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Comparison of the buccal apparatus of modern cephalopods (a, b) and aptychophoran ammonites (c, d) (modified after KEUPP et al. 1999). a-Beaks of modern Cephalopods (AL outer lamella, IL inner lamella). b-Muscular systems of the jaw apparatus (OM bifurcated upper mandibular muscle, SM lateral mandibular muscle, UM lower mandibular muscle). cDerived beaks of the Aptychophora. The specimens studied in this paper do not show any relicts of an outer lamella). d-Possible muscular system of the operculum consisting of the upper mandibular muscle only. The existence of relicts of the other both muscle-cords-as drawn-is rather unlikely.
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Completely preserved jaw apparatuses of the ammonite genera Physodoceras and ? Fontannesiella containing laevaptychi and lamellaptychi, respectively, are described from the Lower Tithonian Solnhofen plattenkalks. In both cases, the unmineralized upper jaw elements are reduced and only constructed by the "inner lamella", while the strongly calcified...
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... buccal mass of all modern cephalopods (nautilids and various coleoids) works with a complex system of muscles which guarantee an optimal biting function by overlapping of vertically and horizontally directed movements of the prominent jaw apparatus. In all modern cephalopods, the upper part of the parrot-like beaks dominates the lower element. The biting and cutting function of the jaws is guaranteed by the rostrum-like biting edges built through the outer lamella, while the muscle systems are inserted nor- mally along the more or less wing-like parts of the inner lamella. The muscle systems contain three essential elements (Fig. ...
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Soft-tissue preservation is very rare in ammonoids. The reconstruction of the internal anatomy relies on few specimens with exceptional preservation, comparisons with recent cephalopods, and inferences based on the extant phylogenetic bracket. Herein, we describe the current knowledge of the soft part-anatomy of ammonoids. Of the digestive tract, t...
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... These layers were formed mostly at relatively large depths in low-energy, often hypoxic or anoxic conditions, which ensured a good preservation of the organic jaw tissues. These layers may contain various jaws of ammonoids (Keupp, 2007;Klug et al., 2012;Schweigert et al. 2016), jaws of nautilids with calcitic tips (Klug et al., 2021a), as well as initially fully organic jaws of various coleoid cephalopods (Klug et al., 2005(Klug et al., , 2010a(Klug et al., , 2010b(Klug et al., , 2020a. Findings in situ, i.e. directly in the shells or fossilized bodies of cephalopods, are especially important, despite the fact that in coleoids, remnants of head tissues often prevent detailed study of the jaw apparatus (e.g. ...
... Age: Late Jurassic (Tithonian) The Plattenkalk of the Solnhofen Fossil-Lagerstätte are famous for their rich paleofauna, collected for hundreds of years and exhibited in natural history museums around the world. Ammonoids can be found frequently in the Plattenkalk, most of them preserved as flattened imprints and with common presence of aptychi inside the body-chambers (Keupp, 2007). Collection Georg Gasser: 2 specimens, Laevaptychus sp. ...
In Gasser’s paleozoological collection, cephalopods account for 12% of all specimens. Ammonoidea, Coleoidea, Orthoceratoidea, Nautiloidea and Bactritoidea are the groups represented. Ammonoidea are best documented, with a good variety of genera and species. A preliminary revision was carried out by a former volunteer at the museum (Helmuth Buratti) some ten years ago. Unfortunately, about 40% of the specimens lack information related to their geographic origin. The largest portion of the cephalopod collection comes from Central Europe with the main areas of origin being Germany and the territories of the former Austro-Hungarian Empire. Historical Fossil-Lagerstätten and famous fossiliferous lithostratigraphic groups like the Muschelkalk and Solnhofen Plattenkalks of the German regions of Baden-Württemberg and Bavaria, are well represented by ammonoids, nautiloids and coleoids. The oldest specimens date back to the Silurian and Devonian and come from the German regions of Sauerland (North-Rhine Westphalia) and Hesse, as well as from Poland or from the classic “Barrandian” area in the Czech Republic. The youngest specimen is from the Early Oligocene at Itzehoe (northern Germany). Interestingly, ammonoids from Northern Italy, and especially Trentino-South Tyrol, are relatively rare in the collection. They seem to be linked rather to chance
findings by local collectors or Georg Gasser himself, than to a systematic collecting activity. The area is represented, e.g., by some Triassic ammonoids from the St. Cassian Formation (Dolomites; Bozen/Bolzano Province).
