The earliest reef-building anthaspidellid sponge Rankenella zhangxianensis n. sp. from the Zhangxia Formation (Cambrian Series 3), Shandong Province, China
The earliest reef-building anthaspidellid sponge Rankenella zhangxianensis n. sp. from the Zhangxia Formation (Cambrian Series 3), Shandong Province, China
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DOI：
10.1017/jpa.2015.53
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发表时间：
2016-01
影响因子：
1.4
通讯作者：
Jeong‐Hyun Lee;J. Woo;Dong-Jin Lee
中科院分区：
文献类型：
--
作者：
Jeong‐Hyun Lee;J. Woo;Dong-Jin Lee
摘要本文报道了已知最早的造礁珊瑚海绵Rankenella zhangxianensis n.例如，寒武系张夏组第3统（第5阶晚期-古掌阶早期）存款。Rankenella zhangxianensis主要分布在Epiphyton-Rankenella-Cambroctoconus生物礁中，少量分布在礁间颗粒灰岩中。该物种具有anthaspidellid-type规则的梯形骨针网络，包括dendronclones和trabs，其特征是trabs平行/亚平行于胃表面，分叉并满足皮肤表面，这是典型的属。与R。mors和R. hamdii，分别报道于澳大利亚晚寒武世2统-晚寒武世3统和伊朗晚寒武世3统-早芙蓉纪，R. Zhangxianensis的特征是皮壁较厚，皮面与交叉道之间的夹角较大（约90°），分化的管道较少。另一方面，R. Zhangxianensis主要表现为倒圆锥形，远不如其他两种的圆锥形、指状、盘状或碗状。中国寒武系3统生物礁是世界范围内发育的芙蓉纪和早奥陶世珊瑚礁的祖先。它们代表了在寒武纪统2末期古囊动物灭绝后造礁后生动物的复苏。
Abstract This study reports the earliest known reef-building anthaspidellid sponge, Rankenella zhangxianensis n. sp., from the Cambrian Series 3 (late Stage 5—early Guzhangian) deposit of the Zhangxia Formation, Shandong Province, China. Rankenella zhangxianensis mostly occurs within Epiphyton-Rankenella-Cambroctoconus reefs, with minor occurrence from inter-reef grainstone. The species has anthaspidellid-type regular ladderlike spicule networks consisting of dendroclones and trabs, and is characterized by trabs parallel/subparallel to the gastral surface that diverge and meet the dermal surface, which is typical of the genus. Compared to R. mors and R. hamdii, reported from the late Cambrian Series 2—late Cambrian Series 3 of Australia and the late Cambrian Series 3—early Furongian of Iran, respectively, R. zhangxianensis is characterized by a relatively thicker wall, high angle (∼90°) between dermal surfaces and intersecting trabs, and minor occurrence of differentiated canals. On the other hand, R. zhangxianensis mainly shows obconical shape, which is far less diverse than the other two species showing conicocylindrical, digitate, explanate, or bowl shapes. These Cambrian Series 3 reefs from China are the ancestors of the Furongian anthaspidellid-microbial reefs and the Early Ordovician anthaspidellid-microbial reefs that flourished worldwide. They represent the resurgence of reef-building metazoans after the extinction of archaeocyaths at the end of Cambrian Series 2.