The upper member of the Jafnayn Formation in Wadi Rusayl and Al Khoud, Seeb Area in north Oman contains Nemkovella stockari Less & Özcan, 2007, an Early Eocene orthophragminid recorded here for the first time from the Arabian Peninsula. N. stockari, the only orthophragminid identified in Jafnayn Formation, is quite distinct from any other species from Tethys in having spiral and orbitoidiform chambers around the isolepidine embryon developed before the onset of annular chambers. The Oman specimens exhibit equal-sized principal auxiliary chambers and symmetrical spirals and are assigned to N. stockari bejaensis Özcan, Boukhalfa & Scheibner, 2014, an advanced form of the N. stockari lineage. The associated alveolinids, revised in this study, rotaliids and other age-diagnostic foraminiferal taxa in the transgressive basal part of the upper member have enabled us to revise the age as middle Ilerdian (Early Eocene), assignable to SBZ 7/8 and 8; OZ 3/4. Integrating a new record of this species from Arabian Plate margin in Belen, S Turkey, and previous records from north Africa, N. stockari appears to be a diagnostic marker for the Early Eocene along the southern peri-Tethys platforms, facilitating the Tethyan correlation by orthophragminids. The palaeobiogeographic distribution of N. stockari is discussed.

中文翻译：

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来自阿曼北部 Jafnayn 组的早始新世 orthophragminids 和 alveolinids：Nemkovella stockariLess & Özcan, 2007 in Tethys 的意义

位于阿曼北部 Seeb 地区的 Wadi Rusayl 和 Al Khoud 的 Jafnayn 组上层成员包含 Nemkovella stockari Less & Özcan，2007，这是首次从阿拉伯半岛记录到的早始新世 orthophragminid。N. stockari 是在 Jafnayn 组中鉴定出的唯一正丝虫科，与来自 Tethys 的任何其他物种有很大不同，因为在环形室出现之前，在异油烯胚胎周围有螺旋状和轨道状的室。阿曼标本具有大小相等的主辅助室和对称螺旋，并归入 N. stockari bejaensis Özcan, Boukhalfa & Scheibner, 2014，这是 N. stockari 谱系的高级形式。本研究中修订的相关肺泡素，上段海侵基底部分的轮虫类和其他年龄诊断有孔虫类群使我们能够将年龄修正为中伊勒德阶（早始新世），可归属于 SBZ 7/8 和 8；盎司 3/4。将来自土耳其南部贝伦的阿拉伯板块边缘的该物种的新记录与北非的先前记录相结合，N. stockari 似乎是沿南特提斯地台南部早始新世的诊断标记，促进了特提斯相关性正交菌属。讨论了猪蹄草的古生物地理分布。stockari 似乎是沿南特提斯台地南部早始新世的诊断标记，促进了正蝶类的特提斯相关性。讨论了猪蹄草的古生物地理分布。stockari 似乎是沿南特提斯台地南部早始新世的诊断标记，促进了正蝶类的特提斯相关性。讨论了猪蹄草的古生物地理分布。