Horse outward similarity is an unreliable measure of relatedness. Besides the horse, there are six other species of genus "Equus" in the Equidae family. These are the ass or donkey, "Equus asinus"; the mountain zebra, "Equus zebra"; plains zebra, "Equus quagga"; Grévy's zebra, "Equus grevyi"; the kiang, "Equus kiang"; and the onager, "Equus hemionus". Horses can crossbreed with other members of their genus. The most common hybrid is the mule, a cross between a "jack" (male donkey) and a mare. A related hybrid, a hinny, is a cross between a stallion and a jenny (female donkey). Other hybrids include the zorse,
Africanus Fabius Maximus Africanus' brother, Paullus Fabius Maximus and his wife, Marcia. Africanus Fabius Maximus Africanus Fabius Maximus was the younger son of Quintus Fabius Maximus (consul 45 BCE). Although commonly referred to as Africanus Fabius Maximus, it remains unclear whether that was his official name or whether it was Quintus Fabius Maximus Africanus. His elder brother was Paullus Fabius Maximus (consul 11 BCE) and his sister was Fabia Paullina, who married Marcus Titius. It is believed that Africanus was named in honour of his famous family ancestor Publius Cornelius Scipio Africanus Aemilianus. The career of Africanus Fabius Maximus is much less clear