|
|
|
|
|
| Carrera,Marcelo G; Ortega,Gladys. |
| A nearly complete specimen of a hexactinellid sponge has been recovered from Lower Ordovician siliciclastic rocks of the Argentine Precordillera. The material was collected in the upper member of the Los Azules Formation (Sandbian). A new species of the genus Cyathophycus Walcott, C. extendis, is erected. The taxonomic position of the genus is still controversial. Their recent assignment to the family Dictyospongiidae is discussed; Cyathophycus has been considered as a transitional form between protospongiids with simple regular skeletons and dictyospongiids with more complex skeletons. Previous studies have stated that hexactinellid evolution through the Cambrian-Ordovician interval, like other sponge groups at this time, appears to have been based on... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Porifera; Hexactinellida; Ordovician; Argentina. |
| Ano: 2009 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0002-70142009000300001 |
| |
|
|
| Carrera,Marcelo G.; Ernst,Andrej. |
| 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., Aostipora 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... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Bryozoans; Ordovician; Argentina; Precordillera. |
| Ano: 2010 |
URL: http://www.scielo.org.ar/scielo.php?script=sci_arttext&pid=S0002-70142010000300006 |
| |
|
|
|
