Goedert James L, Kiel Steffen, Thomas Eric J, Kriwet Jürgen
Burke Museum of Natural History and Culture, University of Washington, Seattle, WA 98195 USA.
Department of Palaeobiology, Swedish Museum of Natural History, Box 50007, 10405 Stockholm, Sweden.
Palaontol Z. 2024;98(3):443-467. doi: 10.1007/s12542-024-00692-y. Epub 2024 Jul 9.
Abundant shark and rare actinopterygian teeth are reported from a locality within the early Eocene (Ypresian) lower part of the Crescent Formation exposed in the Hamma Hamma River valley on the eastern Olympic Peninsula, Washington State, USA. This part of the Crescent Formation is predominantly submarine volcanic basalt with some sedimentary interbeds deposited in deep water. The teeth are derived from sediments that appear to directly overlay and in places interfinger with the margins of an anomalous lenticular barite deposit; one tooth was found in the barite. Genera represented include deep-water taxa (aff. , , , ) and open marine, epipelagic sharks (, , , , , ). The only other fossils found were two fragmentary shark vertebrae, numerous shark dermal ossicles, a single teleost tooth () and abundant, minute valves of a discinid brachiopod. This is the first report of macrofossils from the lower part of the Crescent Formation and the only early Eocene shark assemblage described from the North Pacific Basin. The shark assemblage also corroborates paleodepositional interpretations of the lower Crescent Formation as being in part ancient volcanic seamounts during early Eocene time.
在美国华盛顿州奥林匹克半岛东部哈马哈马河谷暴露的始新世早期（伊普雷斯阶）新月组下部的一个地点，发现了大量鲨鱼牙齿和罕见的硬骨鱼牙齿。新月组的这一部分主要是海底火山玄武岩，伴有一些深水沉积的夹层。这些牙齿来自似乎直接覆盖在一个异常透镜状重晶石矿床边缘并在某些地方与之交互的沉积物；在重晶石中发现了一颗牙齿。所代表的属包括深水类群（亲缘关系为……）和开阔海洋的上层鲨鱼（……）。发现的其他化石仅有两块破碎的鲨鱼椎骨、大量鲨鱼皮内骨、一颗硬骨鱼牙齿（……）以及大量微小的盘形腕足动物瓣膜。这是关于新月组下部大型化石的首次报道，也是北太平洋盆地描述的唯一始新世早期鲨鱼组合。该鲨鱼组合也证实了对新月组下部在始新世早期部分为古代火山海山的古沉积解释。
