibly global climate c...

A c. 0.30 m thick cherty limestone bed in the Dalong Formation at Gujiao (Guizhou) has yielded a highly diverse Changhsingian nautiloid assemblage. Its age is late Changhsingian, indicated by the co‐occurring ammonoid Pseudotirolites sp. This assemblage is composed of nine species and five taxa in open nomenclature in nine genera, including one new...

In the latest Famennian, black shale deposition occurred in many regions, some suggested a marine transgression as the explanation while others saw a link with higher organic input from the land. In either case, the Hangenberg Black Shale was most likely deposited under low oxygen conditions, which enabled exceptional fossil preservation in some re...

Occurrences of Late Permian coiled nautiloids are widespread but they have never been analysed in terms of spatial and temporal disparity changes. Morphometric analyses using the cardinal Raupian conch parameters: conch width index, umbilical width index and whorl expansion rate with subsequent analysis by using principal components analysis and no...

Cruziana reticulata is an arthropod‐related ichnospecies that is characterized by a conspicuous net‐like scratch pattern whose initial formation and later preservation require the presence of consolidated substrates in shallow marine fine‐grained bottoms. There are two scenarios in which epifaunal to shallow infaunal benthic organisms may access fi...

A synthetic study on biostratigraphy, sedimentology and geochemistry of the upper Viséan to Serpukhovian succession in South China is being undertaken in order to comprehensively understand the evolutionary change of the biota and global correlation around the Viséan-Serpukhovian Boundary. Four of the studied sections belong to the deep-water (slop...