ammonoid

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ammonoid

[′a·mə‚nȯid]
(paleontology)
A cephalopod of the order Ammonoidea.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
The minimum test was used by Jablonski (1987, 1994) to test Cope's Rule among Cretaceous molluscs and by Boyajian and Lutz (1992) to analyze the evolution of sutural complexity in ammonoid cephalopods.
The third important pelagic group, the ammonoids, are not yet well studied near the Guadalupian-Lopingian boundary.
Emergence and collapse of the Frasnian conodont and ammonoid communities in the Holy Cross Mountains, Poland.
However, the problem associated with the identification of the Jurassic - Cretaceous boundary persists for shallow water marine and continental sedimentary successions in which biostratigraphic data are derived from several groups of benthic macrofossils, foraminifera, ostracods and charophytes that are uncorrelated to ammonoid or planktonic zonations.
(3) Ammonoids evolved to have more complex suture patterns--and, thus, stronger shells--through time.
Fascination with "the story behind the story" led Tim to produce The Trias and its Ammonoids: The Evolution of a Time Scale (Tozer, 1984), an engrossing account of the development of Triassic biochronology in the 19th and 20th centuries, laced with fascinating character sketches of the main protagonists.
Theoretical approaches have been applied to fossil nautiloids (e.g., Westermann, 1973) and ammonoids (Westermann, 1975; Hewitt and Westermann, 1986; Jacobs, 1990; Daniel et al., 1997).
Minimum suture complexity in ammonoids increased slightly during the initial trend, but Boyajian and Lutz (1992) argue that the trend was passive (based on the behavior of the variance).
However, in Mesozoic ammonoids a combination of pronounced sculpture and colour bands is relatively common (Mapes & Davis 1996).
The presence of Lower Cretaceous ammonoids in the Maestrat Basin (E Spain) has been known since the second half of the nineteenth century (e.g., Vilanova, 1859; Coquand, 1865).
The primary decorative stone, ~80% by surface area, is a light beige limestone that contains abundant ammonoids and belemnoids (Figure 1).