During the Cenomanian–Turonian transition (~94 Ma), what is today Central Russia formed part of the northern epicontinental margin of the Tethys Ocean. Diverse marine vertebrate faunas inhabited these palaeoenvironments, but their fossils are incompletely documented. Here, we report the discovery of marine reptile remains, recovered together with pterosaur, chondrichthyan, and actinopterygian fish material from a basal-most glauconitic sand and gravel layer of the Dmitrov Formation. These strata are exposed in an active quarry near the village of Malyy Prolom in the Shatsky District of Ryazan Oblast, Central Russia. The Dmitrov Formation deposits are middle–upper Santonian, but unconformably contact the underlying lower–middle Cenomanian Yakhroma Formation via a condensed boundary horizon that contains the vertebrate fossils with bivalve shell fragments and siliceous and phosphatic clasts. Such sedimentary characteristics indicate a high-energy shoreface setting where the vertebrate teeth and bones were likely reworked during cyclical regressions commencing in the latest Cenomanian–early Turonian. Time-averaging is also evidenced by the mixed occurrences of brachauchenine pliosaurids, elasmosaurid and polycotylid plesiosauroids, ophthalmosaurid ichthyosaurians similar to Pervushovisaurus, and a possible yaguarasaurine mosasauroid. These taxa are typical of Cenomanian–Turonian assemblages from across the northern peri-Tethys, and represent components of what were probably palaeobiogeographically widespread marine reptile faunas.

在 Cenomanian-Turonian 过渡期间（~94 Ma），今天的俄罗斯中部形成了特提斯洋北部大陆边缘的一部分。不同的海洋脊椎动物群栖息在这些古环境中，但它们的化石记录不完整。在这里，我们报告了海洋爬行动物遗骸的发现，这些遗骸与翼龙、软骨鱼类和放线鱼类材料一起从 Dmitrov 组的最基底的海藻砂和砾石层中发现。这些地层暴露在俄罗斯中部梁赞州沙茨基区 Malyy Prolom 村附近的一个活跃采石场中。Dmitrov 组矿床为中上桑托阶，但不整合地通过包含脊椎动物化石、双壳贝壳碎片和硅质和磷酸盐碎屑的浓缩边界层与下层中下部 Cenomanian Yakhroma 组接触。这样的沉积特征表明，在最近的森诺曼阶 - 早期的土伦阶开始的周期性回归期间，脊椎动物的牙齿和骨骼可能会重新加工，从而形成高能量的岸面环境。短尾龙科、薄板龙科和多子叶蛇颈龙科、眼科龙科鱼龙科的混合出现也证明了时间平均 这样的沉积特征表明，在最近的森诺曼阶 - 早期的土伦阶开始的周期性回归期间，脊椎动物的牙齿和骨骼可能会重新加工，从而形成高能量的岸面环境。短尾龙科、薄板龙科和多子叶蛇颈龙科、眼科龙科鱼龙科的混合出现也证明了时间平均 这样的沉积特征表明，在最近的森诺曼阶 - 早期的土伦阶开始的周期性回归期间，脊椎动物的牙齿和骨骼可能会重新加工，从而形成高能量的岸面环境。短尾龙科、薄板龙科和多子叶蛇颈龙科、眼科龙科鱼龙科的混合出现也证明了时间平均Pervushovisaurus和可能的 yaguarasaurine mosasauroid。这些分类群是来自北特提斯山脉北部的森诺曼阶-土伦阶组合的典型代表，代表了可能是古生物地理上广泛分布的海洋爬行动物群的组成部分。