کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9104170 | 1153201 | 2005 | 17 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Early Cambrian arthropods-new insights into arthropod head and structural evolution
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم کشاورزی و بیولوژیک
دانش حشره شناسی
پیش نمایش صفحه اول مقاله
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چکیده انگلیسی
The Cambrian Maotianshan-Shale lagerstätten have yielded fossils of a great variety of taxa, particularly arthropods. We report further information on two of these arthropods, Fuxianhuia protensa and Chengjiangocaris longiformis and present a new species, Shankouia zhenghei. Their morphologies shed new light on the early evolution of Arthropoda, which can be resolved into three major phases. In the first phase, new features such as segmental uniramous limbs were developed. The second phase is characterized by segmental sclerotizations of body and appendages. In this phase, the head included only the segments bearing lateral eyes and antennae. A shield-like structure is recognized as the expanded tergite of the second head segment. This tergite housed a pair of sac-like structures. Formerly interpreted as appendages in Fuxianhuia, they are regarded here as gut diverticula. Behind the head, all tergites free from the shield-like one are tripartite, made of an elevated middle region and pleurotergites. All post-antennal limbs comprise a multi-annulated rod and an exopod flap. The antenna is limb-shaped and was, most likely, the only structure suitable for food gathering. Remarkably, the two head segments are those anterior segments, which are not expressed by Hox genes. The third step is the development of euarthropod characteristics.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Arthropod Structure & Development - Volume 34, Issue 2, April 2005, Pages 189-205
Journal: Arthropod Structure & Development - Volume 34, Issue 2, April 2005, Pages 189-205
نویسندگان
Dieter Waloszek, Junyuan Chen, Andreas Maas, Xiuqiang Wang,