Tommotiids from the Lower Cambrian of South China

1990/03/01 by S. Conway Morris, Simon Conway Morris, Chen Menge · 8 citations
Earth and Planetary Sciences · Biochemistry, Genetics and Molecular Biology · #Paleontology and Stratigraphy of Fossils #Evolution and Paleontology Studies #Genomics and Phylogenetic Studies

paper · doi:10.1017/s0022336000018345

Abstract

Tommotiids are a geologically short-lived group of early skeletal fossils, most abundant in the Lower Cambrian. Redescriptions of a lapworthellid ( Lapworthella rete Yue, 1987) and a tannuolinid ( Tannuolina zhangwentangi Qian and Bengtson, 1989) from the Jiulaodong Formation, Maidiping, Sichuan, augment previous accounts. Lapworthella rete approaches the L. dentata–L. schodackensis complex, but has a prominent external pattern of polygons that probably represent imprints of epithelial cells. Description of Tannuolina zhangwentangi emphasises ultrastructural features, including the mode of growth, development of canals, and possible epithelial imprints on the interior surfaces. Data on size variation of epithelial imprints in tommotiids are reviewed to try to infer possible variations in genome content of the cells. In addition, poorly preserved lapworthellids ( Lapworthella sp.) are described from the Qiongzhusi Formation, Meishucun, Yunnan.

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• TANNUOLINA AND MICRINA (TANNUOLINIDAE) FROM THE LOWER CAMBRIAN OF EASTERN YUNNAN, SOUTH CHINA, AND THEIR SCLERITOME RECONSTRUCTION
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• First record of a bivalved larval shell in Early Cambrian tommotiids and its phylogenetic significance
• Tommotiids from the early Cambrian (Series 2, Stage 3) of Morocco and the evolution of the tannuolinid scleritome and setigerous shell structures in stem group brachiopods
• Chronology of early Cambrian biomineralization
• Sclerite fusion, ultrastructure, micro‐ornament and homology in early Cambrian eccentrothecimorph tommotiids
• A New Tannuolinid Problematic from the Lower Cambrian of the Sukharikha River in Northern Siberia
• Exceptionally preserved early Cambrian bilaterian developmental stages from Mongolia. [europepmc]

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