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UPPER ORDOVICIAN BRYOZOANS OF THE PIN FORMATION (SPITI VALLEY, NORTHERN INDIA)
Author(s) -
SUTTNER THOMAS J.,
ERNST ANDREJ
Publication year - 2007
Publication title -
palaeontology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.69
H-Index - 63
eISSN - 1475-4983
pISSN - 0031-0239
DOI - 10.1111/j.1475-4983.2007.00726.x
Subject(s) - ordovician , paleontology , geology , laurentia , baltica , gondwana , subtropics , biostratigraphy , facies , ecological succession , paleozoic , fauna , ecology , tectonics , biology , structural basin
Abstract: Twenty‐nine species of bryozoans from the Upper Ordovician–Lower Silurian Pin Formation (Spiti, India) have been identified. Eight of these are new: Trematopora minima , Ulrichostylus bhargavai , Ptilodictya exiliformis , Phaenopora ordinarius , Oanduellina himalayaica , Pesnastylus ? vesiculosum , Ralfina ? originalis and Pinocladia triangulata . The fossil record and facies analyses of the area investigated indicate shallow‐water conditions within the subtropical–tropical realm. The distribution pattern of fossils among the Ordovician/Silurian succession on the Northern Gondwana shelf and the influence of the Late Ordovician cooling phases on marine organisms are distinctive owing to a dramatic reduction in diversity globally. As far as the bryozoan taxa of Spiti are concerned, only one ( Helopora fragilis ) of the 29 species was recorded above the Ordovician/Silurian boundary. Observed bryozoan communities are very similar to faunas of Laurentia, the Baltic, Siberia and southern China of early–late Ordovician age.