Another excellent episode of Dr Who, this time sorting out relations with the Silurians, who are described as Homo reptilicus. Interesting name. Species are described in what’s known as binomial nomenclature, with the genus name first, and species name second. Thus Homo sapiens is in the genus Homo [humans and closely related, but now all extinct, relatives], and the species sapiens [thinking]. So Homo sapiens is “thinking man”.
This binomial naming assumes evolutionary relationships, so Homo sapiens, and Homo habilis for instance, shared a common ancestor. The point, for the pedantic scientist, is that the Silurians evolved long before we did, and from reptilian stock. Their genus name would have to be the reptilian group from which they evolved, so it wouldn’t be Homo. Their species name would be their “defining characteristic”, which in this case must be that they think.
They are not reptilian humans, they are thinking reptiles. So it’s not Homo reptilicus, it’s Reptilicus sapiens.