Olaf Höltke

Mr. Olaf Höltke


Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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31 December 2024 in Palaeobiodiversity and Palaeoenvironments
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Journal Article
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DUDieter Uhl
Dieter Uhl
MWMichael Wuttke
Michael Wuttke
MAManuela Aiglstorfer
Manuela Aiglstorfer
CGCarole Gee
Carole Gee
FGFederica Grandi
Federica Grandi
SWSonja Wedmann
Sonja Wedmann
Deep-time (=pre-Quaternary) maar lakes and certain other, hydrologically deep volcanogenic lakes, are often excellent Konservat-Lagerstätten representing unique windows into past biota and ecosystems. Many deposits from such lakes contain animal and plant remains in extraordinary preservation, often with soft tissues or fine morphological and anatomical details preserved. Such Lagerstätten have the potential to provide in-depth information on a variety of organisms, which is important for understanding their biology and ecology, their evolution and palaeobiogeography, but also for elucidating entire ecosystems with their numerous biotic and abiotic interactions. The formation of such Lagerstätten is intimately linked to volcanic processes, amongst which phreatomagmatic explosions that formed maar-diatreme volcanoes are probably the most important, but also other volcanic processes can lead to the formation of deep volcanogenic lakes (e.g. in certain calderas). Maar lakes and other volcanogenic Konservat-Lagerstätten occur in a large number of volcanically active regions worldwide, although older deposits are often difficult to access as they are more likely to be eroded or covered by younger deposits. The accessibility of many of the better-known localities is often connected to the mining of natural resources, ranging from diamonds, to volcanic rocks such as basalts to the lacustrine sediments that may have filled volcanic craters, including diatomites and ‘oil-shales’. Most or even all of the maar and other volcanogenic lakes presented here in greater detail, can be considered as important geoheritage sites. Although currently some of these deposits have at least some kind of legal protection as monuments of natural heritage, others remain in danger of being exploited commercially for natural resources and hence, ultimately destroyed. Moreover, many scientific questions related to these ancient lakes and their biota covered here in more detail, as well as those related to lakes only briefly mentioned in passing, have not been posed, let alone answered. This makes maar lakes and other volcanogenic lakes important resources for present-day and future research. The present contribution should be seen as a global call to scientists to find further localities that represent similar volcanogenic lacustrine settings, as they may be the source of vital and surprising new information about the plants, animals, and environments of the past. Examples of pre-Quaternary maar and other volcanogenic lakes that are presented here in greater detail include the following localities: Paleocene: Menat (France); Eocene: Messel, Eckfeld (Germany), Mahenge (Tanzania); Oligocene: Enspel, Rott, Hammerunterwiesenthal, Baruth, Kleinsaubernitz (Germany); Miocene: Foulden Maar, Hindon Maar Complex (New Zealand), Randeck Maar, Hirnkopf-Maar, Höwenegg, Öhningen (Germany); Pliocene: Ruppach-Goldhausen (Germany), Camp dels Ninots (Spain).

1 April 2016 in Palaeodiversity
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Rodrigo Brincalepe SalvadorRodrigo Brincalepe Salvador
Rodrigo Brincalepe Salvador
OHOlaf Höltke
Olaf Höltke
MRMichael W. Rasser
Michael W. Rasser
DKDietrich Kadolsky
Dietrich Kadolsky
The type specimens of fossil land and freshwater gastropods deposited in the Staatliches Museum für Naturkunde Stuttgart (SMNS), Germany, are listed and illustrated herein, comprising circa 180 nominal species-group taxa from Cenozoic fossil sites, mainly in the Baden-Württemberg and Bayern states in southern Germany. The list is arranged in alphabetical order of the specific epithets, with information on the original description, taxonomical status, type locality, record number in the collection and comments. A systematically arranged list of the taxa is also given, as well as a list arranged by authorship of the species-group names. At least one type specimen (holotype, lectotype, syntype or neotype) of each nominal species/subspecies is figured here, and further specimens were figured when they added information. In some cases lectotypes are designated herein.

29 September 2019 in Lethaia
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MRMichael W. Rasser
Michael W. Rasser
OHOlaf Höltke
Olaf Höltke
Rodrigo Brincalepe SalvadorRodrigo Brincalepe Salvador
Rodrigo Brincalepe Salvador
The Randeck Maar lake sediments from SW Germany were deposited during a climatic phase known as the Mid‐Miocene Climatic Optimum, providing a unique window into this last favourable period for a more thermophilous fauna in Central Europe. Previous palaeoecological reconstructions of Randeck Maar's environment focused on the flora and vertebrate fauna. Here, we present a palaeoecological analysis using gastropods as proxies by means of an actualistic genus‐level approach. This approach is grounded in comparisons of habitat preferences between extant and fossil congeners and thus obviously requires a sound taxonomic framework. Despite being commonly applied in the literature, this approach has hardly been defined so far. Therefore, we thoroughly delineate it, exploring its applicability, potential and shortcomings. The molluscan fauna of Randeck Maar counts with 32 species of continental snails, mostly terrestrial pulmonates, related to the following palaeohabitats: littoral, supralittoral, rocky walls, shrubland, forests and open habitats. The gastropods indicate a warm‐temperate climate with a dry season, in line with previous works on Randeck Maar's flora and vertebrates.

