A morphologically bizarre fish larva is described based on a single specimen from Eocene (Bartonian) locality of Gornyi Luch, Krasnodar Region, Northern Caucasus, SW Russia. The fossil larva described here was collected form the Kuma Horizon and inhabited an open marine setting with bottom waters characterized by poorly oxygenated conditions, where it was associated with abundant pelagic fish taxa. This fossil fish larva exhibits a peculiar morphology, being characterized by remarkably expanded and thickened bones that form an armour‐like protective covering, a strong and greatly elongate pelvic‐fin spine and a unique head spination that comprises a conical and posterodorsally directed supraoccipital spine, a rostral spine formed by the nasals, and enormous spines on the preopercle and opercle. Moreover, this fish larva has an advanced insertion of the dorsal fin and 17 principal rays in the caudal fin thereby revealing its affinity to percomorph fishes. The hypertrophied bony plates encasing the head and forming a bony armour are shared with the so‐called tholichthys larval stage of chaetodontid butterflyfishes, as well as with the larval stages of some other percomorphs. Comparison with selected percomorph larval morphotypes (e.g. families Chaetodontidae, Malacanthidae, Ostracoberycidae and Scatophagidae) suggests that the Eocene larva described herein exhibits a unique combination of characters that would support an attribution to a new, previously undescribed taxon.

中文翻译：

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来自俄罗斯北高加索地区始新世的类oli幼虫（Teleostei，Percomorpha）

基于来自俄罗斯西南高加索地区克拉斯诺达尔地区Gornyi Luch始新世（Bartonian）地区的单个标本，描述了一种形态奇异的鱼幼虫。这里描述的化石幼虫是从Kuma Horizo​​n采集的，居住在一个开放的海洋环境中，其底部水域的氧化性很差，并伴有丰富的中上层鱼类。这种化石鱼幼虫表现出独特的形态，其特征是骨骼明显扩张和增厚，形成了盔甲状的保护性覆盖物，坚硬且大大延长的骨盆鳍脊柱和独特的头部旋转，其中包括圆锥形和后气味定向的枕骨上棘，由鼻形成的延髓脊柱，在前oper和前oper上有巨大的刺。而且，这种鱼幼虫在尾鳍中预先插入了尾鳍和17条主射线，从而显示出它对高粘鱼的亲和力。包围头部并形成骨甲的肥大的骨板与所谓的拟齿象蝶鱼的tholichthys幼虫期以及某些其他变态虫的幼虫期共享。与选定的过膜幼虫形态学类型（例如，Chaododontidae，Malacanthidae，Ostracoberycidae和Scatophagidae家族）的比较表明，本文所述的始新世幼虫表现出独特的字符组合，可以支持归因于先前未描述的新分类单元。包围头部并形成骨甲的肥大的骨板与所谓的拟齿象蝶鱼的tholichthys幼虫期以及某些其他变态虫的幼虫期共享。与选定的过膜幼虫形态学类型（例如，Chaododontidae，Malacanthidae，Ostracoberycidae和Scatophagidae家族）的比较表明，本文所述的始新世幼虫表现出独特的字符组合，可以支持归因于先前未描述的新分类单元。包围头部并形成骨甲的肥大的骨板与所谓的拟齿象蝶鱼的tholichthys幼虫期以及某些其他变态虫的幼虫期共享。与选定的过膜幼虫形态学类型（例如，Chaododontidae，Malacanthidae，Ostracoberycidae和Scatophagidae家族）的比较表明，本文所述的始新世幼虫表现出独特的字符组合，可以支持归因于先前未描述的新分类单元。