Data from: The oldest turritelline gastropods: from the Oxfordian (Upper Jurassic) of Kutch, India

Turritellid gastropods are important components of many Cretaceous-Recent fossil marine faunas worldwide. Their shell is morphologically simple, making homoplasy widespread and phylogenetic analysis difficult, but fossil and living species can be recognized based on shell characters. For many decades, it has been the consensus that the oldest definite representatives of Turritellidae are from the lower Cretaceous, and that pre-Cretaceous forms are homeomorphs. Some morphological characters of the present turritelline species resemble those of mathildoids, but many diagnostic characters clearly separate these two groups. We here describe and/or redescribe – based on examination of more than 1800 near complete specimens -- four species from the Upper Jurassic Dhosa Oolite Member of the Chari Formation in Kutch, western India, and demonstrate that they are members of Turritellidae, subfamily Turritellinae, on the basis of diagnostic characters including apical sculptural ontogeny (obtained from SEM study), spiral sculpture, and growth line patterns. The four species are in order of abundance, Turritella jadavpuriensis Mitra and Ghosh, 1979; Turritella amitava new species; Turritella jhuraensis Mitra and Ghosh, 1979 and Turritella dhosaensis new species. The turritelline assemblages occur only on the northeastern flank of the Jhura dome (23°24’47.57”N, 69°36’09.26”E). Age of the Dhosa Oolite has recently been confirmed based on multiple ammonite species. All these points indicate that these fossils are the oldest record of the family Turritellidae – by almost 30 million years – in the world.锥螺科（Turritellidae）腹足类是全球范围内众多白垩纪至现代海洋化石动物群的关键组成组分。其壳体形态结构简洁，致使趋同演化（homoplasy）现象广泛分布，系统发育分析难度较高，但可借助壳体特征对化石及现生类群进行识别。数十年来，学界普遍认为锥螺科最确凿的代表类群源自下白垩统，而白垩纪前的相关类群均为同形类群。现生锥螺亚科物种的部分形态特征与马蒂螺超科（Mathildoidea）相似，但诸多鉴定特征可清晰区分这两个类群。本文基于对1800余件近乎完整标本的检视，对采自印度西部库奇盆地查里组上侏罗统多萨灰岩段的4个物种进行了描述与/或重新描述，并通过壳顶雕刻纹饰的个体发育序列（基于扫描电子显微镜（SEM）研究获取）、螺旋雕刻纹饰及生长线样式等鉴定特征，证实它们隶属于锥螺科锥螺亚科（Turritellinae）。按丰度由高到低排序，这4个物种依次为：Turritella jadavpuriensis Mitra & Ghosh, 1979、新种Turritella amitava、Turritella jhuraensis Mitra & Ghosh, 1979以及新种Turritella dhosaensis。该锥螺亚科组合仅发现于朱拉穹隆东北翼（23°24′47.57"N, 69°36′09.26"E）。近期已通过多种菊石类物种确认了多萨灰岩段的地质年代。以上所有证据均表明，这些化石是目前全球已知锥螺科最古老的记录，其地质年代较此前的记录早近3000万年。