ABSTRACT

Adalatherium hui is a latest Cretaceous (Maastrichtian) gondwanatherian mammal based on only a single specimen, a virtually complete, articulated, and well-preserved skull and postcranial skeleton. The specimen is the most complete and best preserved of any mammaliaform from the Mesozoic of the southern supercontinent Gondwana. It was discovered in the Anembalemba Member of the Maevarano Formation in the Mahajanga Basin of northwestern Madagascar. The holotype specimen includes the only complete lower jaw and the only postcranial remains known for Gondwanatheria, which, other than the cranium of Vintana sertichi (also from the latest Cretaceous of Madagascar), are represented only by isolated teeth and fragmentary dentaries. Despite being represented by an immature individual, A. hui is third only to V. sertichi and Coloniatherium cilinskii as the largest Mesozoic mammaliaform (based on body fossils) from Gondwana. Here, we (1) review the paucity of mammaliamorph skull and postcranial skeletal material from the Mesozoic of Gondwana relative to the record from Laurasia; (2) review the systematic paleontology of A. hui; (3) provide an overview of the history of discovery of the holotype specimen; (4) detail the preservation of the holotype, its preparation history, and the imaging techniques used to study it; (5) provide an overview of the geological context of A. hui, which indicates that the species lived close to the end-Cretaceous extinction event in a highly seasonal, semiarid climate; and (6) estimate the body mass of A. hui in the context of other Mesozoic mammaliaforms.

摘要

辉al是一种最新的白垩纪（马斯特里赫特）冈瓦纳特哺乳动物，仅基于一个标本，实际上是一个完整的，铰接的，保存完好的头骨和颅后骨骼。该标本是南部超大陆冈瓦纳中生代所有哺乳动物中最完整和保存最完好的。它是在马达加斯加西北部Mahajanga盆地Maevarano组的Anembalemba成员中发现的。完整标本包括唯一完整的下颌和唯一的以冈瓦那提亚为名的颅后遗骸，除了文塔纳·塞蒂奇的头盖骨（也来自马达加斯加的最新白垩纪），仅以孤立的牙齿和零碎的牙齿为代表。尽管由不成熟的人A. hui代表仅次于V. sertichi和Collinatherium cilinskii，是冈瓦纳地区最大的中生哺乳动物体（基于人体化石）。在这里，我们（1）回顾了冈瓦纳中生代哺乳动物体头骨和颅后骨骼材料相对于劳拉西亚的记录的稀缺性；（2）回顾了A. hui的系统古生物学；（3）概述完整样本的发现历史；（4）详细描述了整型的保存，其制备历史以及用于研究整型的成像技术；（5）概述辉石的地质背景，这表明该物种在高度季节性的半干旱气候中生活在接近白垩纪灭绝事件的位置；和（6）估计体重A.辉在其他中生代mammaliaforms的上下文中。