نتایج جستجو برای: ammonite
تعداد نتایج: 211 فیلتر نتایج به سال:
Abstract This study focuses on a condensed sequence of alternating carbonate–clastic sediments the Barrington Member, Beacon Limestone Formation (latest Pliensbachian to early Toarcian) from Somerset (SW England). Abundant ammonites confirm (apart absence Clevelandicum and Tenuicostatum ammonite subchronozones) presence Hawskerense Subchronozone Fallaciosum–Bingmanni subchronozones. Well-preser...
We provide a biochronology of Jurassic planktonic foramininfera, using first order linkage to ammonite and nannofossil stratigraphy geochronology. This enigmatic understudied group microfossils occurred from middle Toarcian through Tithonian time, ~180 ~143 Ma; its origin is unknown. There are three genera: Globuligerina, Conoglobigerina Petaloglobigerina. The genus with smooth pustulose test s...
The idea that physical processes involved in biological development underlie morphogenetic rules and channel morphological evolution has been central to the rise of evolutionary developmental biology. Here, we explore this idea in the context of seashell morphogenesis. We show that a morphomechanical model predicts the effects of variations in shell shape on the ornamental pattern in ammonites,...
The temporal coincidence between large igneous provinces (LIPs) and mass extinctions has led many to pose a causal relationship between the two. However, there is still no consensus on a mechanistic model that explains how magmatism leads to the turnover of terrestrial and marine plants, invertebrates and vertebrates. Here we present a synthesis of ammonite biostratigraphy, isotopic data and hi...
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