The earliest complete glyptodonts (Glyptodontidae, Cingulata) found belong to the Propalaehoplophorinae from Santa Cruz Formation (late early Miocene, Burdigalian) in Patagonia, Argentina. Although several skulls and mandibles have been described from this formation, and assigned to five genera (Propalaehoplophorus Ameghino, Cochlops Ameghino, Asterostemma Ameghino, Eucinepeltus Ameghino, and Metopotoxus Ameghino), the fossil record and knowledge of juvenile specimens of glyptodonts are still poor. Here, we provide a detailed morphological description of a mandible of a juvenile propalaehoplophorinae glyptodont from the Santa Cruz Formation, using micro-computed tomography and scanning electron microscopy images. We compare the juvenile mandible with adult specimens and discuss the taxonomic assignment, the juvenile and adult mandibular and dental characters, and dental eruption and tooth wear.

发现的最早完整的象牙齿科（Glyptodontidae，Cingulata）属于阿根廷巴塔哥尼亚的圣克鲁斯组（早中新世，布尔迪加利安晚期）的Propalaehoplophorinae。尽管一些头骨和下颌骨已从此形成所描述的，并转让给五个属（Propalaehoplophorus阿梅吉诺，Cochlops阿梅吉诺，Asterostemma阿梅吉诺，Eucinepeltus阿梅吉诺和MetopotoxusAmeghino）的化石记录和幼稚的Glyptodonts标本的知识仍然很薄。在这里，我们使用微计算机断层扫描和扫描电子显微镜图像，提供了来自圣克鲁斯组的幼体propalaehoplophorinae glyptodont下颌骨的详细形态学描述。我们将少年下颌骨与成年标本进行比较，并讨论分类学任务，少年和成年下颌骨和牙齿的特征以及牙齿萌出和牙齿磨损。