1 December 2017 in Palaeodiversity
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Rodrigo Brincalepe SalvadorRodrigo Brincalepe Salvador
Rodrigo Brincalepe Salvador
OHOlaf Höltke
Olaf Höltke
MRMichael W. Rasser
Michael W. Rasser
Herein we present an account of the fossil terrestrial and freshwater gastropods from the locality of Hohenmemmingen (Baden-Württemberg state, SW Germany) based on museum collections. The fossil outcrops belong to the Silvana Beds of the Upper Freshwater Molasse, being of Early/Middle Miocene age. In total, 23 gastropod species, all pulmonates, are documented in the material (whereas 33 species had been previously reported in the literature): five freshwater species and 18 terrestrial. From an actualistic palaeoecological approach, this palaeoevironment featured a humid and warm forest cover, with a well-vegetated and likely shallow water body.

26 February 2024 in Diversity
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OHOlaf Höltke
Olaf Höltke
EMErin Maxwell
Erin Maxwell
MRMichael W. Rasser
Michael W. Rasser
In recent years, new findings and new methods (stable isotopes of oxygen, zinc, and nitrogen; 2D and 3D modeling; and geometric morphometric analyses of the teeth) have enhanced our knowledge of the Neogene shark fauna and its paleobiology. Several papers deal with the large Otodus (Megaselachus) species, including the construction of a 3D model, as well as insights into its lifestyle and diet. In addition, the skeletal remains of Carcharias gustrowensis, Carcharodon hastalis, and Keasius parvus and a natural tooth set of Carcharodon hubbelli have been described in the last 13 years, and the dentition of the Neogene species Carcharoides catticus, Megachasma applegatei, and Parotodus benedenii has been reconstructed. Stable isotope analyses of the teeth from the Neogene species of Araloselachus, Carcharias, Carcharodon, Galeocerdo, Hemipristris, and Mitsukurina have given insights into the trophic positions of these genera during the Neogene, and shark teeth preserved near the skeletal remains of prey animals (mammals) and shark bite traces on these remains provide direct evidence of trophic interactions. The tooth shape, fossil locality, and paleoenvironment have been used to better understand the taxa Carcharhinus dicelmai, Megalolamna paradoxodon, Pachyscyllium dachiardii, and P. distans. Among extant species, Galeorhinus galeus can be traced back to the Eocene. Alopias superciliosus, Rhincodon typus, and possibly A. vulpinus can be traced back to the Oligocene. Species present by the Miocene include Alopias vulpinus, Carcharhinus amblyrhynchoides, C. amblyrhynchos, C. albimarginatus, C. amboinensis, C. brachyurus, C. brevipinna, C. falciformis, C. glaucus, C. leucas, C. limbatus, C. longimanus, C. macloti, C. obscurus, C. perezi, C. sealei, Centrophorus granulosus, Cetorhinus maximus, Dalatias licha, Deania calcea, Galeocerdo cuvier, Glyphis glyphis, Heptranchias perlo, Isurus paucus, Lamna nasus, Negaprion brevirostris, Odontaspis ferox, Pseudocarcharias kamoharai, Sphyrna media, S. mokarran, and possibly Carcharodon carcharias. First appearing in the Pliocene are Scymnodon ringens, Somniosus rostratus, and Zameus squamulosus. For some extant species (Carcharias taurus, Hexanchus griseus, Isurus oxyrinchus, Notorynchus cepedianus, and Sphyrna zygaena), it is not clear whether the assigned Neogene teeth represent the same species. The application of new methods to more fossil shark taxa, a detailed search for shark fossils, and better knowledge of the dentition of extant species (especially those with minute-sized teeth) will further enhance our knowledge of the evolution and paleobiology of sharks.

10 June 2022 in Folia Malacologica
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Journal Article
Open access
Rodrigo Brincalepe SalvadorRodrigo Brincalepe Salvador
Rodrigo Brincalepe Salvador
OHOlaf Höltke
Olaf Höltke
BVBárbara L. Valentas-Romera
Bárbara L. Valentas-Romera
MRMichael W. Rasser
Michael W. Rasser
Herein, we revise an extensive set of mollusc fossils from the Upper Freshwater Molasse deposits of Öhningen palaeolake (SW Germany; Middle Miocene, MN7). Based on material housed in paleontological collections in Europe and North America, we present the first thorough systematic account of the phylum from this historic locality. A total of ten species were identified from Öhningen: three freshwater gastropods (Lymnaea dilatata Noulet, 1854, Gyraulus cf. applanatus (Thomä), Planorbarius mantelli (Dunker)), two terrestrial gastropods (Granaria cf. schuebleri (Klein), Palaeotachea sylvestrina (Schlotheim)), and five bivalves (Anodonta splendens Goldfuss, A. lavateri (Münster), Pseudunio flabellatus (Goldfuss), “Dreissena” sp., Pisidium escheri (Mayer-Eymar, 1865)). Three freshwater and five terrestrial gastropod genera mentioned in older literature could not be found in the available material. Ours is the first report of a Dreissenidae from Öhningen.