نتایج جستجو برای: conodonts

تعداد نتایج: 238  

Journal: :Proceedings. Biological sciences 2001
P C Donoghue

Recognition that conodonts were the earliest vertebrate group to experiment with skeletal biomineralization provides a window in which to study the origin and early evolution of this developmental system. It has been contended that the conodont skeleton comprised a classic suite of vertebrate hard tissues, while others suggest that conodont hard tissues represent divergent specializations withi...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2009
Steven M Stanley

Ammonoids and conodonts, being characterized by exceptionally high background rates of origination and extinction, were vulnerable to global environmental crises, which characteristically intensified background rates of extinction. Thus, it is not surprising that these taxa suffered conspicuous mass extinctions at the times of three negative Early Triassic global carbon isotopic excursions that...

Journal: :Annals and Magazine of Natural History 1887

Journal: :New Zealand Journal of Geology and Geophysics 1968

Journal: :Frontiers in Earth Science 2023

Conodonts are jawless vertebrates deposited in marine strata from the Cambrian to Triassic that play an important role geoscience research. The accurate identification of conodonts requires experienced professional researchers. process is time-consuming and laborious can be subjective affected by level opinions appraisers. problem exacerbated limited number experts who qualified identify conodo...

2000
Philip C. J. Donoghue Mark A. Purnell

—Conodont element function and feeding mechanisms are of considerable paleobiological importance, yet many details remain poorly understood and speculative. Analysis based on morphology, physical juxtaposition, and patterns of surface damage and microwear on pairs of Pa elements from individuals of Idiognathodus indicates that these elements crushed food by rotational closure, which brought the...

2008
Philip C. J. Donoghue Mark A. Purnell Richard J. Aldridge Shunxin Zhang

SYNOPSIS Little attention has been paid to the suprageneric classification for conodonts and existing schemes have been formulated without attention to homology, diagnosis and definition. We propose that cladisticsprovidesanappropriatemethodology to test existing schemesof classification and in which to explore the evolutionary relationships of conodonts. The development of a multielement taxon...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید