A detailed study is carried out on the taxonomy of the bryozoan fauna from the upper levels of the San Juan Formation (Darriwilian) in the Talacasto and Cerro Viejo sections, Argentinean Precordillera. Three bryozoan genera are described and two new species are erected: Lamottopora multispinosa sp. nov., Aostiporn sanjuanensis sp. nov., and Phylloporinidae sp. indet. The paleoecological significance of the bryozoan fauna is discussed. The ramose bryozoans Lamottopora and Aostipora dominate in the Talacasto section. Some colonies probably lived attached directly to the substrate, while others occur attached to the surface of the abundant sponge fauna in the section. The majority of bryozoans at the Cerro Viejo section occur as epibionts, with bases attached to the surface of sponges. Bryozoans collected in the matrix are scarce compared to the Talacasto section, and comprise a few fragments of ramose bryozoans and two small fragments of the reticulate Phylloporinidae sp. indet were recorded exclusively in this locality. The presence of this delicate form in Cerro Viejo is further evidence of the quiet water conditions suggested for these levels. Only the laminar form Nicholsonella occurs in slightly older levels (Floian) of the San Juan Formation. The low diversity recorded here shows a slight decoupling with the global pattern. The first local radiation (three genera) is minor compared with the important radiation that the phylum experienced elsewhere.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 47 • No. 3