Ammonoid Life and Habitat

Westermann, Gerd E. G.

doi:10.1007/978-1-4757-9153-2_16

Cited by 225 publications

(377 citation statements)

References 118 publications

(211 reference statements)

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“…For specimens where sex can be determined, 44% are males, 52% are females, and 4% are juveniles. These proportions are representative of a living community (19) and not of an egg-laying habitat transiently occupied by females (20). Predation indicators, such as healed injuries, are present on 5% of scaphite specimens (Fig.…”

Section: Resultsmentioning

confidence: 99%

Ammonite habitat revealed via isotopic composition and comparisons with co-occurring benthic and planktonic organisms

Sessa

Larina

Knoll

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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Ammonites are among the best-known fossils of the Phanerozoic, yet their habitat is poorly understood. Three common ammonite families (Baculitidae, Scaphitidae, and Sphenodiscidae) co-occur with wellpreserved planktonic and benthic organisms at the type locality of the upper Maastrichtian Owl Creek Formation, offering an excellent opportunity to constrain their depth habitats through isotopic comparisons among taxa. Based on sedimentary evidence and the micro-and macrofauna at this site, we infer that the 9-m-thick sequence was deposited at a paleodepth of 70-150 m. Taxa present throughout the sequence include a diverse assemblage of ammonites, bivalves, and gastropods, abundant benthic foraminifera, and rare planktonic foraminifera. No stratigraphic trends are observed in the isotopic data of any taxon, and thus all of the data from each taxon are considered as replicates. Oxygen isotope-based temperature estimates from the baculites and scaphites overlap with those of the benthos and are distinct from those of the plankton. In contrast, sphenodiscid temperature estimates span a range that includes estimates of the planktonic foraminifera and of the warmer half of the benthic values. These results suggest baculites and scaphites lived close to the seafloor, whereas sphenodiscids sometimes inhabited the upper water column and/or lived closer to shore. In fact, the rarity and poorer preservation of the sphenodiscids relative to the baculites and scaphites suggests that the sphenodiscid shells may have only reached the Owl Creek locality by drifting seaward after death.A mmonites have constituted a primary data source for the fields of evolution, paleoceanography, biostratigraphy, and paleoecology for more than a century; their ubiquity, diversity, occurrence in a wide variety of marine environments, and readily preservable shell account for their utility in both paleontological and geological studies. Ammonites have been used extensively in studies of heterochrony because their shells preserve distinct ontogenetic changes that can be tracked in evolving lineages (1, 2); they are valued in paleoceanographic research because, like most mollusks, they are inferred to have precipitated their aragonitic shells in isotopic equilibrium with the surrounding seawater (3, 4). Thus, shell chemistry may record temperature, via oxygen isotopes (δ 18 O) (5), and water mass properties, such as strontium isotopes ( 87 Sr/ 86 Sr), which are used to estimate numerical age (6). Ammonites are also a textbook example of an index fossil; besides being abundant and widespread, they evolved rapidly, making them the dominant Mesozoic tool for relative dating and correlation of shallow water strata. For example, the 35-My-long stratigraphic record of Upper Cretaceous deposits in the US Western Interior Seaway (WIS) has been partitioned into 66 ammonite zones (7). Finally, ammonites underwent a spectacular extinction at the close of the Mesozoic. Explanations for why the ammonites, which were flourishing immediately before the Cretaceous-P...

