Q.  Were there other human species?

A.  Many different species have been identified in modern and ancient humans, but there is actually only one human species, and it's preferable to call these various groupings "Landraces".

Q.  What's the distinction between a species and a landrace?

A.  If all those in a given population can potentially interbreed freely, then that population is a single species.

Q.  How should Landraces be designated?

A.  With double-quotes around their tags, such as Homo "Neanderthal", Homo "Sapiens", or Homo "Habilis".

Q.  How do landraces arise?

A.  Through natural selection of genes under particular conditions, often based on locality. For example, a population living in cold latitudes will select for ability to cope with the cold.

Q.  Where is there more on this?

A.  See The Truth About Human Species.