Progress in understanding middle Eocene nassellarian (Radiolaria, Polycystinea) diversity; new insights from the western equatorial Atlantic Ocean

Middle Eocene deep-sea sediment sequences cored at Ocean Drilling Program Site 1260 (Leg 207; equatorial Atlantic Ocean), yielded diverse and abundant radiolarian faunas which are conducive to biostratigraphic and palaeoceanographic researchs, as well as to the study of radiolarian diversity dynamics during this epoch of dramatic climate changes. However, many species present in these sediments still have not been formally described and are therefore neglected in most biodiversity surveys. In an effort to improve the taxonomic resolution of middle Eocene radiolaria, 15 new species of nassellarian are described and illustrated. The species are: Cymaetron ? dilatatus n. sp., Eucyrtidium levisaltatrix n. sp. (Eucyrtidiidae), Siphocampe pollen n. sp., Spirocyrtis ? renaudiei n. sp. (Artostrobiidae), Pterocyrtidium eep n. sp. (Rhopalosyringiidae), Petalospyris cometa n. sp., Petalospyris castanea n. sp. (Cephalospyrididae), Velicucullus armatus n. sp. (Theophormididae), Lychnocanium nimrodi ...

采自大洋钻探计划（Ocean Drilling Program）第207航次、大西洋赤道海域1260站位的中始新世深海沉积岩心序列，产出了多样且丰富的放射虫（radiolarian）动物群，可用于生物地层学与古海洋学研究，以及探究该剧烈气候变化时期的放射虫多样性动态。然而，这些沉积物中的诸多物种尚未被正式描述，因此在多数生物多样性调查中被忽视。为提升中始新世放射虫的分类学分辨率，本次研究描述并图示了15个新的罩笼虫类（nassellarian）物种，分别为：膨胀杯钟虫？新种（Cymaetron ? dilatatus n. sp.）、轻褶真帽虫新种（Eucyrtidium levisaltatrix n. sp.，新帽虫科（Eucyrtidiidae））、花粉管壶虫新种（Siphocampe pollen n. sp.）、勒诺迪旋壳虫？新种（Spirocyrtis ? renaudiei n. sp.，关节刺虫科（Artostrobiidae））、翼状帽虫新种（Pterocyrtidium eep n. sp.，棒管虫科（Rhopalosyringiidae））、彗星瓣壳虫新种（Petalospyris cometa n. sp.）、栗色瓣壳虫新种（Petalospyris castanea n. sp.，头壳虫科（Cephalospyrididae））、武装盔壶虫新种（Velicucullus armatus n. sp.，神篓虫科（Theophormididae））、尼姆罗德亮壳虫新种（Lychnocanium nimrodi ...）