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Section: Resultsmentioning

confidence: 99%

Ammonite habitat revealed via isotopic composition and comparisons with co-occurring benthic and planktonic organisms

Sessa

Larina

Knoll

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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“…Functional interpretations of a keel were usually related to hydrodynamics (Chamberlain & Westermann 1976, Frank 2010, although such hypotheses are difficult to test. Such a keel might hypothetically have provided greater hydrodynamic stability for the shell and thus saved energy during inactivity (Westermann 1996, Frank 2010, and the keel ornamentation may have increased streamlining (Spath 1919). Keels are, however, usually developed in smooth, mainly compressed nautiloids (except for Deltocymatoceras), which are typical for pelagic, low-energy environments (Tintant & Kabamba 1985, Wilmsen 2000.…”

Section: Functional Morphology and Ontogenymentioning

confidence: 99%

“…88, 4, 2013 1987), benthic to nekto-benthic (nostoceratids) and pelagic (baculitids) life-style (e.g., Westermann 1996, Tsujita & Westermann 1998. Only three species with planispiral shell -giant Lewesiceras peramplum, medium-sized L. mantelli and smaller S. cf.…”

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confidence: 99%

The endemic and morphologically remarkable nautilid genus Deltocymatoceras Kummel, 1956 from the Late Cretaceous of Central Europe

Frank¹,

Wilmsen²,

Košťák³

2013

Bull. Geosci.

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The endemic Late Cretaceous nautilid genus Deltocymatoceras Kummel, 1956 is represented by Deltocymatoceras leiotropis (Schlüter, 1876) and D. rugatum (Fritsch & Schlönbach, 1872). Characteristic for this genus is a bulbous involute shell with strong radial ribbing and a ventral keel, which appears in post-juvenile ontogenetic stages. The combination of these morphological features is unique among post-Palaeozoic nautiloids. Both species are restricted to the Late Turonian-Middle Coniacian of Central Europe and England. Until now, the type species D. leiotropis was known based only on the holotype specimen. This specimen is re-described with revised occurrence and for the first time photographically illustrated. The only preserved syntype from the type specimens of D. rugatum was re-discovered during this revision and more than thirty other specimens were studied. Representatives of Deltocymatoceras show clear morphological changes during their ontogeny and acquisition of maturity, most notably the appearance of a ventral keel in premature stages and its disappearance at maturity. The hypothesis of a close phylogenetic affinity of Deltocymatoceras to the genus Cymatoceras Hyatt, 1884 is based on similar morphological features such as the suture, ribbing, shell shape and early ontogenetic development. The ventral keel is quite an exceptional feature of morphology in post-Palaeozoic nautiloids. In particular the combination with an involute depressed shell is only shared with representatives of the genus Angulithes Montfort, 1808 (Cretaceous-Palaeogene) and Gryponautilus Mojsisovic, 1902 (Triassic). The combination with a compressed and evolute planispiral shell is more common in Palaeozoic and some post-Palaeozoic nautiloids. The ventral keel is discussed here in relation to its functional aspects (hydrodynamic stability) in combination with the strong radial ribbing (protection of the shell against mechanical damage). The appearance of the genus concurred with the late Turonian shallowing/cooling associated with the "Hyphantoceras Event" and the availability of an ecologic niche (i.e., absence of medium-sized, keeled ammonites at that time). Low abundance, an endemic occurrence, and the very short stratigraphic range of the genus (~3.5 Ma) reflect the limited evolutionary success of the Deltocymatoceras lineage.• Key words: Nautilida, taxonomy, phylogeny, ontogeny, palaeogeography, functional morphology, biostratigraphy. May 17, 2013; published online September 12, 2013; issued October 31, 2013. Jiří Frank, Institute of Geology and Palaeontology, Faculty of Science, Charles University, Albertov 6, 128 43 Praha 2, and National Museum, Department of Palaeontology, Václavské náměstí 68, 115 79 Praha 1, Czech Republic; jiri_frank@nm.cz • Markus Wilmsen, Senckenberg Naturhistorische Sammlungen Dresden, Museum für Mineralogie und Geologie, Sektion Paläozoologie, Königsbrücker Landstrasse 159, D-01109 Dresden, Germany; markus.wilmsen@senckenberg.de • Martin Košťák, Institute of Geology and Palaeontology, Facult...

