In central South America, theropod remains are relatively scarce in comparison to the southern part of the continent, with shed teeth being the primary fossils found in this region. We examined 179 isolated teeth from the Bauru Basin, Brazil, using linear discriminant analysis (LDA; N = 178) and phylogenetic analysis (N = 174). The LDA used eight measurements, and the phylogenetic analysis used seven morphotypes. Although the results of the LDA suggest the presence of various South American theropod clades, such as Carcharodontosauridae, Noasauridae, and Spinosauridae, the phylogenetic analysis using a constrained dentition-based matrix classified the morphotypes as Abelisauridae (morphotypes I–IV, VI, and VII) and Therizinosauria (morphotype V). Given the considerable number of homoplastic characters and missing data, the phylogenetic analyses could not precisely determine the taxonomy of morphotypes V, VI, and VII in the unconstrained dataset. Morphological comparisons, nevertheless, strongly suggest that all morphotypes should be classified as abelisaurid theropods. We propose that the palaeogeographical distribution of Abelisauridae in South America was influenced by climatic conditions. These apex carnivores are likely to have adapted well to increased climate changes that led to semi-arid conditions. Our research sheds light on the evolutionary and ecological aspects of theropod dinosaurs in this region, contributing to a better understanding of the ancient ecosystems of central South America.

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白垩纪晚期兽脚类恐龙的生物地理学：来自南美洲中部的证据

在南美洲中部，与该大陆南部相比，兽脚亚目恐龙遗骸相对稀少，脱落的牙齿是该地区发现的主要化石。我们使用线性判别分析（LDA；N = 178）和系统发育分析（N = 174）检查了来自巴西巴乌鲁盆地的 179 颗孤立牙齿。LDA 使用了八个测量值，系统发育分析使用了七个形态型。尽管 LDA 的结果表明存在各种南美兽脚亚目进化枝，例如鲨齿龙科、诺阿龙科和棘龙科，但使用基于约束齿列矩阵的系统发育分析将形态型分类为阿贝力龙科（形态型 I-IV、VI 和 VII） ）和镰刀龙目（形态V）。鉴于大量同质性状和缺失数据，系统发育分析无法精确确定无约束数据集中形态型 V、VI 和 VII 的分类。然而，形态学比较强烈表明所有形态类型都应归类为阿贝力龙科兽脚类恐龙。我们认为阿贝力龙科在南美洲的古地理分布受到气候条件的影响。这些顶级食肉动物很可能很好地适应了导致半干旱条件的气候变化。我们的研究揭示了该地区兽脚类恐龙的进化和生态方面，有助于更好地了解南美洲中部的古代生态系统。