A new delthyridoid spiriferid genus from the Dra Valley, Morocco, and its phylogenetic affinities (Brachiopoda, Lower Devonian)

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作   者：

Schemm-Gregory M; 

作者机构：

Forschungsinstitut & Nat Museum Senckenberg;  Germany;  D-60325 Frankfurt; 

关键词：

Morocco;  Spiriferida;  Palaeobiogeography;  Lower Devonian;  Brachiopoda;  Phylogeny; 

期刊名称：

Palaontologische Zeitschrift

i s s n：

0031-0220

年卷期：

2008 年 82 卷 4 期

页   码：

385-401

页   码：

摘   要：

Multiplicatispirifer, a new delthyridoid brachiopod genus with a gently divergent capillate micro-ornamentation and bifurcating costae on flanks, sulcus and fold, has been identified in the Mdaouer-el-Kbir Formation of the Dra Valley (southern Anti-Atlas, Morocco). Its type species Multiplicatispirifer foumzguidensis n. gen., n. sp., at present the only species of this genus, is described. This form has hitherto been determined as Fimbrispirifer or Struveina by various authors. In this work, the new genus is compared with the multiplicate and capillate spiriferid genera with bifurcating costae which also have costae in the sulcus and on the fold: Costispirifer and Perrryspirifer from North America, Elymospirifer from South China, Borealispirifer from Asia and Multispirifer from Central Europe. The relation of Multiplicatispirifer to the fimbriate Fimbrispirifer, Struveina and Vandercammenina, from which it is distinguished by its capillate micro-ornamentation, is discussed. The new genus is hitherto only known from the Moroccan southern Anti-Atlas. Its closest relatives, taxa of Costispirifer, occur in the Eastern American Realm (Gaspe, Canada and eastern United States) and the Nevada Province (western United States). Multiplicatispirifer occurences are restricted to the Lower/Upper Emsian boundary interval (upper Lower Devonian). the reasons for a possible migration corridor between North America and North Africa before Emsian time are discussed.