A new species of Hypolophites (Chondrichthyes, Myliobatiformes) is described from an assemblage of isolated pavement teeth recovered from the Lower Clayton Limestone Unit of the Midway Group (Paleocene) near Malvern, Arkansas. These teeth were collected from several localized lag deposits containing an abundance of chondrichthyan and osteichthyan teeth, invertebrate remains, and trace fossils indicative of a marginal-shallow marine depositional environment. To date, only four additional species of Hypolophites have been reported from Paleocene deposits that occur along the west coast of central-northern Africa and in central New Jersey, USA. The identification of Hypolophites beckeri n. sp. in southwestern Arkansas extends the distribution of this biostratigraphically significant genus ~1,750 km westward into the Mississippi Embayment and Gulf Coastal Plain of the USA. The distribution of Hypolophites species during the Paleocene attests to the uniformity of shallow marine shelves between western Africa and the Atlantic and Gulf Coastal Plains of the USA, as well as myliobatiform diversification following the K/Pg mass extinction event.UUID: http://zoobank.org/3a1580d1-a2f4-49b6-8170-69a778c49181

中文翻译：

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美国阿肯色州马尔文附近的中途群（古新世）下克莱顿石灰岩单元中的一种新种的次生水母

一种新的物种次磷酸岩(Chondrichthyes, Myliobatiformes) 是从在阿肯色州马尔文附近的中途岛群（古新世）的下克莱顿石灰岩单元中回收的一组孤立的路面牙齿中描述的。这些牙齿是从几个局部的滞后沉积物中收集的，这些沉积物中含有丰富的软骨鱼和骨鱼牙齿、无脊椎动物遗骸以及表明边缘浅海沉积环境的微量化石。迄今为止，仅新增四种次磷酸岩据报道，发生在非洲中北部西海岸和美国新泽西州中部的古新世沉积物中。的识别次叶藻n. sp。在阿肯色州西南部，这一具有生物地层意义的属向西延伸约 1,750 公里，进入美国的密西西比湾和墨西哥湾沿岸平原。的分布次磷酸岩古新世时期的物种证明了西非与美国大西洋和墨西哥湾沿岸平原之间浅海陆架的均匀性，以及 K/Pg 大规模灭绝事件后的菌形多样化。UUID：http://zoobank.org/3a1580d1-a2f4-49b6-8170-69a778c49181