Canine sexual dimorphism in Egyptian Eocene anthropoid primates: Catopithecus and Proteopithecus

Two very small late Eocene anthropoid primates, Catopithecus browni and Proteopithecus sylviae, from Fayum, Egypt show evidence of substantial sexual dimorphism in canine teeth. The degree of dimorphism suggests that these early anthropoids lived in social groups with a polygynous mating system and intense male–male competition. Catopithecus and Proteopithecus are smaller in estimated body size than any living primates showing canine dimorphism. The origin of canine dimorphism and polygyny in anthropoids was not associated with the evolution of large body size.

两种产自埃及法尤姆的始新世晚期体型极小的类人猿灵长类（anthropoid primates）——布朗卡托猴（Catopithecus browni）与西尔维亚原护猴（Proteopithecus sylviae）——的化石，展现出其犬齿存在显著性别二态性（sexual dimorphism）的证据。该性别二态性的程度提示，这些早期类人猿曾生活在采用多配偶制交配体系、存在激烈雄性间竞争的社会群体中。相较于现存所有表现出犬齿性别二态性的灵长类物种，卡托猴与原护猴的估算体型更小。类人猿的犬齿性别二态性与多配偶制的起源，并未与大体型的演化进程相关联。