Very little is known on Earth about two thirds of the race of the Golgafrinchans, (excepting the Circling Poets of Arium
, of course);
One third, however, comprises a very important, if little known, footnote in the Evolution
here on Earth
. (At least according The Hitchhiker's Guide to the Galaxy
Thousands of years ago, the 'B' Ark, from Golgafrincham, crashed into earth, having been sent there by the rest of Golgafrincham, for being "a load of useless bloody loonies."
The assorted superfluous members of Golgafrinchan society, such as Telephone Sanitizers, Insurance Salesmen, and Public Relations Executives, were sent off, to allow the other two thirds to live
"full, rich, and happy lives, until they were all suddently wiped out by a virulent disease contracted from a dirty telephones."
The assorted trash of Golgafrinchan Society managed to live for at least several years after the crash, as evidenced by Ford Prefect and Arthur Dent,
After failing to invent fire, the Golgafrinchans mostly died out, excepting several who rafted in a river somewhere near islington, leaving the humans to re-occupy their former environmental niche,
as can be clearly seen by the continuation of the project that Deep Thought assigned to the planet regarding the answer to Life, The Universe, and Everything.
I understand that it is repeated several times in the book that the Golgafrinchans replaced the humans, by Arthur Dent and Ford Prefect,
but if you believe the conclusions those two come to, I might begin to believe that some Golgafrinchan genes may have survived.