نتایج جستجو برای: trilobite

تعداد نتایج: 345  

Journal: :BioEssays : news and reviews in molecular, cellular and developmental biology 2003
Nigel C Hughes

Preservation permitting patterns of developmental evolution can be reconstructed within long extinct clades, and the rich fossil record of trilobite ontogeny and phylogeny provides an unparalleled opportunity for doing so. Furthermore, knowledge of Hox gene expression patterns among living arthropods permit inferences about possible Hox gene deployment in trilobites. The trilobite anteroposteri...

2007
Nigel C. Hughes

The good fossil record of trilobite exoskeletal anatomy and ontogeny, coupled with information on their nonbiomineralized tissues, permits analysis of how the trilobite body was organized and developed, and the various evolutionary modifications of such patterning within the group. In several respects trilobite development and form appears comparable with that which may have characterized the a...

Journal: :Indian journal of experimental biology 2014
T C Srijayat P J Pradeep A Hassan A Chatterji F Shaharom Andrew Jeffs

The trilobite larvae of C. rotundicauda were tested to determine their colour preference and light sensitivity until their first moulting (25 days post hatching) under laboratory conditions. Maximum congregation size of the trilobite larvae was found in the white zone respectively where (n = 12) followed by yellow (n = 8) and orange (n = 8), which showed the larval preference for lighter zones....

2017
Melanie J Hopkins Feiyang Chen Shixue Hu Zhifei Zhang

The early Cambrian Guanshan biota of eastern Yunnan, China, contains exceptionally preserved animals and algae. Most diverse and abundant are the arthropods, of which there are at least 11 species of trilobites represented by numerous specimens. Many trilobite specimens show soft-body preservation via iron oxide pseudomorphs of pyrite replacement. Here we describe digestive structures from two ...

2017
Nigel C. Hughes Paul S. Hong Jinbo Hou Giuseppe Fusco

Citation: Hughes NC, Hong PS, Hou JB and Fusco G (2017) The Development of the Silurian Trilobite Aulacopleura koninckii Reconstructed by Applying Inferred Growth and Segmentation Dynamics: A Case Study in Paleo-Evo-Devo. Front. Ecol. Evol. 5:37. doi: 10.3389/fevo.2017.00037 The Development of the Silurian Trilobite Aulacopleura koninckii Reconstructed by Applying Inferred Growth and Segmentati...

The aim of this study is to analyze the assemblage of trilobites in the Silurian sequences of Iran by exploring stratigraphic section of the Silurian Niur Formation (Asadli section).  Based on comprehensive field studies and laboratory investigations three Trilobite genera were identified in the study area including Calymene blumenbachii, Gravicalymene convolva, Dalmanites brevigladiolus </...

2005
Seth Finnegan Mary L. Droser

—Relative abundance data are of primary importance in paleoecology, but it is not always obvious how they should be interpreted. Because relative abundance is expressed as a proportion of the total sample, change in the abundance of one group necessarily changes the relative abundance of all groups in the sample. There are two possible interpretations for a trend in the relative abundance of a ...

Journal: :رخساره های رسوبی 0
حامد عامری فتانه زمانی

cambrian sediments are widely exposed in the kerman province. parts of these deposits are containing trilobite fossils. one of the suitable areas for paleontological studies is kamar siah section. this section located about 60 km north east of kerman. these sediments have 200 m thickness with fossil invertebrates of trilobites, brachiopod, gastropods and stromatolite which includes kuhbanan and...

Journal: :Proceedings of the Japan Academy 1975

2017
Hugh Trenchard Carlton Brett Matjaz Perc

Energy saving mechanisms in nature allow following organisms to expend less energy than leaders. Queues, or ordered rows of individuals, may form when organisms exploit the available energy saving mechanism while travelling at near-maximal sustainable metabolic capacities; compact clusters form when group members travel well below maximal sustainable metabolic capacities. The group size range, ...

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