论志留纪陕西珊瑚属Shensiphyllum Ge et Yü,1974

ON SILURIAN SHENSIPHYLLUM GE ET Yü, 1974

ShensiphyllumGeetYü,1974为丛状复体珊瑚,以发育一列马蹄型鳞板,羽榍扇形排列为主要特征,是志留纪四射珊瑚已知唯一发育马蹄型鳞板的属。该属在我国上扬子区广泛分布于上兰多维列统(Llandovery)特列奇阶(Telychian)中,主要产自川北、陕南的宁强组、云南大关的大路寨组(中、上Telychian阶))、湖北长阳的纱帽组及四川朝天的王家湾组(下特列奇阶)。文中报道和描述川北朝天王家湾组中发现的3个新种Shensiphyllumsimplexsp.nov.,S.proliferumsp.nov.,S.intermediumsp.nov.。王家湾组是已知ShensiphyllumGeetY櫣产出的最低层位。详细讨论该属的骨骼构造特征、生长繁殖方式,探讨该属起源及其演化,根据新资料修订该属的属征,赞同将该属置PhacellophyllidaeWedekind科。

The genus Shensiphyllum, as a special kind of fasciculate compound rugose corals, is characterized by one row horseshoe-shaped dissepiment and fan-like septal trabeculae. These features are unique among the known Silurian rugosan genera. This genus is widespread in the Upper Yangtze region Silurian, especially in the Ningqiang Formation （middle-upper Telychian） of southern Shaanxi and northern Sichuan, the Daluzhai Formation （middle-upper Telychian）, northeastern Yunnan and the Shamao Formation, western Hubei. Three new species Shensiphyllum simplex sp. nov., S. proliferum sp. nov. and S. intermedium sp. nov. are described and illustrated in this paper, which are found from the Wangjiawan Formation （lower Telychian） , Guangyuan, northern Sichuan, representing the first appearance horizon in the Yangtze region. In the present paper, the diagnostic features of Shensiphyllum, its growth gemmation manner and the skeletal structure features are discussed in detail, and it possibly originated from Stauriidae is inferred. Based on the present study, the diagnosis of Shensiphyllum needs to be modified and further supplemented, and its taxonomic position should be assigned to the family Phacellophyllidae Wedekind, 1922.