Weichteile ectocochleater paläozoischer Cephalopoden in Röntgenaufnahmen und ihre paläontologische Bedeutung

Zeiss, Arnold

doi:10.1007/bf02987923

Cited by 18 publications

(5 citation statements)

References 6 publications

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“…X-ray pictures suggest that some Devonian goniatites from the Wissenbacher Schiefer (Germany) show partly preserved soft tissue, including tentacles and buccal masses within the shells (Sturmer, 1969;Zeiss, 1969;Bandel, 1988). However, several reports of such "softpart" preservation of invertebrates are now questioned: e.g .. images of "tentacles" and "mantle sacks" of goniatites and bactritids may be the fractured wall of the body chamber (Otto, 1994).…”

Section: Soft-part Preservationmentioning

confidence: 99%

Ammonoid Taphonomy

Maeda

Seilacher

1996

Topics in Geobiology

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Section: Soft-part Preservationmentioning

confidence: 99%

Ammonoid Taphonomy

Maeda

Seilacher

1996

Topics in Geobiology

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“…Berthold & Engeser (1987) argued that reduction of arm number was an additional shared derived feature of ammonoids and coleoids. The evidence for arm reduction in ammonoids stems from X-ray studies of the Devonian Hunsruck shale (Zeiss 1969). These images suggest ten arms in ammonoids, a number equal to that in fossil and modern coleoids.…”

Section: Phylogenymentioning

confidence: 99%

Nautilus —a poor model for the function and behavior of ammonoids?

Jacobs

Landman

1993

LET

108

120

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Inferences drawn from the biology, function, and behavior of closely related living forms facilitate interpretation of the mode of life of groups known only from the fossil record. The choice of phylogenetically relevant modern ‘model organisms’ can have critical bearing on the resulting interpretations. The biology and behavior of fossil ammonoids are often interpreted in the light of evidence derived from the study of modern Nautilus. However, examination of the fossil record and cladistic analyses both indicate that coleoids are much more closely related to ammonoids than is Nautilus. Coleoid biology and behavior differ dramatically from the biology and behavior of Nautilus. Thus, the inclusion of coleoids as examples, rather than reliance on Nautilus alone, produces a strikingly different vision of ammonoid biology and suggests that inferences of ammonoid biology and behavior that rely exclusively on Nautilus should be reviewed. Two features related to swimming ability in Nautilus, static stability and large retractor muscles, are much reduced in many ammonoids, leading to the interpretation that ammonoids were poorer swimmers than Nautilus. However, reexamination of the evidence indicates that static stability should not play a role in the swimming of ammonoids with long body chambers. In addition, functional arguments suggest that a coleoid‐like swimming mechanism should have evolved prior to the loss of the body chamber in coleoids. Thus, a coleoid‐like swimming mechanism is likely to have evolved prior to the separation of ammonoid and coleoid lineages. A mechanism is proposed by which a coleoid swimming mechanism, independent of retractor muscle size, could function in ammonoids with long body chambers.□Ammonoids, ammonites, evolution, functional morphology, Nautilus, phylogeny.

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“…However, Osgood (1970: 340-341), studying additional markings, has attributed their formation to feeding burrows, though his interpretation may be subject to reinterpretation. Notwithstanding these curious markings, X-ray examination of the soft parts of several Devonian nautiloids has shown them to have a relatively small number of tentacles (Zeiss 1969;Sturmer 1970) so the notion of a few tentacles in the early forms may be perfectly valid.…”

Section: Possible Changes In Locomotion and Life Habit From Monoplacomentioning

confidence: 99%

The bearing of the new Late Cambrian monoplacophoran genus Knightoconus upon the origin of the Cephalopoda

Yochelson

Flower

Webers

1973

LET

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Yochelson, E. L., Flower, R. H. & Webers, G. F.: The hearing of the new Late Cambrian monoplacophoran genus Knightoconus upon the origin of the Cephalopoda. Knightoconus, a new genus of the Hypseloconidae (Mollusca: Monoplacophora) from rocks of early Franconian age in Antarctica, is multiseptate. The multiple septa are a criticàl feature to be expected in a form ancestral to cephalopods. Fossil cephalopods, however, invariably have a siphuncle as well as septa; some gastropods, some hyolithids, and some monoplacophorans also have septa but lack a siphuncle. Therefore, only the siphuncle can be considered a unique and particularly significant feature of the cephalopod shell. Hypothetical reconstructions of molluscan anatomy support the notion that cephalopods may have been derived directly from a hypseloconid having a high, slightly curved, multiseptate, bilaterally symmetrical shell, by the subsequent development of a siphuncle.

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Weichteile ectocochleater paläozoischer Cephalopoden in Röntgenaufnahmen und ihre paläontologische Bedeutung

Cited by 18 publications

References 6 publications

Ammonoid Taphonomy

Ammonoid Taphonomy

Nautilus —a poor model for the function and behavior of ammonoids?

The bearing of the new Late Cambrian monoplacophoran genus Knightoconus upon the origin of the Cephalopoda

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