Fossil Unguicheylidae fam. nov., a new fossil family of prostigmatic mites (Acari: Prostigmata) from the Cretaceous Taimyr amber

Dataset for the paper 

Unguicheylidae fam. nov., a new fossil family of prostigmatic mites (Acari: Prostigmata) from the Cretaceous Taimyr amber

Alexander A. Khaustov, Dmitry D. Vorontsov, Evert E. Lindquist

A new monotypic fossil family Unguicheylidae fam. nov. with type genus and species Unguicheylus quadriocellatus sp. nov. is described from the early-Cretaceous (Albian–lower Cenomanian) amber of northern Siberia (Taimyr amber, Baikura locality). The new family is provisionally placed in the superfamily Anystoidea and most similar to the family Pseudocheylidae, but differs mainly in having apomorphically adnate cheliceral bases (free, mobile bases in Pseudocheylidae), and the tarsi of all legs lacking annulated pretarsal stalks bearing reduced claws (present, apomorphic to Pseudocheylidae).

The specimen was partially broken during the preparation. This dataset documents the specimen before and after the breaking, at high magnification.

Amber piece were cut and polished following protocols of Sidorchuk (2011, 2013) and tools described by Sidorchuk and Vorontsov (2018). During the polishing away of the cracked layer of amber that obscured the ventral side of the mite, the block of amber broke in several pieces, leaving the major part of the mite in one piece and two of its legs and a palp in the two smaller pieces. After that, the preparation was stopped and the mite was imaged with highest available resolution using water and saturated fructose as immersion media.  

The mite was imaged using Zeiss AxioImager A2 and Nikon Eclipse E800 compound microscopes with 40x (water immersion) and 100x (oil immersion) objectives using Nomarski DIC. Stacks of images, comprising multiple focal planes, were obtained with an Olympus OM-D E-M10-II digital camera. Figures herein contain images assembled from multiple focal planes using Helicon Focus 7.6, using algorithm B with subsequent manual addition of significant details like thin setae from the individual focal planes. High-resolution images were taken with a Zeiss LSM-880 confocal laser scanning microscope (CLSM) equipped with an Airyscan super-resolution detector. A 488 nm laser was used for excitation, while detection range was set above 540 nm. For a scan, the amber piece was immersed in saturated fructose.

本数据集对应论文《Unguicheylidae fam. nov.：白垩纪塔姆拉琥珀中发现的前气门螨类（蜱螨亚纲：Prostigmata）新化石科》
作者：Alexander A. Khaustov、Dmitry D. Vorontsov、Evert E. Lindquist

本文记述了采自西伯利亚北部早白垩世（阿尔布期-森诺曼阶早期）塔姆拉琥珀（巴库拉产地）的新单型化石科Unguicheylidae fam. nov.，其模式属和模式种为Unguicheylus quadriocellatus sp. nov.。该新科暂置于赤螨总科（Anystoidea），与伪螯螨科（Pseudocheylidae）形态最为相近，主要区别在于：其螯肢基部为衍征式愈合（伪螯螨科的螯肢基部游离且可活动），且所有足的跗节均无带有退化爪的环纹前跗柄（伪螯螨科具有此类结构，且为其衍征）。

该标本在制备过程中部分断裂。本数据集记录了标本断裂前后的高倍放大影像。

琥珀标本按照Sidorchuk（2011、2013）的操作规范进行切割与抛光，并使用Sidorchuk与Vorontsov（2018）描述的工具开展制备工作。在抛光去除遮挡螨类腹面的琥珀裂纹层时，琥珀块碎裂为多块，其中螨类主体完整保留为一块，另有2条足和1个须肢分别残留在两块较小的碎片中。此后制备工作终止，随后以水和饱和果糖作为浸没介质，以当前可达到的最高分辨率对该螨进行成像。

本研究使用蔡司AxioImager A2与尼康Eclipse E800正置显微镜完成成像，搭配40倍（水浸）和100倍（油浸）物镜，采用诺马斯基差分干涉对比度（Nomarski DIC）技术。通过奥林巴斯OM-D E-M10-II数码相机获取包含多个焦平面的图像堆栈。本文所用图像均通过Helicon Focus 7.6软件对多焦平面图像进行合成，采用算法B，并后续手动添加单个焦平面中的纤细刚毛等关键细节。高分辨率图像通过配备Airyscan超分辨率检测器的蔡司LSM-880共聚焦激光扫描显微镜（CLSM）拍摄，使用488 nm激光激发，检测波段设置为540 nm以上。扫描过程中，琥珀标本浸没于饱和果糖溶液中。