Middle Jurassic bryozoans from the Carmel Formation of southwestern Utah

被引:14
|
作者
Taylor, PD
Wilson, MA
机构
[1] Nat Hist Museum, Dept Palaeontol, London SW7 5BD, England
[2] Coll Wooster, Dept Geol, Wooster, OH 44691 USA
关键词
D O I
10.1017/S0022336000040671
中图分类号
Q91 [古生物学];
学科分类号
0709 ; 070903 ;
摘要
Very few Jurassic bryozoan faunas are known outside Europe. Here we describe seven species of calcareous cyclostome bryozoans and one bioimmured soft-bodied ctenostome bryozoan (Simplicidium sp.) from the Middle Jurassic (?Bathonian) Carmel Formation of Utah. Three of the cyclostomes are placed in open nomenclature due to inadequate preservation and/or the lack of key reproductive polymorphs. A new genus, Patulopora, is established for Diastopora cutleri Cuffey and Ehleiter, 1984, following the discovery of gonozooids that place this species in the Multisparsidae rather than in the Plagioeciidae. Another of Cuffey and Ehleiter's (1984) species-Berenicea duofluvina-is reassigned to Microeciella on the basis of the gonozooids, and a similar but distinctly smaller form is described as M. pollostos new species. A second new species-Hyporospora nielsoni-is a rare colonist of hardground undersurfaces. The Carmel bryozoan fauna is compared with better-known faunas from the northern European Middle Jurassic. Species richness and colony-form diversity fall well within the expected values for bryozoan faunas of this age, and endemism is detectable only at relatively low taxonomic levels. Evolutionary patterns based on studies of contemperaneous European bryozoan faunas during this time of cyclostome evolutionary radiation are reinforced by the palaeogeographically distant Carmel bryozoan fauna.
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页码:816 / 830
页数:15
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