Equus stenonis is one of the most prevalent European Pleistocene fossil horses. It is believed to be the possible ancestor of all Old World Early Pleistocene Equus, extant zebras and asses, and as such provides insights into Equus evolution and its biogeography and paleoecology. The Equus stenonis holotype skull (IGF560) was first described by Igino Cocchi in 1867, from the Early Pleistocene locality of Terranuova (Upper Valdarno basin, Italy). IGF560 is a nearly complete, although medio-laterally crushed and badly compressed skull. Here we provide the first application of a new virtual reconstruction protocol, termed Target Deformation, to the Equus stenonis holotype. The protocol extends beyond classic retrodeformation by using target specimens as a guide for the virtual reconstruction. The targets used as a reference are two fragmentary, yet well-preserved E. stenonis skulls, coming from Olivola (Italy; IGF11023) and Dmanisi (Georgia; Dm 5/154.3/4.A4.5), both Early Pleistocene in age. These two specimens do not display any major deformation, but preserve different, only slightly overlapping portions of the skull. The virtual reconstruction protocol we carried out has shown its feasibility, by producing two 3D models whose final morphology is perfectly congruent with the natural variability of a comparative sample of E. stenonis specimens. This study shows the potential of using even broken or otherwise fragmentary specimens to guide retrodeformation in badly distorted and damaged specimens. The application of Target Deformation will allow us to increase the availability of comparative specimens in studies of fossil species morphology and evolution, as well as to the study of taphonomic processes.

斑马马是欧洲最流行的更新世化石马之一。它被认为是所有旧世界早期更新世的可能祖先马属，现存的斑马和驴，因此可以洞察 马属进化及其生物地理学和古生态学。的斑马马Igino Cocchi于1867年首先从Terranuova（意大利上瓦尔达诺盆地）的更新世地方描述了全称头骨（IGF560）。IGF560几乎是完整的，但头骨的内侧受压并严重受压。在这里，我们提供了一种称为目标变形的新虚拟重建协议的第一个应用程序，用于斑马马完整型 该协议通过使用目标样本作为虚拟重建的指导，扩展了经典的反变形。用作参考的目标是两个零散但保存完好的目标斯诺氏大肠杆菌来自奥利沃拉（意大利; IGF11023）和达马尼西（乔治亚州; Dm 5 / 154.3 / 4.A4.5）的头骨，均属早更新世。这两个标本没有显示出任何大的变形，但是保留了不同的，仅略微重叠的头骨部分。我们执行的虚拟重建方案通过生成两个3D模型显示了其可行性，这些3D模型的最终形态与比较样本的自然变异性完全一致斯诺氏大肠杆菌标本。这项研究表明，甚至可以使用破裂或破碎的样本来指导严重变形和损坏的样本的逆向变形。目标变形的应用将使我们能够在化石物种形态和演化的研究以及对胶相过程的研究中增加比较标本的可用性。