ABSTRACT

Among the several fossils of South American tayassuids, it is remarkable the presence of a well-preserved skull from southern Brazil (Chuí Creek, Santa Vitória do Palmar, Santa Vitória Formation). Here, we provide an update in the taxonomic arrangement and anatomical description of this specimen assigned to Brasiliochoerus stenocephalus based on the combination of the following traits: 1) long rostrum with a markedly convex profile; 2) anterior margin of the orbits located behind the vertical plane of the distal part of M3; 3) facial crests of the zygomatic arch forming an angle of about 80° relative to the molar series; 4) postorbital process more developed and ventrally projected in comparison to other tayassuids; 5) absence of a sagittal crest and presence of short parasagittal crests; 6) presence of curved temporal crests; 7) accentuated basicranial flexion; 8) bunodont and brachydont cheek teeth; 9) conspicuous pneumatization; 10) short postcanine diastema; and 11) cranium with no postorbital depression. This specimen was collected from sedimentary levels that contain a diverse assemblage of Pleistocene terrestrial mammals. Based on living analogous species, the presence of this taxon indicates dry and relatively open environments at some part of the Late Pleistocene in the study area.

摘要

在南美 tayassuids 的几个化石中，值得注意的是一个来自巴西南部（Chuí Creek、Santa Vitória do Palmar、Santa Vitória Formation）的保存完好的头骨。在这里，我们提供了分配给Brasiliochoerus stenocephalus的这个标本的分类学安排和解剖学描述的更新基于以下特征的组合：1) 长长的讲台，轮廓明显凸出；2) 眼眶前缘位于 M3 远端垂直面后方；3) 颧弓面嵴与磨牙系列成约80°角；4) 与其他 tayassuids 相比，眶后过程更加发达和腹侧突出；5) 矢状嵴缺失和矢状旁嵴短；6) 存在弯曲的颞嵴；7) 增强的基本颅骨弯曲；8) bunodont 和 brachydont 颊齿；9) 显眼的气化；10) 短的犬后间隙；和 11) 没有眶后凹陷的颅骨。该标本是从沉积层收集的，其中包含多种更新世陆生哺乳动物。基于现存的类似物种，