Complex sentence: The ancient Greek philosopher Aristotle was the first to describe the species of "Camelus": in his 4th century BC "History of Animals" he identified the one-humped Arabian camel and the two-humped Bactrian camel.
Split into simpler sentences: The ancient Greek philosopher Aristotle (4th century BC) was the first to describe the species of "Camelus". He named two species in his "History of Animals": the one-humped Arabian camel and the two-humped Bactrian camel.