... The jaw apparatuses (in both sexual dimorphs, macroconch and microconch), on the basis of their morphology and composition, especially on the overall shape and structure of the lower jaws Lehmann, 1988Lehmann, , 1990, have been classified into five morphotypes: (1) normal type Lehmann, 1980Lehmann, , 1988, (2) anaptychus type (Lehmann, 1990), (3) aptychus type (Lehmann, 1990), (4) rhynchaptychus type Lehmann, 1988Lehmann, , 1990Tanabe et al., 2013; = neoanaptychus type of Dagys et al., 1989), and (5) intermediate type (Tanabe et al., 2015). The jaw apparatus of the aptychus type (this study) is characterized by the presence of a pair of calcareous plates (aptychus) in the lower jaw, first developed in Table 1 Stratigraphic occurrences of Lamellaptychus and associated ammonite species (modified from Tanabe et al., 2015) Schindewolf, 1958;Keupp, 2007 ? Neochetoceras steraspis (Oppel) ? ...
The largely Kimmeridgian-Tithonian (Late Jurassic) aptychus Lamellaptychus rectecostatus (Peters, 1854) is considered to represent the jaw apparatus of the ammonite superfamily Haploceratoidea (Family Oppeliidae). However, here, from the Ogrodzieniec quarry (southern Poland), we present its unusual allochthonous occurrence embedded in a perisphinctid, Perisphinctes (Kranosphinctes) sp., and co-occurring with a late early Oxfordian Cordatum Subzone (Cordatum Zone) ammonite assemblage. The assemblage includes Cardioceras (Cardioceras) cf. cordatum (Sowerby), Neocampylites delmontanus (Oppel), Lissoceratoides erato (d’Orbigny), Bukowskites distortus (Bukowski), Trimarginites cf. arolicus (Oppel), Glochiceras sp., Holcophylloceras zignodianum (d’Orbigny) and Euaspidoceras (Euaspidoceras) perarmatum (Sowerby).
... Since the introduction of ultraviolet (UV) uorescence for the analysis of fossils from the Upper Jurassic Solnhofen Limestone lithographic limestones of Germany in the early 20th century (Miethe & Born 1928), the technique has been increasingly used in the analysis of exceptionally preserved fossils from this famous fossil Lagerstätte. Fossils from a wide range of phyla have been studied using UV including decapods (Schwiegert 2011), ammonites (Keupp 2007), sh ( (Fig. 1). The Solnhofen Limestone is famous for its well-bedded, ultra ne-grained lithographic limestones (often called plattenkalk) and referred to as such herein) that formed in the calm basins of the Solnhofen lagoons on the northern margin of the Tethys Ocean (Viohl 1998;Munnecke et al. 2008). ...
... Cephalopods in the form of ammonites, belemnites and teuthoids occur frequently in the Solnhofen Limestone and are sometimes exceptionally well preserved (Fuchs et al. 2015). Many have been reported with aspects of their soft tissues preserved, including impressions of tentacles with hooklets in belemnites and teuthoids (Klug et al. 2016), the musculature of the mantle in teuthoids (Klug et al. 2015) and the siphuncle and pellicula in ammonites (Keupp 2007). Although ammonites make up a large portion of the fossils from the Solnhofen plattenkalks, they are often poorly preserved due to the aragonitic composition of the shell which is readily dissolved during diagenesis (Seilacher et al. 1976). ...
... Although ammonites make up a large portion of the fossils from the Solnhofen plattenkalks, they are often poorly preserved due to the aragonitic composition of the shell which is readily dissolved during diagenesis (Seilacher et al. 1976). This dissolution leaves behind an external or composite mould in the matrix, occasionally with the original outline and the calcitic aptychi in the body chamber (Keupp 2007). ...
Laser-Stimulated Fluorescence (LSF) has seen increased use in palaeontological investigations in recent years. The method uses the high flux of laser light to reveal details sometimes missed by ultraviolet (UV) and optical wavelengths. In this study, we compare the results of LSF with UV on a range of fossils from the Upper Jurassic Solnhofen Limestone Konservat-Lagerstätte of Bavaria, Germany. The methodology follows previous protocols with modifications made to enhance laser beam intensity. Our experiments show the value of LSF in revealing shallow subsurface detail of specimens, previously not widely applied to Solnhofen fossils. In particular, fossil decapods from the Solnhofen Limestone reveal full body outlines, even under the matrix, along with details of segmentation within the appendages such as limbs and antennae. The results indicate that LSF can be used on both vertebrate and invertebrate fossils and may surpass the information provided by traditional UV methods in some specimens.