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“…This organic-rich layer covers dorsal, ventral and lateral walls inside the ammonoid body chamber and forms part of the dorsal shell wall. It is well studied in different ammonoid genera (Quenstedt 1845(Quenstedt -1849Sandberger 1851;Merkt 1966;Nassichuk 1967;Walliser 1970;House 1971;Senior 1971;Tozer 1972;Bayer 1974;Kulicki 1979;Mapes 1979;Birkelund 1981;Doguzhaeva 1981;Zakharov & Grabovskaya 1984;Korn 1985Korn , 2000Doguzhaeva & Mutvei 1986, 1996Keupp 2000;Kulicki et al 2001;Korn et al 2014). The part of the wrinkle layer, which extends from the body chamber and covers the surface of the penultimate whorl in front of the aperture in the tightly coiled planispiral ammonoid shells was also repeatedly described (Senior 1971, Tozer 1972, Birkelund 1981, Doguzhaeva 1981, Keupp 2000, Korn 2000, Kulicki et al 2001, Klug et al 2004.…”

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confidence: 99%

“…In the past, this layer was described under different names: "Runzelschicht" for the dorsal part of the layer and "Ritzstreifen" for lateral and ventral parts (Sandberger 1851, Walliser 1970, Bayer 1974, Korn 1985, Keupp 2000, as "black layer" (Klug 2004) and as "wrinkle layer" (Teichert 1964;Bayer 1974;Mapes 1979;Birkelund 1981;Zakharov & Grabovskaya 1984;Doguzhaeva & Mutvei 1986, 1996Keupp 2000;Korn 2000;Kulicki et al 2001;Kröger et al 2005;Korn et al 2014). The structure of this layer in different ammonoid genera significantly varies in terms of type and proportions of mineral and organic components (since this layer is partly mineralized) as well as in the size and shape of the wrinkles (Keupp 2000, Kulicki et al 2001, Korn et al 2014.…”

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confidence: 99%

Wrinkle layer and supracephalic attachment area: implications for ammonoid paleobiology

Mironenko¹

2015

Bull. Geosci.

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In many planispiral ammonoid shells, the dorsal wrinkle layer is located not only inside the body chamber, but also protruded beyond the apertural edge, covering the part of the penultimate shell whorl in front of the aperture (similar to the black layer of Recent Nautilida). This external (relative to the body chamber) part of the wrinkle layer was rarely the focus of research and its implications for ammonoid paleobiology have not been studied in detail. This paper deals with this area found on the shells of seven genera of planispiral Jurassic (Callovian and Oxfordian) ammonites from Central Russia. The size and shape of this area as well as the surface structure of well-preserved specimens are described. The proposed name "supracephalic attachment area" (SCAA) represents the location and presumed biological significance of this part of the wrinkle layer. The implications of the existence of this area for the ammonoid mode of life, soft body structure and aperture orientation are discussed. The location of the part of the wrinkle layer outside of the body chamber proves that some part of the ammonoid soft body (likely the cephalic region) moved forward beyond the aperture during active swimming. This forces a review of calculations of ammonite aperture orientation which were based on the postulate that the soft body was located largely within the body chamber. Aleksandr A. Mironenko, Kirovogradskaya st. 28, 117519 Moscow, Russia; paleometro@gmail.com The ammonoid wrinkle layer -a part of the shell with more or less prominent wrinkles on the surface -has been studied for more than 150 years. This organic-rich layer covers dorsal, ventral and lateral walls inside the ammonoid body chamber and forms part of the dorsal shell wall. It is well studied in different ammonoid genera (Quenstedt

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Ammonoid Life and Habitat

Cited by 225 publications

References 118 publications

Ammonite habitat revealed via isotopic composition and comparisons with co-occurring benthic and planktonic organisms

Ammonite habitat revealed via isotopic composition and comparisons with co-occurring benthic and planktonic organisms

The endemic and morphologically remarkable nautilid genus Deltocymatoceras Kummel, 1956 from the Late Cretaceous of Central Europe

Wrinkle layer and supracephalic attachment area: implications for ammonoid paleobiology

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