Mid-Permian (Kubergandian-Murgabian) bivalves from the Khuff formation, Oman: Implications for world events and correlation

Ten species, of which six are newly recognized, from ten genera, Nuculopsis , Phestia, Edmondia, Dyasmya, Janeia ?, Liebia ?, Vnigripecten, Cyrtorostra , Schizodus and Astartella ?, are described from the basal part of the Khuf f Formation. Some forms apparently related to Dyasmya are discussed, along with the characters of Janeia and the classification of the aviculopectinid s. The fauna has a special significance because it is associated with a major mid-Permian transgressive unconformity found in the Middle East and many ot her parts of the world. Because the transgression succeeds a major regressi on which is widely represented by hiatus or non-marine deposits, the fauna contributes significantly to understanding the world correlation of the tim e. An important world-wide change in fauna also takes place. The fauna from the lower part of the Khuff is regarded as not older than Kubergandian or its equivalent (Roadian and "Upper" Ufimian = Sheshminsk) but from the biva lves alone might range from Kubergandian to Murgabian or it's probable equi valent the Kazanian.