... Mesozoic records, which show their widespread geographical distribution, include those from the upper Toarcian of Spain (Martínez 2007), the Middle-Upper Jurassic of Russia (Rogov 2004a, b) and the Lower Cretaceous of Antarctica (Thomson 1972). Ammonite specimens from the Upper Jurassic (Tithonian) Solnhofen Limestone of Germany have yielded complete jaw apparatuses (Keupp 2007), including the first Jurassic ammonite jaw apparatus preserved in situ and in three dimensions (Schweigert 2009). ...
Ammonite aptychi from the Lower Jurassic of Port Mulgrave near Whitby, U.K., are reported for the first time in association with ammonites of the Family Hildoceratidae, Subfamily Harpoceratinae. The aptychi are preserved in shale, varying in their completeness and exhibiting a range of sizes, but are identified as Cornaptychus sp. and cf. Lamellaptychus sp. Some Cornaptychus specimens are preserved with ammonites identified as Tiltoniceras antiquum. The aptychi, especially Cornaptychus, are comparable with aptychi associated with ammonites of the Harpoceratinae elsewhere, notably in the Posidonia Shale of Toarcian age in Germany. The ammonite aptychi were further analysed using an Environmental Scanning Electron Microscope (ESEM) in order to determine their composition and assess whether this might have implications for their occurrence and preservation potential compared with that of the ammonite shells.
... The inner plate of the lower jaw of many Jurassic ammonites either was very thin and short, or probably absent. For example, the findings of the inner plate have never been described in Laevaptychi-bearing lower jaws (Keupp 2007). However, many of the Cretaceous ammonites are characterized by a very long and thick inner plate, for example such plates of Crioceratites and Aegocrioceratites were depicted by Engeser & Keupp (2002, figs 5, 6) as anaptychi and later identified as inner plates of lower jaws (Tanabe et al. 2015). ...
To date, bivalve calcitic plates which cover the outer chitinous lamella of the lower jaws of Jurassic and Cretaceous ammonoids (aptychi sensu stricto) have been classified into several morphotypes (form genera) based on shape, surface sculpture and internal microstructure. However, previous works on aptychi microstructure focused mainly on thick morphotypes (e.g. Laevaptychus and Lamellaptychus), whereas little was investigated for thin Praestriaptychi. In this study, the microstructure of Praestriaptychi of Upper Oxfordian Perisphinctes and of recently discovered aptychi of aspidoceratid microconch Mirosphinctes (both belonging to the superfamily Perisphinctoidea) is described. These aptychi are compared with Laevaptychi of Upper Oxfordian macroconchs Euaspidoceras (a dimorphic counterpart of Mirosphinctes). This study demonstrated that the aptychi of Perisphinctes and Mirosphinctes differ from each other and from Laevaptychi in their microstructure, number of calcitic layers and in growth patterns. The aptychi of both aspidoceratid dimorphs are similar in terms of growth pattern, but differ in microstructure and the number of calcitic layers. Neither aptychi of Perisphinctes nor of Mirosphinctes have a tubular layer with a honeycomb surface pattern, which is typical for Laevaptychus. This indicates that aptychi were extremely diverse and their microstructure varied significantly not only within the superfamily, but even within a dimorphic pair of aspidoceratid ammonites. A lack of a tubular layer in Praestriaptychus indicates that it developed independently in Lamellaptychus of Haploceratoidea and Laevaptychus of Aspidoceratidae.
... One poorly known Middle Jurassic specimen of Sigaloceras (Hollingworth and Hilton 1999) shows extensive organic remains, which are, however, difficult to interpret. The Kimmeridgian and Tithonian Fossillagerstätten of the Solnhofen/Eichstätt region as well as Nusplingen yielded several ammonite specimens, displaying remains of the digestive tract with stomach contents and more or less complete buccal masses (Schweigert 1998(Schweigert , 2009Frickhinger 1994Frickhinger , 1999Dietl 1999, 2001;Keupp 2000Keupp , 2007Keupp , 2011a. ...
