Tableau élémentaire de l'histoire naturelle des animaux

Cuvier, Georges

doi:10.5962/bhl.title.45918

Cited by 266 publications

(45 citation statements)

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“…Class Cephalopoda Cuvier, 1798Subclass Ammonoidea Zittel, 1884Order Phylloceratida Arkell, 1950Superfamily Phylloceratoidea Zittel, 1884 Family Juraphyllitidae Arkell, 1950 Genus Tragophylloceras Hyatt, 1900…”

Section: Systematic Partmentioning

confidence: 99%

Ammonites from the Apoderoceras beds (Early Pliensbachian) in São Pedro de Muel (Lusitanian Basin, Portugal)

Meister¹,

Dommergues²,

Rocha³

2012

Bull. Geosci.

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The lowermost Portuguese Pliensbachian is characterized by the association of Apoderoceras dunrobinense Spath, Tragophylloceras numismale (Quenstedt) and Vicininodiceras aff. mouterdei Donovan. This ammonite fauna indicates the lower part of the Jamesoni Chronozone (lower to middle Taylori Subchronozone). Thanks to the numerous specimens collected, the ontogeny and variability of A. dunrobinense Spath, could also be investigated. The paleogeographical distribution of these ammonites underlines the close connections between the Lusitanian Basin and the Euroboreal seas during the Early Pliensbachian.•

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Section: Systematic Partmentioning

confidence: 99%

Ammonites from the Apoderoceras beds (Early Pliensbachian) in São Pedro de Muel (Lusitanian Basin, Portugal)

Meister¹,

Dommergues²,

Rocha³

2012

Bull. Geosci.

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“…Class Cephalopoda Cuvier, 1797Angusteradulata Lehmann, 1967 Discussion. -Despite the fact that many new data concerning morphology, ecology, evolution, stratigraphic range and geographic distribution of Palaeozoic cephalopods have been accumulated since 1950, the classification of Palaeozoic cephalopods still rests strictly on morphological features.…”

Section: Systematic Partmentioning

confidence: 99%

"An endocochleate experiment" in the Silurian straight-shelled cephalopod Sphooceras

Turek¹,

Manda²

2012

Bull. Geosci.

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Sphooceras truncatum (Barrande, 1860), a Silurian straight-shelled cephalopod with a short finger-shaped shell, is one of a few cephalopods in which natural truncation of the apical part of the phragmocone from the rest of the conch is confirmed. Periodic natural removal of the apical part of the shell (4 to 5 phragmocone chambers) preceded formation of a terminal callus and a calcareous plug closing the septal foramen. The apical callus probably originated by fusion of the truncation septum with episeptal deposits. These structures temporarily formed the new apex on which two additional calcareous layers had been secreted. A unique specimen preserves a colour pattern in the convex apical region, which proves that the shell in Sphooceras was temporarily completely surrounded by mantle extending from the body chamber, i.e. the cephalopod was at least temporarily endocochleate. The co-occurrence of different growth stages of S. truncatum together with one type of short juvenile orthoceracone shell, with a maximum of eight phragmocone chambers and a very small subglobular initial chamber indicates that these embryonic shells may belong to Sphooceras. Two other genera are discussed, both previously included in the family Sphooceratidae: Disjunctoceras Gnoli in Kiselev, 1992 and Andigenoceras Gnoli in Kiselev, 1992. The newly discovered thickening of the apex in "Disjunctoceras" disjunctum, the type species of Disjunctoceras, indicates that this species does not differ substantially from Sphooceras and should be reassigned to this genus. Similarly, representatives of Andigenoceras also possess characteristic features of Sphooceras. Sphooceras has many features characteristic for modern cephalopods: short, thin-walled, semi-internal shell; phragmocone reduced to only a few chambers; uncalcified connecting rings; apical callus (a structure analogous to the belemnite rostrum); retractor muscle scars situated dorsally; very small protoconch without cicatrix. In some exceptionally well-preserved cephalopods with orthoceracone shell radula with seven rows of teeth were observed. All these features support the thesis that some straight-shelled cephalopods are evolutionarily closer to coleoids than nautiloids and their separation from nautiloids is legitimate. Vascular imprints on the surface of the cameral deposits provide further support for their primary origin and the existence of a cameral mantle. The character of cameral deposits in Sphooceras demonstrates that the systematic value of these structures in other straight-shelled cephalopods, a subject of controversy, has limited value. The morphology of Sphooceras also demonstrates that the boundary between endocochleate and ectocochleate cephalopods is not sharp, i.e. internalisation of the shell in cephalopods occurred repeatedly.•

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“…For nearly 200 years, biologists have recognized the importance of the formfunction relationship for understanding the diversity of life [1][2][3][4][5][6]. Classically, the mechanics of biological systems are viewed as limits on biological diversity: the immutable laws of physics restrict how organisms evolve [7].…”

Section: Introductionmentioning

confidence: 99%

Mechanical sensitivity reveals evolutionary dynamics of mechanical systems

Anderson

Patek

2015

Proc. R. Soc. B.

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A classic question in evolutionary biology is how form-function relationships promote or limit diversification. Mechanical metrics, such as kinematic transmission (KT) in linkage systems, are useful tools for examining the evolution of form and function in a comparative context. The convergence of disparate systems on equivalent metric values (mechanical equivalence) has been highlighted as a source of potential morphological diversity under the assumption that morphology can evolve with minimal impact on function. However, this assumption does not account for mechanical sensitivity-the sensitivity of the metric to morphological changes in individual components of a structure. We examined the diversification of a four-bar linkage system in mantis shrimp (Stomatopoda), and found evidence for both mechanical equivalence and differential mechanical sensitivity. KT exhibited variable correlations with individual linkage components, highlighting the components that influence KT evolution, and the components that are free to evolve independently from KT and thereby contribute to the observed pattern of mechanical equivalence. Determining the mechanical sensitivity in a system leads to a deeper understanding of both functional convergence and morphological diversification. This study illustrates the importance of multi-level analyses in delineating the factors that limit and promote diversification in form-function systems.

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Tableau élémentaire de l'histoire naturelle des animaux

Cited by 266 publications

References 0 publications

Ammonites from the Apoderoceras beds (Early Pliensbachian) in São Pedro de Muel (Lusitanian Basin, Portugal)

Ammonites from the Apoderoceras beds (Early Pliensbachian) in São Pedro de Muel (Lusitanian Basin, Portugal)

"An endocochleate experiment" in the Silurian straight-shelled cephalopod Sphooceras

Mechanical sensitivity reveals evolutionary dynamics of mechanical systems

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