منابع مشابه
Mammal-like occlusion in conodonts
—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...
متن کاملThe interrelationships of ‘complex’ conodonts (Vertebrata)
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...
متن کاملThe efficacy of dentine adhesive to sclerotic dentine.
OBJECTIVE To evaluate the effect of a dentine bonding system to sclerotic dentine in comparison with normal dentine. METHODS The efficacy of the dentine bonding system to sclerotic dentine was examined by measuring wall-to-wall polymerization contraction gap width. The dentine cavity wall was pretreated with an experimental dentine bonding system with and without a dentine primer. The dentine...
متن کاملHereditary dentine disorders: dentinogenesis imperfecta and dentine dysplasia
The hereditary dentine disorders, dentinogenesis imperfecta (DGI) and dentine dysplasia (DD), comprise a group of autosomal dominant genetic conditions characterised by abnormal dentine structure affecting either the primary or both the primary and secondary dentitions. DGI is reported to have an incidence of 1 in 6,000 to 1 in 8,000, whereas that of DD type 1 is 1 in 100,000. Clinically, the t...
متن کاملAn Experimental Investigation of Post-depositional Taphonomic Bias in Conodonts
The different types of elements that occurred together in conodont apparatuses are not recovered from the fossil record in the expected numbers. The causes of this are complex and difficult to study. Numerous complete articulated skeletons of Ozarkodina excavata (Branson and Mehl) have been recovered from the Eramosa Member at Hepworth, Ontario, and as a consequence, several of the potential bi...
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ژورنال
عنوان ژورنال: Nature
سال: 1994
ISSN: 0028-0836,1476-4687
DOI: 10.1038/368591a0