... One poorly known Middle Jurassic specimen of Sigaloceras (Hollingworth and Hilton 1999) shows extensive organic remains, which are, however, difficult to interpret. The Kimmeridgian and Tithonian Fossillagerstätten of the Solnhofen/Eichstätt region as well as Nusplingen yielded several ammonite specimens, displaying remains of the digestive tract with stomach contents and more or less complete buccal masses (Schweigert 1998(Schweigert , 2009Frickhinger 1994Frickhinger , 1999Dietl 1999, 2001;Keupp 2000Keupp , 2007Keupp , 2011a. ...
... In only two cases, ichnofossils of more or less questionable imprints of ammonite soft parts have been described. Some Late Jurassic ammonites from Germany are associated with traces which are difficult to interpret, but which may represent imprints of soft-parts or of scavengers (Frickhinger 1999;Keupp 2007). Summesberger et al. (1999) found roll marks and supposedly soft-part imprints of Late Cretaceous ammonites in Slovenia. ...
Soft-tissue preservation is very rare in ammonoids. The reconstruction of the internal anatomy relies on few specimens with exceptional preservation, comparisons with recent cephalopods, and inferences based on the extant phylogenetic bracket. Herein, we describe the current knowledge of the soft part-anatomy of ammonoids. Of the digestive tract, the buccal mass, oesophagus, crop, stomach and caecum are rarely preserved. Stomach contents have become known from eleven species. Remains of the cephalic cartilage are scarce and suggest the presence of a simple lens eye. Only little has become known of ammonite gill anatomy. Unequivocal imprints of arm crowns have not been discovered yet, but we reinterpreted a baculitid that possibly preserves an arm crown with (?) ten short and thin retractable arms. An ink sac was absent, while a hyponome was present. There is no evidence for a hood in ammonoids.
... The lower jaw of this morphotype (= anaptychus sensu stricto, F igs. 10.4b, 10.9.2) was defined by having a widely open outer lamella (wing), a short and reduced inner lamella (crest and lateral wall), and a more or less pointed rostrum (Lehmann 1970(Lehmann , 1980. The anaptychus-type jaw apparatuses are known from the Jurassic Psiloceratidae and Arietitidae (Psiloceratoidea) (Schmidt 1928;Lehmann 1970Lehmann , 1975Cope and Sole 2000;Keupp 2000), Dactylioceratidae, Eoderoceratidae, and Amaltheidae (Eoderoceratoidea; see Schmidt 1928;Lehmann 1979;Cope 1994;Cope and Sole 2000;Keupp 2000), all of which belong to the suborder Ammonitina (Table 10.1). In addition, Schmidt (1928, pl. ...
... The lower jaw of this morphotype (= anaptychus sensu stricto, F igs. 10.4b, 10.9.2) was defined by having a widely open outer lamella (wing), a short and reduced inner lamella (crest and lateral wall), and a more or less pointed rostrum (Lehmann 1970(Lehmann , 1980. The anaptychus-type jaw apparatuses are known from the Jurassic Psiloceratidae and Arietitidae (Psiloceratoidea) (Schmidt 1928;Lehmann 1970Lehmann , 1975Cope and Sole 2000;Keupp 2000), Dactylioceratidae, Eoderoceratidae, and Amaltheidae (Eoderoceratoidea; see Schmidt 1928;Lehmann 1979;Cope 1994;Cope and Sole 2000;Keupp 2000), all of which belong to the suborder Ammonitina (Table 10.1). In addition, Schmidt (1928, pl. ...
... 10.4b), dactylioceratids (F ig. 10.9.2), and amaltheids, but not to those of the arietitids ( Asteroceras and Arnioceras), and eoderoceratid ( Promicroceras), whose outer chitinous lamella is wholly covered with a thin univalved calcareous layer (Lehmann 1971;Cope 1994;Cope and Sole 2000;Keupp 2000). Based on this evidence, Tanabe et al. (2012) suggested that the anaptychus-type lower jaws might have originally had a thin calcareous layer on the ventral side of the outer chitinous lamella. ...
Current knowledge on the ammonoid buccal mass and jaw apparatus is synthesized based on in situ fossil records from 109 genera that are distributed in 30 superfamilies of 8 suborders of Devonian to Cretaceous age. As in those of modern cephalopods, the jaw apparatus of ammonoids consists of upper and lower elements. Comparative anatomical examination of the attachment scars of chitin-secreting cells (beccublasts) on the jaw lamellae allow us to reconstruct the buccal mass structure of ammonoids. The jaw apparatuses of ammonoids can be classified into the normal, anaptychus, aptychus, intermediate, and rhynchaptychus types based mainly on the differences in overall morphology and lamellar composition in the lower jaws. The fairly large variation of the jaw morphology and the variety of food remains preserved in the digestive tract and buccal cavities in Mesozoic ammonoids may reflect diversity of feeding and diets ranging from predatory via scavenging to microphagous habits.
... In ammonoids, multicuspidate radulae (Fig. 11.11) seem to be related to the aptychus type of jaw. Several hypotheses were made on the feeding habits related to this particular jaw apparatus (see also Tanabe et al. 2014), most of them include a microphagous diet (Morton and Nixon 1987;Kennedy et al. 2002;Keupp 2007;Seilacher 1993;Tanabe and Landman 2002) and zooplankton (Kruta et al. 2011). ...
The radula is a molluscan feeding device that was also present in ammonoids. It consists of a ribbon with regularly arranged chitinous teeth disposed in transversal rows located between the upper and lower jaws. This chapter describes the radula in twelve ammonoid genera. The radula is composed of seven teeth per row: the rachidian tooth, two lateral teeth on each side of the rachidian tooth, and the marginal teeth on the external part of the ribbon. Marginal plates are only present in a few taxa. Compared to Recent cephalopods, the radula of ammonoids is similar in morphology and number of elements to that of coleoids. The radula in the Goniatitina is unicuspidate and shows little variation so far, while the radula in the Ammonitina and Ancyloceratina is more variable and consists of multicuspidate rachidian and lateral teeth and elongate marginal teeth.
... Shell-wall duplication was interpreted by Birkelund (1981) in Gaudryceras as indication that its juvenile shell was exceptionally covered by the mantle. Additionally, in situ fossil buccal masses are commonly located near the centre of the body chamber, supporting a jaw-function rather than an operculum-function (Schindewolf 1958;Lehmann 1976Lehmann , 1980Lehmann , 1988Kennedy and Cobban 1976;Tanabe 1983;Morton and Nixon 1987;Tanabe and Fukuda 1987;Mapes 1987;Bandel 1988;Nixon 1988Nixon , 1996Seilacher 1993;Westermann 1996;Kennedy et al. 2002;Wippich and Lehmann 2004;Doguzhaeva et al. 2007;Keupp 2007;Landman et al. 2007b. As shown by Wani (2007), in situ preservation of buccal masses in the body chamber of ammonoids coincides with the in situ deposition of the ammonoid shell itself (Chamberlain et al. 1981;Wani et al. 2005). ...
... One of the specimens revealed a planktic snail and three tiny planktic crustaceans (Isopoda) in its buccal mass (Kruta et al. 2011). As already stated by Westermann (1996), knowledge on stomach or crop contents is scarce (Lehmann and Weitschat 1973;Lehmann 1975Lehmann , 1976Lehmann , 1985Lehmann , 1988Summesberger 2000;Keupp 2007). See Klug and Lehmann (2015) for a review. ...
... Numerous problems related to the dietary and feeding habits for the diversely shaped buccal organs are still unsolved, even for some extant cephalopods (Nesis 1986(Nesis , 1987Lehmann 1988). Westermann (1996) noted that besides the micro and mesophagy documented by crop/stomach contents, macrophagy and even duraphag ous strategies might have also been present in ammonoids (Schindewolf 1958;Lehmann et al. 1980;Tanabe 1983;Nesis 1986;Tanabe and Fukuda 1987;Lehmann and Kulicki 1990;Hewitt 1993;Seilacher 1993;Keupp 2007). Westermann (1996) suggested that most ammonoids belonged to the pelagic food-web. ...
The current knowledge about the ammonoid/habitat relation is reviewed and in part newly interpreted. The autecology of ammonoids, such as ontogeny and habitat, based on morphological and geochemical analyses in association with results from modern relatives, forms the foundation for subsequent interpretations. Synecological interactions (predator-prey, infestation) are discussed with reference to sedimentary facies and the corresponding biofacies. Arguments for a possible mode of life and habitat are given based on the modern data on the food/prey habits and predation habitats of ammonoids. The state of the art in scientific investigations on ammonoid life and habitat is summarized, reviewed and in part reinterpreted. Traditional assumptions based on facies analyses are strengthened or contradicted by more recent methods such as morphospace and stable isotope analyses. Not yet tested hypotheses, speculations and mathematical models are tested by comparing the results with new geophysical data.
